901
FXUS61 KCTP 131548
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1148 AM EDT Sun Jul 13 2025

.SYNOPSIS...
* Continued seasonably warm and humid
* Afternoon and evening focused showers and thunderstorms are
  expected through Monday, with the most widespread activity,
  featuring locally heavy downpours this afternoon and evening.
* At this point, Tuesday looks like the driest day of the next
  seven

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
Real heavy rain falling and moving very slowly over nrn York Co and
Dauphin Co with more rain on the way. Additional development
should happen early this aftn to the west. However, placement of
these TSRA is a low-certainty. Guidance from machines and WPC
ERO pegs our central mountains with the highest QPF and risk of
FF. However, very recent CAM guidance is not in very strong
agreement. The cu out the window are pretty flat, even compared
to yesterday. In fact, it looks like any stratocu day in Central
PA from high atop Innovation Park. The forcing of a weak short
wave trough just entering wrn PA will be a driver. We need
kickers/lifting mechanisms. With slow-moving things, that can be
terrain, as it has been tthe past few days, or boundaries
drifting around from old or nearby convection. So, with all
these things in mind... we dropped a FF Watch for almost all of
the CWA effective until 1 AM local. As with many flash flooding
situations, the strongest convection may linger into the night.
But, with only a weak 15-20KT LL inflow, there isn`t much
support to continue the watch past midnight at this point. While
we may need another watch for the SE tomorrow (Mon), but we`ll
likely wait until whatever occurs today dies off or even until
morning tomorrow to consider a watch for tomorrow.

Still some threat of SVR gusts, but only MRGL risk over most of
the area. SPC did up the risk in the NErn counties. So, we`ll
have lots to watch-out for this aftn and evening. Temps will be
a function of when you get sun or have gotten rain.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM MONDAY/...
The showers/thunderstorms ongoing in the late evening should be
diminishing in coverage. But, they still could have heavy
rainall. Have limted the time of the FF Watch to 1AM with out
much support for widespread convection and only a meager LL
inflow. Short MBE vectors do last all night and Monday. The
moisture and approach of a stronger/longer-wave trough will
create widespread SHRA/TSRA in the aftn/evening on Monday -
mainly over the eastern half of the area. ERO stays up in the
SLGT risk range for the SE half of the area, too. May have to
think about another FF Watch for Mon aftn/evening. But will
likely hold off until mid shift or Mon AM to make that decision
to see where the heaviest stuff falls on Sun.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Front pulls further east and out of the area Monday evening
into Tuesday morning, allowing for a brief period of no
precipitation across central Pennsylvania through the morning
hours on Tuesday.

As the cold front continues across central Pennsylvania on
Monday, PWATs in the 1.50"-2.00" range will continue to promote
some potential for isolated instances of flash flooding across
eastern Pennsylvania which remains consistent with WPC`s
Marginal Risk for Excessive Rainfall. Flooding potential will
also be exacerbated by antecedent rainfall, so will need to
continue to monitor rainfall trends through the weekend with
regards to the flooding threat on Monday.

Large-scale pattern remains fairly consistent; however,
allowing for continued chances for diurnally driven showers and
thunderstorms across central Pennsylvania throughout much of the
long-term forecast period. Focus for precipitation Tuesday
afternoon/evening will be stationed across the southern tier of
Pennsylvania with increasing coverage during the afternoon hours
on Wednesday, Thursday, and Friday.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Deep convection already occurring around MDT/CXY and sliding
only slowly eastward. LIFR occurred at MDT as it went thru
there, and may not improve too quickly cuz of the slow movement.
This cluster of storm will approach LNS shortly, but is moving
into slightly cooler, more-stable air thanks to the earlier low
stratus.

Development of new convection to the west seems highly likely,
but coverage of the storms is tough to pinpoint, even on a
multiple county size scale. This is thanks to disparate guidance
from near term model output. So, Prob30s will carry the day with
confidence low in timing. When/if the storms get over the
airfields, they could drop to IFR per current drops at CXY and
MDT, but will hold onto mentions at MVFR since that is the mor-
likely outcome. Will re-evaluate as any get closer to the
terminals.

Stabilization should occur as we get into the evening, but
isolated storms may continue going past midnight. Coverage
should be much more sparse, so will leave out mentions of TSRA
overnight at this point. Overnight, patchy fog is likely where
it rained earlier, and there is a 50% chc that the marine
stratus gets back into the far eastern terminals (LNS, MDT as
well as MUI) through the night.

Still a 90% chc for a break in the convection between 08Z and
14Z. But the approach of a deeper upper trough from the west is
a good signal that storms will form again Monday. Will just
mention after 16Z with the next pkg. Most of the storms will be
SE of IPT-UNV-AOO depending on timing of the trough axis, but a
few are possible to the NW of that area.

Outlook...

Tue-Wed...Mainly VFR. Isold PM TSRA poss, mainly south.

Thurs...Sct/Nmrs SHRA/TSRA.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for PAZ006-011-012-017>019-
024>028-033>037-041-042-045-046-049>053-056>059-063>066.

&&

$$

SYNOPSIS...Lambert/Dangelo/RXR
NEAR TERM...Lambert/Dangelo/RXR
SHORT TERM...Dangelo/RXR
LONG TERM...NPB
AVIATION...Dangelo/RXR