Area Forecast Discussion
Issued by NWS -- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KPBZ 150551
Area Forecast Discussion
National Weather Service Pittsburgh PA
1251 AM EST Wed Feb 15 2017
A cold front and a subsequent crossing trough of low pressure
will return snow shower chances to the forecast through
.NEAR TERM /THROUGH TONIGHT/...
Latest radar loop shows a line of rain showers moving along
into northwest PA from the Lake Erie shoreline. These showers
are just ahead of a cold front that will drop through the area
later this morning. Hi-res models handling this line well, show
a continued eastward progression, with very little southward
expansion. This seems prudent given the dry air sampled by the
00z sounding last night.
Further upstream, snow showers are moving over Lake Erie,
accompanying the main push of colder air arriving aloft. Along
with the aforementioned line of rain showers, these will largely
stream eastward, due to the mean flow being nearly WSW. Still,
a southward expansion of low stratus is evident on satellite and
near-term guidance shows this moisture overtaking the northern
half of the forecast area. This should result in light snow
showers north of Pittsburgh and eventually into the Ridges as
moisture pools southward and inversions deepen. Snow
accumulations should remain light through the day, as residence
time of any snow showers will be fleeting.
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
NW flow and upper troughing should maintain scattered to
numerous snow showers across the area through Thursday. Lake
surface to 850mb temperature differences are progged to be
around 10 degrees on Wednesday, so minimal lake enhancement is
Colder air is progged to advect in Wednesday night and Thursday
increasing enhancement off the lakes, though temperature
inversion heights should be lowering, helping to limit
accumulations. More favorable moisture is progged in the snow
growth region over the ridges late Wednesday through early
Thursday. This combined with upslope flow should produce more
numerous snow showers in the ridges also, though lowering
inversion heights should also help limit accumulations. Through
the 48 hr period the a few inches of snow are possible mainly N
of PIT and in the ridges.
Building high pressure should end the snow showers Thursday with
dry and warmer weather expected Friday.
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Ridging should maintain dry weather through Saturday. A weak
trough is progged to track across the Carolinas Sunday though
most of the precip associated with it is expected to stay S o
the area. Ridging builds back across the Eastern CONUS early in
the week resulting in mainly dry weather and above average
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --VFR conditions are in place at the start of the forecast. A cold
frontal passage overnight will lead to dropping ceilings, into
the MVFR or low-end VFR range. Rain showers will quickly change
to snow showers, with these most numerous north of I-80 and down
the ridges through the day. MVFR to brief and isolated IFR
restrictions are possible in these showers. Northwest winds will
gust to between 15 and 25 knots during the late morning and
afternoon hours. Borderline MVFR ceilings will linger.
Restrictions are likely through Thursday as cold flow persists
out the Lakes Region.
-- End Changed Discussion --