NATIONAL WEATHER SUMMARY

 

MAY 2013

 

1^st-11^th…A major Spring storm moved through the Rockies Wednesday, providing weather more fit for Winter. Snow fell in the Northern Rockies and into the Plains as the storm strengthened, and Winter Storm Warnings were posted for southern Minnesota and adjacent areas of Wisconsin due to the anticipation of up to a foot of new snow in the area by the end of Thursday. This storm is extending a cool and wet spring for the Plains and parts of the Midwest. This storm will continue to move into the Plains Thursday, allowing snow to fall from Colorado to Minnesota. Cool air will filter into the Southern Plains and Southwest, bringing temperatures in the 20s. Freeze Watches are posted for the area. Meanwhile, another storm along the Gulf Coast swept Gulf of Mexico moisture into the Southeast and Florida. This moisture provided wet weather in the form of heavy rain and thunderstorms for the southern half of Florida. Meanwhile, a building high pressure ridge continued to provide pleasant to warm conditions for California and the Southwest. These warm conditions will continue for the next several days, with some inland areas of Central California experiencing their first triple digit heat of the year.

A pair of storm systems affected the country on Wednesday, bringing active weather to some areas. The first storm moved northward through the Southeast and Appalachian Mountains Wednesday, bringing areas of light to moderate rain from North Carolina through New England. Upwards of 3 inches of rain fell on parts of the Northeast, with over 3 inches in Central Park, NY by mid afternoon. This storm will continue to weaken throughout the rest of the day and into Thursday, allowing precipitation to diminish. The second storm moved through the Rockies and into the western Plains. This storm was not as strong as the previous storm that brought several inches of snow to the Plains and Upper Midwest, but scattered rain and even some thunderstorms were noted from eastern Colorado through Minnesota. A few showers continued in the West, but the region remained mostly dry as a high pressure system began to build once a low pressure system moved out of the area. This high pressure system will provide a warming trend that will last into the weekend, with temperatures pushing into the 90s and some 100s for the Southwest. The Northeast rose into the 60s and 70s, while the Southeast saw temperatures in the 70s and 80s The Southwest rose into the 70s and 80s, while the Northwest saw temperatures in the 60s and 70s.

Showers and thunderstorms developed over the Eastern States on Friday, while severe thunderstorms developed in eastern Texas. The storms developed along a strong cold front that stretched from a low pressure system over the Great Lakes and Northeast, through the Eastern Valleys and Lower Mississippi River Valley, into the central Texas. Heavy rainfall, strong winds, and large hail was reported from the Lower Great Lakes through central Texas as some of these storms have turned severe. Quarter size hail was reported at Houma, Louisiana, and Houston, Texas while 60 mph winds were reported at Bay City, Texas. Heaviest rainfall was reported at Beaumont, Texas with a mid-day total of 4.95 inches of rain. This caused major flooding for southeastern Texas and southern Louisiana. This system has a history of producing tornadoes, but they have not yet been reported with this system by mid-day on Friday. Meanwhile out West, shower and thunderstorm activity diminished over the Rockies and Western states throughout the day as higher pressure build over the West Coast and pushed moisture away to the east. A few widespread showers and thunderstorms persisted across the Rockies from Montana through New Mexico, but severe thunderstorms and heavy rainfall has not developed. To the north, a weak cold front moved over the Northern Plains and Upper Midwest, which brought a few scattered showers to North Dakota and northern Minnesota.

 

19^th-25^th…Heavy rains and chances of severe thunderstorm activity continued for areas of the Plains into the Midwest on Tuesday as a broad, nearly stationary low remained over the Northern Plains. As the system lingered, ample moisture streamed northward from the Gulf of Mexico, while an associated cold front reached from the low southward through Central and Southern Plains. The sharpening cold front combined with a dry line in the Southern Plains and the moisture laden conditions of the Central U.S. set the stage for multiple clusters of thunderstorms to develop across the Plains and into the Mid-Mississippi Valley. Portions of eastern/central Oklahoma, north-central Texas, northwestern Arkansas, southern Missouri, and far southeastern Kansas remained at moderate risk of severe thunderstorm activity as environmental conditions remained favorable for strong tornadoes, damaging wind gusts, and very large hail. Areas surrounding this moderate risk region from the parts of the central Texas into the Upper Great Lakes and Upper Mississippi Valley were at slight risk of severe thunderstorm development with hail and isolated tornadoes. Meanwhile, areas of heavy rain and widely scattered showers persisted near the low and its associated warm front in portions of the north-central U.S. Continued precipitation in this already saturate region combined with rapid runoff maintained flood concerns from parts of North Dakota into northwestern Wisconsin. Elsewhere, scattered showers and thunderstorms developed in the Mid-Atlantic and southeastern corner of the nation as a weak upper trough of low pressure dropped southward over the region. To the north, additional showers were possible in the Northeast.

Heavy rainfall and strong thunderstorms developed over southern Texas and northern Mexico on Friday, as onshore flow from the Gulf of Mexico maintained warm and humid conditions. Rainfall totals reached over 2 inches by mid-day for the region. Uvalde, Texas saw a mid-day total of 2.06 inches of rain. Wind gusts up to 50 mph also accompanied this system. To the north, showers and thunderstorms developed over the Plains as a broad low pressure system moved off the Rockies and into the Plains. This pushed a warm front eastward, which allowed for showers and thunderstorms to pop up from North Dakota through Kansas. These storms have not yet turned severe but there was a slight chance of severe thunderstorm development across northeastern Colorado and into western Kansas and Nebraska. Large hail and strong winds were likely in these areas, with possibly a tornado or two. Meanwhile in the East, a trough of low pressure and associated cold front allowed for showers and thunderstorms to persist from the Mid-Atlantic states through Maine. Strong winds and heavy rainfall were reported from Pennsylvania through Maine. Out West, a trough of low pressure over the Pacific Northwest kicked up a few more scattered showers across Washington and Oregon, which moved into Idaho and western Montana.

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