Technical Discussion

Synopsis...

Lake effect snow will diminish throughout the day and tonight as pressure gradient relaxes and winds go more westerly.  Temperatures will remain very cold and below average as large dome of high pressure builds in from Midwest.  Temperatures in single digits this morning in IA/IL.  This airmass will moderate as it moves eastward but bring the chilliest air of the season the Commonwealth tomorrow and Thursday.  Weak clipper system to affect portions of region Friday night before large amplification of E-CONUS trough on Sunday/Monday which will spawn strong SFC low and bring us an eventful end to the weekend.

Near Term (Tues-Tues Night)...

Snow showers ongoing this morning across western portions of the state.  Expect this activity to persist throughout the day with isolated locations picking up an additional few inches of snow.  Winds will remain gusty and temperatures in the 20s and 30s.  Eastern portions of the state should see some more sun today and no snow making it a bit more bearable to walk around outside.  Temperatures drop off tonight and could fall nicely in areas with fresh snowpack.  Limiting factors to radiational cooling will be persistent cloud cover and winds.  It seems as if the places with the most snow pack will have the most clouds and places with least snow pack will be clear, allowing low temperatures to be fairly uniform across the state tonight in the teens to near 20 in the Southeast.

Short Term (Wed-Thurs)...

High pressure begins to take control on Wednesday as winds slacken and become westerly.  Temperatures will remain well below average even though eastern areas of the state will see a decent amount of sunshine (especially on Thursday).  Snow showers will be confined to the usual NW/NC zones on Wed allowing for a reprieve across central and southern areas.

Long Term (Fri-Sat)...

Clouds will increase on Friday ahead of weak clipper passing north of the region.  Some warm advection snow is possible on Friday night and looks to be mainly in the northern half of the state where some places could pick up a few inches.  Temperatures will moderate on Friday and Saturday as 850mb temps warm to -5C and 500mb ridge slides over the region.  Definitely not warm by any means but much closer to normal.  Weather pattern becomes very active again late in the weekend as shortwave dives out of the Rockies into the Plains.  Large discrepancies between the models at this point with eventual track of system and this has a drastic impact on p-type for our region.  GFS is the furthest east of the models with the low going from Nashville, up the Appalachians. This would be the more wintry scenario while the ECMWF argues for all rain as the low goes over Chicago.  The key for the track is when do the arctic and polar jets phase (farther east would be better for snow) and how amplified the ridge is in the West (flatter means snow more likely for us).  Storm is still 6 days away so refrained from mentioning any precip in the forecast although did mention storm possibility in discussion.  Whatever scenario pans out, next will will be bitterly cold (thicknesses near 510 with -20 C 850 temps) with lake effect snow showers.

-ddpdtdt