Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 261454
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1054 AM EDT Thu Apr 26 2018

.SYNOPSIS...
High pressure will be here for a short time today. A series of
troughs will then begin to cross the region over the weekend.
Each shot of energy will knock the temperatures down a little,
and give us a few rain showers. A stretch of fair weather with
a warming trend will start Monday as high pressure builds over
the Atlantic Coast. Above normal temperatures are likely for the
middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Cloudy skies continue though the building high pressure
continues to erode clouds as the upper level low pulls
northeastward. Orographic lift and cool air will make it tough
to get rid of clouds over the NW half of the area late this
morning early this afternoon. Will keep on with the call that
it should break up slowly from S-N and most of it slink away
very late in the day and early this evening.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
However...a fast moving wave over AR this morning which will
become caught up in the SW flow just ahead of the longest-
wavelength upper trough axis. The pressure dips only a mb or
two as it treks up the lee side of the Apps late tonight and
Friday. There will be a little moisture added into the system as
it moves northward. So, a period of rain is likely for mainly
the SE half/third of the area - centered on Fri morning. The
chance for rain tapers off to the NW and POPs will not be
noticeable for the far NW. However, 100 POPs on tap for the SErn
third of the area.

A broad area of lowered pressure and many sfc troughs will be
left circulating over ONT and the NE CONUS. The deepening trough
looks like it could cut off as it moves over the Lower Lakes in
the middle of the weekend. So, while much of Fri night looks
dry, the big trough axis generates an area of showers for
Saturday which transits most of the area. Likely POPs are on tap
for the nrn half of more of the area. Temps will still get into
the 60s in the SE, but could hold in the 40s NW.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A shot of arctic air is going to try to make it in Saturday
night and Sunday with 8H temps near -10C and 1000-500 thickness
less than 530dam. The consistency across the models is pretty
good with this mass field result, so confidence in cold temps
and a gusty NW wind is high. The lake/8H temp difference might
be enough to generate SHSN at night/Sun AM. But, it warms up
nicely on Sun. The crest/ridge axis of high pressure dropping
down from central Canada will probably be on Mon. While temps
will get cold Sat night - U20s NW to N40 SE - the worry for
frost in the areas growing now is practically nil as wind stays
up/gusty most of the night and clouds linger over the NW half
and could bleed into the ridge and valley region. Freeze/frost
will be more of a worry Sun night/Mon morning as the sky clears
out and wind would go calm. Temps Mon morning could get into the
30s everywhere and upper 20s again in the northern valleys.
But, the difference in wind and sky cover should lead to at
least a frost if not freeze in some of the growing areas. The
next chunk of counties (around AOO- UNV- IPT) does not go active
for frost/freeze products until May 1st.

The high pressure will continue to slide to the E and S and set
up along or just off the Atlantic Seaboard for the middle of the
week. Look for temperatures finally rising above average and
real spring weather arriving next week with many areas finally
seeing a substantial green-up.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Drier air aloft is slowly mixing down eroding the cloud layers
and will result in clearing skies by late morning. Model
soundings and SREF prob charts support a near certainty of
widespread VFR conditions for this afternoon. Low pressure
lifting up the eastern seaboard will likely spread rain and
lowering cigs into southern Pa around dawn Friday.

Outlook...

Fri...Rain/low cigs possible, mainly eastern Pa.

Sat...AM fog possible.

Sun...Breezy. AM low cigs/flurries possible W Mtns.

Mon...No sig wx expected.

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo/Ceru
SHORT TERM...Dangelo
LONG TERM...Ross/Dangelo
AVIATION...Fitzgerald/Ceru



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