482
FXUS61 KCTP 271423
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1023 AM EDT Thu Jun 27 2024

.SYNOPSIS...
*Seasonable end to the week with comfortable humidity
*Return of heat+humidity fuels T-storms this weekend
*Cooler & dry start to July; heat & T-storms by the 4th

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
1020AM/1420UTC: Increased cloud cover by 20-30% this morning
particularly over the Alleghenies based on the latest GOES
Geocolor visible satellite imagery. Theme of the day remains
decreasing humidity as a more refreshing airmass pours into
central PA from the northwest.

Previous Discussion Issued: 521 AM EDT Thu Jun 27 2024

A secondary push of cooler and drier air will move Southeast
across the region this morning. Variable amounts of clouds
this morning will give way to increasing increasing sunshine
this afternoon. PWAT will dive to around 0.6-0.7 of an inch
over much of the region by later today or about -1 sigma. Highs
today will be in the low to mid 70s over the higher terrain of
the north and west and low to mid 80s in the Central and
Southern Valleys.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY NIGHT/...
High pressure near Chicago late this afternoon will build to
the east and become centered over Western New York and
Northwestern Pennsylvania tonight with clear skies, cool
temperatures and light wind, leading to the formation of valley
fog given moist ground from yesterdays widespread convection and
air/water T spreads 20-30 degrees.

Lows tonight will vary from the chilly mid and upper 40s across
the Northern Mountains to the upper 50s and low 60s in the
Southern Valleys.

Partly cloudy and slightly warmer conditions are likely Friday,
as low pwats persist over PA and a return southerly flow
develops as the surface high passes off the coast. Latest model
data suggests some showers and storms may develop Friday night
over the western portion of the forecast area.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Latest medium range guidance is showing an unusual lack of
spread among its members, all of which track a surface low
north of PA Saturday, with a trailing cold front coming through
Sat night into early Sunday. The lack of spread with regards to
timing of the front, combined with progged GEFS pwats of
+2-3SD, supports an increasing confidence in showers/tsra
Saturday. A leading warm front could produce showers/tsra as
early as Friday night and a slowing cold front could cause
convection to linger into Sunday, mainly over the southeast
counties. However, ensemble plumes indicate the most widespread
convection should occur Sat afternoon and evening.

There is some potential for severe wx Saturday PM, as decent
mid level flow overspreads an increasingly moist warm sector.
Ensemble plumes currently indicate moderate CAPE in the 1000
J/kg range and model 0-6km shear is in the 35-40kt range. If the
cold front slows enough, severe wx would also be possible
across the eastern edge of the forecast area Sunday PM.

Latest EPS and GEFS both support fair weather with near to
slightly below normal temps and low humidity early next week
associated with high pressure building east from the Grt Lks. A
seasonably cool and dry start to July!

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
IFR and MVFR stratus across the central mountains and
Alleghenies this morning will break up into fair weather cu and
eventually dissipate today. All TAF sites will be VFR by mid
morning. Winds will remain from the NW with gusts generally
less than 20 kts.

Outlook...

Fri...Generally VFR.

Sat-Sun...Thunderstorm impacts possible.

Mon...Generally VFR.

&&

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

&&

$$

SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert/Steinbugl
SHORT TERM...Lambert
LONG TERM...DeVoir/Steinbugl
AVIATION...Dangelo/Colbert