Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
1245 PM EST Monday Mar 2 2015
dry conditions and well below normal temperatures can be expected
today before a storm system brings warmer temperatures and the potential
for heavy rain Tuesday and Tuesday night. A period of sleet and
freezing rain will be possible early on Tuesday with ice
Near term /until 6 PM this evening/...
1010 am...back edge of snow now progressing into County Warning Area as shortwave
axis swings through and moisture dries up from the top down. Expect a
few more hours of shsn with negligible additional accumulation.
Lower clouds will slowly clear with time...although some high
clouds may start to arrive by later in the afternoon. Minor tweaks
to afternoon temperatures.
Dry conditions expected through the day as high pressure
transitions quickly over the area...and temperatures will change
little with persistent cold air advection behind the front.
Daytime maximum temperatures will be only several degrees warmer than current
readings...and winds will decrease this afternoon as the high
centers over the area.
Short term /6 PM this evening through Wednesday/...
temperatures will fall overnight to the single digits across the
north and upper teens over southern zones as timing of warm air
advection ahead of the next frontal system has been pushed back
slightly. Shortly after sunrise precipitation will begin to
overspread the region from south to north moisture advection and
warmer temperatures aloft along with the cold surface temperatures
will provide an ideal setup for freezing rain for a relatively
brief period before changing all over to rain. Held off on
advisories for now to limit confusion with current the black ice
Special Weather Statement...but expect headlines later today.
Precipitation will be persistent after changing over to rain..and
this combined with warmer air and higher dewpoints will support
snow melt until cold front passage on Tuesday night.
Small stream and river rises should be anticipated and some ice
cover is likely to pop...especially over southern basins.
Long term /Wednesday night through Sunday/...
most of the operational and ensemble solutions show the cold front
racing toward the East Coast Wednesday night. This would bring a
quick end to lingering snow showers behind the front.
Large area of high pressure will build in and provide a quiet but
cold end to the week. Temperatures begin to moderate on Saturday...but
by Sunday...forecast confidence wanes as model solutions
Aviation /18z Monday through Saturday/...
spotty MVFR conditions in shsn/flurries will continue for a few
more hours...ending when instability wanes later this afternoon.
VFR conditions are then expected tonight...but with lowering and
thickening clouds as time GOES on. Precipitation will arrive from
southwest to northeast after 12z. Snow is expected at the
start...but freezing rain and possibly sleet will mix in as well
Outlook.../Monday night through Friday/...
widespread restrictions are expected into Thursday with a
persistent moisture feed from the southwest.
an increase in flow and stage is expected to cause ice movement
starting Tuesday...beginning on the southernmost river basins. The
current forecast continues to have a high level of uncertainty about
precipitation phase and amounts as well as the degree of snow melt.