Area Forecast Discussion
Issued by NWS

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FXUS61 KPBZ 271744
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1244 PM EST Thu Feb 27 2020

.SYNOPSIS...
Scattered snow showers are expected through part of Saturday with
crossing upper level disturbances. Dry weather should return Sunday
under high pressure.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
8 AM Update...
Based on recent webcams, snowfall reports, and in collaboration with
neighboring offices, the Winter Weather Advisory has been amended to
a Winter Storm Warning for eastern Tucker County, WV. Periods of
snow should persist through the morning hours in conjunction with a
crossing shortwave, with a few additional inches of snowfall
expected given steep lapse rates through the dendritic growth zone.
Additional shortwave activity trekking through upper troughing should
support additional bouts of snow showers this afternoon through
evening. In addition, reduced visibility in blowing snow should
persist through the duration of the day as pressure gradient remains
tightly packed across the ridges.

Previous...
Numerous snow showers are expected this morning as a digging upper
trough moves across the Upper OH Valley region and the Lower Great
Lakes. Some decrease in coverage is expected later this morning as
the deepening trough axis exits, though the area will remain under
broad upper troughing through the day, maintaining at least scattered
snow showers. More numerous snow showers should persist for areas N
of I 80, and in the ridges, where lake and terrain enhancement is
also expected.

Expecting another 1 or 2 inches for a daytime accumulation N of I 80
and in the ridges, with less than an inch elsewhere. Will maintain
the Winter Weather Advisory as is in the ridges. A tightening
pressure gradient and mixing should also result in gusty winds to
around 35 mph areawide today, with gusts up to 50 mph in the WV and
MD ridges. After temperatures reach the morning low, little recovery
is expected through the day in cold advection.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
Upper troughing is progged to persist across much of the Eastern
CONUS through Saturday. Shortwaves rotating through the trough should
maintain scattered snow showers across the region. The boundary layer
flow backs to the WSW later tonight and Friday ahead of one of those
shortwaves, which should minimize the lake and terrain enhancement,
however a weak sfc wave crossing the OH Valley region could result
in some increase in the snow showers south of I 70.

The boundary layer flow is progged to become more WNW again on
Saturday, though lowering temperature inversions and the passage of
the upper trough axis should result in lowering chances for snow
showers.

The snow should end by Saturday night as high pressure builds in.
Temperatures are expected to be 5 to 10 degrees below average through
the period.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Ridging ahead of a Central/Wrn CONUS trough is progged to build
across the region Sunday with dry weather expected. Warm, moist
advection in WSW flow ahead of the approaching trough should return
mainly rain chances to the region Monday. Increasing rain chances
should then continue through Wednesday as the warm, moist advection
increases ahead of the slowly approaching trough. Temperatures are
expected to return to above average levels through the period.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...

Shortwave activity trekking across the region under upper troughing
will maintain a continued, convective environment where scattered to
numerous snow showers should continue to impact all ports through
tonight. This will result in the occasional deterioration to
low MVFR/IFR in heavier snow showers. In addition, steep low level
lapse rates should support the mix down of strong wind in snow
showers, assisting in the occasional reduction to visibility.

High resolution models indicate dry advection at mid and lower
levels overnight in westerly flow, which should help improve
restrictions to MVFR/VFR by Friday morning.

.Outlook...
Periodic snow showers under upper troughing will maintain occasional
restrictions in the forecast Friday afternoon through evening, with
building high pressure yielding the return of VFR Saturday.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...Winter Storm Warning until 7 PM EST this evening for WVZ514.

&&

$$


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