FXUS61 KCTP 261913

AFDCTP



Area Forecast Discussion

National Weather Service State College PA

313 PM EDT Thu Jun 26 2025



.SYNOPSIS...

* Flash flood and severe t-storm risk increased this afternoon

  and evening over east central PA  

* Breaking heat gives way to drenching downpours into the last

  weekend of June; unsettled pattern continues to start July



&&



.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...

Severe T-storm watch #464 issued for a portion of south central

PA until 10PM EDT. From MCD #1455: Thunderstorm activity has 

begun to initiate across portions of the Appalachians. This 

activity is expected to continue to expand in coverage through 

the afternoon/evening. The environment to the east is hot and 

unstable (with MLCAPE around 1000-2000 J/kg) and temperatures in

the upper 80s to 90s. Despite the weak flow aloft and weak 

shear, steep low-level lapse rates (around 7.5-8 C/km) and moist

profiles will support potential for wet downbursts and damaging

outflow winds. This area will be monitored for watch potential 

through the afternoon.



Several changes/updates in the near term: 



1. [Flash] flood watch over east central PA: 3pm to midnight

Signals from the 00 and 12Z HREF continue to favor slow moving

storms along lee-side trough and backdoor frontal zone. Both

HREF and RRFS show pockets of elevated probabilities of >2"/hr 

rainfall rates by mid-late afternoon into the evening. Despite

the lack of synoptic/kinematic support, the favorable 

thermodynamic profile (1.75-2.00" PWs and max CAPEs 2000-3000 

J/Kg) combined with the likelihood of slow cell motions with the

potential for repetitive convection along the aforementioned 

boundaries are key drivers of the watch with point rain amounts

2-4" possible over a short duration. No change to the D1 SLGT

risk ERO from WPC. 



2. SPC convective outlook upgrade from risk level 1 to 2 (SLGT)

Full sunshine this morning across south central into southeast 

PA allowing temps to rise into the mid 80s to low 90s. While not

as extreme, hot/humid conditions will lead to scattered

thunderstorm development through the evening. Winds aloft are 

weak, suggesting disorganized/pulse convective modes. However, 

steep low-level lapse rates and moderate CAPE values will once 

again result in a risk of locally damaging wind gusts. 



Heat Advisory remains in effect until 7 PM EDT.



Showers will gradually fade into late tonight. There appears to

be an emerging signal for fog and low clouds overnight into 

early Friday morning particularly across the eastern half of 

the CWA with plenty of residual moisture and low level easterly 

flow.



&&



.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...

Low clouds are likely to persist through the first part of

Friday thanks to an east to southeast low level flow. Any

convection would be mainly confinded to along and west of the

Allegheny Mtns. Max temps will be 10 to 20 degrees cooler vs.

Thursday with the largest 24hr delta over the middle to lower

Susq Valley. The fairly robust easterly flow signal may offer

some downside risk to max T particularly over the eastern

portion of the forecast area. Highs will generally range from 

around 70F in the Endless Mtns and northeast Coal Region to the

80-85F range along the western periphery of the CWA. 



Unsettled pattern continues through the last weekend/end of June

with daily opportunities for drenching downpours. After a brief

cool down on Friday, seasonably hot/humid summertime conditions

return from Saturday into Monday. 



&&



.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...

The anomalous upper-level ridge that brought heat to much of 

the eastern United States will continue to gradually be 

suppressed to the south in the extended period, and long range 

models suggest that it should be replaced by an upper level 

trough over the northeastern United States by the middle of next

week.



As for sensible weather...the unsettled pattern will persist 

into at least the first half of the upcoming weekend, with 

SHRA/TSRA likely on Saturday, especially in the afternoon and

evening. Sunday looks like the better day of the weekend, with 

a small area of high pressure building in, and keeping PoPs less

than 40 percent. An approaching cold front and upper trough 

will bring more widespread SHRA/TSRA later Monday into Tuesday.

After that, we could be in for a welcome shot of cooler and 

drier weather for the middle to later part of next week.



&&



.AVIATION /19Z THURSDAY THROUGH TUESDAY/...

Scattered thunderstorms may produce short term restrictions this

afternoon and evening; accounted for this risk via PROB30s.

There is an emerging signal for more prolonged MVFR to IFR cigs

later tonight into Friday particularly across the eastern 3/4 of

the airspace due to a developing east to southeast low level

flow. Confidence in sub-VFR across ZNY sector is very high >80%

into Friday morning. 



Outlook...



Fri...IFR/MVFR cigs trending toward MVFR/VFR by the afternoon.

Additional showers possible. 



Sat-Mon...Periods of showers and t-storms with times of fog and

low clouds overnight.



&&



.CTP WATCHES/WARNINGS/ADVISORIES...

Flood Watch until midnight EDT tonight for PAZ028-037-041-042-

046-049>053-056>059-063>066.

Heat Advisory until 7 PM EDT this evening for PAZ034>036-

063>065.



&&



$$



SYNOPSIS...Steinbugl

NEAR TERM...Steinbugl

SHORT TERM...Steinbugl

LONG TERM...Colbert

AVIATION...Steinbugl

