NATIONAL WEATHER SUMMARY

 

JANUARY 2012

 

1^st-7^th…The Midwest and Mississippi River Valley remained sunny and unseasonably warm on Friday. A ridge of high pressure continued to build from the Plains over the Mississippi River Valley, and into the Eastern US. This brought plenty of sunshine which allowed for temperatures to reach into the 40s across the Upper Midwest, while the Midwest and Mid-Mississippi River Valley reached into the 50s and 60s. In the Northeast, however, a series of weak frontal boundaries moved from the Great Lakes and into the Northeast. This kicked up a few more light and scattered snow showers. To the South, high pressure over the Gulf of Mexico and Southeastern US created onshore flow from the western Gulf of Mexico into eastern Texas. This produced scattered showers and thunderstorms, most of which remained just offshore. Rainfall totals have remained less than a tenth of an inch for Brownsville, Texas and South Padre Island, Texas.

In the West, a trough of low pressure and associated cold front moved eastward from the Pacific Northwest, into the Rocky Mountains, but another cold front quickly moved in behind it. This brought light rain showers to Oregon and far northern California. This system had little available moisture, thus rainfall totals were light and evaporated before it reached the surface in most areas. A few areas saw light snow showers at higher elevations across the region.

 

8^th-14^th…The most active weather in the country on Monday occurred along the Gulf Coast as a storm developed along the coast of Texas. This storm pulled a bunch of moisture into Texas and the Lower Mississippi Valley and produced widespread rain and even some snow showers in the colder air over western Texas and New Mexico. This prompted Winter Storm Warnings for western Texas. Meanwhile, a persistent high pressure system continued to promote extremely dry conditions throughout the West. The current dry period has been record-setting in its duration and is stoking fears of droughts in the region. The East continued its dry streak as well for most areas. The one exception to this was in the Mid-Atlantic as a mixture of rain and snow fell from Kentucky through Virginia. The rest of the country remained dry in what has already been a very dry winter. The Northeast rose into the 20s and 30s, while the Southeast saw temperatures in the 60s and 70s. The Upper Midwest rose into the 30s and 40s, while the Rockies saw temperatures in the 30s and 40s. The Southwest rose into the 60s and 70s.

Wintry weather persisted across the Northeast on Friday, as a strong winter storm moved over the region. A low pressure system continued to move northeastward, and into eastern Canada. Flow around this system pulled moisture in from the Atlantic Ocean, which triggered rain and freezing rain showers along the coast of the extreme Northeast. Colder temperatures behind this system allowed for snow showers to develop across the Great Lakes, Ohio River Valley, and the interior Northeast. Most areas saw 1 to 3 inches of new snow, while downwind shores of the Great Lakes reported 4 to 7 inches of new snow. High pressure over the Plains built eastward over the Mississippi River Valley. This brought cooler temperatures and strong winds to the Midwest. Wind gusts have ranged from 20 to 30 mph from Missouri through Indiana. To the north, a weak trough of low pressure quickly moved into central Canada. The system pushed a weak frontal boundary through Montana and into the Northern Plains. This kicked up scattered snow showers across northeastern Montana and western North and South Dakota. Further west, a low pressure system that developed in the Gulf of Alaska approached the Pacific Northwest. This pushed clouds onshore with a few light and scattered showers, but most of the precipitation remained offshore. The rest of the Western US remained under a strong ridge of high pressure. This brought another sunny and dry day to California and the Southwest.

 

15^th-21^st…A major winter storm moved into the Pacific Northwest on Wednesday and brought areas of coastal rain, very significant snowfall to the lowlands, heavy mountain snow, and strong winds gusting to 55 mph to the Washington, Oregon, and northern California coasts. A variety of Winter Storm Warnings, Winter Weather Advisories, and Wind Warnings remained in effect for these regions through the day. Snow accumulations of up to 2 feet were expected in the mountains, 8-16 inches were expected in the interior southwest valleys of Washington, and 3-8 inches were expected near the coasts from northwestern California through Washington. Heavy snowfall in the mountains combined with warming created possible avalanche conditions in the southern and central Cascades. Meanwhile, strong onshore winds carried ample Pacific moisture inland across the Northwest and supported heavy snow showers from the Northern Intermountain West, and the northern tier of the Central Great Basin into the Northern Rockies. Winter Storm Warnings and Winter Weather Advisories were in effect for these regions in anticipation of today's snowfall. East of the Continental Divide, a few pockets of light to moderate lake effect snow showers formed downwind of the Great Lakes, while generally drier and calmer weather conditions developed throughout much of the East as high pressure became the dominant of the region. Windy weather conditions continue in the Northeast as low pressure lifted further into eastern Canada. An associated cold front extended through the western Atlantic Ocean and across northern Florida, triggering showers in the Florida Peninsula.

More heavy snow persisted across the West, while severe weather developed in the Southeast. A low pressure system moved from the West Coast and into the Rocky Mountains. This continued to push ample moisture onshore from the Pacific Ocean, while a cold front draped across the Rockies. This combination allowed for heavy snow showers to develop across the Great Basin and Central Rockies, with lighter snow in the Northern Rockies, Pacific Northwest, and high elevations of California. Snowfall accumulation ranged from 3 to 5 inches in the Northern Rockies, while 2 to 4 inches have been reported in the Sierra Nevadas. Heavier snow showers developed in the Great Basin with 10 to 14 inches of new snow reported in northern Utah. The Colorado Rockies saw a mid-day total of 3 to 6 inches of snow. Thus, winter weather advisories have been issued across most of the Western US. Additionally, strong winds accompanies this system with gusts from 50 to 60 mph at high mountain passes. Strongest winds have been reported up to 63 mph at Casper, Wyoming. Nearly white-out conditions created dangerous roads and travel across the Rockies. Meanwhile in the East, a low pressure system moved over the Tennessee and Ohio Valleys, and pushed a cold front into the Southeast. Warm and moist air poured in ahead of this system from the Gulf of Mexico and allowed for scattered showers and thunderstorms to develop from Alabama through North Carolina. Some of these storms turned severe. Quarter to golf ball size hail was reported in Columbus, Georgia, while numerous trees and power lines blew down in Senoia, Georgia.

 

22^nd-28^th…More rain and snow developed across the West, wintry weather moved into the Great Lakes and Northeast, and severe weather popped up across the Southeast on Monday. A low pressure system and associated cold front moved onshore from the Pacific Ocean and pushed a strong cold front over California and into the Southwest. This brought more heavy rain and mountain snow to most of California, the Great Basin, and the Southwestern US. Rainfall totals have ranged from 1 to 2 inches, while snowfall in the Sierras ranged from 5 to 8 inches. The Great Basin and Four Corners saw 2 to 5 inches of new snow. Winter weather advisories have been issued from California through Colorado and Arizona. High wind advisories have been issued in some areas of the Southwest, due to strong winds with gusts from 50 to 60 mph. Meanwhile in the East, a low pressure system moved over the Great Lakes and produced a wide area of snow, freezing rain, and rain showers from northern Minnesota through New York and Pennsylvania. Snowfall accumulation reached up to 4 inches along downwind shores of the Great Lakes. Meanwhile, the system produced a cold front that extended down the Eastern Seaboard. This pulled in additional moisture and energy from the Gulf of Mexico, which lead to heavy showers and thunderstorms, some of which have turned severe. Heaviest rainfall was reported in Scottsboro, Alabama with a mid-day total of 0.55 inches and strong winds have blown down multiple trees and power lines in Millbrook, Alabama. Tornadoes have also been reported: one in Greenville, Alabama and one in Claton, Alabama.

The eastern half of the nation saw an active weather day on Thursday, with snow in the Northeast and thunderstorms in the Southeast. A low pressure system that developed over the western Gulf of Mexico continued on its northward track over the eastern Valleys. This system produced a warm front that led it into the Ohio River Valley and Northeast. Snow and freezing rain showers developed to the north of this front, while rain showers developed along and south of this front. Snowfall accumulation ranged from 1 to 3 inches from northern Illinois to western Pennsylvania. Heaviest rain was reported in Wright-Patt Air Force Base, Ohio with a mid-day total of 1.18 inches of rain. At the same time, a strong cold front extended south of this system, and continued to sweep through the Southeastern states. Abundant moisture and energy fed this system from the Gulf of Mexico, which allowed for heavy rain and strong thunderstorms to develop. Some of these storms have turned severe with strong winds and hail. Multiple power lines were blown down in Venice, Louisiana, while rainfall totals reached up to 2.24 inches in McComb, Mississippi. Tornadoes have not yet developed, but tornado watches have been issued across most of Alabama. Elsewhere, a low pressure system over the Northwest pushed a cold front through the Idaho and into the Great Basin. This produced a wide swath of rain, freezing rain, and mountain snow. Western Montana and Idaho reported 2 to 4 inches of new snow, while light flurries persisted across the Pacific Northwest. A few light rain showers developed along the tail end of this system in northern California.

 

29^th-31^st…Another fairly mild day greeted the Lower 48 states Monday as the mild and dry Winter continued. The heaviest precipitation fell in the Northwest as a high pressure system that has kept California and the Southwest dry pushed a storm into the Pacific Northwest. This storm produced rain and high elevation snow from the coasts of Washington and Oregon through northern Idaho and Montana. Any precipitation is good news as the majority of the country has experienced below normal precipitation. Meanwhile, snow fell through the Upper Midwest ahead of a warm front that was set to move through the area later in the afternoon and evening. Breezy conditions accompanied by low relative humidity instigated high fire danger in the Southeast, especially Alabama. This is a testament to how dry the air is in the region. Aside from a few snow showers, the Northeast was dry as well due to a high pressure system.

Mild air in the Plains allowed afternoon temperatures to shoot up 30 degrees above normal. To find the truly cold air, one would have to travel to Alaska where temperatures have been greater than 50 degrees below zero. The Northeast rose into the 20s, 30s, and some 40s, while the Southeast saw temperatures in the 60s and 70s. The Upper Midwest rose into the 30s and 40s, while the Plains saw temperatures in the 60s and 70s. The Northwest rose into the 40s and 50s.

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