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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

                            
000
FXUS61 KCTP 171913
AFDCTP

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

.SYNOPSIS...
A weak cold front will push south across the region late this 
afternoon and this evening, then 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.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Visible satellite imagery at 1900z shows mostly SCT/BKN cu east
of the Laurels and Alleghenies. Radar imagery shows a few
showers initiating along a WSW-ENE boundary intersecting the
PA-NY border in Potter county. MLCAPE generally less than 250
J/kg except for a narrow corridor between Lancaster and 
Wellsboro where MLCAPE exceeds 500 J/kg. A few showers may 
support thunder, but no severe weather is expected. 

A general clearing trend will take place tonight as the frontal
boundary pushes further south, although clouds will be linger
around the Laurels and near the PA-MD border as the front slows
and becomes nearly stationary by daybreak. 

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
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.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
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.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
A few shra/tsra developing this afternoon, as a weak cold front
crosses the area. Best chance for TSRA will be over the South 
Central Mountains and the Susquehanna Valley where CAPE is 
highest.

Behind the front, ceilings expected to dip to MVFR for several
hours, before improving for tonight. IFR conditions ongoing at
KJST late this afternoon into early evening. 

.Outlook...

Sat...Isolated aftn shra/tsra possible western highlands.

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

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

Tue...Mainly VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Fitzgerald/Lambert/Colbert
NEAR TERM...Fitzgerald/Lambert/Colbert
SHORT TERM...Fitzgerald/Lambert/Colbert
LONG TERM...Fitzgerald/Steinbugl
AVIATION...Colbert