Weather Underground Forecast for Monday, December 17, 2012.
A complex storm system will maintain unsettled weather activity in the East on Monday, while disturbances from the Pacific Ocean move inland across the West with ample moisture and wet weather conditions.
In the East, the parent low of the complex storm system will lift northeastward from the Upper Great Lakes into Ontario, Canada on Monday. As the system progresses, cold air will support a wintry mix of precipitation with areas of rain, freezing rain, sleet, and snow near the Northeast and southeastern Canadian border. Snow in the Northeast may be heavy at times and is expected to leave behind snow accumulations of 3 to 9 inches, while freezing rain and sleet create up to a tenth of ice accumulation. Meanwhile, a stronger low associated with this complex storm will strengthen over the Tennessee Valley. Light to moderate rain showers will develop near the low across the Tennessee Valley into the Ohio Valley and the Mid-Atlantic with chances of showers spreading into Lower New England as the system lifts northeastward toward the Central Appalachians. Thunderstorms in Tennessee and Kentucky may turn severe during the afternoon with hail and damaging wind gusts. This low will pick up strength as it heads northeastward and reaches New England and the interior Northeast with heavy rain and significant snow Monday night into Tuesday. To the south, the strongest convective activity will remain ahead of an associated cold front that will begin the day extending from the Tennessee Valley low to the Central Gulf Coast. As the energetic cold front advances eastward toward the Atlantic Ocean, clusters and bands of rain and thunderstorms are expected along and ahead of the cold front across the southeastern quadrant of the nation. Much of the Southeast and the Carolinas are at slight risk of severe thunderstorm development through the afternoon and evening hours. Fast moving supercells in the region may trigger damaging wind gusts and isolated tornado threats.
Out West, a series of Pacific disturbances will move inland, bringing significant rain, snow and high winds to the Pacific Northwest, California, and the Intermountain West. Moderate and heavy rains will impact the coastal areas and lower valleys of the Northern California and the Pacific Northwest, while cold temperatures support lower snow levels and heavy snows in the inland mountains and across areas of the Intermountain West. A variety of High Wind Advisories and Warnings, Winter Weather Advisories, Winter Storm Warnings, and Blizzard Warnings will remain in place over the northwestern quadrant of the nation as these disturbance move inland.
Temperatures in the Lower 48 states Sunday have ranged from a morning low of -17 degrees at Clayton Lake, Maine to a high of 84 degrees at Weslaco, Texas