FXUS61 KPBZ 250532

Area Forecast Discussion
National Weather Service Pittsburgh PA
132 AM EDT Wed Apr 25 2018

Occasional rain will continue until passage of a late Wednesday
cold front. Thursday will be dry, but another low will bring
rain for Friday.


Rain should continue to taper off overnight as a dry slot
advances N across the area. Scattered showers are expected to
develop Wednesday with the approach and passage of a cold
front/mid level trough. A much reduced temperature range can
be expected given the clouds with relatively warm overnight
lows, but cool daytime highs.


Low pressure riding up the eastern seaboard will be departing
Wednesday night. Precip will taper off from southwest to
northeast. It may take until Thursday morning before QPF leaves
Jefferson county PA . The column cools which could lead to wet
snow mixing in closer to dawn north of I-80 Thursday morning. As
of now, any accumulation will be on the grass, since there
could be a decent rate which would allow snow to accumulate.
High pressure pays a quick visit Thursday into Friday morning
before the next in a series of troughs moves overhead.

Differences on the track of low pressure and ability for
northern and southern branches to phase leads to below average
confidence for Friday. GEPS and GEFS keep surface cyclone east
of the mountains, which still would spread measurable QPF to a
good part of the area save for eastern Ohio. However there are
some operational members that have trended toward systems not
phasing thus bringing low pressure up the windward side of the
Appalachians. This would still result in measurable rainfall,
however it will be much more expansive and cover the entire
forecast area. Either way, the system is moving at a decent
clip, so no flooding is foreseen.

Temperatures will be below normal the entire short term.


- Below normal temps this weekend
- Damp Saturday north of US 422
- Dry and warm next week

Yet another full latitude trough develops over the eastern
CONUS. This will funnel in below normal temperatures Saturday
and Sunday as H8 temp plunge back below zero. The mid level
energy will generate showers mainly north of US 422 on Saturday,
however it would not be surprising to see pops get extended
further south if the trough is stronger than presently forecast.
No ptype issues at this juncture given precip onset time. In
addition, the amount of warm air in the lowest few thousand
feet should offset cold temps 5KFT and above.

Once the trough departs late Sunday high pressure builds as do
H5 heights. This will make temperatures jump early next week to
above normal. With southwest winds at the surface and H8 temps
progged around 12C, would not be surprised to see lower 80s
across northern West Virginia next Tuesday. There are some
timing questions regarding the next weather system at the very
end of the forecast, however that can be hashed out with
Wednesday's shift as it becomes the new day 7. So if you are
looking for spring weather, you will like the forecast as we
head back to work next week.


Expect most terminals to deteriorate towards MVFR/local IFR
overnight, with some spotty MVFR mist developing as well. MVFR
will continue past sunrise. A period of IFR ceilings is possible
during the day with the approach and passage of a cold front
and midlevel trough, although any visibility restriction from
showers should be brief. Slow improvement is expected behind the
front into the evening.

The next chance for general restrictions is expected with the
crossing of weak low pressure on Friday.




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