Area Forecast Discussion
Issued by NWS State College, PA-- Highlight Changed Discussion --
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FXUS61 KCTP 231527
Area Forecast Discussion
National Weather Service State College PA
1127 AM EDT MON MAY 23 2016
The slow moving storm system that brought rainy cool weather all
weekend will slowly edge away from the region today and Tuesday.
A noticeably warmer and more summer-like pattern is forecast from
mid week into the holiday weekend.
.NEAR TERM /THROUGH TONIGHT/...
We still have a few areas of low clouds to burn off in some of the
river valleys. But most of the fog has burned off and many areas
are mostly sunny with only patchy high clouds.
We are now on the western side of the upper low. Most of the
widespread rain is to our east. The SREF, GEFS, and HRRR all
imply the potential from 2 PM until at least 5 PM of showers and
thunderstorms developing from central areas to the east. QPF is
very light and it could be hit or miss.
Any showers will be instability driven and should diminish during
the evening hours.
.SHORT TERM /TUESDAY/...
Overnight Monday into Tuesday will have light surface flow so some
potential for overnight fog in the valleys again. The flow aloft
becomes more anticyclonic and weakly anticyclonic at the surface.
Thus all the guidance is warm with 10 to 14C range. Should be a
mostly sunny dry day with temperatures mainly in the 70s.
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Extended guidance continues the idea the development of an eastern
ridge/western trough pattern, bringing the arrival of the first
extended period of summer-like temperatures and humidity.
By Wednesday... central PA will be under rising
heights as the low lifts out and the ridge bulges east. At the
same time a weakening back door cold front will be sliding out of
Canada into the rising heights aloft. The models use this to
develop showers and thunderstorms Wed afternoon and evening.
Precip confidence is never terribly high with surface fronts
moving into ridges aloft.
By Thursday we will be embedded in a broad wsw flow aloft.
Slightly above normal PWATS support the idea that humidity will
become noticeable over most of the area for the first time this
warm season. It also means we will be susceptible to mainly
afternoon convection pretty much on a daily basis into the
weekend. The limiting factor will be the eventual sharpness of the
upper ridge and how warm we manage to get aloft. The GFS is very
aggressive poking the Bermuda ridge strongly up over the eastern
U.S. Saturday while the ECMWF is a little flatter. The NAEFS is
more in line with the GFS which hints that Saturday could be the
day with smallest convective chances. I don`t have anything more
than chance pops in the extended given the muddy nature of the
ridge and low confidence that it will be able to shield us from
upstream convection that will be embedded in the flow.
The highest confidence part of the forecast is for temperatures to
be above normal through the end of the month.
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --VFR is the rule this morning over the region and should remain so
into this afternoon. Satellite and radar show mostly clear skies
some patches of high clouds. The flow is from the northeast today.
The short-term models still show some bands of showers developing
over central and eastern areas. Not a lot of organization. With
the upper-level low to our east these will be more hit or miss.
Kept VCTS in TAFS in southern and eastern areas. The 3km HRRR
implies best chance of rain/thunder is after 18Z today and highest
probabilities would imply KMDT and KLNS. Basically, from KSEG
south has best probabilities and lower as you move north and west.
Most or all activity should diminish before sunset. Mainly VFR
overnight perhaps patchy MVFR in some valleys.
Tue-Wed...VFR/No sig wx expected.
Thu-Fri...Chance of mainly P.M. showers/tstms.
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NEAR TERM...Grumm/La Corte
SHORT TERM...Grumm/La Corte
LONG TERM...La Corte