Synopsis...
Strong high pressure over S. Canada will slide eastward tonight and tomorrow reinforcing the chilly air which will set the stage for a major winter storm on Tuesday and Wednesday. This prolonged event has the potential to bring all wintry precip types to the state with icing being a major threat. The typical northwesterly flow and mountain snow showers will follow in the wake of the storm for Thursday.
Near Term (Sun Night-Mon)...
Partly cloudy skies will persist overnight as high pressure moves in the region. Temperatures will be able to drop a lot tonight in most places due to the lack of cloud cover. Expect lows in the teens across much of the state with 20s S and E. Monday will begin fairly pleasant but cold as high pressure dominates. High clouds will overspread the region throughout the day and lower/thicken by evening as the first impulse from the approaching storm system nears the region. High temperatures on Monday will struggle to make it to freezing across the state.
Short Term (Mon Night-Wed AM)...
Lots to discuss with the upcoming storm system. First waves moves in on Monday night. Timing looks to be a bit after midnight in the west and near dawn in the east. Most areas should see at least a period of snow with this WAA precip but SE/CR/PM have the best chance of mixing with pl/zr by dawn on Tuesday. Total liquid is 0.3-0.6 for most of the state with this first wave and should lead to 3-5" of fresh snow across northern and central regions. Fairly good model agreement with this first wave although precip types/amounts still have to be refined for the zones. Will leave it to future shifts to fine tune the forecast :) Wintry precip will taper off to zr dz/flurries Tuesday afternoon. This respite would be a key time for road crews to clear roads because of much heavier precip coming at night. The next wave will start after dark across the west and move eastward quickly overnight. Total QPF is 0.6"+ with this system leading to a total of 1-1.5" total across much of the state total with the whole system. SREF means show this as well. Bottom line is that there is lots of consensus on generalities of this storm as well as the total precip. Hard part is nailing down the precip types/times of changeover. At this point our thinking is that LH/Centre Region/NE/NSQ have the best chance of significant icing with more sleet/snow in NC. SE/RV/CR/NW/PM should change to plain rain for a time on Tuesday night/ Wed morning as sfc temps rise above freezing. Strength of high pressure over Canada will be key to see how strong the CAD is during the course of the event. Still time to fine tune this forecast so did not get into specifics in the zone forecasts.
Long Term (Wed PM-Thurs)...
Storm departs quickly on wed afternoon and winds turn westerly, ushering in chilly temps and changing any leftover precip to snow showers and 850s crash to -10C by evening. The usual mtn snow showers will continue overnight and Thursday but winds will die down by Thurs as high pressure again takes control.
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Dan DePodwin
Pennsylvania State University
College of Earth & Mineral Sciences
Undergraduate of Meteorology
General Option; Forecasting Focus
Geographic Information Sciences Focus
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