141
FXUS61 KCTP 160329
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1129 PM EDT Sun Jun 15 2025

.SYNOPSIS...
* Rain chances continue through Wednesday, with highest chances
  for locally heavy rainfall on Tuesday.
* A warming trend emerges for Wednesday and Thursday, fueling
  some potential for severe thunderstorms on Thursday.
* A brief drop in temperatures for Friday, with temperatures
  increasing steadily into the weekend, with high temperatures
  on Sunday reaching into the mid-80s to lower 90s.

&&

.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
03Z/11pm EDT Update: Little change in the forecast so far this
evening with scattered showers across the southern half of the
forecast area. The SPS for fog continues as is; however,
localized visibility drops will be possible across Schuylkill
County and the south-central mountains overnight. Confidence in
this restrictions being as widespread/continuous overnight
remains lower; however, so have not issued any additional fog
headlines this evening and will continue to monitor trends.

Previous Discussion, Issued 8:42 PM EDT 06/15/2025:
Current radar outlines very little in the way of precipitation
across central Pennsylvania; however, model guidance shows
moderate agreement in rain shower potential persisting across
the southern tier overnight. Additional rainfall overnight will
generally remain light, generally below 0.10", well-below FFG
values with flooding risk on a downward trend overnight. Fog
potential will be the bigger story overnight, with higher
elevations along the Allegheny Front with recent HREF
probabilities for visibilities dropping below 1/2SM virtually
certain across elevations AOA ~2000-2500ft AGL overnight. Have
collaborated with WFO LWX to issue a SPS for locally dense fog
across higher elevations of the Allegheny Front overnight with
some potential for a short-fused Dense Fog Advisory possible
should trends worsen overnight. Any motorists overnight will
need to monitor visibility trends, and be prepared for rapidly
changing conditions as they traverse the higher elevations of
central Pennsylvania tonight. Low temperatures overnight will
remain fairly uniform, ranging from the mid-to-upper 50s.

&&

.SHORT TERM /7 AM MONDAY MORNING THROUGH WEDNESDAY/...
Stationary front stationed near the Greenbrier Valley continues
in the short-term allowing for a continued chance for
precipitation across the southern half of the forecast area
(generally south of Interstate 80) on Monday. Cloud cover will
remain fairly persistent, once again, on Monday and will lead to
less instability across central Pennsylvania which should keep
any thunderstorm elements out of the forecast as a whole. Model
guidance does some signal for very marginal instability making
way into far western Somerset/Cambria counties that will promote
slight chance of afternoon/evening thunderstorm; however, a
decreasing trend has been outlined in the Sunday evening
forecast package.

PWAT values begin to increase Tuesday morning into Wednesday
with best forcing overhead as a surface boundary sets up over
central Pennsylvania. Relatively warmer air will work into the
western half of the forecast area, allowing for slightly more
instability in place on Tuesday to allow for thunderstorm
mentions across the western highlands, with some clearing on
Wednesday allowing for enhanced destabilization. From a
hydrology perspective, rainfall is expected to be efficient
across western Pennsylvania (where PWAT values approach 1.75")
which will bring into account flooding concerns, outlined by
WPC`s D3 MGRL ERO across the western half of the area, with the
SLGT risk clipping Somerset/Elk counties. Severe threat on
Wednesday remains fairly minimal, with the best shear in place
across northern Pennsylvania where cloud cover will likely limit
destablization.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Influence of the upper-level trough continues into the long-term
period before gradually drifting eastward by Friday. Period of
most interest in the long-term will be Thursday, especially in
the afternoon/evening hours with some severe potential in the
cards across much of central Pennsylvania. Low pressure
stationed across southern Canada with warm front stretched into
the northern Atlantic and a cold front stationed across the
Ohio Valley will allow for some residence time in the warm
sector ahead of an afternoon approach by a surface cold front.
Ample moisture will remain in place, with dew points in the
upper 60s to lower 70s across the eastern half of the forecast
area. This threat is also noted in the Storm Prediction Center
D5 Severe Outlook, with a 15% contour. Do want to highlight
that some uncertainty does remain with regards to frontal
passage time; however, model guidance is continuing to indicate
that ingredients will be in place for some severe potential
across central Pennsylvania on Thursday.

Cold frontal passage brings in relatively dry conditions for
Friday with upper-level heights beginning to increase. Diurnal
showers and thunderstorms will remain in the cards for the
weekend, as temperatures trend well-above seasonal averages with
relatively humid conditions. Sunday will remain the hottest day
of the long-term with forecast high temperatures reaching into
the mid-to-upper 80s across the northern tier to the lower 90s
across the south-central mountains, with heat index values
pushing close to the century mark late Sunday PM. HeatRisk
values on Sunday outline the warm temperatures/heat index
values, with widespread moderate (level 2/4) risk conditions
with areas of the south-central mountains and western highlands
reaching into the major (level 3/4) risk for heat-related
impacts.

&&

.AVIATION /04Z MONDAY THROUGH FRIDAY/...
Poor flying conditions will prevail overnight and the next
several days, as there is nothing really out there to push out
the wet pattern. Widespread MVFR conditions are ongoing with
some areas of IFR mixed in near the PA/MD border.

Ceilings will remain IFR most places overnight with a very slow
improvement back to MVFR on Monday.

Outlook...

Mon-Wed...Daily chances for showers and thunderstorms, peaking
during the afternoon/evening hours each day.

Thu...A better chc of more numerous showers and storms with a
cold frontal passage.

Fri...Improving conditions.

&&

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

&&

$$

SYNOPSIS...NPB
NEAR TERM...NPB
SHORT TERM...NPB
LONG TERM...NPB
AVIATION...Gartner/RXR