NATIONAL WEATHER SUMMARY

 

MARCH 3013

 

1^st-9^th…The Eastern half of the nation saw a chilly day on Friday with widespread snow showers. A ridge of high pressure that built over the East continued to push cold air in from Canada. At the same time, a weak trough of low pressure moved through the ridge. These systems in combination allowed for widespread scattered snow showers to develop from the Mid-Mississippi River Valley through the Ohio and Tennessee Valleys. Most areas saw a dusting of snow with accumulation from 1 to 2 inches, while some areas saw periods of freezing rain as temperatures warmed up during the afternoon. Higher elevations of the Central Appalachians saw up to 3.5 inches of new snow. Daytime highs ranged in the 30s to lower 40s, which is about 10 to 20 degrees below seasonable for the region. Frost and freeze advisories have been issued for the Southeast as overnight and early morning low temperatures dropped to near freezing.

Meanwhile, out West, a trough of low pressure moved over the northern Rockies and triggered widespread scattered snow showers. Isolated areas across Montana and Idaho saw around 1 inch of new snow. Further west, a system over British Columbia brought more rain and mountain snow showers to Washington. Mid-day rainfall totals ranged around a half of an inch. High pressure over the rest of the West Coast and Southwest created offshore flow and warming temperatures. High temperatures ranged from the mid-60s to mid-70s for much of California.

Precipitation diminished in the East on Friday, while a strong winter storm moved across the Southwest. A low pressure system moved over southern California and into the Desert Southwest and brought abundant moisture in from the Pacific Ocean. This triggered heavy rain showers and high elevation snow showers across the southern half of California, far southern Nevada, most of Arizona, and into Utah, Colorado, and New Mexico. Heaviest snowfall was reported in Forest Lakes, Arizona with a mid-day total of 11 inches, while rainfall totals ranged from 1 to 2 inches across southern California and Arizona. As this system advanced northeastward throughout the day, the storm pushed moisture into the Great Basin as well as the Central and Southern Rockies, and produced increasingly heavy precipitation. Winter storm advisories have been issued from the Southwest through the Upper Midwest. At the same time, the leading edge of this system pulled moisture in from the Gulf of Mexico, which allowed for scattered showers and thunderstorms to pop up across the Southern and Central Plains. These storms have not yet turned severe, but there was a chance of severe thunderstorm development in northern Texas. In the East, a strong low pressure system slowly moved offshore, allowing for heavy rain and heavy snow showers to taper off for the coast of New England from New Jersey through southern Maine.

 

10^th-16^th…Another winter storm continued across the Midwest on Monday and became centered over the Upper Great Lakes by the afternoon. Cooler temperatures to the north and west of this system supported a mix of light to moderate scattered rain and snow showers in the Upper Great Lakes. At the same time, an associated cold front moving pushing across the Eastern Valleys toward the Appalachians met with ample moisture from the Gulf of Mexico and allowed for more showers, periods of heavy rain, and thunderstorms to develop ahead of the front from the southern Great Lakes to the Central Gulf Coast. Areas of southern Alabama and the Florida Panhandle saw the greatest potential for thunderstorm development through the afternoon. Meanwhile, out West, a few scattered snow showers developed along and near a frontal boundary dropping across the Northern and Central Rockies.

Snow showers persisted for the ipper Midwest and Great Lakes on Friday, while another system slid across the Northern Plains throughout the day. A low pressure system moved over the Great Lakes and into eastern Canada. As this system advanced eastward, a cold front trailed behind the system to the west, which allowed for snow and freezing rain showers to spread from southern Minnesota, across Wisconsin, and into northern Illinois and Indiana. Snowfall totals in these areas ranged from 1 to 2 inches, with isolated amounts up to 4 inches. At the same time, another frontal boundary extended southeastward from the low pressure system and triggered scattered snow showers across New York State and parts of the Northeast. Heaviest snowfall fell along the downwind shores of the Lower Great Lakes. Behind these frontal boundaries, another system dropped into the Northern Plains from Canada. A trough of low pressure over Canada slid southward and brought cool and snowy conditions with it. This triggered heavy snowfall across most of North Dakota, far northern South Dakota, and moved into northern Minnesota. Snowfall accumulation ranged from 3 to 5 inches by Friday night. Winter weather advisories have been issued for the region from the Dakotas through the Upper Midwest, as dangerous roads and travel conditions affected these areas. Further west, a few light and scattered showers persisted for the Pacific Northwest and Rockies as onshore flow from the Pacific brought moisture into these areas. Significant precipitation has not developed. Meanwhile, the Southeast started to warm back up with temperatures in the mid-70s across the Eastern Valleys and Southeast. The Desert Southwest saw another warm day as highs reached into the mid- to upper 80s.

 

17^th-23^rd…A strong Pacific storm moved through the Northwest and California Wednesday, renewing rain and high elevation snow from Washington through Northern California. This storm was relatively warm, thus snow was reserved for the higher elevations of the Sierra Nevadas of California and Cascades of the Northwest. This rain and snow was very welcomed along the West Coast, especially in California where many areas have received much less rainfall that normal for this past winter. In addition to the precipitation, Wind Advisories warned of wind gusting to 65 mph, making travel dangerous at the higher elevations. In the Northeast, cold flow off Lake Ontario and Lake Erie produced scattered snow showers through the area. Meanwhile, a cold front moved from south Texas to along the Gulf Coast, aiding another round of scattered showers and a few thunderstorms to the area. This front was followed by a high pressure system that brought dry conditions through the Plains. The Northeast rose into the 30s and 40s, while the Southeast saw a range of temperatures from the 40s in the Tennessee Valley to the 70s in Florida. The Northern Plains rose into the 20s and 30s, while the Northwest saw temperatures in the 40s and 50s.

Snow spread from the Rockies and through the Plains on Friday, while showers and thunderstorms developed in the South. As a low pressure system moved off the Rockies and through the Plains, flow from the south pulled moisture in from the Gulf of Mexico. This allowed for scattered showers and thunderstorms to develop from the Southern Plains and across the Lower Mississippi River Valley. Periods of heavy rainfall developed in these areas with rainfall totals over 1 inch. The heaviest rainfall was reported at Monticello, Arkansas with a mid-day rainfall total of 1.68 inches. Meanwhile, cooler temperatures along the northern side of this system created snow showers across the Northern and Central Plains. Snowfall totals range from 3 to 5 inches across the Dakotas. At the same time, the back side of this system allowed for periods of heavy snow showers to persist across the Rockies and High Plains. Winter weather advisories remained in effect from Colorado through western Nebraska and Kansas as up to 7 inches were expected by Friday evening.

Meanwhile in the East, scattered snow showers continued over the Great Lakes and Northeast. A low pressure system pulled northeastward and away from the Northeast but allowed for a few scattered snow showers to persist from Pennsylvania through Maine. Snowfall accumulation ranged from 1 to 4 inches in these areas.

Snow continued across portions of the Midwest and picked up along the Mid-Atlantic and Northeast Coasts on Monday as the strong storm of the East lift northward. In the Midwest, generally moderate scattered snow showers continued from in the Ohio Valley and parts of the eastern Tennessee Valley on Monday as an area of low pressure over Kentucky lifted northeastward over the central Appalachians. Sufficient moisture and chilly temperatures over the region translated into possible snow storm conditions in these areas through the afternoon and evening. Thus far, storm totals of up to 4 to 10 inches have been reported in the impacted areas of the Midwest with locally higher amounts of up to 18.5 inches reported in southern Illinois. In addition to snow, gusty north and northeast winds cause areas of blowing snow, lowered visibilities, and potentially dangerous driving conditions. Meanwhile, the other portion of this late season storm lifted northward through the western Atlantic Ocean, remaining just offshore of the East Coast, through the morning and became positioned just east of Delaware this afternoon. This low strengthened and allowed strong winds to spread across the Mid-Atlantic and New England Coast with plenty of moisture. Areas of rain and snow developed along the immediate coastline, while cold temperatures supported snow showers across inland areas. More accumulating snow blanketed the higher elevations of the Central Appalachians. Snow accumulations of 6 to 8 inches were expected at elevations above 1,500 feet, while 4 to 6 inches of snow were anticipated elsewhere in the mountains. Out West, an upper wave of low pressure reached the Pacific Northwest and the northern tier of California with limited moisture on Monday, and created chances of light, isolated rain showers.

Thunderstorm activity spread across the southern Plains and Southeast on Friday, while widespread rain and snow spread from the Northern Rockies into the Northern Plains. A low pressure system moved off the Rockies and into the Plains, pulling Pacific moisture eastward with it. The back side of this system allowed for a few rain and snow showers to persist for the Pacific Northwest and northern Rockies, while the leading edge of this system brought showers into Northern Plains and Upper Midwest. Many areas saw a combination of rain and snow showers as temperatures were just above freezing before the system moved in and brought cooler air with it.

 

Meanwhile, to the south, a frontal boundary extended from the southern Plains through the Tennessee Valley. Moisture from the Gulf of Mexico brought energy into this system, and allowed for up scattered showers and thunderstorms to develop from northern Texas, through Arkansas, and into the Tennessee Valley. Some of these storms turned severe with large hail, strong winds, and periods of heavy rainfall. Heaviest rainfall was reported at Fort Leonard Wood, Missouri with a mid-day total of 1.09 inches of rain. There have been multiple reports of 1 inch in diameter hail across central Oklahoma.

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