Eastern Derecho June 2013-Draft

Size: px
Start display at page:

Download "Eastern Derecho June 2013-Draft"

Transcription

1 Abstract: Eastern Derecho June 2013-Draft Richard H. Grumm National Weather Service Office State College, PA A strong mid-tropospheric short-wave coming over a sharp 500 hpa ridge produced a series of mesoscale convective complexes on June One MCS classified as a derecho producing widespread wind damage from the western Great Lakes into southeastern Pennsylvania. The severe weather in Pennsylvania was observed mainly between 0600 and 1200 UTC 13 June 2013 with the long-lived derecho producing MCS. This system included a deep surface cyclone for so late in the season and NCEP models produced significant amounts of QPF with the system. Overall, most forecast systems grossly over forecast the QPF relative to observed rainfall data. These over predictions of QPF lead to the issuance of flood watches and concerns about flooding that did not materialize due to the general lack of heavy rainfall. Probabilistic QPF threshold values from the NCEP SREF showed high end rainfall amounts were a low probability outcome. This paper shows the pattern in which the derecho producing MCS developed. The pattern and thus the pattern of the precipitation was relatively well predicted, though as stated earlier the NCEP models grossly over predicted the rainfall.

2 1. Overview A derecho (Hinrichs 1888) developed over the western Great Lakes region (Fig. 1) spreading severe weather from southern Minnesota to southern Pennsylvania from the afternoon hours of 12 June through the early morning hours of 13 June 2013 (Fig. 2) before moving over the western Atlantic. The intense synoptic pattern produced additional convection over the Mid- Atlantic region during the afternoon and evening hours of 13 June 2013 (Fig. 2b). The strong pattern produced over 400 reports of severe weather on both the 12 th and 13 th of June The derecho of June 2013 was dominated by straight-line wind damage as implied by the name derecho coined by Hinrichs (1888) who used the Spanish term derecho to distinguish such events from tornadic events. Derechoes are a subset of mesoscale convective systems (MCS:Zisper 1982). The definition of derechoes evolved over the 20 th Century (Howard et al. 1985; Johns and Hirt 1987;Johns et al 1990) such that a derecho is widespread convective windstorm with a concentrated area with winds over 50kts spanning at least 240 miles (400km). The National Weather Service definition further requires that the convective system last at least 6 hours. The two primary types of derechoes (Johns and Hirt 1987) include serial and progressive derechoes. A climatology of derechoes (Bentley and Mote 1998) showed the highest areas of derechoes was form the southern Plains into the Great Lakes and extending eastward with some derecho activity reaching the Mid-Atlantic region. Two significant derechoes impacted the eastern United States including the 15 July 1995 and the 29 June 2013 derecho. The derecho of 15 July 1995 brought damaging winds across New York into southern New England. The 29 June 2012 (Grumm and Ross. 2012; NWS Sterling 2013) brought damaging winds and massive power outages from Indiana to the Washington-Baltimore metropolitan area. MCS s and derechoes often develop over or on the flanks of large mid-tropospheric ridges. Many derechoes are classic ring-of-fire events occurring in the ideal spot on the northern fringes of a massive mid-tropospheric anticyclone. Several other fast moving MCS s classifying as derechoes or ridge-rollers have been identified (Galarneau and Bosart 2006; Galarneau et al. 2008). The massive derecho which impacted the Mid-West and Mid-Atlantic region on June 2013 was a ridge-roller event (Grumm and Ross. 2012). The key to forecasting MCSs and the subset of these systems, derechoes, is knowing the patterns and environments in which they form (Evans et al. 2001). These patterns can then be diagnosed and evaluated in numerical guidance to aid in anticipating the evolution of MCSs and derecho producing MCS s. The advent of high resolution models and improved data assimilation is slowly making the stronger forced convective systems more predictable (Weisman et al 2013). The evolution of storm scale ensembles may improve forecasts of these systems over the next decade.

3 This case study will document the derecho event of 13 June The focus is on the pattern and evolution of the system. The second area of convection which developed on 13 June and affected the Ohio Valley and Mid-Atlantic region is not covered here. Forecasts of the pattern from NCEP systems and regional scale models are presented. 2. Data and Methods Satellite and radar data were obtained using AWIPS. All data shown were produced from AWIPS. Storm reports were taken locally and the Storm Prediction Center plots are displayed herein. The definition of a derecho was met here but this term and MCS are used interchangeably understanding that a derecho is subset of an MCS. The large scale pattern was reconstructed using the, GFS, RAP, and Climate Forecast System V2 data displayed in GrADS (Doty and Kinter 1995). Employing the methods of Hart and Grumm (2001) standardize anomalies were computed to see if any of the fields associated with MCS s departed significantly from normal. 3. The Pattern The 500 hpa pattern (Fig. 3) over the United States showed a ridge off the East Coast on 9 June and the gradual evolution of strong ridge over the south-central United States from June 2013 (Figs. 3c-f). A cut-off low off the California coast (Fig. 3a-b) moved over the western flanks of the evolving ridge; and southern Plains heat episode. This short-wave came over the ridge was clearly visible at 13/0000 UTC (Fig. 3e) though it likely interacted with a northern stream wave visible to the northeast. These two features produced a deep trough over the northeastern United States by 14/0000 UTC (Fig. 3f). A regional perspective in 6-hour increments showed the evolution of the short-waves from 12/1800 through 14/0000 UTC (Fig. 4). These data show that the MCS developed in strong northwesterly flow and the northern derecho which affected southern Minnesota southeastward into Pennsylvania was associated with a well-defined 500 hpa short-wave in this northwesterly flow. In addition to the strong wave at 500 hpa, an unseasonably strong surface cyclone was associated with the convective evolution (Fig. 5); there was a strong southwesterly jet at 850 hpa (Fig. 6) in the warm sector of the evolving cyclone; and there was a surge of high precipitable water (PW:Fig 7) air with the system. Interestingly the PW anomalies were on the order of +1σ to at times +2σ above normal. The GFS initialized extremely high CAPE (Fig. 8a) over the Mid-West where the MCS developed during the afternoon hours of 12 June As the system moved across Pennsylvania, the analyzed CAPE between 13/0600 and 13/1200 UTC was relatively low. Clearly, the high CAPE environment was present during 13 June (Figs. 8d-e) supporting the active and widespread convection in that region.

4 Surface based CAPE from the 13km RAP (not shown) also showed limited CAPE in Pennsylvania during the peak convective time between 13/0500 and 13/1000 UTC. The RAP did analyze strong low-level with 850 hpa u-wind (Fig. 9) anomalies behind the implied convection (Fig. 10) winds were over 40kts and the 850 hpa jet core had +4 to +5s above normal wind anomalies, a strongly forced system. 4. Observations The infrared (IR) satellite and lightning data (Fig. 1) showed snap shots of the cold cloud shield associated with the MCS at 13/0115 and 13/0915. These data and loops of satellite data showed some areas of convection developed ahead of the main MCS and the core of the coldest cloud tops was with the derecho. The system had an extremely linear lightning pattern near the coldest cloud tops as it raced across Ohio from 13/0615 and 13/0715 UTC (Fig. 11) and into western Pennsylvania by 13/0815 UTC. The total time in the images shows that this system met the 6 hour duration litmus test for a derecho. By 13/1115 (Fig. 11) lightning was diminishing as the MCS was weakening over southeastern Pennsylvania, though another MCS had clearly developed on the southwestern flank of the derecho producing MCS over West Virginia. The radar evolution of the low-end showing the systems evolution (Fig. 12) shows that the system was off the East Coast by 13/1500 UTC. Radar evolutions show the system as it crossed central Pennsylvania (Fig. 13). At 13/0919 UTC the system had enhanced echoes over southwestern Pennsylvania with strong in-bound winds behind the enhanced cells. Like many QLCS the winds showed better indications of the organization of the system than the reflectivity data. The system moved through State College and after it passed out bounds behind the line were evident at 1037 UTC. There was a concentrated region of wind damage from State College southward into Huntingdon County, Pennsylvania. An area near Warriors Mark along Dungarvin (see A :Fig. 14 and Fig. 15) road had an approximate 4 mile area of extensive tree damages and downed wires 1. The zoomed in radar data showed a bowing segment with strong out bound winds moving through State College. A similar feature had moved through Warriors Mark (see A Fig. 14) around 13/1009 UTC (not shown) producing a concentrated area of wind damage (Fig. 15). The bowing features created focused areas of damage in central Pennsylvania near both Warriors Mark and in State College. 5. Forecasts The overall pattern the potential for both convection and rainfall were relatively well predicted by the NCEP guidance systems to include the GEFS, GFS, NAM, and SREF. Other centers models also performed well with the pattern. The quantitative precipitation forecasts (QPFs) from 6 NAM and GFS cycles leading up to the event are shown in Figures 16 & 17 respectively. 1 Serendipitous bike ride by the author on the morning of 13 June found the damage swath.

5 Both the NAM and GFS QPFs showed a clipper-like low precipitation pattern expanding to the east. The NAM field (Fig. 16) was smoother and had close 75 and at times 100 mm (Fig. 16b) contours for the 24 hour period. The NAM from 12/0600 UTC (Fig. 16d) had a wide area of 75mm or more QPF over northern Pennsylvania with smaller 75mm contours forecast in the 12/1200 UTC cycle (Fig. 16a). The GFS forecasts showed a wave like pattern in the QPF field particularly the forecasts issued at 11/0000 UTC (Fig. 17a). The similar to the NAM, the GFS had high QPF values north of the low track in the easterly flow associated with the cyclone, though it did show some convective rainfall tracking with an implied MCS. In the eastern United States, most of these QPFs grossly over forecast rainfall. From a probabilistic perspective 3 SREF thresholds of QPF are shown in Figure It should be noted that Flash Flood Guidance (FFG) over Pennsylvania ranged from near 25 to about 80 mm depending on location. The probability of over 75mm of QPF (Fig. 18) was relatively low over Pennsylvania. Rarely did 2 or more members predict in excess of 75 mm of QPF. The probability of 50 mm (Fig. 19) was higher ranging from 40 to 60% at times. The SREF grossly over predicted the rainfall north of the surface cyclone. In Pennsylvania much of the region where the probability of 50mm exceeded 40% the FFG was over 75mm. Finally, the probability of 25mm of QPF (Fig. 20) showed that this was the higher and more likely outcome. Similar forecasts for the GEFS resulted in rainfall probabilities similar too the SREF with rainfall amounts in 24 hours in excess of 50mm being a low probability outcome. 6. Summary Work in progress. Derecho producing MCS s often occur on the periphery of large ridges during the warm season. The derecho of 13 June 2013 formed on the periphery of a ridge which may qualify it as a ridge roller (Galarneau and Bosart 2006). This event and had the additional impact of a strong and well defined mid-tropospheric short-wave (Fig. 4) and an attendant deep surface cyclone. Many events often lack this strong signal in the larger scale forcing. The NAM, GFSF, and SREF grossly over predicted the rainfall north of the surface cyclone. All three systems over predicted the overall QPF and the actually period of heavy rainfall. Over central Pennsylvania nearly 90% of the rainfall occurred in less than 3 hours. Despite over predicting the total QPF Not one of these systems produced such rapid rainfall rates. 7. References

6 Bentley, M. L., and T. L. Mote, 1998: A climatology of derecho-producing mesoscale convective systems in the central and eastern United States Part I: Temporal and spatial distribution. Bull. Amer. Meteor. Soc., 79, Bosart, L. F., W. E. Bracken, A. Seimon, J. W. Cannon, K. D. LaPenta, and J. S. Quinlan, 1998: Large-scale conditions associated with the northwesterly flow intense derecho events of July 1995 in the northeastern United States. Preprints, 19th Conf. on Severe Local Storms, Minneapolis, MN, Amer. Meteor. Soc., Coniglio, M. C., D. J. Stensrud, and M. B. Richman, 2004: An observational study of derecho-producing convective systems. Wea. Forecasting, 19, Coniglio, M.C., and D. J. Stensrud, 2004: Interpreting the climatology of derechos. Weather Forecasting, 19, Craven, J. P., and H. E. Brooks, 2004: Baseline climatology of sounding-derived parameters associated with deep moist convection. Natl. Wea. Dig., 28, Doty, B.E. and J.L. Kinter III, 1995: Geophysical Data Analysis and Visualization using GrADS. Visualization Techniques in Space and Atmospheric Sciences, eds. E.P. Szuszczewicz and J.H. Bredekamp, NASA, Washington, D.C., Evans, Jeffry S.; Doswell, Charles A. (2001). "Examination of Derecho Environments Using Proximity Soundings". Weather and Forecasting 16 (3): 329. 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., [Available at the AMS Online Store.] Galarneau, T. J., and L. F. Bosart, 2006: Ridge Rollers: Mesoscale Disturbances on the Periphery of Cutoff Anticyclones. Preprints, Severe Local Storms Special Symposium, Atlanta, GA, Amer. Meteor. Soc. 7pp. Grumm, RH, and C Ross: 2012: Chesapeake and Ohio Express: The Derecho of June On line article. Hinrichs, G., 1888: Tornadoes and derechos. Amer. Meteor. J.,5,

7 Johns, Robert H.; Hirt, William D. (1987). "Derechos: Widespread Convectively Induced Windstorms". Weather and Forecasting 2: 32. Schoen, J.M W. S. Ashley. 2011: A Climatology of Fatal Convective Wind Events by Storm Type. Weather and Forecasting 26:1, Online publication date: 1-Feb Abstract. Full Text. PDF (1569 KB) Weisman, ML, C. Evans, and L Bosart: 2013: The 8 May 2009 Super-derecho: Analysis of real-time explicit convective forecast. WAF,

8 Figure 1. GOES IR and 1-minute lightning showing the MCS over northern Indiana at 0115 UTC 13 June and over western Pennsylvania at 0915 UTC 13 June Return to text.

9 Figure 2. Storm reports from the Storm Prediction Center (SPC) color coded by type. Data valid through 1200 UTC 13 and 14 June Return to text.

10 Figure 3. Return to text. NWS State College Case Examples

11 Figure 4. As in Figure 3 except for 6-hour increments from a) 1800 UTC 12 June through f) 0000 UTC 14 June Return to text.

12 Figure 5. As in Figure 4 except for mean sea-level pressure (hpa) and pressure anomalies. Return to text.

13 Figure 6. As in Figure 4 except for 850 hpa winds and u-wind anomalies. Return to text.

14 Figure 7. As in Figure 4 except for precipitable water (mm) and precipitable water anomalies. Return to text.

15 Figure 8. As in Figure 4 except for layered CAPE (JKG-1). Shading is as in the color bar and contours are every 800JKg-1. Return to text.

16 Figure 9. As in Figure 6 except for 13km RAP 850 hpa winds and u-wind anomalies. Return to text.

17 Figure 10. As in Figure 9 except RAP synthetic reflectivity at each initialization time. Return to text.

18 Figure 11. As in Figure 1 except for clockwise from top 0615, 0715, 0815, and 1115 UTC. Return to text.

19 Figure 12. Radar summary of the evolution of the MCS of 13 June Image courtesy of the Storm Prediction Center. Return to text.

20 Figure 13. KCCX radar at 0.5 degrees showing reflectivity on left side and corresponding base velocity on the right side. Times are 0915 UTC, 1037 UTC, and 1134 UTC. Return to text.

21 A Figure 14. As in Figure 13 except zoomed in view at 1014 and 1023 UTC showing the mini-bow echo feature which moved across State College. The A in the upper velocity pattern is the point of extensive damage referred to in the text. Out bound winds were 50-58kts behind the bowing segment outlined. Return to text.

22 B A Figure 15. Area of tree and wire damage from the intersection of Dry Hollow and Dungarvin road to Frogtown. Limbs and branches littered large stretches of Dungarvin road and numerous trees were down in the woods and properties along the road. Power crews were fixing poles and wires near points A and B. These points are displaced off the roads as not obscure the map data. Limbs and branches were down sporadically along all of Dry Hollow road to the north of the main damage swath shown here. Return to text.

23 Figure 16. Return to text. NWS State College Case Examples

24 Figure 17. Return to text. NWS State College Case Examples

25 Figure 18. Return to text. NWS State College Case Examples

26 Figure 19. Return to text. NWS State College Case Examples

27 Figure 20. Return to text. NWS State College Case Examples

28

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Chesapeake and Ohio Express: The Derecho of June 2012

Chesapeake and Ohio Express: The Derecho of June 2012 Chesapeake and Ohio Express: The Derecho of 29-30 June 2012 Richard H. Grumm, Charles Ross And Contributors from the Albany MAP and the Storm Prediction Center National Weather Service Office State College,

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

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

Low-end derecho of 19 August 2017

Low-end derecho of 19 August 2017 Low-end derecho of 19 August 2017 By Richard H. Grumm and Charles Ross National Weather Service State College, PA 1. Overview A cluster of thunderstorms developed in eastern Ohio around 1800 UTC on 19

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

Mid Atlantic Severe Event of 1 May 2017 Central Pennsylvania QLCS event By Richard H. Grumm National Weather Service, State College, PA 16803

Mid Atlantic Severe Event of 1 May 2017 Central Pennsylvania QLCS event By Richard H. Grumm National Weather Service, State College, PA 16803 1. Overview Mid Atlantic Severe Event of 1 May 2017 Central Pennsylvania QLCS event By Richard H. Grumm National Weather Service, State College, PA 16803 A strong upper-level wave (Fig.1) moving into a

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

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

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

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

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

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

The Long-lived eastern US tornadic supercell of 20 July 2017

The Long-lived eastern US tornadic supercell of 20 July 2017 1. Overview The Long-lived eastern US tornadic supercell of 20 July 2017 By Richard H. Grumm and Elissa A Smith National Weather Service State College, PA A long lived supercell developed near the eastern

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

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

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

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

Indiana County Flash Flood of 22 June 2017

Indiana County Flash Flood of 22 June 2017 Indiana County Flash Flood of 22 June 2017 By Richard H. Grumm National Weather Service State College, PA 1. Overview Slow moving thunderstorms brought 3 to 4 inches of rainfall to Indiana County, PA during

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

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

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

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

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

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

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

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

Mid-Atlantic Severe Event of 1 June 2012

Mid-Atlantic Severe Event of 1 June 2012 Mid-Atlantic Severe Event of 1 June 2012 1. Introduction An unseasonably deep midtropospheric ridge (Fig. 1) brought a strong cold front into the Mid-Atlantic region on 1 June 2012. A surge of warm moist

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

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

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

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

HRRR and the Mid-Mississippi Valley Severe and Heavy rainfall event of October 2014

HRRR and the Mid-Mississippi Valley Severe and Heavy rainfall event of October 2014 HRRR and the Mid-Mississippi Valley Severe and Heavy rainfall event of 13-14 October 2014 By Richard H. Grumm National Weather Service State College, PA contributions by Charles Ross 1. Overview A deep

More information

The Severe Weather Event of 7 August 2013 By Richard H. Grumm and Bruce Budd National Weather Service State College, PA 1. INTRODUCTION and Overview

The Severe Weather Event of 7 August 2013 By Richard H. Grumm and Bruce Budd National Weather Service State College, PA 1. INTRODUCTION and Overview The Severe Weather Event of 7 August 2013 By Richard H. Grumm and Bruce Budd National Weather Service State College, PA 1. INTRODUCTION and Overview A fast moving short-wave (Fig. 1) with -1σ 500 hpa height

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

Thanksgiving Snow and Arctic Front 25 November 2005 By Richard H. Grumm National Weather Service State College, PA 16801

Thanksgiving Snow and Arctic Front 25 November 2005 By Richard H. Grumm National Weather Service State College, PA 16801 Thanksgiving Snow and Arctic Front 25 November 2005 By Richard H. Grumm National Weather Service State College, PA 16801 1. INTRODUCTION An approaching arctic front brought light snow to most of western

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

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

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

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. 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

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

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

Krymsk Flood of 6-7 July 2012-Draft

Krymsk Flood of 6-7 July 2012-Draft 1. Overview Krymsk Flood of 6-7 July 2012-Draft A flood ripped through the Russian town of Krymsk overnight on 6-7 July 2012. The flood killed 172 people and 35000 people were injured or suffered losses

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

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

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events March Madness: The 2 March 2012 super outbreak-draft by Richard H. Grumm National Weather Service State College PA 16803 and Kyle Imhoff

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

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

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

Historic Eastern United States Winter Storm of January 2016: Record snow along the megalopolitan corridor 1. Introduction

Historic Eastern United States Winter Storm of January 2016: Record snow along the megalopolitan corridor 1. Introduction Historic Eastern United States Winter Storm of 22-24 January 2016: Record snow along the megalopolitan corridor by Richard H. Grumm National Weather Service State College, PA 16803 1. Introduction An historic

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

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

26 July 2012 Derecho Events

26 July 2012 Derecho Events 1. Overview 26 July 2012 Derecho Events By Richard H. Grumm And Charles H. Ross National Weather Service State College, PA 16803 On 26 July 2012 two lines of thunderstorms (Fig. 1) brought severe weather

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

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

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

5A.3 THE USE OF ENSEMBLE AND ANOMALY DATA TO ANTICIPATE EXTREME FLOOD EVENTS IN THE NORTHEASTERN U.S.

5A.3 THE USE OF ENSEMBLE AND ANOMALY DATA TO ANTICIPATE EXTREME FLOOD EVENTS IN THE NORTHEASTERN U.S. 5A.3 THE USE OF ENSEMBLE AND ANOMALY DATA TO ANTICIPATE EXTREME FLOOD EVENTS IN THE NORTHEASTERN U.S. Neil A. Stuart(1), Richard H. Grumm(2), John Cannon(3), and Walt Drag(4) (1)NOAA/National Weather Service,

More information

Isolated severe weather and cold air damming 9 November 2005 By Richard H. Grumm National Weather Service Office State College, PA 16801

Isolated severe weather and cold air damming 9 November 2005 By Richard H. Grumm National Weather Service Office State College, PA 16801 Isolated severe weather and cold air damming 9 November 2005 By Richard H. Grumm National Weather Service Office State College, PA 16801 1. INTRODUCTION Two lines of convection moved over the State of

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

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

09 December 2005 snow event by Richard H. Grumm National Weather Service Office State College, PA 16803

09 December 2005 snow event by Richard H. Grumm National Weather Service Office State College, PA 16803 09 December 2005 snow event by Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION A winter storm produced heavy snow over a large portion of Pennsylvania on 8-9 December

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

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

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

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

Summary of November Central U.S. Winter Storm By Christopher Hedge

Summary of November Central U.S. Winter Storm By Christopher Hedge Summary of November 12-13 2010 Central U.S. Winter Storm By Christopher Hedge Event Overview The first significant snowfall of the 2010-2011 season affected portions of the plains and upper Mississippi

More information

P4.9 THE SEVERE THUNDERSTORM OUTBREAK IN FINLAND ON 5 JULY 2002

P4.9 THE SEVERE THUNDERSTORM OUTBREAK IN FINLAND ON 5 JULY 2002 P4.9 THE SEVERE THUNDERSTORM OUTBREAK IN FINLAND ON 5 JULY 2002 Ari-Juhani Punkka* and Jenni Teittinen Finnish Meteorological Institute, Helsinki, Finland 1. INTRODUCTION On 5 July 2002 a fast propagating

More information

Pennsylvania Severe Weather of September 2016

Pennsylvania Severe Weather of September 2016 Pennsylvania Severe Weather of September 2016 By Richard H. Grumm National Weather Service State College, PA 1. Overview September 2016 was a relatively quiet month for severe weather across most of the

More information

Patterns of Heavy rainfall in the Mid-Atlantic Region 1. INTRODUCTION

Patterns of Heavy rainfall in the Mid-Atlantic Region 1. INTRODUCTION 5A.2 Patterns of Heavy rainfall in the Mid-Atlantic Region by Richard H. Grumm * And Ron Holmes National Weather Service Office State College, PA 16802 1. INTRODUCTION The patterns associated with heavy

More information

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

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

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

The North American Heat Wave of July 2011-Draft

The North American Heat Wave of July 2011-Draft 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 16803 The meteorological conditions

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

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

Eastern United States Synoptic Rain Event May 2014-Draft

Eastern United States Synoptic Rain Event May 2014-Draft 1. Overview Eastern United States Synoptic Rain Event 15-16 May 2014-Draft heavy rain and flooding event By Richard H. Grumm National Weather Service State College, PA A deep 500 hpa trough with -4σ height

More information

Historic Central Pennsylvania Flash Floods of 21 October 2016 by Richard H. Grumm National Weather Service State College, PA 16803

Historic Central Pennsylvania Flash Floods of 21 October 2016 by Richard H. Grumm National Weather Service State College, PA 16803 1. Introduction Historic Central Pennsylvania Flash Floods of 21 October 2016 by Richard H. Grumm National Weather Service State College, PA 16803 A slow moving frontal system produced heavy rainfall in

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 Southern Express 18-19 February 2012: Probabilities, Potentials and uncertainty by Richard H. Grumm National Weather Service State

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

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

Eastern United States Winter Storm of February Dealing with Divergent Model and Ensemble Forecast Systems

Eastern United States Winter Storm of February Dealing with Divergent Model and Ensemble Forecast Systems Eastern United States Winter Storm of 12-14 February 2014 Dealing with Divergent Model and Ensemble Forecast Systems By Richard H. Grumm National Weather Service State College, PA 16803 1. Introduction

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

A LOOK AT TROPICAL STORM GASTON FLOODING IN VIRGINIA

A LOOK AT TROPICAL STORM GASTON FLOODING IN VIRGINIA J12B.4 A LOOK AT TROPICAL STORM GASTON FLOODING IN VIRGINIA John Billet* and Keith Lynch NOAA/NWS Wakefield, VA 1. INTRODUCTION Hurricane Gaston made landfall north of Charleston, SC on Sunday morning

More information