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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 170329

Area Forecast Discussion
National Weather Service State College PA
1129 PM EDT Sun Jun 16 2019

An unsettled and stormy weather pattern is expected across 
central Pennsylvania this week. There will be multiple rounds 
of heavy downpours with the potential for localized flooding 
and isolated severe storms. Temperatures and humidity levels are
forecast to remain near average for mid to late June.


SFC cold front has settled into the Laurel Highlands this
evening, delinated by broken band of showers with embedded
heavier downpours. No lightning has been scanned within the
shower zone for quite some time, even while potentially tornadic 
cells were being warned upon over eastern OH and western PA. 
SFC CAPES still in the 300 to 500 J/kg range across the southern
tier of PA, but the front may not make it much farther south
tonight than it already is. While slightly drier air is
filtering southward across the northern tier, the south will
stay soupy with at least a chance of showers continuing
throughout the night. Break in shower chances across central
areas will last through most of the night, but models prog the
boundary to lift back northward overnight from the Laurels, and
so showers may build back towards the West Central and Central
Mountains after 09z. Weak high pressure nosing into northern PA 
may bring a few BINOVC, but fog formation would accompany it if
it happens. Already some locally dense fog showing up at KDUJ
and KBFD. Skies remain essentially overcast overnight.


Active weather pattern continues into early next week. SPC is 
targeting south-central and southeastern PA with a SLGT risk of
severe storms, with an isolated severe storm possible farther to
the north.

WPC is highlighting southwestern and south-central PA with a
SLGT risk for excessive rainfall/flash-flooding on Monday. The
airmass will be plenty juicy, with the 12z GEFS projecting PWATs
to reaching 1.5 to 2 inches (which is +1 to +2 SD above-normal).


Fairly relentless stream of showers and scattered thunderstorms
in store for much of central PA Mon into Thu as an E-W oriented 
frontal boundary wiggles over the region. Though it won't be
raining the entire time, it will definitely be a soggy and
cloudy run of weather.

Models hint at a drier period toward the end of the week into 
first half of the weekend, which translates to just isolated 
showers focused on the NW half. But precip chances increase 
again as another storm is progged to lift into the Great Lakes 
Sunday brushing our western areas.

Though elevated dewpoints will keep muggy conditions in place
with above average low temps, highs will top out a bit below
normal each day.


A dying cold front sagging into southern Pa will be the focus 
for scattered showers late tonight. However, the main concern 
overnight will be low clouds and fog developing just north of
this boundary. 03Z surface analysis shows IFR cigs/vsbys across
the northern mountains, with mainly VFR conditions noted across
the rest of the region. SREF/HREF probability charts support 
the continued likelihood of low cigs across the northern 
mountains overnight, with the Laurel Highlands also likely to 
experience IFR/LIFR cigs toward dawn Monday. Elsewhere, plenty 
of low level moisture, a diminishing wind and breaking clouds 
support the idea of patchy fog. However, confidence is not high 
in significant fog formation due to an approaching area of low 
pressure and associated return of cloud cover late tonight, 
which would diminish the threat of radiation fog.

Models indicate an area of low pressure will track across
southern Pa Monday, producing rain and low cigs across the
central part of the state. Somewhat more favorable conditions
are possible along the southern tier of the state, where
precipitation will fall as scattered showers, rather than a
steady rain, and cigs are likely to be higher. More favorable 
conditions are likely over the northeast corner of the state, 
where little rain is expected and VFR cigs appear likely.


Tue...AM low cigs/fog possible. 

Wed...AM rain/low cigs possible.

Thu...AM rain/low cigs possible. Scattered PM tsra impacts

Fri...AM low cigs possible W Mtns.


Astronomical summer (solstice) begins Friday, June 21st at
1154AM EDT (1554 UTC).




NEAR TERM...DeVoir/Evanego
SHORT TERM...Evanego
LONG TERM...RXR/Steinbugl