Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
244 PM EST Thursday Nov 27 2014
cold northwest flow will keep scattered snow showers across the
region tonight. High pressure will bring dry and chilly
Near term /through Friday/...
shortwave trough producing snow showers late this afternoon will
exit east toward sunset with a northwest fetch from the lakes
producing snow showers overnight. Inversion heights will allow for
some accumulating snow along the I-80 corridor and in the
ridges...with 1-2 across the north and 1-3 highest Southeast Ridge
elevations. Surface ridge will bring subsidence late tonight into
Friday with snow showers ending early morning. Still cold Friday
as surface high shifts east.
Short term /Friday night through Sunday/...
southwest low level flow will develop Friday night into Saturday
with upper level flow becoming more zonal. A shortwave and warm
advection will bring clouds and possibly a bit of light snow early
Saturday north of Pittsburgh. Temperatures will warm dramatically
Saturday night and Sunday ahead of an approaching upper trough and
cold front. Low level moisture will increase ahead of the front
allowing for scattered rain showers Saturday night and Sunday.
Temperatures will warm to over +5 at 850mb Sunday afternoon with
maximum temperatures well into the 50s Sunday.
Long term /Sunday night through Thursday/...
front will clear the area early Monday morning. Showers will end
but temperatures will cool down on Monday. Seasonable temperatures middle
week with the next disturbance and cold front arriving late
Tuesday and Wednesday. &&
Aviation /20z Thursday through Tuesday/...
MVFR conditions are expected through the afternoon as an area of
snow showers drifts southward in advance of a secondary cold
front. Occasional IFR visibilities are anticipated as this area of snow
moves across the taf site...thus tempo groups were added for the
next several hours with timing used from radar. Strengthening cold
advection and northwest flow will support lake enhanced and
upslope snows through tonight but current thinking is that
restrictions associated with snow showers will generally remain
confined to the northern sites. An improvement to VFR is expected
Outlook.../Friday through Monday/...
VFR returning by Friday as ridge builds eastward. The next chance
for restrictions will be Sunday with the passage of a cold front.