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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 172357

Area Forecast Discussion
National Weather Service State College PA
758 PM EDT Fri May 17 2019

A weak cold front overhead will push south and to near the MD
border by morning, then try to return north as a warm front on 
Saturday. Low pressure will track north of Pennsylvania Monday, 
as its trailing cold front comes through the state.


Heating waning and the showers, esp those across the nrn
territories (of PA) are almost gone. The only CAPE left is over
SWrn PA, and even those showers hav only produced sporadic cloud
flashes and perhaps only 1-2 CGs. Expect those to remain more-
steady state, though, this evening as the short wave energy
rolls overhead there. However, they, too continue to inch
southward. Much of the night will be dry over 90% of the CWA.
Keeping just a low PoP along the MD border, and in the far west near 
sunrise. Much drier air (~50F dewpoints already and 40s overnight) 
moving in from the north. However, clearing may take a while, and 
may self-destruct (fog) in those places that did receive rain late 
today. Will hold off on mentions of fog for the time being. If it 
clears as expected, mins could touch 40F in the nrn valleys.


The frontal boundary will return as a warm front pushing north
on the region Saturday. Heating of warm, humid air mass south 
of this boundary will likely result in scattered diurnally- 
driven convection, focused mainly along the spine of the 
Appalachians in the afternoon and evening.


Rising heights and building upper level ridging will spell a 
warmer and more humid sensible wx trend Sunday-Monday. While 
there will be plenty of dry breaks, we still cannot rule out a 
few spotty showers or isolated t-storm during this time. Expect 
sparse coverage with limited rainfall. 

Medium range guidance lends increasing confidence in a period 
of dry/cooler weather Tuesday, as high pressure and low pwat air
mass builds southeast into the area. 00Z NAEFS indicates 
Pennsylvania will be on the northern periphery of a building 
subtropical ridge the second half of next week. Shortwave riding
over the top of the ridge will bring back the chance of showers
both Wednesday and Thursday. This potential will likely continue
into Friday as a nearby boundary on Thursday will lift back
north through the region.


Spotty shra/tsra drifting southeastward across central PA this 
evening, as a weak front drifts southward across the area. 
Behind the front, shra should come to an end overnight.

The front will remain stalled just to our south on Saturday, 
and a few -shra could pop up across mainly southwestern PA.


Sat...Isolated aftn shra/tsra possible Laurel Highlands.

Sun...Scattered aftn shra/tsra possible area-wide.

Mon...AM low cigs possible NW mtns. Scattered aftn tsra impacts
possible eastern PA.

Tue-Wed...Mainly VFR.




NEAR TERM...Dangelo
SHORT TERM...Fitzgerald/Lambert/Colbert
LONG TERM...Fitzgerald/Gartner