Area Forecast Discussion
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551
FXUS61 KPBZ 191146
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
746 AM EDT Thu Apr 19 2018

.SYNOPSIS...
Snow and rain showers will plague the region today with, and in
the wake of passing low pressure. Dry weather can then be expected
through early next week along with more seasonal temperature.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
No changes were needed for the predawn update.

Previous...
A crossing shortwave generated a widespread, albeit soft rain
last night, but the passage has initiated cold advection over
the region, and the next in series of disturbances will not be
so agreeable. Expect snow showers to develop toward, or shortly
after daybreak as the deeper trailing system reinitiates lift
and resultant precipitation.

The forecast has been altered considerably from previous to
account for the aforementioned frontal penetration as well as
quicker progression expectations as per the latest deterministic
trends. Expect more widespread snow showers, and some rain over
the south, during the first half of the day with diminished
coverage thereafter. No accumulation problems are expected given
filtered late-April sun, warm ground, and system progession, but
the convection will be accompanied by decent wind gusts of 20
to 30 mph, up to 40 mph on the highest elevations. A Wind
Advisory was considered for those areas, but deeper mixing did
not coincide with higher wind aloft and momentum transfer was
marginal at best.  Day shift will monitor.

As the HRRR handled the overnight shortwave and precip. well,
that solution was appropriated for this mornings POP trends with
only minor alterations. No real changes were needed/made to the
cold temperature forecast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
Friday and Saturday will be cool days of improvement as surface
high pressure builds under cold northwest flow. Expect highs
for those days 10 to 15 degrees under the averages respectively.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Split flow is projected over the CONUS next week with nrn
stream ridging and a progressing srn stream low forecast to
support dry conditions with a trend toward more seasonable
warmth for the Upper Ohio.

The next chance for precipitation now looks to be with the
advance of that srn stream low, which may shunt sufficient
moisture for some light rain by Tuesday night as it phases with
a more powerful nrn stream system. Confidence in the scenario is
not good given doubts about phase-timing.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Ceilings are expected to bounce between IFR and LIFR as snow
showers push through with this passing trough during the late
morning and ceiling levels at times drop below 500ft. As we
begin to dry out throughout the day, wind gusts aloft will make
their way to the surface--25 to 30 kts from the NNW.

Overall improvement can be expected tonight, but MVFR stratcu
will linger in the cold flow off the Lakes.

OUTLOOK...General VFR may then be anticipated through early next
week as high pressure builds.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.

&&

$$



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