Altoona, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

601
FXUS61 KCTP 131052
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
652 AM EDT Wed Aug 13 2025

.SYNOPSIS...
* Cold front moves in from the north tonight and slows/stalls
  over the state tonight. Storms today may produce heavy rain.
* Afternoon thunderstorms are possible Thursday, mainly S
* Dry Friday with low humidity
* PM thunderstorms return Saturday

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Showers finally entering Warren Co at 08Z. But, outflow boundary
is moving ahead of the cells. That should assist in diminishing
these SHRA/TSRA. But, they likely won`t go away totally with
patchy rain and a stray CG or two. The forcing is still good,
and heating of the day will certainly help deep convection
become widespread. Cloud cover from current convection will
spread across the CWA, and probably keep it a bit cooler than
prev fcsts had it being, esp in the NW. The best shot at sun
today is the SE/Lower Susq where a few spots could hit 90F. Td
in the L-M70s could push AppT close to 100. But, the uncertainty
of just how much cloud cover there will be and how early it will
get that far SE keeps confidence low in places getting to 100F
heat index that we will stay away from a heat advy at this
point.

PWAT in the 1.5-1.8" range today and little shear makes the
possibility of heavy downpours real. NAM even makes points of
>2" rainfall. Thus, we are in a MRGL risk for excessive
rainfall. Have mentioned +RA possible in the wx grids. But, it`s
been so dry for the past 14 days that generating flooding is
going to be a tall order. Shear is low (20-30kts), so the risk
for severe is pretty low, especially if clouds keep things a
little cooler than forecast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Convection should be on-going this evening. Again, some risk of
+RA/flooding exists, mainly with repeated cells passing over the
same spot. But, again, antecedent conditions are dry. The cold
front moving down from the N should get into the central mtns
tonight and slow down considerably. That will leave a lifting
mechanism in place for the central and srn zones for Thursday.
The higher (30-40) PoPs should be in the SE half with the NW
staying dry as the dewpoints there drop into the M50s - even
while Lancaster Co holds onto dewpoints in the L70s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Lowering humidity on Friday will bring some minor/temporary
relief to summertime humidity, but overall there is no end to
our run of hot/above normal temperatures through mid August.

Minor plume of moisture along a weak trough will allow for a few
diurnal TSRA Saturday along the spine of the Appalachians.
A cold front then moves down into the area later Sunday, and
should have scattered to numerous SHRA/TSRA in advance of and
along the front. The sfc high behind that front should be strong
enough to push the front to the srn border, but it could linger
nearby. That would lead to isold SHRA/TSRA into mid-week. So we
can`t quite shake 20-30 PoPs for next week.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Mid and high clouds will continue to increase from west to east
this morning as a result of the deep, moist southwesterly flow
ahead of a cold front.

Look for generally VFR with some limited IFR/LIFR CIGS/vsbys
across the Lower Susq Valley through 13Z. Winds will remain
relatively light from the SE through SW.

During the daylight hours today, we`ll see building clouds
throughout the morning with an area of briefly weakening
showers and scattered TSRA over NW in a zone of maximum llvl
moisture advection.

Afterward, scattered to widespread showers and thunderstorms
developing for the afternoon (with brief MVFR to IFR) as the
primary axis of deep- layer moisture shifts east across the
region ahead of a cold front approaching from the northwest.

Forcing for these storms will mainly be ahead of slow moving
front, which makes predictability for the timing of these storms
tricky. Most sites will likely see a shower overhead at some
point today, but due to the cellular based storm mode, timing
the occurrence at any one location is difficult. Will continue
to employ prob30 groups to highlight the window where
thunderstorms are possible.

Outlook...

Thu...Lingering showers/and a few PM storms possible across the
southern airspace.

Some valley fog is possible through about 12Z today, and a
tempo group has been included to highlight this at sites were
confidence in fog formation is highest.

Fri...AM fog possible; otherwise VFR.

Sat...Mainly VFR.

Sun...Mainly VFR, but chance of a shower or storm north late.

Mon...Chance of a shower early, then clearing.

&&

.CLIMATE...
It`s been a very dry period over the last 2 weeks or so. Here
are the precipitation totals and rankings for the first 11 days
of August (month to date):

MDT: T (2nd driest); last measurable rain 7/31
IPT: 0.00" (driest); last measurable rain 7/30
AOO: 0.01" (2nd driest); last measurable rain 8/6
BFD: 0.09" (T5th driest); last measurable rain 8/6
STC: T (T2nd driest); last measurable rain 7/28

&&

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

&&

$$

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