NATIONAL WEATHER SUMMARY

 

MARCH 2012

 

 

1^st-10^th…Saturday is a much quieter day compared to Friday's huge tornado outbreak that swept through parts of the Midwest and South. The cold front that was responsible for the disaster on Friday continued to advance eastward and brought strong to severe showers and thunderstorms and high winds across the Deep South, Mid-Atlantic and Southeast on Saturday. Several tornadoes developed over southern Georgia and the Florida Panhandle, which destroyed homes and knocked down power lines and large trees. In addition, hail and strong winds also occurred over parts of the Southeast. Farther north, the storm system over the Ohio Valley moved northward into the Great Lakes Saturday. A mix of rain and snow fell from the Upper Midwest and Great Lakes to the Northeast. The heaviest was over northern Michigan and central New England. Moving to the West, moist onshore flow aided in producing light rain and high elevation snow over parts of the Pacific Northwest. Also, light snow developed over portions of the northern and central Rockies. Temperature wise, much colder air filtered through the central and eastern sections of the nation Saturday after that devastating cold front moved through. Highs over the Midwest were only in the 20s and 30s, while the Southern Plains and Deep South, except southern Texas, experienced highs in the 50s and 60s only.

A long cold front was the main weather producer in the country Friday. This front pulled moisture northward from the Gulf of Mexico, instigating widespread moderate to heavy rain along thunderstorms from eastern Texas through Mississippi. As the front moved into the Gulf of Mexico in the afternoon, it lost most of its moisture. Farther to the north, a smaller cold front moved through the Upper Midwest and into the Northeast. This front was mainly lacking any significant moisture, thus only scattered snow showers were observed from Michigan through New York. The cold temperatures were limited to the Upper Midwest as afternoon temperatures only rose into the 20s and 30s. A cool pocket was also observed in New Mexico with temperatures in the 30s and 40s. Much of the West was once again under the influence of a high pressure system that providing widespread dry conditions. The hottest region in the country was the Desert Southwest as Southern California and Arizona saw temperatures in the 60s, 70s, and some 80s.

 

11th-17^th…The only notable storm system to affect the country on Monday began the day over the Central Plains before it moved northeastward into the Upper Midwest. While this storm did produce some severe weather in the Lower Mississippi Valley on Sunday, it was mostly lacking significant moisture Monday. Instead, only light to moderate showers were noted from the central Gulf Coast through the Upper Midwest. In the afternoon, this rain diminished to showers along the Appalachians and parts of the Great Lakes. Breezy conditions accompanied this storm, but the wind was not strong enough to rise to advisory levels. Meanwhile in the West, the first in a series of storms to affect the region slammed into the Northwest. This storm brought rain and high elevation snow to Washington and Oregon, mainly leaving California dry until the evening. In addition, intense winds were expected for much of the Northwest, with the strongest winds likely in the high elevations. More storms are likely for the rest of the week, which is good news for the Golden State after a largely dry Winter. Generally mild conditions were experienced in the country with no major cold area. The Northeast rose into the 50s and 60s, while the Southeast saw temperatures in the 70s and 80s. The Northern Plains rose into the 40s and 50s, while the Northwest saw temperatures int he 30s, 40s, and 50s.

The entire nation saw significant weather on Tuesday, as the West saw rain and heavy snowfall, while the entire country east of the Rockies was in the midst of a very unusual warm spell. The Northwest saw the greatest snowfall amounts with snow levels dropping to near sea level in many places. Snow descended into northern California as well, where a dusting was reported throughout the high elevations. Further south, in the lower elevations, heavy rain was reported. Close to an inch and a half of rainfall was reported throughout coastal northern California with amounts around an inch inland. In the Sierra Nevada mountains, temperatures remained warm, but snow levels were between 4000 and 5000 feet. Snow was expected to continue throughout the next several days. Heavy rain made it as far south as the San Francisco Bay Area, but tapered off to the south. Rainfall was noted south through the Central Coast of the state, but light accumulations were reported. East of the Rocky Mountains, extremely warm temperatures were reported. Highs in the Plains reached 30 degrees or more above normal in some locations, while the eastern coast experienced highs 10 to 20 degrees above normal. The warmth wasn\'t as pronounced in the Southeast, as average highs for this time of year are warmer. In addition to the warm weather, relatively clear skies were noted for most of the region, except for northern New England, where clouds brought some moderate rain and snow to Maine.

Much of the Eastern U.S. experienced another warm weather day on Wednesday, while wet weather activity continued in the West. Record high temperatures were likely for areas in the Midwest states this afternoon as high pressure in the western Atlantic maintained southwest winds across the region. Many cities were expected to see daytime highs up to about 35 degrees above normal. Chicago, which has a normal high of 46 degrees today and a record of 76 degrees (1995), was forecast to reach a high of 77 degrees. Another example is Kansas City, Missouri. The city was forecast to reach 88 degrees today, while the normal and record highs for the city are 54 and 82 degrees(1935) respectively. As for active weather in the East, areas of light freezing drizzle, sleet, and snow showers formed in parts of Maine through the afternoon. A Winter Weather Advisory remained in effect for the northern half of the state as snow accumulations of up to 1 inch along with up to a tenth of an inch of ice are anticipated. To the south, isolated showers and thunderstorms continued to pop up near the Southeast coast today as disturbances pushed through the region. In the West, coastal and valley rain and high elevation snow continued across areas of the Northwest and northern California as a lingering trough of low pressure continued to send frontal disturbances toward the Pacific Northwest coast with ample moisture. Winter Storm Warnings and Winter Weather Advisories remained in effect for western Washington and northwestern Oregon.

 

18^th-24^th…Active weather began to ramp up across the central U.S. on Monday as a cold front moved into the Plains and met ample moisture from the Gulf of Mexico. This combination kicked up significant rain and thunderstorms from northern Texas through eastern South Dakota and across parts of Arkansas and Missouri during the afternoon. These storms were expected to intensify through the rest of the afternoon. Areas of extreme western Arkansas, southeastern Oklahoma, and central/northeastern Texas remained at moderate risk of severe weather activity on Monday. The strongest of these storms were expected to produce damaging winds, large hail, and a few tornadoes. Meanwhile, areas from south-central Texas to Missouri and eastern Dakotas/western Minnesota remained at slight risk for severe weather activity through tonight. Elsewhere, light showers and thunderstorms formed in southern Wisconsin and parts of North Carolina, while above normal temperatures continued to dominate the eastern half of the nation. In the West, a trough of low pressure supported more areas of rain and high elevation snow from parts of the Southwest through the Northern Intermountain West and Northern Rockies. Winter Weather Advisories and Winter Storm Warnings remained in effect for the mountains of western New Mexico, southeastern Arizona, central Utah, and much of Montana. A Blizzard Warning remained in effect for Havre and Chinook, Montana through the rest of the day in anticipation of significant snow accumulation and gusty winds. Total snow accumulations of 4 to 8 inches remained likely over the Plains with 10 to 20 inches in the mountains. Visibilities were expected to be below half a mile and near zero at times as gusty northwest winds of 25 to 40 mph with gusts to 60 mph create periods of blowing snow. Elsewhere, rain and light snow continued in the Pacific Northwest.

Severe weather moved over the Mississippi River Valley on Friday, as a low pressure system moved in from the Plains. A strong low pressure system advanced eastward from the Plains and pushed a cold front over the Mississippi River Valley and into the Eastern Valleys. This system pulled warm and moist air in from the Gulf of Mexico, which triggered moderate to heavy showers and thunderstorms. Some of these storms turned severe with tornadoes reported in southern Illinois and southeastern Missouri with multiple reports of large hail across the region. Heaviest rains developed along the southern side of this system, due to ample Gulf moisture. Rainfall totals surpassed 3 inches across southern Louisiana.

Behind this system, temperatures have decreased across the Plains and Midwest and dry conditions returned as high pressure built in. However, ahead of this system, unseasonably warm temperatures persisted along the East Coast. Highs have reached into the mid-70s in parts of the Northeast, while the Mid-Atlantic states remained in the lower 80s.

Meanwhile out West, a cold front brought a few snow showers to the Northern Rockies with snowfall accumulation from 1 to 3 inches. Further west, a strong low pressure system approached the West Coast but has not yet moved onshore. Thus, most of California and the Pacific Northwest saw a sunny and dry day.

 

25^th-31^st…A transitional weather day occurred in the country on Monday as a storm left the East Coast and another storm moved through the West. The storm that exited the East Coast provided diminishing rain to North Carolina, leaving the rest of the eastern third of the country dry.

 

Meanwhile, cold temperatures continued to pour into the Northern Plains and Upper Midwest. These areas experienced a record shattering Spring heat wave last week, but temperatures Monday were in the 40s and and 50s for the most part. In the West, a cool storm moved through the Intermountain West while also draping its cold front through the Southwest. This storm produced rain and high elevation snow from California through Idaho, but by afternoon its precipitation was mainly corned in the Intermountain West. Breezy conditions were noted in the Plains where Wind Advisories warned of southeast winds up to 45 mph. Winds this strong had the potential to cause property damage throughout the area. The Northeast rose into the 30s and 40s, while the Southeast saw temperatures in the 70s and 80s. The Upper Midwest rose into the 40s and 50s, while the Northwest saw similar temperatures.

Wintry weather moved through the Great Lakes, while more rain and mountain snow developed over the Northwest on Friday. A low pressure system moved from the Plains and up the Ohio River Valley. This pushed a warm front over the Midwest, which triggered scattered showers and thunderstorms throughout the day. Cooler temperatures along the northern side of this system allowed for freezing rain and snow showers to develop across Michigan. The southern side of this system pulled a cold front through the Southern Plains and into the Lower Mississippi River Valley. Moisture poured in ahead of this front from the Gulf of Mexico, which produced moderate to heavy showers and thunderstorms across the Southeast. Heaviest rainfall was reported in Tupelo, Mississippi with a mid-day total of 2.48 inches of rain. Behind this system, a ridge of high pressure built over the Plains and created warm and dry conditions. Dangerous fire weather conditions became a concern due to low humidity, warm temperatures, and strong winds. High temperatures ranged 15 to 25 degrees above seasonable for the Northern and Central High Plains.

Meanwhile in the West, heavy rain and heavy mountain snow showers developed across the Pacific Northwest, northern California, and moved into the Intermountain West and Northern Rockies. Flooding remained a concern for the region due to heavy rain and early season snow melt. Mid-day rainfall totals ranged around an inch across northern California, with 2 to 5 inches of snow reported at high elevations.

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