Mid-Atlantic Derecho event of 29 June 2012
|
|
- Jodie Preston
- 5 years ago
- Views:
Transcription
1 Mid-Atlantic Derecho event of 29 June 2012 Richard H. Grumm Charles H. Ross And Elyse Colbert National Weather Service Office State College, PA Overview An area of convection developed over eastern Michigan around 0015 UTC 29 June 2012, raced across Lake Erie, entered western Pennsylvania around 0415 UTC, reaching central Pennsylvania at 0615 and then crossed the State (Fig. 1) before racing out and over the western Atlantic. The Mesoscale convective system (MCS) created a swath of wind damage with some embedded hail reports from northwestern Pennsylvania southeastward and into Maryland, Delaware, and New Jersey (Fig. 2). This MCS met the definition of a derecho in that it was a widespread convective windstorm with a concentrated area with winds over 50kt lasting spanning at least 240 miles (400km). This derecho was a classic ring-of-fire event occurring in the ideal spot on the northern fringes of a massive mid-tropospheric anticyclone (Fig. 3). Several other fast moving MCS s classifying as derechoes or ridge-rollers have been identified (Galarneau and Bosart 2006; Galarneau et al. 2008). In this case, the MCS developed on the edge of the +1σ height anomalies in southern Michigan and fairly parallel to the 5880 m contour. The northwest flow side of a ridge is an ideal location of MCS evolution. As seen in Figure 3, the system lowered the heights slightly over the Mid-Atlantic region. The large ridge and massive area impacted by extreme heat in the Mid-Mississippi Valley was likely the more new worthy event of June The regional view of the precipitable water (PW) fields showed the surge of high PW air over the Great Lakes on 28 June (Fig. 4). As the PW surge moved to the southeast it peaked near +3s above normal (Fig. 4d) at 0000 UTC 29 June as the surge of warm moist air raced to the southeast. There were hints in several model and ensemble runs of potential convective development over the region. Forecasts for overnight convection were generally indicating a 60% chance of thunder and the possible development of an MCS. The higher resolution 4km models were not particular clear on this evolution and its exact details. This case study will document the Mid-Atlantic derecho event of 29 June The radar data showed a textbook bow echo with impressive winds behind the line with 50-70kts of winds in the lower elevation slices. This was one of the stronger MCS observed on KCCX and moved through extremely fast. Based on the wind data in the radar and the damage swath, this event is classified here as a derecho. 2. Data and Methods
2 Satellite and radar data were obtained using AWIPS. All data shown were produced from AWIPS. Model data and standardized anomalies were produced using GrADS (Doty and Kinter 1995). 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. 3. Regional Pattern Figure 3 suggested the Mid-Atlantic region was in the ring-of-fire in the northern periphery of a strong ridge. A surge of deep moisture (Fig. 4) moved over this ridge. The surge of high PW air was associated with a strong low-level jet (LLJ) at 850 hpa (Fig. 5). The wind anomalies peaked at 2-3σ above normal at the height of the event over south-central Pennsylvania and Virginia (Fig. 5e). The MCS developed on the northern edge of this feature (Fig. 1). The combination of deep moisture and strong winds produced high values of 850 hpa moisture flux and large moisture flux anomalies (Fig. 6). Typically, high moisture flux anomalies are good indicators of heavy rainfall, though in this case and other convective cases, it serves as a good proxy for forcing for strong convection. The lack of heavy rainfall was likely related to the speed at which the system moved. The strong moisture flux and winds were associated with a surge of high CAPE air. CAPE values typically peak at UTC in the Mid-Atlantic. However the models forecast (not shown) and analyzed (Fig. 7) CAPE to exceed 3600JKg-1 from 0600 to 1200 UTC 29 June Could this keep be realized, it favored large updrafts and the wind shear, over 20kts was in the favorable high end potential damage range. CAPE over 1200 JKg-1 and shear in excess of 20kts is a good indicator for severe convection in the Mid-Atlantic region. The more linear wind profiles supported a strong bow-echo rather than supercell evolutions. The 700 and 500 hpa winds were from the north-northwest at 15m-s (30kts) and 30ms-1 (60kts: Fig. 8). 4. Radar As impressive as the satellite data and wind data in the GFS 6-hour analysis looked, the radar signal with this event was rather incredible. The fast moving derecho generated a cold pool and a strong bow echo signature on radar. Down radial winds of 60 to 80kts moved from northwest to southeast across Pennsylvania. This was a classic case where velocity data was critical to maintain high situational awareness and to reflectivity data was of limited value at times. Unless stated otherwise all reflectivity and velocity data are from the 0.50 degree elevation cut. The KCCX radar showing reflectivity and velocity at 0601 UTC show the echoes over Clarion County with the strong signal in the velocity data. Winds in the velocity in the blue
3 colors were 60 kts to as high as 73kts. The derecho did not look particularly impressive in the reflectivity data, however it was rather impressive in the velocity data (Fig. 9). The echoes along the derecho were at times appeared rather weak and disorganized. However the focused strong low-level jet clearly identified the feature through its life (Figs. 9-13). Once the cold pool and strong LLJ developed, the system was self-sustaining crossing all of Pennsylvania and exiting over the western Atlantic off Delare and New Jersey. The signal in the wind fields implied that at least from Clarion County into Maryland the system maintained 50 to at times 80kts of wind in the lowest elevation cut on the KCCX radar. This clearly meets the definition of a derecho. 5. Summary A rare and potent derecho or MCS affect the Mid-Atlantic region from around 0100 through 1000 UTC 29 June This was likely one of the fastest moving derechoes ever recorded on the KCCX radar and it had one of the more concentrated bands of high winds in excess of 50kts ever observed on KCCX radar. Derechoes of this intensity are quite rare in the Mid-Atlantic region. Though the derecho of June 2012, which would affect Indiana through Virginia, would post an impressive example of how potent ridge-rollers can be likely the strongest event in the eastern United States since 15 July For the 29 June Pennsylvania case, the winds in the 0.50 degree slice often exceeded 70 and at time 80 kts on both sides of the State College County warning area. This derecho developed in the ring-of-fire of an intense ridge. Large ridges producing heat waves area areas where derechoes can and do develop. Some of the strong events of this nature have been term ridge roller (Galarneau and Bosart 2006). A famous ridge roller event occurred in the periphery of the ridge associate with the July 1995 heat wave, that event produced a derecho that came out of Canada devastating the forecasts of northern New York and into central New England. The event of 29 July shared many of the features often associated with derechoes and famous eastern United States derechoes. In this event, the PW, 850 hpa winds and moisture flux signal indicated good moisture and forcing for convection. Moisture flux is normally used for heavy rainfall but has shown good utility in predicting convection. Despite the high moisture flux, the lack of heavy rainfall was likely related to the speed at which the system moved. This also likely played a role in the diminished value of radar reflectivity data verse radar velocity data in diagnosing this event. The radar data shown here indicated strong winds with at time relatively weak to nondescript reflectivity data. The reflectivity data was at times of little value. As with most bowechoes and stronger derechoes, velocity data is often the most important warning tool. As systems move too fast the new elements come and go along the line too fast. Some steadfast guidance on warning on derechoes and bow echoes apply:
4 The structure and organization of derechoes and bow echoes typically are far better identifiable in winds data than reflectivity data. Down radial winds of 45 kts at lower elevation cuts are about a 50% probability warning criteria. Lower to the surface is better above 4kft the probability will fall. Down radial winds of 50kts are greater increase the probability of wind damage. Down radial winds over 60kts are rare and have a high probability of producing damage. Gust fronts at longer ranges are typically ahead of the signature on radar and can reduce lead-times Use the EAV tool and at longer ranges chose a radar that might be down radial or cutting the derecho at lower elevations Base warning decisions on V as it is more reliable when the system develops than the reflectivity data. Despite the strength of the winds this event did not produce broad swaths of damage as experienced in the 15 July 1995 event (Galarneau et al 2008) or anything similar to the event of June 2012 (Fig. 14). Low-level stability based on the time of day may have been one factor limiting the damage produced by this event. Though it did produce a broad swath of damage. 6. References 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., Davies, J. M., 2006a: Tornadoes in Environments with Small Helicity and/or High LCL Heights. Wea. Forecasting, 21, doi: Davies, J.M.. (2006b) Tornadoes with Cold Core 500-mb Lows. Weather and Forecasting 21:6, Online publication date: 1-Dec Abstract. Full Text. PDF (1512 KB) Grams,J.S, R. L. Thompson, D. V. Snively, J. A. Prentice, G. M. Hodges, L. J. Reames. (2012) A Climatology and Comparison of Parameters for Significant Tornado Events in the United States. Weather and Forecasting 27:1, Online publication date: 1-Feb 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. Grams, J. S.,W.A.Gallus Jr., S. E.Koch, L. S.Wharton,A. Loughe, and E. E. Ebert, 2006: The use of a modified Ebert McBride technique to evaluate mesoscale model QPF as a function of convective system morphology during IHOP Wea Forecasting, 21,
5 Markowski, P. M., J. M. Straka, and E. N. Rasmussen, 2002: Direct surface thermodynamic observations within rear-flank downdrafts of nontornadic and tornadic supercells. Mon.Wea. Rev., 130, Rutledge, G.K., J. Alpert, and W. Ebuisaki, 2006: NOMADS: A Climate and Weather Model Archive at the National Oceanic and Atmospheric Administration. Bull. Amer. Meteor. Soc., 87, Markowski, P, Y. Richardson, E. Rasmussen, J. R. Davies-Jones, R. J. Trapp, 2008: Vortex Lines within Low-Level Mesocyclones Obtained from Pseudo-Dual-Doppler Radar Observations. Mon. Wea. Rev., 136, doi: 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) Trapp, R. J., S. A. Tessendorf, E. S. Godfrey, H. E. Brooks, 2005: Tornadoes from Squall Lines and Bow Echoes. Part I: Climatological Distribution. Wea. Forecasting, 20, doi:
6 Figure 1. Select GOES IR images at 0015 UTC, 0415 UTC, 0615 and 1045 UTC 29 June showing MCS evolutions. Insets show 0015 and 1045 UTC images. Return to text.
7 Figure 2. Storm reports from the Storm Prediction Center. Return to text.
8 Figure 3. GFS 00-hour forecasts of 500 hpa heights and height anomalies in 6-hour increments from a) 0600 UTC 28 June 2012 through f) 1200 UTC 29 June Heights every 60m and anomalies in standard deviations as in the color bar. Return to text.
9 Figure 4. As in Figure 3 except for regionalize view of precipitable water and precipitable water anomalies. Return to text.
10 Figure 5. As in Figure 4 except for 850 hpa winds (ms-1) and 850 hpa wind anomalies. Return to text.
11 Figure 6. As in Figure 5 except 850 hpa moisture flux and moisture flux anomalies. Return to text.
12 Figure 7.As in Figure 6 except for GFS 00-hour forecasts of CAPE contours every 1200 JKG-1 and shading as in the color bar. Return to text.
13 Figure 8. As in Figure 5 except for 500 hpa winds. Return to text. NWS State College Case Examples
14 Figure 9. KCCX radar at 0601 UTC (top) and 0606 UTC (bottom) left panels are reflectivity in dbz and right panels are velocity in kts as per color scales. Yellow boxes show warnings. Return to text.
15 Figure 10. As in Figure 9 except for 0620 and 0643 UTC. Darker blue velocity values are over 70kts. Return to text.
16 Figure 11. As in Figure 9 except valid at 0729 and 0739 UTC. Return to text.
17 Figure 12. As in figure 9 except valid 0748 and 0757 UTC. Return to text. NWS State College Case Examples
18 Figure 13. As in Figure 9 except for 0816 UTC. Return to text. NWS State College Case Examples
19 Figure 14. As in Figure 2 except valid for the 24 hours ending 1200 UTC 30 June Return to text.
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 informationMid-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 informationKrymsk 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 informationChesapeake 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 informationSevere 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 informationHeat 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 informationEastern 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 information26 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 informationHeavy 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 informationDeep 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 informationImpacts 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 informationThe 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 information2 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 informationMid-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 informationSevere 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 informationFlooding 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 informationEastern 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 informationEarly 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 informationMid 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 informationPre-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 informationMulti-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 informationMid-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 informationLow-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 informationNational 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 informationConvective 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 informationSouthern 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 informationSouthern 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 informationOrographically 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 informationHRRR 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 informationThe 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 informationTropical 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 informationThe 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 informationCold 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 informationMid 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 informationSouthern 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 informationNational 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 informationWinter 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 information1. 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 informationNortheastern 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 informationIndiana 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 informationSnow, 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 informationPennsylvania 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 informationMid-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 informationNational 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 informationNational 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 informationMemorial 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 informationHeavy 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 informationDevastating 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 informationHurricane 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 informationIsolated 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 informationChapter 14 Thunderstorm Fundamentals
Chapter overview: Thunderstorm appearance Thunderstorm cells and evolution Thunderstorm types and organization o Single cell thunderstorms o Multicell thunderstorms o Orographic thunderstorms o Severe
More informationNCEP 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 informationP PRELIMINARY ANALYSIS OF THE 10 JUNE 2010 SUPERCELLS INTERCEPTED BY VORTEX2 NEAR LAST CHANCE, COLORADO
P12.164 PRELIMINARY ANALYSIS OF THE 10 JUNE 2010 SUPERCELLS INTERCEPTED BY VORTEX2 NEAR LAST CHANCE, COLORADO 1. INTRODUCTION An outstanding question in the field of severe storms research is why some
More informationAlaskan 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 informationThanksgiving 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 information1. 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 informationNational 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 informationThe 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 informationP3.17 THE DEVELOPMENT OF MULTIPLE LOW-LEVEL MESOCYCLONES WITHIN A SUPERCELL. Joshua M. Boustead *1 NOAA/NWS Weather Forecast Office, Topeka, KS
P3.17 THE DEVELOPMENT OF MULTIPLE LOW-LEVEL MESOCYCLONES WITHIN A SUPERCELL Joshua M. Boustead *1 NOAA/NWS Weather Forecast Office, Topeka, KS Philip N. Schumacher NOAA/NWS Weather Forecaster Office, Sioux
More information16 September 2005 Northern Pennsylvania Supercell Thunderstorm by Richard H. Grumm National Weather Service Office State College, PA 16803
16 September 2005 Northern Pennsylvania Supercell Thunderstorm by Richard H. Grumm National Weather Service Office State College, PA 16803 1. INTRODUCTION During the afternoon hours of 16 September 2005,
More informationEastern 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 informationWinter 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 informationSteve Keighton * and Steve Nogueira NOAA/NWS Blacksburg, VA. Nicole Belk NOAA/NWS Charleston, WV
P5.17 SYNOPTIC AND MESOSCALE ANALYSIS OF THE 9 AUGUST 2000 APPALACHIAN-CROSSING DERECHOS Steve Keighton * and Steve Nogueira NOAA/NWS Blacksburg, VA Nicole Belk NOAA/NWS Charleston, WV 1. INTRODUCTION
More informationNational 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 informationNWS-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 information1. 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 information1. 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 informationChapter 3 Convective Dynamics 3.4. Bright Bands, Bow Echoes and Mesoscale Convective Complexes
Chapter 3 Convective Dynamics 3.4. Bright Bands, Bow Echoes and Mesoscale Convective Complexes Photographs Todd Lindley Bright band associated with stratiform precipitation in a squall line system 1 Bright
More informationP4.9 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 information1. 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 informationSouthern 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 informationMesoscale 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 informationP10.18 ORIGINS OF THE GRANITE FALLS, MN TORNADO, JULY 25, 2000 REVISITED
P10.18 ORIGINS OF THE GRANITE FALLS, MN TORNADO, JULY 25, 2000 REVISITED Doug Dokken, Rich Naistat, Bill Togstad, and Kurt Scholz. Keenan Weise, John Nelson, Luke Edholm, and Pat Shanahan. 1. INTRODUCTION
More informationP12.7 MESOCYCLONE AND RFD INDUCED DAMAGING WINDS OBSERVED IN THE 27 MAY 2004 SOUTHWEST OHIO SUPERCELL
P12.7 MESOCYCLONE AND RFD INDUCED DAMAGING WINDS OBSERVED IN THE 27 MAY 2004 SOUTHWEST OHIO SUPERCELL John T. DiStefano* National Weather Service Office, Wilmington, Ohio 1. INTRODUCTION During the early
More informationMinor 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 informationNational 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 informationNew 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 informationNational 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 informationJonathan M. Davies* Private Meteorologist, Wichita, Kansas
4.3 RUC Soundings with Cool Season Tornadoes in Small CAPE Settings and the 6 November 2005 Evansville, Indiana Tornado Jonathan M. Davies* Private Meteorologist, Wichita, Kansas 1. Introduction Several
More informationWARM SECTOR TORNADOES WITHOUT DISCERNIBLE SURFACE BOUNDARIES AND WITH MINIMAL DEEP LAYER SHEA
2.1 WARM SECTOR TORNADOES WITHOUT DISCERNIBLE SURFACE BOUNDARIES AND WITH MINIMAL DEEP LAYER SHEA * Joshua M. Boustead and Philip N. Schumacher National Weaer Service Sioux Falls, SD 1. INTRODUCTION On
More informationWarm 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 informationHistoric 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 informationHeavy 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 informationEastern 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 informationChapter 3 Convective Dynamics Part V ñ Bright Bands, Bow Echoes and MCCs. Bright band associated with stratiform precipitation in a squall line system
Chapter 3 Convective Dynamics Part V ñ Bright Bands, Bow Echoes and MCCs Photographs Todd Lindley (This part contains materials taken from UCAR MCS training module) Bright band associated with stratiform
More informationP10.4 EXAMINATION OF TORNADIC AND NON-TORNADIC SUPERCELLS IN SOUTHWEST VIRGINIA ON 28 APRIL 2002
P10.4 EXAMINATION OF TORNADIC AND NON-TORNADIC SUPERCELLS IN SOUTHWEST VIRGINIA ON 28 APRIL 2002 Steve Keighton*, Kenneth Kostura, and Chris Liscinsky NOAA/National Weather Service Blacksburg, VA 1. INTRODUCTION
More informationA 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 informationArkansas Flash Floods and heavy rainfall-draft By Richard H. Grumm National Weather Service State College PA 16803
Arkansas Flash Floods and heavy rainfall-draft By Richard H. Grumm National Weather Service State College PA 16803 1. INTRODUCTION Training convection associated with deep moisture and a strongly southerly
More informationEarly 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 information2. 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 informationNational 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 information1A.1 A UNIQUE COLD-SEASON SUPERCELL PRODUCES AN EF1 SNOWNADO
1A.1 A UNIQUE COLD-SEASON SUPERCELL PRODUCES AN EF1 SNOWNADO David Sills 1*, Marie-Ève Giguère 2, and John Henderson 3 1 Science and Technology Branch, Environment and Climate Change Canada (ECCC), King
More informationProximity sounding analysis for derechos and supercells: an assessment of similarities and differences
Atmospheric Research 67 68 (2003) 117 133 www.elsevier.com/locate/atmos Proximity sounding analysis for derechos and supercells: an assessment of similarities and differences Charles A. Doswell III a,
More informationThe 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 information11A.2 Forecasting Short Term Convective Mode And Evolution For Severe Storms Initiated Along Synoptic Boundaries
11A.2 Forecasting Short Term Convective Mode And Evolution For Severe Storms Initiated Along Synoptic Boundaries Greg L. Dial and Jonathan P. Racy Storm Prediction Center, Norman, Oklahoma 1. Introduction
More informationP8.10 AN EXAMINATION OF VARYING SUPERCELL ENVIRONMENTS OVER THE COMPLEX TERRAIN OF THE EASTERN TENNESSEE RIVER VALLEY
P8.10 AN EXAMINATION OF VARYING SUPERCELL ENVIRONMENTS OVER THE COMPLEX TERRAIN OF THE EASTERN TENNESSEE RIVER VALLEY by David M. Gaffin* and David G. Hotz National Weather Service, Morristown TN 1. INTRODUCTION
More informationThe 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 informationOn the usage of composite parameters in High-Shear, Low-CAPE environments
P72 On the usage of composite parameters in High-Shear, Low-CAPE environments Keith D. Sherburn* and Matthew D. Parker Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University,
More informationEnsemble 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 informationPatterns 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