Harrisburg, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

324
FXUS61 KCTP 150528
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
128 AM EDT Fri Aug 15 2025

.SYNOPSIS...
* Front stalling over the CWA will be dissipating, but isolated
  showers and thunderstorms are possible each afternoon through
  Saturday
* Drier air over the northern tier should keep it dry there
* New cold front drops in from the north on Sunday, generating
  storms, especially for the northern half of PA

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
An isolated shower or two are still present across central
Pennsylvania this evening; however, most places are
experiencing a pleasant eventing. Clearing comes to almost all
of Central PA with fog again possible tonight, even with
slightly lower dewpoints in the Alleghenies. Winds will remain
calm overnight which will further promote fog development.
Temperatures tonight will dive into the mid 50s in the northwest
mountains near Bradford, and stay near 70 in the Lower
Susquehanna Valley.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM SATURDAY/...
Friday morning will be the coolest of this stretch as high
pressure moves in across New England and the northern Mid-
Atlantic region. The front from Thursday will have moved well
south of Pennsylvania and be draped over central Virginia.
Sunshine and warm temperatures may destabilize the atmosphere
enough for a diurnal shower or two, meaning 20-30 PoPs are
warranted Friday afternoon. Dewpoints will stay much higher than
earlier expectations, as the true drier/cooler airmass stops
halfway thru the CWA.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
While the current cold front dissipates very slowly, another
will approach on the NW flow rolling over the big central US
upper ridge. That second front shouldn`t arrive until Sun. But,
Sat may not be entirely dry (as previously advertised) with
dewpoints still in the 60s everywhere - and upper 60s SE of UNV.
Much of the CWA has a 20 PoP painted over it.

The Sunday cold front will touch off many more SHRA/TSRA esp in
the N. The sfc high behind it should be strong enough to push
the front to the srn border, but it will then linger nearby. Not
much, if any, of a reprieve from SHRA/TSRA is expected with a
constant flow from the WNW and upstream moisture streaming in
every 18-24 hrs. TC Erin is expected to deepen extremely but
remain off-shore as she re-curves into the nrn Atlantic mid-
late week, and PA will not be affected.

&&

.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
Bulk of model guidance indicates the cloud cover across the
northern tier will persist though ~07Z-08Z Friday before
gradually diminishing, leading to clear skies overnight across
central Pennsylvania. Cloud cover across the north is expected
to limit valley fog potential compared to previous evenings, but
very likely will see some fog development, with no restrictions
expected at BFD/IPT/UNV overnight. HREF/GLAMP model guidance
does indicate some fog potential across south-central
Pennsylvania overnight, with decent signals for AOO to drop to
MVFR visibilities for a brief period ahead of sunrise. Current
satellite trends outline some fog potential, so have decided to
introduce these restrictions with the 06Z TAF package.

After 12Z Friday, expected generally VFR conditions to prevail
at all airfields outside of the Lower Susquehanna Valley
(MDT/LNS) with high (~80-90%) confidence. Scattered diurnal
convection is expected along and south and east of a KZER- KRVL-
KHGR line in the 18Z Friday to 02Z Saturday timeframe bringing
brief periods of sub-VFR conditions. HREF model guidance and
recent NBM guidance outlines best chances for precipitation at
LNS with ~30% confidence in TSRA at the airfield with heavy rain
likely dropping visibilities below VFR for a brief window.
Lower confidence of TSRA at MDT, but do expect some showers to
make way into the airfield with lower (~20%) on any restrictions
at the airfield at this time.

Outlook...

Sat...AM fog; otherwise, mainly VFR.

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

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

Tue...A couple of showers possible, mainly west of UNV.

&&

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

&&

$$

SYNOPSIS...Dangelo
NEAR TERM...Bowen
SHORT TERM...Bowen
LONG TERM...Dangelo
AVIATION...NPB