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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 230131

Area Forecast Discussion
National Weather Service State College PA
931 PM EDT Mon Apr 22 2019

A ridge of high pressure will provide us with fair, dry weather
through much of Tuesday. A cold front will bring showers and a 
few thunderstorms late Tuesday and Tuesday night. Wednesday and 
Thursday should feature mainly dry conditions once again under 
the influence of another area of high pressure.


Clear skies cover all but portions of Schuylkill, Lebanon and
Lancaster Counties this evening where scattered residual SC on
the periphery of the offshore coastal low are exiting to the
south late tonight.

Light winds and mostly clear skies are expected overnight as a 
ridge of high pressure slides east across PA. Low temps will be 
in the 40s, to around 50F in the southern valleys.


Tuesday continues to look like the warmest day during the 
upcoming week with a moderate SW breeze kicking in across the 
Central and Western mtns during the afternoon. 

High temps Tuesday will range from the low 70s across the 
Northern and Western Mountains, to the upper 70s in the
southern Valleys and Susq Valley, or anywhere from 12-15F F 
above normal.

There is fairly good model agreement in the next cold frontal 
system moving through the area during the midweek period. 
Showers and sct tstms impact mainly NW areas late Tues and Tue 
night, with diminishing showers surviving into the SE. MRGL risk
SVR is right up to the wrn border.


Cold front assocoated with a potent shortwave should be east of
the area by Wed, but a cooler and breezy day will follow. 

High pressure builds in for the afternoon and overnight, leading
to a chilly start to Thursday before temps rebound back to
slightly above normal. Morning lows likely dip into the upper 
30s in the valleys of the northern mountains.

Models then focus on a digging trough shifting eastward
across the GLakes for Thu night/Fri with a deepening surface low
that lifts into New England on Sat. For central PA, rain chances
increase quickly Thu eve with passage of center of low, and
scattered showers persist into Friday as upper trough swings
through. Model differences remain however, with the GFS bringing
the trough through about 6-12 hours sooner than the ECMWF. 

Sat brings another shot of cooler air and breezy conditions 
with temps recovering back to normal by Sunday. Chance of rain
returns Monday as a warm front lifts toward the region.


High pressure and subsidence are clearing out the sky. Everybody
is VFR and the wind is fairly light out of the N. Only the SErn
counties which are closer to the low off the coast are a little
gusty. The wind should die down at all sites overnight. Just a
little fog is possible in the deepest valleys in the morning. 

Cold front approaches from the NW on Tuesday, but most of the
day will be VFR. Timing from models on arrival/development of
SHRA/TSRA over the NW is highly variable and leads to moderate
to high uncertainty of when to start mentioning them. Only BFD
has any chc of having a shower before 18Z, though. Otherwise,
the storms will push NW to SE across the airspace between then
and 06Z Wed. Expect only brief drops into IFR. The areal
coverage of the storms should decrease as they press into the
central mtns and even more as they try to get into the SE. 


Tue PM...Cold frontal passage, with accompanying SHRA/TSRA.

Wed-Thurs...No sig wx.

Thurs PM-Fri...SHRA/TSRA. Restrictions probable.

Sat...Mainly VFR, low chc SHRA/TSRA.




NEAR TERM...Dangelo/DeVoir
SHORT TERM...Dangelo