Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
301 PM EST Tuesday Dec 1 2015
showers across the area will diminish west to east late tonight
and Wednesday morning. An upper disturbance will bring scattered
snow showers later Wednesday night into early Thursday.
Near term /through Wednesday/...
occluded front moving into eastern Ohio as stacked low pressure
moves into the western Great Lakes. Eastward movement of front
will be slowed by developing waves of low pressure moving
northeast along the front...and this will keep likely to Cat probability of precipitation
basically from the northern West Virginia Panhandle eastward
tonight...tapering to chance probability of precipitation into eastern Ohio. One more wave
of low pressure will race northeast early Wednesday keeping
likely probability of precipitation in the ridges into Wednesday morning. Chance probability of precipitation
elsewhere. Temperatures and probability of precipitation built using a multiple model
blend to reduce timing issues with developing waves of low
Short term /Wednesday night through Friday/...
parent closed middle level low will sweep across the eastern Great
Lakes Wednesday night and early Thursday. A swath of light snow
will accompany the main vorticity center with the low.
Accumulation of an inch or so across the I-80 corridor now looks
likely Wednesday night...with similar amounts in the ridges in
brief northwest flow behind the low during the early morning hours
Thursday. Elsewhere a coating on grassy surfaces is possible.
Snow showers will diminish quickly Thursday as middle level low
exits and surface high turns flow quickly to the west.
Temperatures will remain relatively mild Wednesday ahead of
system and then cool to near seasonal norms Wednesday night into
Thursday with cold advection. Cool and dry high pressure for
Long term /Friday night through Tuesday/...
surface high pressure over the region should keep weather quiet
through the weekend. Low pressure is expected to develop along the
southeastern Atlantic coastline and move up the East Coast Monday
into Tuesday. Appears that the bulk of the rainfall will remain
east of the region...but will continue some chance probability of precipitation depending
on where the western edge of precipitation reaches. Temperatures
will remain above normal for this time of year. Grids were based
on blended guidance.
Aviation /20z Tuesday through Sunday/...
ceilings will continue to range from LIFR to low MVFR through much
of the afternoon into the evening hours. One round of showers can
be expected this afternoon...with another round of rain possible
as a cold front moves across the region this evening. The front
will shift winds from south-southeast to westerly. Although a dry
slot should move into the region behind the front...not sure
whether the drier air will make its way to the surface...and have
kept lower ceilings a few more hours than previous taf issuance.
Ceilings should rise above IFR everywhere but fkl/duj by
Outlook...Wednesday night through Sunday/...
restrictions are likely through Thursday as an upper low crosses the