Early May Cut-off low and Mid-Atlantic rains

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Early May Cut-off low and Mid-Atlantic rains"

Transcription

1 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 It produced a prolonged period of unseasonably cold weather in the Plains to the Gulf States from 2-6 May There were some reports of late season snow from this system in places were spring time observations of snow are rare. As this relatively long-lived cutoff moved northeastward, it produced bands of heavy rainfall in the Mid-Atlantic region and southern New York. The rain fell in the northeast quadrant of the cutoff as it slowly moved northward and merged with westerlies. The initial rain bands in the northeast quadrant of the cutoff were relatively well predicted by the NCEP SREF. The second surge of heavy rainfall across New Jersey and New York, though predicted by the SREF was a relatively low probability outcome event.

2 1. Overview A deep 500 hpa cut-off low meandered across the southern United States and into the northeast from 2-9 May 2013 (Fig. 1). Beneath this deep low 850 hpa temperatures were -3 to -4σ below normal (Fig. 2). This air mass brought a late season cold snap to the plains and reports of snow well south for the month of May. The deep low (Fig. 1) moved beneath a blocking mid-latitude ridge which was focused over northeastern Canada (Fig. 1a-c). As the ridge weakened with time the close low moved northeastward into the Mid-Atlantic region and northeastern United States before getting absorbed into the westerlies around 1200 UTC 10 May 2013 (Fig. 1i). Bell and Bosart (1993) noted the amplification of a ridge over the western United States and adjacent eastern Pacific during the evolution of a cut-off over the eastern United States. Note the strong ridge in Figure 1a-c during the evolution of the cut-off of May The cut-off Early and late season cut-off lows. The implied impulse in the northwest flow east of the ridge axis was the feature which would deepen and become the deep cut-off over the southern Plains. Visually, the process was similar to that outlined by Bell and Bosart (1993). The evolution shown in Figure 1 is similar to the cut-off evolution shown by Nieto et al. (2005:Fig. 1) to include the re-absorption into the westerlies during the final stage. The cut-off of 2-10 May 2013 was nearly poster child for their described evolution of cut-offs. From a climatological perspective, cut-off development in the United States and North America peaks in the months of July to September, with strong secondary maximum in April-May-June and weaker signal in the autumn months of October-November-December (Nieto 2005:Fig 10). The primary location of cut-off evolution over North America is off the coast of California though a secondary maximum extends from the southern plain into eastern Canada (Nieto et al 2005:Fig. 8). Cutoffs can impact the total precipitation and have been shown to produce heavy rainfall events. Payer (2010) identified patterns of heavy precipitation (HP) and low precipitation (LP) cutoff in the northeastern United States. Strong southerly flow with deep moisture and easterly flow tend events tend to produce heavy precipitation events. Events with more northwesterly flow tend to produce few significant precipitation events. Heavy rainfall in northwesterly flow behind a cutoff is not a good location for heavy rainfall. This paper will examine impacts of the enduring cutoff low of 3-9 May The key aspects here are focused on the weather in the Mid-Atlantic region to include several days of locally moderate to heavy rainfall. The persistent cutoff low and much of the associated cold and snow in the plains and southern United States will likely be studied in more detail by others.

3 2. Data and Methods The large scale pattern was reconstructed using the Climate Forecast System (CFS:Saha 2010) 6- hourly data and CFS based 30-year climatic means and standard deviations. The standardized anomalies were computed in Hart and Grumm (2001). All data were displayed using GrADS (Doty and Kinter 1995). The Stage-IV rainfall data were used to get event total, 6,12,24 and longer rainfall estimates. 3. Pattern overview The 500 hpa pattern from 1200 UTC 2 to 10 May 2013 (Fig. 1) showed a weakening cutoff low over the Gulf States at 1200 UTC 2 May 2013 and a strong 500 hpa ridge off the West Coast. East of this strong ridge a small wavelength trough was dropping into the plains (Fig. 1a). This system cut-off over the southern Plains at 1200 UTC 3 May and the previous cutoff became less descript over Florida (Fig. 1b). The second stronger cutoff had -3 to -4s height anomalies near the low center as it drifted across the southern plains on 4-5 May (Fig. 1c-d) and began to fill in as it reached the southeastern United States. The system turned northward up the East Coast and began to get absorbed into the westerlies on 9-10 May. This cut-off clearly persisted from 3-9 May and became an open wave on 10 May The deep cutoff low was associated with a pool of cold air at 850 hpa (Fig. 2). This cold air brought -3 to -4s 850 hpa temperatures into the Deep South. NCDC daily low maximum temperature data suggest 40 to 53 daily low maximum temperature records were set or tied from 2-5 May in the central and southern United States. Similarly, 32 to 66 daily record low temperature records were set or tied from 2-6 May These data suggest that the cutoff brought unseasonably cool weather to much of the central and southern United States during the first week of May The composite pattern and anomalies over the central United States (Fig. 3) shows that in the mean the 500 hpa cutoff and cold 850 hpa temperatures persisted for most of the period covered by the NCDC period of cooler than normal temperatures. As the 500 hpa cutoff moved into the Mid-Atlantic region it produced several bands of rain to the north and east of the 500 hpa low center (Figs. 4-5). The stronger bands of rain on 7 and 8 (Figs. 4c-d and 5a-b) May were associated with deep south-southeasterly flow on the north east side of the cutoff. As the flow became more westerly and northwesterly on 9 May (Figs. 5c-d) the rainfall amounts were considerably lower. The more notable periods of rain were observed in the mountains of North Carolina (Fig. 4b-c) and Virginia (Fig. 4c & 5a) and southeastern New York (Fig. 5b).

4 The heavy rainfall over the 48 hour period from 1200 UTC 7-9 May (Fig. 6) showed that there were several distinct and persistent rainbands that brought locally heavy rainfall to the Mid- Atlantic region. For the most part the bands were oriented from southeast to northwest over North Carolina, Virginia, Pennsylvania, New Jersey and New York. 4. Forecast The large scale pattern was generally well predicted with 4-7 days of lead-time and is not shown here. The focus here is on the NCEP SREF forecasts for initial bands of rainfall on 7-8 May 2013 on the northeast side of the 500 hpa cut-off low. The 6 SREFs predicted a band of moderate to heavy rainfall to impact the mountains of Virginia between 1200 UTC 7-8 May 2013 (Fig 6). Forecasts for the second period of heavy rainfall from 0000 UTC 8-9 May (Fig. 7) showed the correct general region though rainfall over 25 mm was forecast as a 40% outcome. The region to be affected and the pattern of the rainfall was well forecast but the SREF underestimated the rainfall. 5. Summary A From a climatological perspective, cut-off development in the United States and North America peaks in the months of July to September, with strong secondary maximum in April- May-June and weaker signal in the autumn months of October-November-December (Nieto 2005:Fig 10). The two cut-off of April and May 2013 occurred during the secondary maximum time of year. Lasting 5-6 days the cut-off of 2-8 May 2013 was a relatively long-lived cut-off. Most cut-offs only lasted about 2 days (Nieto et al 2005). Previous research suggested subtropical cut-off were shorter-lived than polar cut-offs. The intrusion of cold air may be a key factor in some of the longer-lived polar cut-offs. The 7-day event of May 2013 showed the importance of cold air in maintaining this long-lived cut-off. Figures 4,5, and 6 all suggest that the favorable location of heavy rainfall is in the northeastern quadrant of a slow moving 500 hpa low. During this warm season example, the heavy rain fell in bands oriented from south-southeast to north-northwest. There was clearly no heavy rainfall in the westerly flow and northwesterly flow quadrants of the 500 hpa cutoff low. 6. Acknowledgements 7. References Bell, Gerald D., Lance F. Bosart, 1993: A Case Study Diagnosis of the Formation of an Upper-Level Cutoff Cyclonic Circulation over the Eastern United States. Mon. Wea. Rev., 121,

5 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., Grumm, R.H. and R. Hart. 2001: Standardized Anomalies Applied to Significant Cold Season Weather Events: Preliminary Findings. Wea. and Fore., 16, Hart, R. E., and R. H. Grumm, 2001: Using normalized climatological anomalies to rank synoptic scale events objectively. Mon. Wea. Rev., 129, Nieto, Raquel, and Coauthors, 2005: Climatological Features of Cutoff Low Systems in the Northern Hemisphere. J. Climate, 18, doi: Saha, Suranjana, et. al., 2010: The NCEP Climate Forecast System Reanalysis. Bull. Amer. Meteor. Soc., In Press (DOI: /2010BAMS3001.1).

6 Figure 1. CFS 500 hpa heights (m) and height anomalies (standard deviations) in 24 hour periods from a-i) 1200 UTC 2-10 May Contours every 60 m and standardized anomalies as in color bar. Return to text.

7 Figure 2. As in Figure 1 except for 850 hpa temperatures (C ) and temperature anomalies. Return to text.

8 Figure 3. CFS based composite pattern focused over the central United States from 1200 UTC 2 May through 0000 UTC 6 May Return to text.

9 Figure 4. Stage-IV 12 hour accumulated precipitation (mm) valid for the periods ending at a) 0000 UTC 6 May, b) 1200 UTC 6 May, c) 0000 UTC 7 May, d) 1200 UTC 8 May Values in mm as in color bar. Return to text.

10 Figure 5. As in Figure 4 except for 8 and 9 May Return to text. NWS State College Case Examples

11 Figure 6. As in Figure 4 except for total estimated precipitation from 1200 UTC 7 May though 1200 UTC 9 May Return to text.

12 Figure 7. NCEP SREF forecasts showing the probability of 25mm or more QPF for the 24 hour period ending at 1200 UTC 8 May 2013 from NCEP SREFS initialized at a) 0900 UTC 5 May 2013, b) 1200 UTC 5 May 2013, c) 0900 UTC 6 May, d) 2100 UTC 6 May, e) 0300 UTC 7 May and f) 0900 UTC 7 May Return to text.

13 Figure 8. As in Figure 7 except for the 24 hours ending 0000 UTC 9 May 2013 and forecasts from a) 0900 UTC 6 May, b) 2100 UTC 06 May, c) 0300 UTC 7 May, d) 0900 UTC 7 May, e) 1500 UTC 7 May, and 2100 UTC 07 May Return to text.

14

15

16

17

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

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

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

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

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

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

Eastern United States Wild Weather April 2014-Draft

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

More information

Heavy 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

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

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

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

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

More information

Southern United States 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

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-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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

National Weather Service-Pennsylvania State University Weather Events

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

More information

National Weather Service-Pennsylvania State University Weather Events

National Weather Service-Pennsylvania State University Weather Events National Weather Service-Pennsylvania State University Weather Events 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

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

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

Warm Episode of December 2015:

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

More information

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

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

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

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

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

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

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

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

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

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

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

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

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

More information

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

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

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

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

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

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

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

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

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

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

The high latitude blocking and impacts on Asia

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

More information

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

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

More information

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

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

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

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

Analysis of Fall Transition Season (Sept-Early Dec) Why has the weather been so violent?

Analysis of Fall Transition Season (Sept-Early Dec) Why has the weather been so violent? WEATHER TOPICS Analysis of Fall Transition Season (Sept-Early Dec) 2009 Why has the weather been so violent? As can be seen by the following forecast map, the Fall Transition and early Winter Season of

More information

The Arctic Outbreak of 4-8 January 2014

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

More information

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

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

Eastern Derecho June 2013-Draft

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

More information

Recent Trends in Northern and Southern Hemispheric Cold and Warm Pockets

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

More information

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

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

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

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

Record snow blankets the United Kingdom 5-6 January 2010

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

More information

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. 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

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

Weather and Climate Summary and Forecast October 2017 Report

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

More information

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

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

Synoptic Meteorology

Synoptic Meteorology M.Sc. in Meteorology Synoptic Meteorology [MAPH P312] Prof Peter Lynch Second Semester, 2004 2005 Seminar Room Dept. of Maths. Physics, UCD, Belfield. Part 9 Extratropical Weather Systems These lectures

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

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

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

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

More information

The Pennsylvania Observer

The Pennsylvania Observer The Pennsylvania Observer October 1, 2015 September 2015 - Pennsylvania Weather Recap By: Quinn Lease The month of September will be remembered for its above normal temperatures and dry conditions that

More information

Weather and Climate Summary and Forecast October 2018 Report

Weather and Climate Summary and Forecast October 2018 Report Weather and Climate Summary and Forecast October 2018 Report Gregory V. Jones Linfield College October 4, 2018 Summary: Much of Washington, Oregon, coastal California and the Bay Area and delta region

More information

Weather and Climate Summary and Forecast March 2018 Report

Weather and Climate Summary and Forecast March 2018 Report Weather and Climate Summary and Forecast March 2018 Report Gregory V. Jones Linfield College March 7, 2018 Summary: The ridge pattern that brought drier and warmer conditions from December through most

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

North Pacific Climate Overview N. Bond (UW/JISAO), J. Overland (NOAA/PMEL) Contact: Last updated: August 2009

North Pacific Climate Overview N. Bond (UW/JISAO), J. Overland (NOAA/PMEL) Contact: Last updated: August 2009 North Pacific Climate Overview N. Bond (UW/JISAO), J. Overland (NOAA/PMEL) Contact: Nicholas.Bond@noaa.gov Last updated: August 2009 Summary. The North Pacific atmosphere-ocean system from fall 2008 through

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

National Wildland Significant Fire Potential Outlook

National Wildland Significant Fire Potential Outlook National Wildland Significant Fire Potential Outlook National Interagency Fire Center Predictive Services Issued: September, 2007 Wildland Fire Outlook September through December 2007 Significant fire

More information

National Weather Service-Pennsylvania State University Weather Events

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

More information

Weather and Climate Summary and Forecast November 2017 Report

Weather and Climate Summary and Forecast November 2017 Report Weather and Climate Summary and Forecast November 2017 Report Gregory V. Jones Linfield College November 7, 2017 Summary: October was relatively cool and wet north, while warm and very dry south. Dry conditions

More information

New England Record Maker Rain Event of March 2010

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

More information

Multiscale Analyses of Inland Tropical Cyclone Midlatitude Jet Interactions: Camille (1969) and Danny (1997)

Multiscale Analyses of Inland Tropical Cyclone Midlatitude Jet Interactions: Camille (1969) and Danny (1997) Multiscale Analyses of Inland Tropical Cyclone Midlatitude Jet Interactions: Camille (1969) and Danny (1997) Matthew Potter, Lance Bosart, and Daniel Keyser Department of Atmospheric and Environmental

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

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