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For: 2012 and Type: ALL these are the cases :

We have 26 events/cases to display for 2012 and Type: ALL

2012-07-07

A strong short wave came over the ridge producing several MCS’s over the eastern United States on 7 July 2012. One MCS developed over western New York and raced across north-central Pennsylvania and southeastward into New Jersey. This MCS qualified as a derecho as it produced a swath of wind gusts over 58kts and down trees over a 290 mile long path. Most of the damage was close to a strong circulation on the eastern edge of the derecho producing MCS. A second area of convection developed over Ohio and moved eastward across south-central Pennsylvania producing both wind and hail reports in its path across the State. Both convective areas produced expansive cold cloud tops identifying each MCS.

2012-07-06

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 due to the flooding. The floods were caused by a slow moving upper low which pushed moisture from the Black Sea into the coastal hills which are 400 to 500 m high. This resulted in torrential rains in the higher terrain to the southwest of Krymsk which resulted in flash flooding. Satellite imagery (Fig. 2 &3) showed showers over the region after 0000 UTC 06 July 2012 with an enhanced region of cold cloud tops indicative of deep convection by 0800 UTC. A second round of deep convection, as indicated by satellite, developed over the region around 2000 UTC and the coldest cloud tops evolved around 2300 UTC 6 July and persisted through 0200 UTC 7 July when the system began to weaken and warm. By 0600 UTC 7 July most of the significant rainfall had likely ended. The convection developed near an 850 hPa cyclone (Fig. 4). The cyclone was relatively strong for the time of year and location with height anomalies on the order of -1 to -2 below normal. North of the Black Sea the 850 hPa heights were above normal, indicating a large anticyclone over Russia. The 850 hPa low moved westward over time, retrograding over the Black Sea. The southwesterly flow southeast of the cyclone center brought moist Black Sea air into the terrain along the shore of Black Sea, west of Krymsk (Fig. 1). It will be shown that forecasts from ensemble forecasts systems and deterministic models predicted the potential for rain in the region where satellite imagery indicated rainfall and in close proximity to Krymsk, where the deadly flash flood was observed. Furthermore, high resolution model data indicated that the flow favored some heavy rainfall in the hills near Krymsk. These data suggest that this event was relatively predictable. Ensembles...local area models...anomalies...floods.

2012-06-30

A massive derecho tracked from Indiana across the Ohio Valley and across Virginia and the District of Columbia. This massive derecho produced strong winds, downed trees and power lines, and caused over 3 million people to lose power. This ridge-roller derecho occured over a strong ridge which was producing a record heat event in the southeasetern United States. This paper documents the event. keyworkds: ridge roller derecho anomalies ensembles.

2012-06-29

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 +1 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 28-29 June 2012. 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 2012. 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.

2012-06-28

The pattern over the United States was dominated by a strong ridge which produced relatively warm and dry weather over the country. The ridge intensified toward the middle of the month producing hot dry weather over the western Plains and Rocky mountains. The daily number of records tie or broken exceed 80 per day from 18 to 28 June 2012. During this period there were several days where over 100 new records were set. The impact of the hot dry weather has not been fully realized. In Colorado two large files impacted tens of thousands of people and destroying hundreds of homes. The heat likely will impact agricultural production in the central United States. This paper will document the pattern of June 2012 and focus on the massive ridge which produced period of record high temperatures from 18 to 30 June 2012. The pattern will be shown from the perspective of standardized anomalies. These standardized anomalies aid in identifying warm potential high impact events from both a diagnosis and forecast perspective. This method is used to compare the heat event of June 2012 to the historic heat event of July 1936. key words: heat anomalies heat-waves ensembles

2012-06-26

Heavy rainfall impacted the State of Florida from 23-26 June 2012 as the circulation associated with tropical storm Debby lumbered up the West Coast of Florida. Rain from the system affected southern Florida on the 23rd moving into central Florida on the 24th. Rainfall rates in excess of 96mm in 6 hours affected central and northern Florida from 1800 UTC on 24 through 1200 UTC on 26 June 2012. The heaviest rain fell in the Florida panhandle on strong easterly winds. Rainfall in the Florida panhandle exceed 300 mm and there over 250 mm of rain fell between 1800 UTC 25 to 0000 UTC 26 June 2012. This rainfall event was an excellent example on the use of standardized anomalies to identify the potential for heavy rainfall. Forecasts from NCEP models and ensemble prediction systems showed the potential for heavy rainfall in the quantitative precipitation forecasts. These systems also showed the surge of high precipitable water air into the threat regions along with above normal wind anomalies. The signals in the mass fields reinforced the information contained in the model quantitative precipitation forecasts. Standardized anomalies ensembles SREF heavy rainfall

2012-06-20

Strong low-level southerly flow with a plume of deep moisture (Fig. 1) combined with a shallow frontal boundary to produce heavy rainfall over eastern Minnesota and northwestern Wisconsin (Fig. 2). Rainfall in excess of 225 mm (9 inches) caused flooding in Duluth, Minnesota. The heaviest rainfall occurred between 0000-1200 UTC 20 June 2012 (Fig. 2-lower) with radar and hourly rainfall estimates suggesting the heavy rain fell between 0100 UTC and 0700 UTC. The NCEP models and ensemble forecasts systems indicated the potential for heavy rainfall over Minnesota and got the general orientation of the rain bands. However, they were unable to predict the location of the heavy rainfall during this extreme event. The NCEP 4km NAM showed a southwest to northeast oriented rain band (Fig. 3) and the 1800 UTC 19 June 2012 cycle showed some impressive rainfall totals (Fig. 3c) though the band was 50 to 100 km too far to the north and east from where the heavier rain was observed. It will be shown that model resolution was important at predicting some of the higher end QPF values. This paper will document the heavy rainfall event of 20 June 2012. The focus is on the patterns and anomalies associated with high impact heavy rain events and using these data to better anticipate heavy rainfall events.

2012-06-09

A heavy rainfall event impacted southern Alabama and western Florida on 9-10 June 2012. Two locations in western Florida reported in excess of 500 mm (20 inches) of rainfall. The heavy rain came in two distinct periods. The heaviest rain, with some locations receiving in excess of 250 mm (10 inches) occurred with generally east-west bands between 1200 and 1800 UTC 9 June 2012. The rain over the region actually ceased before 0000 UTC 10 June before a more organized convective system, with more north-south oriented bands, moved across the region. The overall pattern over the region showed persistent high precipitable water values with PW anomalies around 2 standard deviations above normal on the warm side of strong east-west frontal boundary. This boundary and local convective scale interactions likely created the nearly ideal conditions for heavy rainfall. The NCEP GFS and SREF were able to predict the pattern and thus indicated the potential for heavy rainfall along the coastal regions of Mississippi, Alabama and Florida. The GFS predicted in excess of 250 mm over portions of this region and the SREF indicated the potential for in excess of 100 mm of QPF. The models clearly indicated a high probability of a heavy rainfall event, despite the very convective nature of the event and its complex evolution. This implies that the front and the local forcing were rather predictable.

2012-06-01

An unseasonably deep mid-tropospheric ridge (Fig. 1) brought a strong cold front into the Mid-Atlantic region on 1 June 2012. A surge of warm moist air ahead of this system produced severe weather from South Carolina to Pennsylvania (Fig. 2). The strong low-level shear and relatively low lifting condensation levels (LCL) likely contributed to the 19 reported tornadoes in Pennsylvania (5) and Maryland (14) with an additional 8 tornadoes in Virginia. The association of high shear and low LCL heights is a potential indicator of increased tornado potential (Brooks et al 2003; Grunwald and Brooks 2011;Craven and Brooks 2004). Supercell tornadoes typically form in the rear-flank downdraft or hook-echo portion of supercells (Markowski 2002) and the downdraft air is the likely source of the low-level vorticity (Markowski and Richardson 2009). Thus, the low LCL heights are theorized to aid in producing relatively warm rear-flank downdrafts which are the likely source of vorticity for the tornadoes produced by supercell thunderstorms. It should be noted that all of the tornadoes on 1 June were weak tornadoes and most occurred in the deep warm air well ahead of the frontal system. This study examines the event of 1 June 2012 and compares some of the key synoptic features and parameters to literature related to severe storms and severe storm modes. In eastern Pennsylvania and Maryland, early in the event the conditions favored rotating storms and most of the tornadoes were associated with discrete cells. However, there were 3 non-supercell tornadoes in western Pennsylvania which occurred in a strongly sheared environment with convective available potential energy below about 800JKg-1. To the west, a quasi-linear convective system (QLCS: Atkins et al. 2005; Atkins et al. 2009) evolved producing at least 3 distinct bowing segments along the longer line of convection. One small cell developed ahead of this line producing the first 2 tornado reports in western Pennsylvania. The distinct bow echoes appeared to account for all of the wind and the lone tornado report in west-central Pennsylvania.

2012-05-27

Ring-of-fire severe weather event with large MCS tracking over the ridge into Pennsylvania producing some flash flooding and many reports of damaging thunderstorm winds. This event began with high PW and high CAPE but lacked strong low-level shear.

2012-05-14

Moderate rainfall with westward shift in the axis of heavy rainfall. Rainfall amounts generally 1-2 inches with no flooding issues. Good example on the use of ensembles and high resolution model data to predict a rainfall event.

2012-05-02

QLCS of rotating storms produced hail, wind, and a short-lived tornado along the line. Of the 3 rotating storms, damage was only reported with the easternmost storm as was the tornado near Ayers Hill, PA.

2012-04-23

Late season nor’easter mountain snows and coastal rains A late season nor’easter brought heavy rain to the coastal plain and locally heavy snow to the mountains of the eastern United States. Snow was observed from the mountains of western North Carolina into New York. The heaviest snow fell in the elevated terrain of Pennsylvania and western New York. Laurel Summit and Seven Spring ski area received 23.7 and 18.5 inches of snow in the mountains of southwestern Pennsylvania. Similar to many historic late season snow events, elevation was critical to snow accumulations. The coastal plain experienced strong winds and rain. After a dry winter, over 2 inches of rainfall fell from North Carolina to Maine. The heaviest rainfall was observed from New Jersey northward across Long Island and Connecticut, eastern New York, and into New England. Some areas in this region received affected 3 to 5.74 inches of rainfall. New Boston, New Hampshire topped the rainfall with 5.74 inches of rainfall. The heavy rainfall was observed in a plume of above normal precipitable water and with strong low-level southerly flow. This resulted in high values of low-level moisture flux with moisture flux standardized anomalies on the order of +5 to +6 standard deviations above normal in this deep moisture plume. Similar to many late season snow events, the heavier snow was confined to higher elevations north and west of the track of the 500 hPa closed cyclone. The deep trough and cold air were well below normal supporting the potential for a late season snow fall. Due to the amount of snow observed, a comparison of this storm and its features is presented relative to the history heavy snow storm of 28 April 1928. It will be shown that the NCEP models predicted this potential late season nor’easter and the potential for snow with at least 3-5 days of lead-time

2012-04-14

The event produced 461 severe weather reports to include 153 tornadoes. A few persistent storms produced many of the tornadoes which crossed Kansas and Oklahoma. In addition to the 153 tornado reports, there were 202 hail reports. The combination of significant hail and tornado reports is typical of supercell dominated events. Despite the large number of tornadoes, there were only 2 report fatalities and numerous injuries all of which were attributed to one storm. This paper will document the historic tornado and severe weather event of 14 April 2012. It also shows some simple SREF probabilities to aid in defining areas of potential severe weather and stronger storms.

2012-04-14

The event produced 461 severe weather reports to include 153 tornadoes. A few persistent storms produced many of the tornadoes which crossed Kansas and Oklahoma. In addition to the 153 tornado reports, there were 202 hail reports. The combination of significant hail and tornado reports is typical of supercell dominated events. Despite the large number of tornadoes, there were only 2 report fatalities and numerous injuries all of which were attributed to one storm. This paper will document the historic tornado and severe weather event of 14 April 2012. It also shows some simple SREF probabilities to aid in defining areas of potential severe weather and stronger storms.

2012-03-23

Eastern North American Warm Episode of March 2012 A strong and persistent mid-tropospheric ridge developed over eastern North America in March 2012. This strong feature produced a sustained period of above normal temperatures to most of eastern North America. Flow about the ridge brought extremely high precipitable water into the central United States and central Canada. Precipitable water anomalies in excess of 6were observed in the plains of Canada and the northern United States. An extremely warm period was observed from 10 to 22 March 2012. During this time period 500 hPa height, 850 hPa temperature, and precipitable water anomalies in excess of 2s were common over a large portion of eastern North America. The pattern and the persistence of the pattern was similar to the pattern which produced the Russian heat wave of July-August 2010. During this period hundreds of high temperature records were broken over large swaths of the eastern United States. The strong southerly flow and moisture plume on the western flank of the ridge produced heavy rainfall in the plains and contributed to severe weather. The deep moisture played a critical role in the severe weather, heavy rainfall, and temperature records. The deep moisture kept overnight lows unseasonably warm and some locations, where precipitable water anomalies were over 4s above normal experienced low temperatures which were higher than previously recorded high temperatures for the date. This paper presents the persistent pattern which brought the period of sustained warmth eastern North America. It is shown that the warm episode of March 2012 shared all the characteristic associated with a summer-time heat wave to include the plume of high precipitable water air transported poleward of the mid-tropospheric anticyclone. Finally, the predictability of this event is examined using the National Centers for Environmental Predictions Global Ensemble Forecast system. Keywords: Standardized anomalies. Ensembles heat wave warm episode.

2012-03-02

March Madness: The 2 March 2012 super outbreak- Abstract: A vigorous short-wave swept across the Mid-Mississippi and Ohio Valleys on 2 March 2012 resulting in one of the largest early spring severe weather outbreaks since 1950. This system produced over 870 reports of severe weather to include an estimated 128 tornadoes. This was the second deadly severe weather and tornado event to affect the central United States in less than three days. The strong trough brought a brief surge of warm moist air into the Mid-Mississippi and Ohio Valleys. The warm air produced unusually high CAPE along with strong low-level winds. Above the warm moist air was relatively dry air which led to an elevated mixed layer over the region. Many of the regional soundings and model forecast soundings showed the classic “Type-I” or load-gun soundings often associated with many high end severe weather and tornado events. This paper will document the deadly tornado and severe weather event of 2 March 2012. The focus is on the pattern, the elevated mixed layer, and the value of standardized anomalies to aid in identifying extreme high impact events. Key words: EML Tornadoes ensembles R-Climate anomalies.

2012-02-29

A mid-tropospheric trough moved into a strong ridge over the Gulf States. Strong southerly flow between the systems produced a surge of above normal precipitable water into the eastern plains and the Mid-Mississippi Valley resulting in a two-day severe weather event. North of the surface cyclone associated with the wave heavy snow was reported from the upper-Midwest into New England. The warm air and strong winds produced 36 tornadoes over 2 days and in excess of 400 reports of severe weather. Initial data from the Storm Prediction Center suggests 7 people were killed in the tornado outbreak with 6 deaths in Harrisburg, Illinois. This was one of the largest severe weather and tornado outbreaks in the Midwest since 1950. The last major February event was the Super Tuesday event of 6 February 2008 which had over 500 severe reports and 93 tornadoes. This paper will document the event of 28-29 February 2012. The focus is on the pattern and the value of standardized anomalies to aid in identifying extreme high impact events.

2012-02-19

Southern Express 18-19 February 2012: Probabilities, Potentials and uncertainty Abstract: A strong southern stream short-wave brought snow and severe weather from Texas to Virginia. The severe weather extended from Texas to Georgia as the upper-level wave raced eastward. Farther north and on the cold side of the surface cyclone, snow was observed. The heaviest snow was observed eastern Kentucky to Virginia. Forecasts from most ensemble forecast systems indicated that the high probability outcome would spare the major cities of the northeastern United States from a major snow event. A few NCEP GFS runs did indicate a potential for the storm to track farther north, favoring a precipitation shield as far north as Philadelphia and New York. Some human produced forecasts gravitated toward these low probability GFS forecasts. Incredibly, and despite ensemble forecasts showing a southward tracking storm, just twenty four hours prior to the event a few human forecasters maintained the potential for snow for Washington, Baltimore, and potentially, Philadelphia. This paper will document the event and demonstrate the value of ensembles in forecasting winter storms. It will be shown that the high probability outcomes must be the basis of forecasts to avoid over forecasting the potential of a low probability event. A simple method of assessing predictability is presented to encourage forecasters to make better use of uncertainty in the forecast process.

2012-01-30

The high latitude Eurasian Anticyclone of January-February 2012 A strong blocking anticyclone developed over northern Russia in late January 2012. As the anticyclone strengthened, a closed 5640m ridge with near 3 above normal height anomalies over northern Russia. At the surface an anticyclone developed with a closed 1060 hPa and at times a closed 1064 hPa contour. This massive deep anticyclone transported warm moist air into the Arctic, producing warm conditions and rain in the Spitsbergen Islands to near 80 degrees north latitude. But the high impact, if not historic, weather event occurred to the south where the strong easterly flow on the southern flank of the anticyclone pushed arctic air into eastern, central and eventually Western Europe. The cold air resulted in over 150 weather related deaths by 2 February 2012. The winter of 2011-2012 had been relatively mild for most of Europe. As the cold air surged westward, it brought snow and temperatures fell to near normal then to well below normal. The mild conditions were rapidly replaced by harsh winter conditions. As the cold weather swept into Western Europe it brought snow to Rome, Italy for the first time in 26 years. Temperature fell below -32C (-26F) over portions of Eastern Europe. This paper will document the anticyclone and the cold episode that affected much of Europe over the period of 30 January through 3 February 2012.and its impacts. The focus is on the use of anomalies to analyze this and similar high impact weather events. Forecasts from the NCEP GFS and GEFS are presented to show the value of using climate data in the forecast process to better anticipate extreme weather events.

2012-01-30

The high latitude Eurasian Anticyclone of January-February 2012 A strong blocking anticyclone developed over northern Russia in late January 2012. As the anticyclone strengthened, a closed 5640m ridge with near 3 above normal height anomalies over northern Russia. At the surface an anticyclone developed with a closed 1060 hPa and at times a closed 1064 hPa contour. This massive deep anticyclone transported warm moist air into the Arctic, producing warm conditions and rain in the Spitsbergen Islands to near 80 degrees north latitude. But the high impact, if not historic, weather event occurred to the south where the strong easterly flow on the southern flank of the anticyclone pushed arctic air into eastern, central and eventually Western Europe. The cold air resulted in over 150 weather related deaths by 2 February 2012. The winter of 2011-2012 had been relatively mild for most of Europe. As the cold air surged westward, it brought snow and temperatures fell to near normal then to well below normal. The mild conditions were rapidly replaced by harsh winter conditions. As the cold weather swept into Western Europe it brought snow to Rome, Italy for the first time in 26 years. Temperature fell below -32C (-26F) over portions of Eastern Europe. This paper will document the anticyclone and the cold episode that affected much of Europe over the period of 30 January through 3 February 2012.and its impacts. The focus is on the use of anomalies to analyze this and similar high impact weather events. Forecasts from the NCEP GFS and GEFS are presented to show the value of using climate data in the forecast process to better anticipate extreme weather events.

2012-01-22

Gulf States Severe weather and Tornado Event of 22-23 January 2012 Abstract: A mid-tropospheric trough moved across the Rocky Mountains and into the Plains on 22 January 2012. As the wave moved eastward it pulled a plume of deep Gulf moisture into the Mississippi Valley. Precipitable water anomalies of 3 to 4 above normal were present in this moisture plume along with a strong 850 hPa jet. The shortwave flooded much of the eastern United States with warm air and triggered a severe weather event in the Mississippi Valley with 247 severe reports on the 22 of January. Severe thunderstorms were observed in the deep moisture plume ahead of the wave and attendant cold front. Severe storms were observed from southern Arkansas to Indiana. Tornadoes were observed as far north as Tennessee but the focus of this January tornado outbreak was from Arkansas to Alabama. The event produced 264 severe weather reports over the two days to include 50 tornadoes. Of the 50 tornadoes, 26 were observed in the State of Alabama, which experienced two deadly tornadoes. The 26 tornadoes in Alabama surpassed the event of 10 January 1975 when there were 13 tornadoes in Alabama. This paper will document the historic tornado and severe weather event of 22-23 January 2012

2012-01-21

A deep trough over northern western North America and a ridge over the eastern Pacific brought a strong 250 hPa jet and a surge of deep Pacific moisture into the western United States from 18-22 January 2012. Reports of over 16 inches of precipitation were observed in the mountains of southern Oregon. Many areas of California had heavy rain or snowfall. The combination of the cold air over western Canada and Alaska and the surge of moisture produced snow in Washington State. Before the ice storm began, the Seattle area had 10-20cm of snowfall. Heavy snow impacted the higher elevations. Farther south and at lower elevations heavy rain dominated. Strong Pacific jets and moisture surges are often associated with El Niño conditions. However, such events can and clearly do occur during El Niña winters. This event was observed during a La Niña winter. This paper will document the West Coast heavy precipitation event of January 2012. The NCEP GEFS precipitation forecasts show that the GEFS did well in predicting the potential for heavy rainfall and the impact of the Pacific moisture plume into the mountains of the western United States.

2012-01-17

Abstract: A strong cold front ripped across the Midwest and into the northeastern United States on 17 January 2012. Unseasonably warm moist air ahead of the front provided moisture and added instability. This resulted in widespread severe weather mainly before 1800 UTC in the Ohio Valley and another widespread convective wind severe event in the eastern Great Lakes. Overall, there were 165 reports of severe weather, including 14 confirmed tornadoes, on 17 January 2012, a relatively high number of severe reports for mid-winter. Southern Indiana and Kentucky were particularly hard hit with 10 verified tornadoes which based on the 1950-2011 climatology is an historic event. The region averages about 0.37 tornadoes per year during the month of January. Other big tornado events in this region included 3 tornadoes in 1964 and 1997, 5 tornadoes in 2008 and 6 tornadoes in January 2006. This paper will document the historic tornado and severe weather event of 17 January 2012.

2012-01-05

The first part of the winter of 2012 will be remembered in many part of the United States as a warm and snowless winter. The combined effects of a persistent La Niña and a positive NAO likely were contributing factors. The MEI was a modest 0.97 for the month of December 2011 but the AO at 2.28 was second only to 2006. The pattern produced a generally warm period over the eastern United States for the month of December 2011. At the end of December 2011 and into early January 2012 an unusually large ridge developed over the western United States. This produced a period of warm weather, breaking many high temperature records from the West Coast to the plains. The sharp ridge pushed a 5820 m contour over the southwest and amplifying the pattern, allowing cold air into the eastern United States. As the western half of the United States basked in unseasonal warmth, the eastern United States briefly experienced the coldest weather of the winter of 2011-12 to date. This paper will examine the conditions associated with the western United States warm up to include some large scale Teleconnections data. Standardized anomalies are used to characterize the pattern. Forecasts from the NCEP 75 and experimental 55km GEFS are used to show that this unusual event was relatively well predicted.

2012-01-03

A deep, fast moving cyclone produced a high wind event across portions of Northern Ireland and Scotland on 3 January 2012. The central pressure bottomed out around 952 hPa based on the United Kingdom Met Service surface analysis. The strongest wind occurred south of the cyclone in the relative cold air mass, north and west of the strong southerly flow in the warm air. Similar to other oceanic cyclone events, the strongest winds were associated with only light or showery precipitation. The cyclone was relatively well predicted by numerical models and ensembles, however, the intense winds south of the cyclone in the cold air were not as well predicted. This mesoscale feature, associated with winds over about 80 mph was not so well predict. Forecasters, using pattern recognition identified this as a “sting jet” and correctly alerted the public for the potential for strong and damaging winds. Identifying and recognizing the pattern and probabilities is more important than names assigned to the phenomena. No debate on the name of the phenomena is offered here. Standardized anomalies were used to assess the strong winds and the overall intensity of the system. The strong winds disrupted transportation, damaged homes, and interrupted power in northern Ireland, Scotland and portions of England. The higher and more damaging winds were farther to the north, closer to the passage of the deep oceanic cyclone. Shapiro-Keyeser Cyclone Ensembles anomalies.