The North American Heat Wave of July 2011-Draft

Size: px
Start display at page:

Download "The North American Heat Wave of July 2011-Draft"

Transcription

1 The North American Heat Wave of July 2011-Draft By Richard H. Grumm And Jason Krekeler 328 Innovation Blvd Suite 330 National Weather Service Office State College, PA The meteorological conditions associated with the persistent heat event of July 2011 Abstract: A persistent upper-level ridge brought a prolonged period of above normal temperatures to much of the United States and southern Canada. A broad mid-tropospheric ridge dominated the pattern the Great Basin to the East Coast. Cool air was limited to the Pacific Coast with a mean trough anchored over the northwestern United States and southwestern Canada. The heat wave peaked in mid-july over the plains. From July 2011 a close 5940 m contour and +2 temperature anomalies dominated most of the central United States leading to record high temperatures and many new record high low temperatures. The ridge and associated warm air moved eastward. During the 3-day period of July hpa and 700 hpa temperatures were +2 to +3 above normal. Record high temperatures were set or broken over much of the eastern United States during this time period. This paper will document the pattern and the anomalies in the pattern during the month of July The value of anomalies in diagnosing heat waves is employed here focusing on the period of peak heat from July 2011.

2 1. INTRODUCTION A strong and persistent blocking ridge over southern North America during the month of July 2011 (Fig.1) brought above normal warmth to much of the eastern United States and southern Canada. The heat peaked in intensity between July over the central United States and southern Canada. Over 100 daily high temperature records were tied or broken between July (Table 1). During this span of time 136 high temperatures records were tied or broken in the State of Pennsylvania (Table 2). The upper-level ridge weakened as it moved eastward, but the anomalous mid-tropospheric temperatures contributed to 2-3 days of record heat in the eastern United States. Previous research has shown the importance of subtropical ridges and heat waves (Brugge 1995), Chang and Wallace 1987; Galarneau et al. 2008; Kunkel et al. 1996; Lipton et al. 2005; Lyon and Dole 1995). Namias (1982) and Robinson (2001) showed the patterns associated with protracted heat waves over North America. Schar and Jendritzky (2004) examined the meteorological conditions associated with the European heatwave of This event primarily impacted central and western Europe. Brugge 1991 showed the importance of a blocking anticyclone during the record heat of August 1990 in the British Isles. Thwaytes (1995) completed a study of Northern Hemispheric heat waves. Strong ridges are a common theme in most of these cited works. Heat waves often have significant impacts on human activities. Goklany (2008) and Changnon et al. (1996) showed that heat waves are a leading cause of weather related deaths. The elderly often suffer the most during heat waves. Palecki et al. (2001) examined mortality rates in Chicago and St. Louis during the 1999 and 1995 Midwestern United States heat waves. Despite the fact that the 1999 event was meteorologically more intense than the 1995 event, the lower mortality rates

3 during the latter event suggests that cities can learn from these events and mitigate their impacts. Prolonged heat waves are often associated with droughts (Chang and Wallace 1987; Lyon and Dole 1995). Grumm (2011) documented the large scale conditions and standardized anomalies of key fields associated with the record heat wave over central Europe during the summer of Russia experienced a prolonged period of record heat for most of the month of July into mid-august. During the peak periods of heat over Moscow, a closed 5940 m contour was present along with 3 above normal temperatures at 850 hpa. The value of standardized anomalies in showing the persistence of heat waves was first examined by Wolfson and Atlas (1986). Their study shows the value of using standardized anomalies to diagnose the persistence of the heat wave of the summer of This paper will document the large scale conditions associated with the North American heat wave of July The focus is on an analysis of anomalies associated with key features. This is based on the work of Lipton et al. (2005) and Grumm (2011) which showed the value of anomalies in identifying heat waves and warm episodes. 2. METHODS The 500-hPa heights, 700-hPa temperatures, and other standard level fields were derived from the National Centers for Environmental Prediction Global Forecast System (NCEP GFS) 00-hour forecasts. The means and standard deviations used to compute the standardized anomalies were derived from the NCEP/NCAR Reanalysis data as described by Hart and Grumm (2001). Anomalies were displayed in standard deviations from normal, as standardized anomalies. All

4 data were displayed using GrADS (Doty and Kinter 1995). The composites used in the analysis were produced from NCEP GFS data. For each 6-hour time period, the NCEP GFS analysis was used to compute the mean field and anomalies of the respective field. Composites were limited to 500-hPa heights, 850-hPa temperatures, 250-hPa winds, and precipitable water. These variables selected based on the work of Lipton et al. (2005) and Namias (1982) and are believed to be important in describing and identifying both a subtropical ridge and a heat wave. The standardized anomalies are computed as: SD (F M) (1) where F is the value from the reanalysis data at each grid point, M is the 21-day running mean for the specified date and time at each grid point and σ is the value of 1 standard deviation at each grid point. Daily images were also produced using GFS data, which represent a single time. The times displayed were based on news accounts of heat records over the United States, east of the Rocky Mountains. The heat maximized over the southern plains (Fig. 2). Any city in the southern Plains would exhibit a similar trend but Oklahoma City was chosen as it was near the region of maximum heat and the data was readily available. The NCDC maximum temperature records data for the month of July was retrieved to determine the records set or tied by station, State, and geographic domain. These data were used to produce the listings in Tables 1 & 2.

5 It should be noted that the GFS with horizontal resolution at T574 (27km) is of finer resolution than the 2.5 x 2.5 degree climate data used here. The actual GFS data used here were on 1 x 1 degree grid which was of finer resolution than the 30-year climatological data use to compute the standardized anomalies. The GFS was remapped to the climate data. The impact is minimal for variables above the planetary boundary layer. However, variables such as precipitable water will generally be higher than those in the re-analysis data and thus will likely produce higher anomalies than the re-analysis data might show. The JRA25 and the NCEP-NCAR re-analysis data are used here to re-construct the pattern associated with previously hot periods from 1948 to present. Whenever practicable the higher resolution data is used. 3. RESULTS a. Composite pattern for July 2011 The composite pattern for July 2011 (Fig. 1) showed a broad ridge over the eastern United States. The expansive 5880 m contour extended from southern California to the Dakotas and over the southeastern United States (Fig. 1a). The 500 hpa heights averaged 0.5 to 1.0 above normal over the central United States during this period of time. The 700 hpa and 850 hpa temperatures indicated that most of the central United States was 0.5 to 2.0 above normal during the month of July. At 850 hpa the largest anomaly was over the southern Plains (Fig. 1c) while the deep warm air at 700 hpa peaked over the Midwestern United States.

6 As with previously documented heat waves and strong ridges, there was a surge of high precipitable water (PW) air along the western periphery of the ridge. PW anomalies were above normal along the Gulf Coast and into the central Plains. PW values remained at or near normal for the month over the northeastern United States. b northern Plains heat surge The period of July 2011 was extremely warm over the northern plains of the United States and the southern plains of Canada. Record high temperatures were set in many locations from 16 to 22 July Minneapolis, MN set a record dew point of 28C (82F). The warm moist air lead to several days of record high and record high-low temperatures over much of the northern plains and Great Lakes region. The large scale pattern during this period (Fig. 3) showed a close 5940 m anticyclone at 500 hpa and a broad area of +1 to 2 height anomalies (Fig. 3a). Both 700 and 850 hpa temperatures were in the +1 to +2s above normal range over most of the eastern United States and southern Canada during this period (Figs. 3b-c). The PW anomalies during the 6-day period averaged +1 to +2 from northern Missouri into southern Canada. The above normal PW values likely contributed to the deep moisture, which limited diurnal cooling and relates back to the record high dew point set in Minneapolis. By 22 July the record high had shift to the south and east of the northern Plains and western Great Lakes. c. Eastern US Heat episode

7 The heat began to affect the eastern United States on 19 July with record high temperatures set in eastern cities from July. The most intense days with the most record high temperature records broken were the 21 nd and 22 rd of July. The data for Pennsylvania (Table 1) shows record highs and daily highs over 100F at 3 of the 4 ASOS sites on July. The State College COOP site broke 100F for the first time since 1988 with a reading of 101F on 23 July 2011, 1 degree below the all-time record high of 102 set on 17 July 1988 and 9 July The large scale pattern associated with the period of extreme heat in the eastern United States (Fig. 4) showed the height anomaly with the 500 hpa ridge over the region during this time period. The 5940 m contour which dominated earlier in the event was no longer present, however, the 10C contour at 700 hpa, at +2 to +3 thermal anomaly was present over most the northeastern United States and Mid-Atlantic region (Fig. 4b). Additionally, the 850 hpa temperatures were over 20C and were associated with +2 to +3 temperature anomalies. The thermal anomalies peaked in the eastern United States at 0000 UTC 22 and 23 July On both days a close 24C contour was present in the eastern United States and 850 hpa temperature anomalies were over 3 above normal. At 0000 UTC 23 July (Fig. 5) a small 5940 m contour was present off the East Coast most of the region from Maryland to southern New England was encompassed by the 24C contour. A large area from central Pennsylvania to the western Atlantic experienced 3 to hpa temperature anomalies. The PW values were abnormally low under much of this hot air from central Pennsylvania to New England.

8 The PW anomalies were slightly above normal in the eastern United States, though the larger PW anomalies were focused on the western periphery of the ridge (Fig. 4d) from Kansas, across Iowa and into Ohio and western Pennsylvania. This moisture plume produced a heavy rainfall event in northern Illinois on 23 July. Chicago received 6.86 inches of rainfall setting a new alltime record rainfall for the city. d. Previous heat waves Three comparative events from the past were selected based on records related to high temperatures in Pennsylvania. The NCEP/NCAR re-analysis for the month of July of 1955 (Fig. 6), and the JRA25 data for the July 1980 (Fig. 7) and July 1998 (Fig. 8) are used here. The pattern during the maximum heat in the eastern United States from July 2011 was similar to the pattern associated with record heat event of July 2010 (Grumm 2010). The pattern for July 1955 (Fig. 6) showed the persistent ridge over central United States and southern Canada and the warm air at 850 hpa over the same general region. The overall pattern at both 500 and 850 hpa was similar to the July 2011 pattern. The pattern for July 1980 (Fig. 7) had the ridge displaced to the south and west with a similar displacement of the temperature anomalies at both 700 and 850 hpa. The pattern for the summer of 1988 showed stronger westerlies (Fig. 8) over the eastern United States with some minor hpa temperature anomalies over the region. The multi-day pattern of July 2010 showed the sharp ridge and warmth in the eastern United States while the monthly pattern (not shown) suggested that the ridge was suppressed to the south and west.

9 e. Temperatures over eastern United States The high temperatures from July 2011 (Fig. 10) show locations where a high temperature record was tied or exceeded. These data show the eastward progression of the record heat and the focus of the heat over the eastern United States from July The heat in the Mid-Atlantic region peaked on 22 nd & 23 rd which matches well with the data in Tables 1 & 2 showing that during the peak heat the Pennsylvania and New York set many records. Pennsylvania tie or exceed 47 and 39 maximum temperature records on the 22 nd and 23 rd respectively. The heat began to retrograde back to the west on the 24 th (Fig. 10f) and the 25 th. f. Forecasts The generalized pattern of the heat wave was well predicted by the NCEP GEFS and GFS. Showing all forecasts would be prohibitive and two forecast examples related to forecasting record temperature (Fig. 11) and forecasting a persistent pattern (Fig. 12) are presented. Figure 11 shows the ensemble mean pattern at 1800 UTC 22 July These data show the potential for above normal 500 hpa heights and 850 hpa temperatures over the region at this time. Additionally, they show the high probability of extremely warm 2m temperatures. This was one of the two warmest days of the event over the eastern United States and the focused heat lines up well with Figure 10. The persistence of the pattern was determined using a 72-hour period to acquire the mean field for the period and the mean anomaly for the period. These data focused the heat for the rd of July over the Mid-Atlantic region. It is impressive to see +2 to +3s temperature anomalies at 700 hpa for such a prolonged period of time. The 850 hpa temperature anomaly was focused over Pennsylvania and Virginia. These data, along with Tables 1 & 2 show that the GEFS was predicting a multi-day event which verified close to the indicated location.

10 4. CONCLUSIONS A large ridge dominated the pattern over most of the eastern United States from the Rocky Mountains to the East Coast during the month of July This produced a prolonged period of above normally warm temperatures over most of the central United States. The most persistent and hottest air was focused over the southern Plains (Figs. 1 & 2). The ridge amplified and moved northward into the northern Plains on 16 July and then moved eastward. This lead to a period of record heat in the northern Plains and Midwest from July and a period of record heat in the eastern United States from July Over Pennsylvania 22 and 23 July were the two hottest days, the temperature in State College topped 100F on 22 and 23 July for the first time since The pattern associated with the heat of July 2011 (Fig. 1) showed a persistent ridge over the United States with an expansive area of above normal 700 and 850 hpa temperatures. A plume of high PW was present on the western periphery of this ridge. This is a classic heat wave pattern which clearly persisted, in the mean, for the month of June. A similarly persistent pattern developed over central Europe in July 2010 producing the Russian heat wave of 2010 (Grumm 2011). These data clearly showed the persistent pattern associated with this event. The ability to predict when persistent patterns may develop may aid in better prepare for future episodes in the future. An interesting aspect of the flow of July 2011 was the high PW in the southern plains and southwestern United States, as diagnosed by the GFS 00-hour forecasts. Despite the high PW over southern plains and southwest, the region was unseasonably dry during this period.

11 During the middle of July, the ridge in the central United States strengthened and moved northward. This caused the warm air to surge into the northern Plains and into southern Canada. A close 5940 m contour developed at 500 hpa (Fig. 3), a feature often associated with summertime heat waves. Though rare, 6000 m contours can appear but during heat waves (July 2003) but this event never quite produced heights over 6000 m. During the surge of warm air from 16 to 22 July, an expansive area of 1 to 2s above normal 850 and 700 hpa temperatures affected the central United States. The warm air moved eastward and produced several days with record high temperatures in the eastern United States. The number of locations in the eastern United States setting or tying record high temperatures peaked on 22 & 23 July Most of the major cities from Washington to Boston saw daytime highs peak at or over 100F. During the peak of the heat in the East, 850 hpa temperatures peaked at over +3 above normal with an expansive region covered by the 24C contour (Fig. 4 & 5). The persistence of the pattern for several days with such anomalous conditions (Fig. 4) likely contributed to the number of records set. Though not shown, many locations set all-time record high low-temperatures. The pattern and the anomalies at 0000 UTC 23 July 2011 show how extensive the warm air mass was and how at 850 hpa the air mass was significantly above normal..the data in Figures 6-9 suggests that no two summers are a like. Cleary, July 1955 and 2011 had a distinct pattern with a northward shifted ridge and positive 500 hpa height anomalies. Despite the extreme warmth and records set in 1988, the monthly data show the ridge was well south and west of the ridge position in July of 1955 and Table 1 (Grumm 2010) showed how

12 episodic heat waves can be in the eastern United States, the episodic nature of heat waves over the eastern United States makes it difficult to compare monthly composites and see a coherent pattern. The two forecasts shown here indicated that the GEFS did well in predicting the overall pattern and the area where the heat would maximize for the period of July 2011 (Fig. 12). The use of multi-period products may be of value in predicting areas of heavy rainfall, persistent heat or cold and persistent drought. The variables chosen here depict the large scale ridge often associated with heat waves, the need for deep warm air, and the flow of warm moist air on the western periphery of most significant ridges. More products of this type need to be developed to address specific forecast issues and problems. The NCDC database could be used to determine heat events across the United States and tie these data back to the patterns associated with heat waves. 5. ACKNOWLEGEMENTS The Climate Prediction Center (CPC) is acknowledged for access to images of 30, 60 and 90-day plots of select cities in the United States. The National Climatic Data Center (NCDC) site was used to gain access to maximum temperatures set or tied for the month of July RERERENCES

13 Brugge, R., 1991: The record-breaking heat wave of 1-4 August 1990 over England and Wales. Weather, 46, Brugge, R., 1995: Heatwaves and record temperatures in North America. Weather, 50, Chang F.C., and J.M. Wallace, 1987: Meteorological conditions during heat waves and droughts in the United States Great Plains. Mon. Wea. Rev., 115, Changnon, S. A., K. E. Kunkel, and B. C. Reinke, 1996: Impacts and responses to the 1995 Heat Wave: A call to action. Bull. Amer. Meteor. Soc., 77, Daily Telegraph 2010: Russian heatwave kills 5,000 as fires rage out of control. 6 August (Similar wire stories on the heat wave and fires were published in early August). Doty, B. E., and J. L. Kinter III, 1995: Geophysical data and visualization using GrADS. Visualization Techniques Space and Atmospheric Sciences, E. P. Szuszczewicz and Bredekamp, Eds., NASA, Galarneau, T. J., Jr., L. F. Bosart, and A. R. Aiyyer, 2008: Closed anticyclones of the subtropics and middle latitudes: A 54-yr climatology ( ) and three case studies. Synoptic-Dynamic Meteorology and Weather Analysis and Forecasting: A Tribute to Fred Sanders, Meteor. Monogr., No. 55, Amer. Meteor. Soc., Goklany, I. 2008: Deaths and death rates from extreme weather events: Journal of American Physicians and Surgeons 14 (4): (2009). Grumm, R.H. 2011: The Central European and Russian Heat Event of July-August 2010,BAMS, to appear October Hart, R. E., and R. H. Grumm, 2001: Using normalized climatological anomalies to rank synoptic scale events objectively. Mon. Wea. Rev., 129,

14 Kunkel, K. E., S. A. Changnon, B. C. Reinke, and R. W. Arritt, 1996: The July 1995 Heat wave in the Midwest: A Climatic perspective and critical weather factors. Bull. Amer. Meteor. Soc., 77, Lejenas, H., and H. Okland, 1983: Characteristics of Northern Hemisphere blocking as determined from a long time series of observational data. Tellus, 35A, Lipton, K., R. Grumm, R. Holmes, P. Knight, and J. R. Ross, 2005: Forecasting heat waves using climatic anomalies. Pre-prints 21 st Conference on Wea. And Fore. and the 17 th Conference on Numerical Weather Prediction, AMS, Washington, DC. Lyon, B., and R. Dole, 1995: A diagnostic comparison of the 1980 and 1988 U.S. summer heat wave-droughts. J. Climate, 8, Madden, R. A., H. Lejenäs, 1989: Flow at 500 mb Associated with a Measure of Persistence over Western Europe. Mon. Wea. Rev., 117, Blocking is persistence of the pattern. Namias, J., 1982: Anatomy of Great Plains protracted heat waves. Mon. Wea. Rev., 110, Neiman, P.J., F.M. Ralph, G.A. Wick, J. D. Lundquist, and M. D. Dettinger, 2008: Meteorological characteristics and overland precipitation impacts of atmospheric rivers affecting the west coast of North America based on eight years of SSMI/satellite observations. J. Hydrometeor., 9, Palecki, M. A., S. A. Changnon, and K. E. Kunkel, 2001: The Nature and Impacts of the July 1999 Heat Wave in the Midwestern United States: Learning from the Lessons of Bull. Amer. Meteor. Soc., 82,

15 Rueters, 2011: Heavy rains soak Chicago as East Coast steams. (Similar wire stories under the topic heavy rains July 2011). Robinson, P. J : On the definition of a heat wave. Jour. of Applied Meteor., 40, Schar, C., and G. Jendritzky, 2004: Hot news from the summer of Nature, 432, Thwaytes, R., 1995: Northern Hemisphere heatwaves. Weather, 50, Tibaldi,S., and F. Molteni, 1990: On the operational predictability of blocking. Tellus,42A, Weaver,S.C., and S. Nigam, 2008: Variability of the Great Plains low level jet: large scale circulation context and hydroclimate impacts. J. Climate,21, Wolfson, N and R. Atlas, 1996: A simple diagnostic tool for the investigation of persistent phenomena with application to the summer 1980 U.S. heat wave. Atmosphere- Ocean,24:2,

16 Figure 1. Mean pattern over the United States and southern Canada from the NCEP GFS 00-hour forecasts for the period of 0000 UTC 1 July through 1800 UTC 31 July Data shown include a) 500 hpa heights (m) and standardized anomalies, b) 700 hpa temperatures ( C) and standardized anomalies, c) 850 hpa temperatures and standardized anomalies, and d) precipitable water (mm) and standardized anomalies. Standardized anomalies are shown in standard deviations from normal, 500 hpa heights are very 60m, 700 hpa temperatures every 5C, 850 hpa temperatures every 4C, and precipitable water is every 4 mm. Return to text.

17 Figure 2. Temperatures from May-July 2011 at Oklahoma City, Oklahoma. Upper panel shows the departure of the daily temperatures from the mean temperatures (black line), middle panel shows the daily departure and the lower panels show the daily high and low temperatures. Return to text. gif

18 Figure 3. As in Figure 1 except for the period of 0000 UTC 16 through July Return to text.

19 Figure 4. As in Figure 1 except for the period of 0000 UTC 21 to 1800 UTC 23 July Return to text.

20 Figure 5. As in Figure 1 except for 0000 UTC 23 July Return to text.

21 Figure 6. NCEP/NCAR re-analysis data showing the mean a) 500 hpa heights and height anomalies and b) the 850 hpa temperatures and temperature anomalies for 0000 UTC 01 July though 1800 UTC 31 July 1955.

22 Figure 7. As in Figure 1 except for 0000 UTC 01 July 1980 through 1800 UTC 31 July Return to text.

23 Figure 8. As in Figure 1 except for 0000 UTC 1 July through 1800 UTC 31 July Return to text.

24 Figure 9. As in Figure 1 except for the mean pattern from 0000 UTC 03 July through 0000 UTC 8 July Return to text.

25 State Records Set PA 136 TX 129 KS 85 NY 78 MI 73 NC 59 WI 56 IN 52 VA 38 IL 36 OH 35 IA 34 NJ 32 WV 31 FL 24 Table 1. List of the number records set or tied by State from July Data based on NCDC data set. Only States that set or tied 24 or more records during the period are listed. Return to text.

26 Date Number of records PA records 14-Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul 57 0 Table 2. Number of records exceed or tied by date and for the State of Pennsylvania. Return to text.

27 Figure 10. Temperatures (F) when temperature was a record or tied a record high. Red values are 100 or greater orange values are less than 100F. Data for the period of a) 19 to f) 24 July Return to text.

28 Figure 11. NCEP GEFS forecasts initialized at 0000 UTC 18 July 2011 showing conditions valid at 1800 UTC 22 July 2011 including a) the ensemble mean 500 hpa heights and the probability of +1.5SD height anomalies, b) ensemble mean 850 hpa temperatures and probability of 850 hpa temperatures exceeding 2.5SD above normal, c) ensemble mean precipitable water and the probability of precipitable water exceeding 2.0SDs above normal, and d) ensemble mean 2m temperatures and the probability 2m temperatures would be 2.5SDs above normal. Return to text.

29 Figure 12. As in Figure 11 except showing ensemble mean pattern and mean anomalies for the 72 hour period from 0000 UTC 21 to 0000 UTC 24 July Data include a) 72-hour mean 500 hpa heights and anomalies, b) 72-hour 700 hpa temperatures and anomalies, c) 72-hour mean 850 hpa temperatures and anomalies and d) 72-hour mean precipitable water and anomalies. Return to text.

30

1. INTRODUCTION. Hellström, SMHI. This includes all record highs and dates for Sweden. 2 Data provided by Jari Tuovinen, Helsinki, Finland.

1. INTRODUCTION. Hellström, SMHI. This includes all record highs and dates for Sweden. 2 Data provided by Jari Tuovinen, Helsinki, Finland. European Heat Event of July 2010 By Richard H. Grumm National Weather Service State College, PA 16803 Contributions by Jari Tuovinen Finnish Meteorological Institute 1. INTRODUCTION A significant heat

More information

Impacts of the April 2013 Mean trough over central North America

Impacts of the April 2013 Mean trough over central North America Impacts of the April 2013 Mean trough over central North America By Richard H. Grumm National Weather Service State College, PA Abstract: The mean 500 hpa flow over North America featured a trough over

More information

Early May Cut-off low and Mid-Atlantic rains

Early May Cut-off low and Mid-Atlantic rains Abstract: Early May Cut-off low and Mid-Atlantic rains By Richard H. Grumm National Weather Service State College, PA A deep 500 hpa cutoff developed in the southern Plains on 3 May 2013. It produced a

More information

Pre-Christmas Warm-up December 2013-Draft

Pre-Christmas Warm-up December 2013-Draft Pre-Christmas Warm-up 21-23 December 2013-Draft By Richard H. Grumm National Weather Service State College, PA 1. Overview A large ridge over the west-central Atlantic (Fig.1) and trough moving into eastern

More information

2 July 2013 Flash Flood Event

2 July 2013 Flash Flood Event 2 July 2013 Flash Flood Event By Richard H. Grumm and Charles Ross National Weather Service State College, PA 1. Overview A retrograding 500 hpa cyclone and anticyclone (Fig. 1) set up deep southerly flow

More information

New Zealand Heavy Rainfall and Floods

New Zealand Heavy Rainfall and Floods New Zealand Heavy Rainfall and Floods 1. Introduction Three days of heavy rainfall associated with a deep upper-level low (Fig. 1) brought flooding to portions of New Zealand (Fig. 2). The flooding was

More information

Heat wave ending severe events of July 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803

Heat wave ending severe events of July 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803 Heat wave ending severe events of 23-25 July 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION A strong subtropical ridge (Fig. 1a) dominated the eastern

More information

Tropical Storm Hermine: Heavy rainfall in western Gulf By Richard H. Grumm National Weather Service Office State College, PA 16803

Tropical Storm Hermine: Heavy rainfall in western Gulf By Richard H. Grumm National Weather Service Office State College, PA 16803 Tropical Storm Hermine: Heavy rainfall in western Gulf By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION Tropical storm Hermine, the eighth named tropical system

More information

Multi-day severe event of May 2013

Multi-day severe event of May 2013 Abstract: Multi-day severe event of 18-22 May 2013 By Richard H. Grumm and Charles Ross National Weather Service State College, PA A relatively slow moving Trough over the western United States and a ridge

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events Abstract: West Coast Heavy Precipitation Event of January 2012 by Richard H. Grumm National Weather Service State College PA 16803

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events Abstract: Tropical Storm Debbie, standardized anomalies and heavy rainfall by Richard H. Grumm National Weather Service State College

More information

The Big Chill of November 2013

The Big Chill of November 2013 The Big Chill of November 2013 Value of anomalies for situational awareness By Richard H. Grumm National Weather Service State College, PA Trevor Alcott National Weather Service, Salt Lake City UT 1. Overview

More information

The Deep South snowfall of February 2010 By Richard H. Grumm National Weather Service Office, State College, PA 16803

The Deep South snowfall of February 2010 By Richard H. Grumm National Weather Service Office, State College, PA 16803 The Deep South snowfall of 11-13 February 2010 By Richard H. Grumm National Weather Service Office, State College, PA 16803 1. INTRODUCTION A surface cyclone tracked across Mexico and the Gulf of Mexico

More information

Memorial Day Weekend 2013: Snow and Cold

Memorial Day Weekend 2013: Snow and Cold Abstract: Memorial Day Weekend 2013: Snow and Cold By Richard H. Grumm National Weather Service State College, PA A slow moving 500 hpa low and associated unseasonably cold air in the lower troposphere

More information

Eastern United States Wild Weather April 2014-Draft

Eastern United States Wild Weather April 2014-Draft 1. Overview Eastern United States Wild Weather 27-30 April 2014-Draft Significant quantitative precipitation bust By Richard H. Grumm National Weather Service State College, PA and Joel Maruschak Over

More information

Heavy rains and precipitable water anomalies August 2010 By Richard H. Grumm And Jason Krekeler National Weather Service State College, PA 16803

Heavy rains and precipitable water anomalies August 2010 By Richard H. Grumm And Jason Krekeler National Weather Service State College, PA 16803 Heavy rains and precipitable water anomalies 17-19 August 2010 By Richard H. Grumm And Jason Krekeler National Weather Service State College, PA 16803 1. INTRODUCTION Heavy rain fell over the Gulf States,

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events New Zealand heavy rain and flood event-draft by Richard H. Grumm National Weather Service State College PA 16803 Abstract:. A record

More information

Early Summer Heat Waves of 2013

Early Summer Heat Waves of 2013 Early Summer Heat Waves of 2013 Abstract: By Richard H. Grumm National Weather Service State College, PA And Trevor Alcott National Weather Service, Salt Lake City Utah From late June into mid-july large

More information

The high latitude blocking and low arctic oscillation values of December 2009

The high latitude blocking and low arctic oscillation values of December 2009 The high latitude blocking and low arctic oscillation values of December 2009 By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION An episode of high latitude blocking

More information

Mid-West Heavy rains 18 April 2013

Mid-West Heavy rains 18 April 2013 Abstract: Mid-West Heavy rains 18 April 2013 By Richard H. Grumm and Charles Ross National Weather Service State College, PA The relatively wet conditions during the first 16 days of April 2013 set the

More information

Record snow blankets the United Kingdom 5-6 January 2010

Record snow blankets the United Kingdom 5-6 January 2010 1. INTRODUCTION Record snow blankets the United Kingdom 5-6 January 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803 A rare winter storm brought heavy snow the United Kingdom

More information

Winter Storm of 15 December 2005 By Richard H. Grumm National Weather Service Office State College, PA 16803

Winter Storm of 15 December 2005 By Richard H. Grumm National Weather Service Office State College, PA 16803 Winter Storm of 15 December 2005 By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION A complex winter storm brought snow, sleet, and freezing rain to central Pennsylvania.

More information

Alaskan heat episode of June 2013-Draft

Alaskan heat episode of June 2013-Draft Alaskan heat episode of 16-19 June 2013-Draft Abstract: By Trevor Alcott National Weather Service Western Region, Salt Lake City UT And Richard H. Grumm National Weather Service State College, PA A strong

More information

Warm Episode of December 2015:

Warm Episode of December 2015: Warm Episode of 11-16 December 2015: Record Warmth over Mid-Atlantic Region By Richard H. Grumm National Weather Service State College, PA 1. Overview A strong 500 hpa ridge over the eastern United States

More information

The southern express: Winter storm of January 2010 By Richard H. Grumm National Weather Service

The southern express: Winter storm of January 2010 By Richard H. Grumm National Weather Service The southern express: Winter storm of 28-30 January 2010 By Richard H. Grumm National Weather Service 1. INTRODUCTION A storm system of Pacific origin tracked across the southern United States from 27-31

More information

NWS-PSU Case Study Site 2010 Severe Weather Case

NWS-PSU Case Study Site 2010 Severe Weather Case NWS-PSU Case Study Site 2010 Severe Weather Case New Years Eve Severe Weather Event of 31 December 2010 by Richard H. Grumm National Weather Service State College PA 16083 Abstract: A surge of warm humid

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events Heavy rainfall of 23 November 2011 by Richard H. Grumm National Weather Service State College PA 16803 Abstract:. A fast moving mid-tropospheric

More information

The high latitude blocking and impacts on Asia

The high latitude blocking and impacts on Asia The high latitude blocking and impacts on Asia By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION An episode of high latitude blocking during the month of December

More information

Southern United States Heavy rain and flood event 6-8 April 2014

Southern United States Heavy rain and flood event 6-8 April 2014 Southern United States Heavy rain and flood event 6-8 April 2014 By Richard H. Grumm National Weather Service State College, PA 1. Overview Heavy rainfall (Fig. 1) affected the southern United States from

More information

A summary of the heat episodes of June 2017

A summary of the heat episodes of June 2017 A summary of the heat episodes of June 2017 By Richard H. Grumm and Elissa A. Smith National Weather Service State College, PA 1. Overview Over 1800 record high temperatures were set or tied during the

More information

1. INTRODUCTION. For brevity times are referred to in the format of 20/1800 for 20 August UTC. 3. RESULTS

1. INTRODUCTION. For brevity times are referred to in the format of 20/1800 for 20 August UTC. 3. RESULTS Heavy rains and precipitable water anomalies 20-23 August 2010-Draft By Jason Krekeler And Richard Grumm National Weather Service State College, PA 16803 1. INTRODUCTION Heavy rain fell across the central

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events Eastern United States Winter Storm and Severe Event of 28-29 February 2012 by Richard H. Grumm National Weather Service State College

More information

1. INTRODUCTION. March. Local time used in text to define dates. 1 Due to UTC time the went passed 0000 UTC 31

1. INTRODUCTION. March. Local time used in text to define dates. 1 Due to UTC time the went passed 0000 UTC 31 New England Record Maker Rain Event of 29-30 March 2010 By Richard H. Grumm National Weather Service Contributions by Frank Nocera National Weather Service Office Taunton, MA 1. INTRODUCTION The second

More information

Deep Cyclone and rapid moving severe weather event of 5-6 June 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803

Deep Cyclone and rapid moving severe weather event of 5-6 June 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803 Deep Cyclone and rapid moving severe weather event of 5-6 June 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION A rapidly deepening surface cyclone raced

More information

The Devastating Western European Winter Storm February 2010 By Richard H. Grumm National Weather Service

The Devastating Western European Winter Storm February 2010 By Richard H. Grumm National Weather Service The Devastating Western European Winter Storm 27-28 February 2010 By Richard H. Grumm National Weather Service 1. INTRODUCTION A strong late winter storm, called Xynthia 1, raced across Western Europe

More information

1995 and 1980 (exact dates would be useful). 1. INTRODUCTION

1995 and 1980 (exact dates would be useful). 1. INTRODUCTION Alaskan Autumn Storm of 22-24 November 2010 By Richard Grumm National Weather Service State College, PA 16803 and Rick Thoman and James A. Nelson National Weather Service Alaska Region 1. INTRODUCTION

More information

Snow, freezing rain, and shallow arctic Air 8-10 February 2015: NCEP HRRR success story

Snow, freezing rain, and shallow arctic Air 8-10 February 2015: NCEP HRRR success story Snow, freezing rain, and shallow arctic Air 8-10 February 2015: NCEP HRRR success story By Richard H. Grumm National Weather Service State College, PA 1. Overview A short-wave (Fig. 1) moved over the strong

More information

Southern United States Winter Storm of 28 January 2014-v1. High Impact Snow on Edge of Forecast Precipitation Shield

Southern United States Winter Storm of 28 January 2014-v1. High Impact Snow on Edge of Forecast Precipitation Shield Southern United States Winter Storm of 28 January 2014-v1 High Impact Snow on Edge of Forecast Precipitation Shield by Richard H. Grumm National Weather Service State College, PA 16803 and 1. Introduction

More information

Heavy Rainfall Event of June 2013

Heavy Rainfall Event of June 2013 Heavy Rainfall Event of 10-11 June 2013 By Richard H. Grumm National Weather Service State College, PA 1. Overview A 500 hpa short-wave moved over the eastern United States (Fig. 1) brought a surge of

More information

Southern Heavy rain and floods of 8-10 March 2016 by Richard H. Grumm National Weather Service State College, PA 16803

Southern Heavy rain and floods of 8-10 March 2016 by Richard H. Grumm National Weather Service State College, PA 16803 Southern Heavy rain and floods of 8-10 March 2016 by Richard H. Grumm National Weather Service State College, PA 16803 1. Introduction Heavy rains (Fig. 1) produced record flooding in northeastern Texas

More information

Winter Storm of February 2008 By Richard H. Grumm National Weather Service Office State College PA 16803

Winter Storm of February 2008 By Richard H. Grumm National Weather Service Office State College PA 16803 1. INTRODUCTION Winter Storm of 11-13 February 2008 By Richard H. Grumm National Weather Service Office State College PA 16803 A potent winter storm brought snow, sleet, freezing rain, and rain to the

More information

This paper will document the pattern which produced the record rainfall of 30 September The goal is to show the pattern the

This paper will document the pattern which produced the record rainfall of 30 September The goal is to show the pattern the The Historic Synoptic-Hybrid rainfall event 30 September 2010 By Richard Grumm And Michael Kozar National Weather Service State College, PA 16803 1. INTRODUCTION A slow moving north-south oriented frontal

More information

Warm Episode over Indian Sub-continent March 2010 By Richard Grumm National Weather Service State College Contributions by Lance Bosart SUNY Albany

Warm Episode over Indian Sub-continent March 2010 By Richard Grumm National Weather Service State College Contributions by Lance Bosart SUNY Albany Warm Episode over Indian Sub-continent March 2010 By Richard Grumm National Weather Service State College Contributions by Lance Bosart SUNY Albany 1. INTRODUCTION A massive subtropical ridge formed over

More information

Mesoscale Convective System and heat episode July 2005 by Richard H. Grumm and Mathew Steinbugl

Mesoscale Convective System and heat episode July 2005 by Richard H. Grumm and Mathew Steinbugl Mesoscale Convective System and heat episode 25-27 July 2005 by Richard H. Grumm and Mathew Steinbugl 1. INTRODUCTION A strong upper-level ridge brought unseasonably high temperatures to the Midwest and

More information

Mid-Atlantic Ice Storm 4 March 2015

Mid-Atlantic Ice Storm 4 March 2015 1. Overview Mid-Atlantic Ice Storm 4 March 2015 By Richard H. Grumm National Weather Service State College, PA A large 500 hpa ridge over the southern United States (Fig. 1a-e)) built into the Mid-Atlantic

More information

Southern Plains Heavy rain and Flooding

Southern Plains Heavy rain and Flooding Abstract: Southern Plains Heavy rain and Flooding By Richard H. Grumm National Weather Service State College, PA A severe weather event affected the southern Plains on 31 May 2013. The severe weather event

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events Heavy Rain 7-8 December 2011 by Richard H. Grumm National Weather Service State College PA 16803 Abstract:. A mid-level short-wave

More information

Northeastern United States Snowstorm of 9 February 2017

Northeastern United States Snowstorm of 9 February 2017 Northeastern United States Snowstorm of 9 February 2017 By Richard H. Grumm and Charles Ross National Weather Service State College, PA 1. Overview A strong shortwave produced a stripe of precipitation

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events Historic Ohio Valley January Severe weather and Tornado Event by Richard H. Grumm National Weather Service State College PA 16803 and

More information

Eastern United States Winter Storm of 1-2 February 2015-DRAFT Northeast Ground Hog Storm

Eastern United States Winter Storm of 1-2 February 2015-DRAFT Northeast Ground Hog Storm Eastern United States Winter Storm of 1-2 February 2015-DRAFT Northeast Ground Hog Storm By Richard H. Grumm National Weather Service State College, PA 1. Overview A major Winter Storm brought precipitation

More information

2. Methods and data. 1 NWS Reno, NV report circulated in the LA Times story maximum wind was observed at 0900 AM 8 January 2017.

2. Methods and data. 1 NWS Reno, NV report circulated in the LA Times story maximum wind was observed at 0900 AM 8 January 2017. The California Extreme Precipitation Event of 8-10 January 2017 By Richard H. Grumm and Charles Ross National Weather Service State College, PA 16803 1. Introduction A strong Pacific jet and a surge of

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events The February Thaw 17-19 February 2011 by Richard H. Grumm National Weather Service State College PA 16803 Abstract: After a cold January

More information

The Impact of the strong subtropical ridge of 2010

The Impact of the strong subtropical ridge of 2010 The Impact of the strong subtropical ridge of 2010 by Richard H. Grumm and Jason Krekeler National Weather Service Office, State College, Pennsylvania And Kevin Lipton National Weather Service Office Albany,

More information

Thanksgiving Eve snow of November 2014

Thanksgiving Eve snow of November 2014 1. Overview Thanksgiving Eve snow of 26-27 November 2014 By Richard H. Grumm National Weather Service State College, PA An early season east coast winter storm (ECWS: DeGaetano et al. 2002) brought snow

More information

Recent Trends in Northern and Southern Hemispheric Cold and Warm Pockets

Recent Trends in Northern and Southern Hemispheric Cold and Warm Pockets Recent Trends in Northern and Southern Hemispheric Cold and Warm Pockets Abstract: Richard Grumm National Weather Service Office, State College, Pennsylvania and Anne Balogh The Pennsylvania State University

More information

Orographically enhanced heavy rainfall of 23 May 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803

Orographically enhanced heavy rainfall of 23 May 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803 Orographically enhanced heavy rainfall of 23 May 2010 By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION During the overnight hours and into the early morning of

More information

East Coast Heavy Rainfall of January 2010 By Richard H. Grumm National Weather Service

East Coast Heavy Rainfall of January 2010 By Richard H. Grumm National Weather Service 1. INTRODUCTION A strong storm moved across the United States from 21 January through 25 January 2010 (Fig. 1). This storm produced record rainfall and snowfall in the western United States from 20-22

More information

THE EASTERN UNITED STATES HEAT WAVE OF 3-8 JULY Richard H. Grumm NOAA/National Weather Service, Weather Forecast Office, State College, PA and

THE EASTERN UNITED STATES HEAT WAVE OF 3-8 JULY Richard H. Grumm NOAA/National Weather Service, Weather Forecast Office, State College, PA and P478 THE EASTERN UNITED STATES HEAT WAVE OF 3-8 JULY 2010 Richard H. Grumm NOAA/National Weather Service, Weather Forecast Office, State College, PA and Kevin S. Lipton* NOAA/National Weather Service,

More information

Hurricane Alex: Heavy rainfall and anomalous precipitable water By Richard H. Grumm National Weather Service Office State College, PA 16803

Hurricane Alex: Heavy rainfall and anomalous precipitable water By Richard H. Grumm National Weather Service Office State College, PA 16803 Hurricane Alex: Heavy rainfall and anomalous precipitable water By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION Hurricane Alex ambled across the Gulf of Mexico

More information

1. INTRODUCTION. Heat waves are not unique to the United States. Deadly heat waves struck Europe in the summers of 2003 and

1. INTRODUCTION. Heat waves are not unique to the United States. Deadly heat waves struck Europe in the summers of 2003 and The eastern United States Heat wave of 3-8 July 2010 -Draft By Richard H. Grumm National Weather Service State College, PA 16803 and Kevin Lipton National Weather Service Albany NY 1. INTRODUCTION A sustained

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events The high latitude Eurasian Anticyclone of January-February 2012 by Richard H. Grumm National Weather Service State College PA 16803

More information

New England Record Maker Rain Event of March 2010

New England Record Maker Rain Event of March 2010 National Weather Association, Electronic Journal of Operational Meteorology, 2011-EJ4 New England Record Maker Rain Event of 29-30 March 2010 RICHARD H. GRUMM National Weather Service, State College, PA

More information

Eastern Derecho June 2013-Draft

Eastern Derecho June 2013-Draft Abstract: Eastern Derecho 12-13 June 2013-Draft Richard H. Grumm National Weather Service Office State College, PA 16803 A strong mid-tropospheric short-wave coming over a sharp 500 hpa ridge produced

More information

1. INTRODUCTION * Figure 1. National Weather Service Storm Prediction Center (SPC) storm reports for December 1, 2006.

1. INTRODUCTION * Figure 1. National Weather Service Storm Prediction Center (SPC) storm reports for December 1, 2006. P1.14 FORECAST ISSUES RELATED TO THE UNPRECEDENTED SEVERE AND HIGH WIND EVENT OF DECEMBER 2006 by Greg A. DeVoir* and Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION

More information

Heavy Rainfall and Flooding of 23 July 2009 By Richard H. Grumm And Ron Holmes National Weather Service Office State College, PA 16803

Heavy Rainfall and Flooding of 23 July 2009 By Richard H. Grumm And Ron Holmes National Weather Service Office State College, PA 16803 Heavy Rainfall and Flooding of 23 July 2009 By Richard H. Grumm And Ron Holmes National Weather Service Office State College, PA 16803 1. INTRODUCTION Heavy rains fall over Pennsylvania and eastern New

More information

The Devastating Mid-Mississippi Valley Floods of 1-2 May 2010 By Richard H. Grumm National Weather Service

The Devastating Mid-Mississippi Valley Floods of 1-2 May 2010 By Richard H. Grumm National Weather Service The Devastating Mid-Mississippi Valley Floods of 1-2 May 2010 By Richard H. Grumm National Weather Service 1. INTRODUCTION A devastating heavy rainfall event affected the Mid-Mississippi Valley (MMV) from

More information

1. INTRODUCTION. The super storm of March 1993 produced severe weather and tornadoes as it s trailing cold front pushed through Florida (Kocin eta 1l

1. INTRODUCTION. The super storm of March 1993 produced severe weather and tornadoes as it s trailing cold front pushed through Florida (Kocin eta 1l 1. INTRODUCTION Super Tuesday and awful Wednesday: the 5-6 February 2008 Severe Weather Outbreak By Richard H. Grumm National Weather Service State College, PA And Seth Binau National Weather Service,

More information

Mid-Atlantic Severe Weather Event of 23 June 2015

Mid-Atlantic Severe Weather Event of 23 June 2015 Mid-Atlantic Severe Weather Event of 23 June 2015 By Richard H. Grumm National Weather Service State College, PA 1. Overview A widespread severe weather event occurred in the eastern United States on 23

More information

The Historic Storm of October 2010 By Richard H. Grumm National Weather Service

The Historic Storm of October 2010 By Richard H. Grumm National Weather Service The Historic Storm of 24-26 October 2010 By Richard H. Grumm National Weather Service 1. INTRODUCTION An historic storm impacted much of the United States from 24-26 October 2010. Though the cyclone was

More information

Convective Heavy rainfall event of 23 July 2013

Convective Heavy rainfall event of 23 July 2013 Convective Heavy rainfall event of 23 July 2013 By Richard H. Grumm and Charles Ross National Weather Service State College, PA Abstract: A record rain event affected southern Lebanon County on 23 July

More information

1. INTRODUCTION. In addition to the severe weather, the

1. INTRODUCTION. In addition to the severe weather, the Anomalous Low and its weather impacts 10-12 May 2008 By Richard Grumm National Weather Service Office State College, PA And Al Cope National Weather Service Office Mount Holly, NJ 1. INTRODUCTION An unusually

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events The southern Express: High Impact Spring Storm of 14-17 April 2011 by Richard H. Grumm National Weather Service State College PA 16803

More information

Weather and Climate Summary and Forecast Summer 2017

Weather and Climate Summary and Forecast Summer 2017 Weather and Climate Summary and Forecast Summer 2017 Gregory V. Jones Southern Oregon University August 4, 2017 July largely held true to forecast, although it ended with the start of one of the most extreme

More information

NCEP Short-Range Ensemble forecasts of an historic rainfall event: The June 2006 East Coast Floods 1. INTRODUCTION

NCEP Short-Range Ensemble forecasts of an historic rainfall event: The June 2006 East Coast Floods 1. INTRODUCTION NCEP Short-Range Ensemble forecasts of an historic rainfall event: The 23-27 June 2006 East Coast Floods By Richard H. Grumm National Weather Service Office, State College PA 16803 And Norman W. Junker

More information

This storm was associated with strong low-level easterly winds at 850 and 925 hpa. Stuart and Grumm (2006) document the value of using u-wind

This storm was associated with strong low-level easterly winds at 850 and 925 hpa. Stuart and Grumm (2006) document the value of using u-wind The Historic Mid-Atlantic Snow storm of 5-6 February 2010-Draft By Richard H. Grumm and John LaCorte National Weather Service Office, State College, PA 16803 1. INTRODUCTION A strong storm moved across

More information

End of heat-event severe event of 7 July 2012

End of heat-event severe event of 7 July 2012 End of heat-event severe event of 7 July 2012 Richard H. Grumm And Elyse Colbert National Weather Service Office State College, PA 16803 1. Overview A widespread severe weather event affected Pennsylvania

More information

Devastating Tornadoes of 22 May 2011-Draft by Richard H. Grumm National Weather Service State College, PA

Devastating Tornadoes of 22 May 2011-Draft by Richard H. Grumm National Weather Service State College, PA Abstract: Devastating Tornadoes of 22 May 2011-Draft by Richard H. Grumm National Weather Service State College, PA A series of tornadoes struck the central United States on Sunday 22 May 2011. Tornadoes

More information

The Arctic Outbreak of 4-8 January 2014

The Arctic Outbreak of 4-8 January 2014 The Arctic Outbreak of 4-8 January 2014 by Richard H. Grumm National Weather Service State College, PA 16803 1. INTRODUCTION An artic outbreak affected much of eastern North American to include the eastern

More information

Anticipating record events using patterns and pattern forecast: Mid-Mississippi Valley floods of April 2011

Anticipating record events using patterns and pattern forecast: Mid-Mississippi Valley floods of April 2011 Anticipating record events using patterns and pattern forecast: Mid-Mississippi Valley floods of April 2011 Richard H. Grumm National Weather Service State College, PA Abstract: A persistent pattern produced

More information

The Spring Storm of April 2007 By Richard H. Grumm National Weather Service Office State College PA 16803

The Spring Storm of April 2007 By Richard H. Grumm National Weather Service Office State College PA 16803 The Spring Storm of 13-16 April 2007 By Richard H. Grumm National Weather Service Office State College PA 16803 1. INTRODUCTION A major spring storm struck the eastern United States from 13 through 16

More information

Flooding and Severe weather of 27 June 2013

Flooding and Severe weather of 27 June 2013 Flooding and Severe weather of 27 June 2013 By Richard H. Grumm National Weather Service State College, PA 1. Overview Flooding and severe weather affected Pennsylvania on 27 June 2013 (Fig 1). The severe

More information

Severe Weather with a strong cold front: 2-3 April 2006 By Richard H. Grumm National Weather Service Office State College, PA 16803

Severe Weather with a strong cold front: 2-3 April 2006 By Richard H. Grumm National Weather Service Office State College, PA 16803 Severe Weather with a strong cold front: 2-3 April 2006 By Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION A strong cold front brought severe weather to much of

More information

Mid-Atlantic Derecho event of 29 June 2012

Mid-Atlantic Derecho event of 29 June 2012 Mid-Atlantic Derecho event of 29 June 2012 Richard H. Grumm Charles H. Ross And Elyse Colbert National Weather Service Office State College, PA 16803 1. Overview An area of convection developed over eastern

More information

The enduring Louisiana rain and flooding of August 2016 by Richard H. Grumm National Weather Service State College, PA 16803

The enduring Louisiana rain and flooding of August 2016 by Richard H. Grumm National Weather Service State College, PA 16803 1. Introduction The enduring Louisiana rain and flooding of August 2016 by Richard H. Grumm National Weather Service State College, PA 16803 Historic flooding impacted Louisiana on 12-15 August 2016 (TWC

More information

record highs. Daily high temperature records were set at most climatic sites in the region. 1. INTRODUCTION

record highs. Daily high temperature records were set at most climatic sites in the region. 1. INTRODUCTION Early January 2007 Warm Episode and Record Warmth of 6 January By Richard H. Grumm, Ron Holmes, And Michael Connelly National Weather Service Office State College PA 16803 1. INTRODUCTION The winter of

More information

Mid Atlantic Heavy rainfall event 1. Overview 2. Methods and Data 3. Pattern

Mid Atlantic Heavy rainfall event 1. Overview 2. Methods and Data 3. Pattern 1. Overview Mid Atlantic Heavy rainfall event With an inertial gravity wave? By Richard H. Grumm National Weather Service, State College, PA 16803 Contributions from the Albany MAP An unseasonably strong

More information

Eastern United States Ice Storm of December 2008 By Richard H. Grumm National Weather Service State College, PA 16803

Eastern United States Ice Storm of December 2008 By Richard H. Grumm National Weather Service State College, PA 16803 Eastern United States Ice Storm of 11-12 December 2008 By Richard H. Grumm National Weather Service State College, PA 16803 1. INTRODUCTION A significant ice storm affected the eastern United States on

More information

The abrupt end of the Persistent Subtropical Ridge of the autumn of 2016

The abrupt end of the Persistent Subtropical Ridge of the autumn of 2016 The abrupt end of the Persistent Subtropical Ridge of the autumn of 2016 1. Introduction by Richard H. Grumm National Weather Service State College, PA 16803 Contributions by Elyse Hagner National Weather

More information

Eastern United States Anafrontal Snow 4-5 March 2015-Draft

Eastern United States Anafrontal Snow 4-5 March 2015-Draft Eastern United States Anafrontal Snow 4-5 March 2015-Draft By Richard H. Grumm National Weather Service State College, PA 1. Overview A 500 hpa ridge over the western Atlantic (Fig. 1) and an approaching

More information

Ensemble Forecasts of the Blizzard of January 2005 By Richard H. Grumm National Weather Service State College Pennsylvania

Ensemble Forecasts of the Blizzard of January 2005 By Richard H. Grumm National Weather Service State College Pennsylvania Ensemble Forecasts of the Blizzard of 22-23 January 2005 By Richard H. Grumm National Weather Service State College Pennsylvania 1. Introduction A fast moving upper-level disturbance produced a wide area

More information

Monthly Long Range Weather Commentary Issued: July 18, 2014 Steven A. Root, CCM, President/CEO

Monthly Long Range Weather Commentary Issued: July 18, 2014 Steven A. Root, CCM, President/CEO Monthly Long Range Weather Commentary Issued: July 18, 2014 Steven A. Root, CCM, President/CEO sroot@weatherbank.com JUNE 2014 REVIEW Climate Highlights The Month in Review The average temperature for

More information

Severe Weather Event of 13 July 2014

Severe Weather Event of 13 July 2014 Severe Weather Event of 13 July 2014 By Richard H. Grumm and Elyse M. Colbert National Weather Service State College, PA 1. Overview Severe weather affected the eastern United States (Fig. 1) from northwestern

More information

Minor Winter Flooding Event in northwestern Pennsylvania January 2017

Minor Winter Flooding Event in northwestern Pennsylvania January 2017 1. Overview Minor Winter Flooding Event in northwestern Pennsylvania 12-13 January 2017 By Richard H. Grumm National Weather Service State College, PA A combination of snow melt, frozen ground, and areas

More information

Weather and Climate Summary and Forecast January 2018 Report

Weather and Climate Summary and Forecast January 2018 Report Weather and Climate Summary and Forecast January 2018 Report Gregory V. Jones Linfield College January 5, 2018 Summary: A persistent ridge of high pressure over the west in December produced strong inversions

More information

A Synoptic Climatology of Heavy Precipitation Events in California

A Synoptic Climatology of Heavy Precipitation Events in California A Synoptic Climatology of Heavy Precipitation Events in California Alan Haynes Hydrometeorological Analysis and Support (HAS) Forecaster National Weather Service California-Nevada River Forecast Center

More information

Hurricane Harvey the Name says it all. by Richard H. Grumm and Charles Ross National Weather Service office State College, PA

Hurricane Harvey the Name says it all. by Richard H. Grumm and Charles Ross National Weather Service office State College, PA Hurricane Harvey the Name says it all by Richard H. Grumm and Charles Ross National Weather Service office State College, PA 16803. 1. Overview Hurricane Harvey crossed the Texas coast (Fig. 1) as a category

More information

Weather and Climate Summary and Forecast October 2017 Report

Weather and Climate Summary and Forecast October 2017 Report Weather and Climate Summary and Forecast October 2017 Report Gregory V. Jones Linfield College October 4, 2017 Summary: Typical variability in September temperatures with the onset of fall conditions evident

More information

Cold frontal Rainband and Mid-Atlantic Severe Weather Event 28 September 2006 by Richard H. Grumm And Ron Holmes

Cold frontal Rainband and Mid-Atlantic Severe Weather Event 28 September 2006 by Richard H. Grumm And Ron Holmes Cold frontal Rainband and Mid-Atlantic Severe Weather Event 28 September 2006 by Richard H. Grumm And Ron Holmes 1. INTRODUCTION A strong cold front moved across central Pennsylvania and the Mid-Atlantic

More information

The historic warm episode of February 2017

The historic warm episode of February 2017 The historic warm episode of February 2017 By Richard H. Grumm National Weather Service State College, PA 1. Overview A winter warm episode brought an extended period of record and near record warmth to

More information

Weather and Climate Summary and Forecast March 2019 Report

Weather and Climate Summary and Forecast March 2019 Report Weather and Climate Summary and Forecast March 2019 Report Gregory V. Jones Linfield College March 2, 2019 Summary: Dramatic flip from a mild winter to a top five coldest February on record in many locations

More information