NATIONAL WEATHER SUMMARY

 

JUNE 2012

 

1^st-9^th…Strong storms and heavy rainfall developed across the Eastern U.S. on Friday as a low pressure system moved up the Ohio River Valley. This system created a warm front that extended eastward and produced moderate to heavy showers and thunderstorms across the Upper Ohio Valley and into the Northeast. At the same time, a cold front stretched southward and produced strong storms through the Southeast. Some of these storms turned severe with strong winds and large hail. Heaviest rainfall fell over Boothville, Louisiana early Friday morning with a total of 2.88 inches of rain. Further south, strong thunderstorms and heavy rain showers persisted over Florida. Flood watches have been issued for the southern tip of Florida as the region has seen heavy rainfall for the past few days now. Heaviest rainfall in Florida reached a mid-day total of 2.55 inches in Hollywood, Florida. In the Plains, a weak trough of low pressure kicked up widespread scattered showers and thunderstorms, but severe weather did not develop across the Central and Northern Plains. Further West, a ridge of high pressure created another hot, dry, and sunny day across the Southwest. Daytime high temperatures reached unseasonably warm conditions again on Friday. This kept fire danger high for southern California, Arizona, and New Mexico.

Much of the West experienced calmer weather conditions Wednesday afternoon as the strong storm system of the region moved into southern Alberta, Canada. Rain showers and high wind continued across the northern tier of the Northern Intermountain West during the afternoon as the system progressed. Prolonged and excessive precipitation maintained flood concerns throughout this area. Meanwhile, the trailing cold front and waves of low pressure along the front moved into the Northern Plains and Central High Plains. Scattered showers and thunderstorms were expected to form ahead of this disturbance during the mid- to late afternoon. In the East, rain and thunderstorms continued near a nearly stationary front extending from the Central Gulf Coast through the Georgia Coast and into the Atlantic. Elsewhere in the South, a slow moving low and plenty of moisture from the Gulf of Mexico produced rain and thunderstorms in central Oklahoma and parts of northern Texas. Elsewhere, a broad trough of low pressure in the jet stream reached across much of the East today. This system supported pockets of light, spotty showers and a few rumbles of thunder in parts of the Mid-Atlantic, Northeast, Upper Mississippi Valley, and Upper Great Lakes.

Rain showers continued across the Deep South on Friday, as well as the Pacific Northwest and Northern Rockies. A ridge of high pressure continued to build over the Eastern U.S., which created another warm, dry, and sunny day. However in the South, a frontal boundary stalled over Florida and the Gulf Coast. This system produced more heavy rain showers and strong thunderstorms from Florida through eastern Texas. Flash flooding warnings have been issued for the Gulf Coast due to heavy rains persisting across the region for the past few days. Rainfall totals on Friday ranged from 1 to 2.5 inches for most of the region, with heaviest rainfall reported in Conroe, Texas with a mid-day total of 2.85 inches.

 

In the North, a low pressure system moved off the Northern Rockies and pushed a cold front from the Plains and into the Great Lakes. This system triggered widespread scattered showers and thunderstorms throughout the day. These storms have not yet turned severe. Meanwhile, out West, scattered showers spread from the Pacific Northwest into the Northern Rockies, as another low pressure system offshore pushed a cold front through the region. To the south, a ridge of high pressure created another hot and dry day over the Great Basin and Southwest. Thus, fire danger remained high across the region.

 

10^th-16^th…The main weather system in the country was a long front that moved through the Plains and Midwest on Monday. Deep moisture streamed northward from the Gulf of Mexico and instigated strong thunderstorms and heavy rain from Iowa through southern Illinois, Missouri, and northern Arkansas. Some of these thunderstorms became severe and produced large, damaging hail in Missouri. No tornadoes were reported as of mid-afternoon, but remain possible into the evening as the line of thunderstorms moves eastward. Dry conditions finally greeted northern Florida after a weekend of torrential rainfall. Showers and thunderstorms did pop up in the Southeast, however, from Alabama through South Carolina. The West once again experienced quite warm afternoon temperatures in the 90s and 100s from California through New Mexico. This was not good news for firefighters in New Mexico and Colorado, where extremely large wildfires continued to rage. The warmest temperatures in the country were noted in the Southern Plains where triple digit temperatures were common. The Northeast rose into the 70s and 80s, while the Southeast saw temperatures in the 80s and 90s. The Southern Plains and Southwest rose into the 90s and 100s, while the Northwest saw temperatures in the 60s, 70s, and some 80s.

Active weather continued across the nation on Wednesday. In the East, a cold front in the Eastern Seaboard kicked up more rain showers in the Northeast on Wednesday, while the southern end of this front maintained chances of showers and thunderstorms in the central Gulf Coast States.

To the West, light to moderate rain showers popped up across the northern tier of the Northern Intermountain West and Northern Rockies as moist winds and a cold front associated with a low pressure system over western Canada moved through the Northwest. Meanwhile, a weak trough of low pressure and moist flow from the Gulf of Mexico supported chances of showers and thunderstorms over portions of the Northern Plains and Upper Midwest. The Northern Plains remained at slight risk of severe weather development with damaging winds and large hail from this afternoon through tonight. To the south, areas of the Southern High Plains were also at slight risk of severe weather activity with large hail and damaging winds through tonight.

A few areas of active weather continued east of the Continental Divide on Friday. In the Central U.S., a frontal system reached from the western Upper Great Lakes into the Central Plains and a warm front extended across Nebraska during the afternoon. Meanwhile, energy ejecting from the Rockies triggered chances of showers and thunderstorms and a slight risk of severe weather development in the Northern and Central High Plains. To the southeast of this activity, a few showers and thunderstorms continued along the central Gulf Coast this afternoon. In the West, generally dry conditions persisted over much of the West as high pressure began to build into the region. This system brought gusty winds and low humidity levels to the Sacramento Valley and eastern slopes of coastal ranges in the northern San Francisco area. These conditions combined with well above normal temperatures increased fire weather concerns across the region. Red Flag Warnings were expected to remain in effect for these areas through Saturday.

 

17^th-23^rd…A relatively inactive day transpired Monday as much of the country was dry.  The strongest storm in the country moved through the Northern Plains and Upper Midwest. The associated warm front moved through the upper Midwest and instigated another round heavy showers and thunderstorms in Minnesota and Wisconsin. In the afternoon, some severe thunderstorms were strong enough to produce Tornado Warnings in Minnesota. As the tail end of the warm front moved into the Ohio Valley, a small area of thunderstorms moved through southeastern Michigan and into Ohio. At least one of these thunderstorms also become severe and instigated a Tornado Warning in Erie County. While temperatures were slightly cooler in California and the Southwest after an intense weekend heat wave, inland areas once again rose into the 90s and 100s. Coastal areas were cooler as the marine layer rebuilt along the coast. The eastern seaboard was mostly dry as a high pressure system stretched along the coast and kept any storms out of the picture. The Northeast rose into the 70s and 80s, while the Southeast saw temperatures in the 80s and some 90s. The Southern Plains and Southwest rose into the 90s and 100s, while the Northwest saw temperatures in the 60s and 70s.

Active weather continued in the Upper Midwest on Wednesday, while an intense heat wave hit the Northeast. In the Midwest, scattered rain showers continued from the Northern Rockies through the Upper Midwest as a frontal system reached from the upper Mississippi Valley through the Central Plains. Areas of heavier rainfall and thunderstorm activity formed ahead of the system in parts of northeastern Minnesota during the afternoon. Parts of Wisconsin, Minnesota, and Iowa remained at slight risk of severe weather development with damaging wind and hail through the evening. Areas of southern Kansas and the Texas and Oklahoma Panhandles were also at slight risk of similar severe weather development late this afternoon. In the East, a large ridge of high pressure in the Eastern Seaboard kicked off the first day of astronomical summer with an intense heat wave in the Northeast and Upper Mid-Atlantic. Heat Advisories and Excessive Heat Warnings remained in effect for these regions through the afternoon as temperatures ranged between 95 and 100 degrees, with even higher heat index values. New York, Philadelphia, and Washington D.C. experienced temperatures in the mid-90s(F) this afternoon with heat indices reaching near the century mark. In the South, scattered showers with periods of heavy rain continued in southern Florida and the central Bahamas as a trough of low pressure with a moist tropical wave remained nearly stationary over the Florida Strait. Additional showers and thunderstorms continued in eastern Texas due moist southeasterly flow streaming in from the Gulf of Mexico.

Rain developed across the Pacific Northwest, while scattered thunderstorms moved into the Northeast on Friday. In the West, a low pressure system off the West Coast pushed a cold front into the Pacific Northwest. This brought cooler temperatures and kicked up widespread rain showers across Washington, Oregon, and northern California. Rainfall totals ranged around a half of an inch across the California and Oregon border. Strong winds developed ahead of this front, with gusts up to 30 and 40 mph at higher elevations. Meanwhile, high pressure over the Southwest maintained hot and dry conditions. In addition to the increased winds ahead of the cold front, this allowed for fire danger to remained high for the Southwest, Great Basin, and Four Corners. In the East, a cold front moved into the Northeast and Mid-Atlantic states from the Midwest. This system pulled in moisture from the Atlantic Ocean and produced scattered showers and thunderstorms throughout the day. Some of these storms have turned severe with strong winds and large hail. Nickel to quarter size hail was reported in Lenoir, North Carolina, while wind gusts up to 60 mph were reported in Poland, Maine. Rainfall totals reached up to 1.74 inches in Frenchville, Maine. In the Gulf of Mexico, a low pressure system brought more heavy rains and scattered thunderstorms to the Yucatan Peninsula, western Cuba, and southern Florida, and remained at a high, 70% chance of tropical cyclone development.

 

24^th-30^th…Tropical Storm Debby remained the big weather story for the country Monday as it moved very slowly toward the Florida Panhandle. The main problem associated with Debby continued to be the significant rain and thunderstorms that it produced throughout the Sunshine State. In addition to the up to 10 inches of rain that fell on the state Sunday, an additional up to 5 inches of rain fell on the state Monday. Rain will continue to fall while Debby remains in the eastern Gulf of Mexico just south of the panhandle. The most recent track of Debby calls for very slow movement to the northeast over the next few days with a possible landfall Thursday morning south of Perry, Florida. The other main weather development was the tremendous heat wave that continued to grip the Plains. Widespread temperatures in the triple digits were noted from Texas through Kansas and Colorado. This heat wave will be long-lasting and eventually spread to the east through the rest of the week. The Northeast rose into the 70s and 80s, while the Southeast saw temperatures in the 90s and 100s. The Southern Plains and Southwest saw temperatures in the 100s, while the Northwest rose into the 70s and 80s.

Tropical Depression Debby became situated about 90 miles east of St. Augustine, Florida Wednesday afternoon. The system moved away from Florida, toward the east, at about 10 mph with maximum sustained winds near 35 mph and higher gusts. Elevated water levels in areas of onshore winds along the southwestern and northeastern coasts of Florida began to subside today, while rainfall associated with Debby continued to diminish across the Florida Peninsula. Meanwhile, to the north, wet weather continued in Upper New England on Wednesday as a low pressure system lingered over the region. Wrap around winds associated with this system continued to draw moisture inland from the Atlantic and stirred up light to moderate rain in Maine through the afternoon. To the west of this activity, hot and dry conditions continued from areas of the Ohio Valley and southern Upper Great Lakes through the Central and Southern Plains. A variety of Heat Advisories, Excessive Heat Warnings, and Red Flag Warnings remained in effect for much of these areas through the day. Meanwhile, a frontal system associated with a low pressure system in southern Saskatchewan reached across the Upper Midwest and the Central Plains into the Great Basin this afternoon. While this system remained pretty dry during the early afternoon, showers and thunderstorms were expected to accompany this system later in the afternoon and evening as it progresses eastward. Further west, monsoon moisture spread across the Southwest and the Central Rockies and created chances of showers and thunderstorms during the afternoon.

A heat wave continued for the eastern half of the nation on Friday, with heat advisories in effect from the Central and Southern Plains through the East Coast. A ridge of high pressure over the Southeast continued to push warm and moist air in from the Gulf of Mexico. This allowed for warm temperatures to continue with highs reaching into the lower 100s and heat index values up to 110 degrees. To the north, a frontal boundary draped across the Northern US, and stretched from the Great Lakes and Midwest through the Northern Plains. Periods of heavy rainfall developed along this front, as well as scattered thunderstorm development. Some of these storms turned severe with strong winds and large hail. Wind gusts over 60 mph were reported in in northern Illinois and eastern South Dakota. Mostly pea size hail was reported in Lafayette, Indiana. Meanwhile out West, a trough of low pressure dipped in from the Gulf of Alaska and pushed a cold front through the Pacific Northwest. This kicked up scattered rain showers throughout the day. Some of these rain showers stretched into far northern California. Heaviest rainfall associated with this system was reported in Quillayute, Washington with a mid-day total of 1.04 inches of rain. Near the Gulf Coast, onshore flow from the western Gulf of Mexico pushed abundant moisture into southeastern Texas. This produced periods of heavy rainfall and strong thunderstorms. Rainfall totals ranged from 1 to 2 inches across the Texas coast.

A "super derecho" of violent thunderstorms left a more than 700-mile trail of destruction across the Midwest and mid-Atlantic on Friday, cutting power to millions and killing thirteen people. More than 600 damaging wind reports were received by NOAA's Strom Prediction Center as the derecho took roughly 12 hours to race from northern Indiana to the southern mid-Atlantic coast. A derecho is defined as a widespread and long-lived wind storm that accompanies rapidly moving showers or thunderstorms. The most severe derechos are given the adjective "super." Winds gusted to 91 mph (equal to that of a category 1 hurricane) at the Fort Wayne International Airport, Ind., Friday afternoon. As the derecho maintained its violent nature, an 81 mph gust was then measured at Tuckerton, on the southern New Jersey coast, early Saturday morning. Downed trees dominated the damaging wind reports and led to the deaths of 13 people, according to Fox News. One of the multiple trees that crashed into homes in Springfield, Va., killed a 90-year-old woman as she was sleeping in her bed, according to the Associated Press. A few hours earlier, a falling tree outside of North Middletown, KY., (located east-northeast of Lexington) killed a man who was attempting to clear some tree limbs off a road. Two boys died by a pine tree fell onto a tent at Parvin State Park, N.J. Damage on Friday was not confined to downed trees. Power poles were also snapped, while some structures sustained damage. At least four semi-trucks were blown over by the winds on I-75 between Findlay and Bluffton, Ohio. States of emergencies have been declared in Virginia, West Virginia and Ohio. With 2.5 million in the dark, Virginia Gov. Bob McDonnell stated that his state experienced its largest non-hurricane power outage in history. Friday's super derecho was triggered by a ripple in the jet stream and fueled by the intense heat that caused Washington, D.C., to set a June record high and Columbia, S.C., to break its all-time record on Friday. Derechos typically strike the lower Midwest states once every year, according to the SPC. The occurrence of derechos, however, are quite rare across the mid-Atlantic, south of Philadelphia. On average, this region endures a derecho once every four years. One of the most recent significant derechos to slam the United States occurred on May 8, 2009. This weather phenomena traveled more than a thousand miles in 24 hours from southeastern Kansas to the southern spine of the Appalachian Mountains. Destruction from the May 2009 derecho totaled millions of dollars with numerous injuries and several deaths reported. One main difference between the May 2009 derecho and Friday's is the number of tornadoes spawned. Forty-five tornadoes were sighted in May 2009, while there was only one unconfirmed report of a tornado on the ground in Newcomerstown, Ohio, Friday afternoon. Winds in the strongest derechos can top 100 mph. The derecho that tore through Wisconsin and Lower Michigan on May 31, 1998, produced a 128 mph wind gust in eastern Wisconsin.

Jim G. Munley, jr.
http://www.jimmunleywx.com