290
FXUS61 KCTP 160910
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
510 AM EDT Mon Jun 16 2025

.SYNOPSIS...
* Rain chances continue through Wednesday, with highest chances
  for locally heavy rainfall across the Western half of the
  state on Tuesday as a warm front drifts slowly northeast
  across the region.
* 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 /THROUGH TONIGHT/...
Very little DTD change from Sunday`s overcast skies and target
area for convection being across far SW PA. A light easterly
llvl flow will help to maintain thick/low-based cloud cover with
daytime temperatures of 5 to 8 deg F below normal

Localized visibility drops will be possible across Schuylkill
County (along the I-81 corridor where the greatest orographic
lift will occur) and the south-central mountains through the mid
morning hours.

Temperatures to start the day will be quite uniform, ranging
from the mid 50s to around 60F.

&&

.SHORT TERM /TUESDAY/...
Stationary front will begin to lift north as a warm front
tonight and Tuesday, which will act to expand the threat for
Flash Flooding from heavy rain/repeat showers and thunderstorm
over the SW Half of the CWA. What`s been a very low probability
for CAPE to exceed 500 J/KG Sunday and again today, will ramp up
significantly Tuesday across the Western Mtns and possibly even
a little east of the I-90 corriodr.I

In addition, an increasing and veering wind field aloft Tuesday
afternoon and evening will lead to 0-1 KM EHI values increasing
to several small areas of 1.5-2 M2/S2. Wouldn`t be surprised to
see either a MRGL or SLGT introduced by SPC for DY2 (limited to
the Western half of PA) where the warm front will help to focus
CI and enhance the depth ou Updrafts

High temperatures today will bounce back to just several deg F
below normal.


PWAT values begin to increase Tuesday morning into Wednesday
with best forcing overhead as a surface boundary warm front
moves into South Central Pennsylvania and the Pocono Mtns.

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 /TUESDAY 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 /09Z MONDAY THROUGH FRIDAY/...
High confidence (>80% chance) in long duration low MVFR to LIFR
conditions through the 16/0600Z TAF cycle thanks to a moist low
level flow from the east/southeast (80 to 150 deg). Cigs near
or below alternate minimums. Periods of rain will be focused
over the southeast half of central PA airspace through 17/0000Z.

Outlook...

Tue...MVFR/IFR with fog and periods of rain.

Wed...VFR/MVFR with rain showers and a few thunderstorms
possible.

Thu...VFR with strong PM t-storms possible.

Fri...VFR with a slight chance of rain showers.

&&

.CLIMATE...
Astronomical Summer (solstice) officially arrives on Friday,
June 20, at 10:42 p.m.

&&

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

&&

$$

SYNOPSIS...Lambert/NPB
NEAR TERM...Lambert/NPB
SHORT TERM...Lambert/NPB
LONG TERM...NPB
AVIATION...Steinbugl
CLIMATE...