Latest Area Forecast Discussion for Central PA

Here is the latest Area Forecast Discussion for Central PA

This text statement is the latest forecast reasoning from the NWS in State College, PA

See the links at the bottom of the page for previous issuances/versions of the statement as well as our other text statements.

235
FXUS61 KCTP 301902
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
302 PM EDT Wed Jul 30 2025

.SYNOPSIS...
* Sweltering heat will close out one of the top-10 warmest
starts to the summer season (June & July) on record.
* Widespread thunderstorms are expected for Thursday and may
lead to potentially significant flash flooding.
* Significant pattern shift to deliver refreshingly cooler, less
humid and rain free conditions to start the month of August.

&&

.NEAR TERM /THROUGH TONIGHT/...
Temperatures have climbed into the upper 80s and low to mid 90s
across much of Central PA this afternoon, with many locations in
the Lower Susquehanna Valley seeing heat index values exceed 100
degrees. The Heat Advisory remains in effect through 8 PM for
the Middle and Lower Susquehanna Valley as well as for the south
central Alleghenies.

Isolated showers and thunderstorms have developed along the
higher terrain and will continue through the evening before
dissipating with the loss of daytime heating. With very weak
shear in place, generally less than 25 knots, it will be tough
for any individual storm to sustain itself. That being said,
steep low level lapse rates and sufficient dry air aloft could
support an isolated strong to severe gust with the strongest
storms.

A few showers will be possible overnight as flow turns southerly
ahead of a cold front that will slowly sink southwards into
central Pennsylvania. Low temperatures tonight will range from
the 60s over the northern and western mountains, to the low to
mid 70s in the southeast.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
*Elevated risk of excessive rain with some higher end flooding
impacts possible across east-central/southeastern PA Thursday

As the aforementioned cold front stalls near the Mason-Dixon
Line on Thursday, all guidance shows a wave of low pressure
developing along it and slowly tracking through the region. This
will trigger widespread thunderstorms capable of producing heavy
rainfall. The environment will be supportive of very efficient
rainfall with PWATs around 2 inches, a warm cloud depth of
13000-14000 feet, and relatively weak flow oriented nearly
parallel to the boundary. Most of the CAMs suggest the potential
for rainfall amounts of 2 to 3 inches with localized amounts of
up to 5 inches across the Lower Susquehanna Valley. Because of
this, WPC, in collaboration with us and our neighboring offices,
has decided to include a moderate risk (level 3 of 4) of
excessive rainfall that includes York and Lancaster Counties.
These areas may potentially see significant flash flooding
impacts.

Additional rainfall is expected farther north into the Middle
Susquehanna Valley as a shortwave moves through well to the
north of the surface boundary. There continues to be a zone of
mid-level frontogenesis depicted in much of the guidance which
should lead to an area of enhanced rainfall. While instability
will be lacking in this part of the forecast area, it still
seems possible for some locations to see as much as 2 or 3
inches of rain with this activity. We have issued a Flood Watch
for both of these areas to highlight the potential for flash
flooding tomorrow.

Major changes in the temperature department for Thursday with
highs 10 to 20 degrees lower vs. Wednesday across the northern
3/4 of the fcst area. Max temps range from the low 70s in the
northern tier to mid 80s along the MD line. The refreshing air
will make inroads into the northern half of the area by Thursday
night, but it may take until early Friday to reach the southern
part of the forecast area. Lows Thursday night will range from
the low 50s in the NW mtns to mid 60s in the far southeast.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A strong high with origins in Canada will move into the
Northeast US and usher in a refreshing airmass, albeit somewhat
slowly on Friday. Models continue to trend slower with the
arrival of dry/less humid air, and we will have to maintain at
least a slight chance of rain all the way up to I-80 into Friday
morning. Another factor to consider will be the potential for
gusty northeast winds as the surface low along the front
deepens. Light rain, cloudy skies, and a northeast wind could
make for a less than ideal start to Friday for southern PA, but
eventually, clearing skies will work their way south. Much of
the area will be firmly in the dry/cooler sector by Friday
evening in the wake of the cold front.

The comfortably cooler and refreshing airmass (much lower
humidity) arrives just in time to begin the month of August.
Slightly below average daytime highs 70-80F and lows 50-60F are
forecast along with no rainfall through the first weekend of
August. The dry spell and pleasant conditions (early taste of
Fall?) should last into early next week with temperatures
gradually increasing to near normal.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
At 18z, beginning to see some towering cu and isolated
SHRA/TSRA pop up, mainly along and southeast of a line from IPT
to UNV to JST. Expect this to continue through the afternoon
and into this evening. A localized downpour and strong wind gust
are possible.

Lingering SHRA/TSRA activity should diminish after sunset.
Locations that receive rain today could see the formation of
patchy fog overnight.

A frontal boundary will sag into southern PA on Thursday, with
considerable cloudiness and more numerous SHRA/TSRA developing.
Model guidance suggests that most locations should see cigs dip
to near or just below 3 kft by Thurs aftn.

Drier weather will return for Friday through the weekend.

Outlook...

Fri... AM SHRA linger over SE PA, with restrictions possible;
trending drier with VFR conditions for the afternoon.

Sat-Mon...VFR.

&&

.CLIMATE...
Record maximum temperatures for 7/30:

MDT: 98 in 1940
IPT: 98 in 1933
AOO: 92 in 1983
BFD: 88 in 1999
STC: 97 in 1933

It has been a very warm start to the [meteorological] summer
season which includes the months of June, July, and August. As
we approach the end of July, here are the June + July average
temperatures and "to-date" rankings for select sites in central
PA:

From June 1st through July 29th:

Harrisburg: 76.7F average temperature ranks tied 7th warmest
Williamsport: 74.0F average temperatures ranks tied 7th warmest
Altoona: 73.0F average temperature ranks 3rd warmest
Bradford: 67.7F average temperature ranks 2nd warmest
State College: 73.0F average temperature ranks tied 6th warmest

From July 1st through July 29th:

Harrisburg: 79.7F average temperature ranks 9th warmest
Williamsport: 76.8F average temperature ranks tied 9th warmest
Altoona: 74.7F average temperature ranks 7th warmest
Bradford: 69.6F average temperature ranks tied 4th warmest
State College: 75.6F average temperature ranks 7th warmest

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for PAZ019-025>028-
034>036-045-046-049>053-056>059-063>066.
Flood Watch from Thursday afternoon through late Thursday
night for PAZ028-036-041-042-046-049>053-056>059-063>066.

&&

$$

SYNOPSIS...Steinbugl/Bauco
NEAR TERM...Bauco
SHORT TERM...Steinbugl/Bauco
LONG TERM...Steinbugl/Bauco
AVIATION...Evanego
CLIMATE...Steinbugl/NPB

Forecaster's
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