Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 260629
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
229 AM EDT Tue Sep 26 2017

.SYNOPSIS...
Unseasonable late-September heat will continue until a sharp but
dry cold front moves through late Wednesday and Wednesday night.
Little rainfall is expected Cooler, fall-like weather will last
few a few days before unusual warmth returns.

&&

.NEAR TERM /THROUGH TODAY/...
High clouds swirling around the center of the upper high/ridge
tonight. Temps have cooled quite a bit from the daytime heat,
but there are no hints of fog just yet. Will keep mentioning fog
for the valleys this morning, though. It is difficult to expect
that what has been happening for many mornings will not occur
again. However, the clouds may be just enough to stave off fog
formation.

Subsidence and lack of moisture will make it difficult for
anything but flat cu to form today. But, still, the model
guidance suggests that a stray shower is possible over the nrn
tier this aftn. Will persist with the dry forecast due to lack
of triggers and VERY warm temps aloft. Tough to believe that we
could have another day of tickling the 90s in late Sept, but
some valley locations could get there again today.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
It should be mostly clear tonight, but clouds could form over
the nrn tier as convergence increases and low level moisture
will be high. The cold front nears from the NW during the
morning, and could be as far as half way through the CWA by the
end of the afternoon. The dewpoints will be in the m-u60s, so
showers are possible. But, the upper heights/temps are so
high/warm that CAPE remains extremely low. Will not tweak POPs
much, and low is still the way to go.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The cold front will bring our first chance of rain in quite a
while - though with the front weakening and falling apart as it
moves through any scattered showers will remain light.

Maria (remaining offshore of the Carolinas) will make it as far
north as the NC/VA line before it takes its hard turn eastward
and finally tracks away from the east coast.

A bit more significant trough will approach for late week into
the weekend, bringing a reinforcement of the cooler temperatures
and a renewed chance for light yet scattered showers as the
airmass remains quite dry.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
06Z TAFS sent.

Expect some fog late, given dewpoints are similar
yesterday.

Widespread VFR conditions overnight. No reason to deviate from
persistence with fog restrictions likely again after midnight
into early Tuesday morning. Based on persistence and latest
model data, believe a period of IFR/LIFR conditions are likely
(mainly between 08Z-13Z) at KBFD/KIPT/KUNV/KAOO/KLNS, possible
at KMDT and very unlikely at KJST.

Wed...Patchy AM fog possible.

Thu...No sig wx expected.

Fri...Evening low cigs/showers possible KBFD/KJST

Sat...AM low cigs possible KBFD/KJST.

&&

.CLIMATE...
Record-challenging late-September heat through today. Daily
high temperature records for 9/26:

Bradford: 79 in 1998

*Williamsport: 92 in 1900

Harrisburg: 91 in 1970

Altoona: 88 in 1998

*Williamsport maximum temperature records are under review for
 Saturday and Sunday 9/23-9/24.

For Monday, the following high temperatures occurred.

Harrisburg - 91 degrees.

Williamsport - 91 degrees - old record was 89 degrees in 1970.

Altoona - 87 degrees.

Bradford - 85 degrees - old record was 83 degrees in 2007.

Johnstown - 85 degrees.

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...RXR
AVIATION...Fitzgerald/Martin
CLIMATE...Martin



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