Harrisburg, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

590
FXUS61 KCTP 111714
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
114 PM EDT Fri Apr 11 2025

.SYNOPSIS...
*Cloudy, chilly and wet end to the week/start to the weekend
*Drying out Sunday with some sun and milder temperatures
*Warmer with late-day rain showers Monday followed by windy and
 cooler weather next Tuesday and Wednesday

&&

.NEAR TERM /THROUGH TONIGHT/...
Morning forecast holding well as moist southeast flow maintains
widespread low clouds and areas of light rain/drizzle/ridgetop
fog this morning with inverted sfc trough over the Alleghenies.

A deep layer 500mb trough evolving over the eastern Great Lakes
southward into the central Appalachians will amplify over the
Mid Atlantic region today as an jet streak rounds the base of
the trough and lifts northeastward along the coastal plain. Max
QPF response tied to favorable left exit region jet dynamics
and strengthening fgen forcing on the NW side of developing sfc
low along the VA/NC coast will be across the southeastern zones
with 0.75-1+ inch rainfall totals fcst near and southeast of
I81. Latest HREF indicates highest probability for >1" is near
and southeast of US30 corridor in Adams/York/Lancaster County.

Light rain/drizzle will continue over the northwestern half to
2/3 of the forecast area through tonight with QPF totals of less
than 0.50 inches. Thermal profiles tonight will be cold enough
to support a rain/wet snow mix over the higher elevations in the
northeastern quadrant of the forecast area, but sfc temps above
32F suggest any slushy coating <0.5" will be limited to non-
paved sfcs.

Cold air damming, combined with low clouds and rain, will
result in a very chilly end to the week by mid April standards
with highs in the mid 40s or 8 to 15 degrees below the historical
average.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
As the surface low tracks from the DelMarVa off the coast, the
llvl flow will back to the north. While QPF amounts will trend
substantially lower on Saturday (<=0.10"), residual wrap around
moisture within the cold conveyor belt/TROWAL on the northwest
periphery of the closed upper low will result in another chilly
and damp day across CPA to start the second weekend of April.
We trimmed daytime maxTs a bit in response to this cool pattern
setup.

Precip tapers off from NW to SE Saturday night. However, low
clouds are likely to get trapped beneath the subsidence
inversion associated with high pressure building into CPA into
early Sunday morning. Min temps will be similar to Friday night
in the 35-40F range.

More seasonable weather is expected on Sunday with a mix of sun
and clouds as high pressure migrates over the Keystone State.
Max temps are projected to climb by +10-15 degrees vs. Saturday
with highs in the 50-60F range or very close to daily climo. A
warm front lifting northeast from the Ohio Valley could provide
more clouds than fcst especially into Sunday night and maybe
even some light rain showers over southwest PA. Lows also trend
warmer vs. Saturday night with the largest MinT24hrChange of +5
to +10F across the western mtns where southerly return flow will
be most active into Monday.

More information below.

A return southwest flow between the exiting surface high and an
approaching cold front over the Grt Lks should result in a warm
Monday with maxtemps several degrees above climo.

The fast-moving cold front is progged to sweep across central
PA Monday afternoon/evening, accompanied by a round of showers
for most of the area. Strong large scale forcing and decent
moisture return support high POPs but relatively low QPF per
the latest EPS plumes (ensemble mean qpf 0.1-0.4 inches)

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
After a brief warm up late Sunday into Monday, before a return
to colder conditions for mid week, as a strong cold front moves
across the region on Tuesday.

Gusty winds and dewpoints in the 20s will prvail for mid week.
Recent wet conditions and ongoing greenup should offset the
risk of fire weather concerns.

Ridging across central Pennsylvania will give us a chance
of some dry and milder conditions for Thursday.

A series of weak lows will be possible by late week, with more
chances of wet weather.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
CIGS and visibilities have been dropping so far today.
Given the time of day, expect things to level off or perhaps
come up a bit, but expect conditions to lower once again
around dark.

Some rain moves into the southeast sites like MDT and LNS later
this afternoon, as an inverted trough lingers over the area.

Did not hit the rain real hard in the TAFs, but as the
upper level low and surface low cut off near the New
England coast, the area of rain could edge westward
late tonight into Saturday.

Not really seeing much change of VFR conditions before
later Sunday.

Outlook...

Sun...Improving conditions/trending VFR.

Mon...Chance of showers and perhaps a thunderstorm, mainly
late.

Tue-Wed...Gusty northwest winds. Perhaps a rain or snow
shower, mainly Tuesday and early Wednesday. Most of the
activity across the far west and northwest.

&&

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

&&

$$

SYNOPSIS...DeVoir/Steinbugl
NEAR TERM...DeVoir/Fitzgerald/Steinbugl
SHORT TERM...Fitzgerald/Steinbugl
LONG TERM...Martin
AVIATION...Martin