Heat the Southwest; Fire Weather in the Central U.S.; Kona Low Impacting Hawaii

A rare March heat wave is ongoing with much above-normal temperatures over the Southwest U.S. through this weekend. Periods of critical fire weather will persist from the central Rockies to the central and southern Plains through the weekend as gusty winds and low relative humidity continue. A Kona low will continue to bring several rounds of moderate to heavy rainfall to Hawaii through Sunday. Read More >

Here is the latest Area Forecast Discussion for Central PA

This text statement is the latest forecast reasoning from the NWS in State College, PA

See the links at the bottom of the page for previous issuances/versions of the statement as well as our other text statements.

107
FXUS61 KCTP 210545
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
145 AM EDT Sat Mar 21 2026

.WHAT HAS CHANGED...
Welcome to Spring!

Minimal changes from previous forecast cycle.

&&

.KEY MESSAGES...
1) A couple of strong to locally severe thunderstorms are
possible across parts of southwest Pennsylvania mainly late
today into the evening

2) First weekend of Spring warmup precedes rain later on Sunday
into Sunday night followed by breezy and much cooler conditions
for Monday

&&

.DISCUSSION...
KEY MESSAGE 1: A couple of strong to locally severe thunderstorms
are possible across parts of southwest Pennsylvania mainly late
today into the evening

Convection moving into Somerset Co is sub-severe at the moment,
but bears watching. It is riding a boundary and developing into
a line. However, the risk for flooding is rather low since
PWATs are rather low and individual cell movements are pretty
fast. This continues to look like the last hurrah for convection
for the night. Once this passes through, our only trouble will
be the advection fog starting to show up across the N and at IPT
already. Some radiational fog is possible S of I-80, but most
of the fog will be low clouds hitting the terrain. Will also
keep watch over the visibilities for a possible dense fog advy.

Prev...
No change to the SPC outlook for Day 1 which still shows a level
1 out of 5 (marginal) severe t-storm risk across the Upper Ohio
Valley into southwest PA.

Widespread layered clouds have advected ESE and now blanket
practically all of the CWA late this afternoon at the nose of a
theta-E ridge - associated with the Swrly LLJ to the South of
an approaching cold front (Southern Lake Huron to the South
Shore of Lake Ontario) and warm front (across Central and
Eastern NY).

LLVL dewpoints within this moist axis range through the 40s,
but low to mid level directional and speed shear will be
increasing as we head through the afternoon/evening hours with
enhanced deep layer UVVEL associated with the thermally indirect
branch (and left exit region) of a 140+ kt nwrly upper level
jet approaching our western zones later this afternoon.

There will be a few to several hour gap with clearing skies
across eastern OH and Western PA late today and early this
evening that will allow the boundary layer to destabilize with a
few to svrl hundred J/KG of CAPE developing and supporting a bkn
line of +SHRA/low-topped TSRA.

Details noted below w/respect to the type of convection and
somewhat limited severe weather threat are still valid.

Hires models depict rain expanding from NW to SE this through
the rest of the afternoon and evening along/ahead of a cold
front. Instability (MUCAPE <500 J/kg) will be limited and
confined mainly to locations near and south of I-80. However,
strong deep layer shear profiles and steep low level lapse rates
will pose an isolated risk of locally strong/severe wind gusts.
Rain should exit most of CPA by 06Z with conditions drying out
to start the weekend.

KEY MESSAGE 2: First weekend of Spring warmup precedes rain
later on Sunday into Sunday night followed by breezy and much
cooler conditions for Monday

Max temps fcst to rise +10-20 degrees day/day to kickoff the
first official weekend of Spring. Highs on Sunday should reach
the upper 50s to lower 70s before a period of rain arrives late
in the day and lasts through Sunday night. A few t-storms will
be possible, with the primary severe risk located in the Ohio
Valley. Colder temps bleeding southward behind a cold front
could mix/turn rain to snow across the northern tier late Sunday
night into early Monday morning. High temps on Monday are
projected to be 15 to 25 degrees colder than Sunday and
punctuated by a chilly and brisk/gusty NW wind.

The rest of next week should feature more temperature swings up
and down with occasional light precip.

The best chance for snow showers next week (mainly across the
Northern and Western Mtns of PA) will be Monday and again
Tuesday night and Wed, followed by another round of rain
showers, mixing with or changing to snow showers late Thursday
into Friday.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Rain has exited the area this evening with some patches of
clearing allowing for some patches of locally dense fog
formation across central Pennsylvania. The highest probability
for restrictions will likely remain at BFD where ample low-level
moisture has allowed for a fairly persistent IFR cloud deck
that is expected to persist through 12Z Sat with high
confidence. The next airfields progged for IFR restrictions
would likely be at JST/LNS where some patches of clearing will
allow for fog formation. There will remain a non-zero
probability in IFR restrictions at the rest of central PA`s
airfields due to recent rainfall and some clearing; however, at
IPT/UNV there is lower confidence in widespread long-duration
IFR restrictions as a more expansive low-level cloud deck
~3000ft AGL is moving across the area, with another area of low-
level (still VFR) cloud decks traversing the Susquehanna Valley
and beginning to make it into MDT. That being said, most
uncertainty with respect to the visibility/ceiling forecast is
honed in in the next six hours, so aviators will need to monitor
current forecast/observational trends across central PA.

Widespread improvement towards VFR is expected after 12Z
Saturday for those airfields that experience restrictions
overnight. BFD/JST/LNS are more likely to remain down into the
morning hours before low-level cloud decks and any fog formation
will mix out leaving a broken deck of mid-to-high level clouds.
Fairly high confidence with respect to all airfields prevailing
VFR after 15Z Saturday and through the end of the 06Z TAF
package.

Outlook...

Sun...Rain overspreads north to south, restrictions possible.

Mon...Rain gradually tapers off north to south, transition to
snow possible mainly north of I-80 (BFD/IPT). Restrictions
possible within rain/snow showers.

Tue...Mainly dry with VFR conditions. Slight chance of snow
shower across northern PA late which could bring some
restrictions.

Wed...Rain and snow showers across northern PA with
restrictions possible.

&&

.CLIMATE...
Astronomical Spring (Vernal Equinox) officially kicked off today
March 20th at 10:46 a.m.

&&

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

&&

$$

WHAT HAS CHANGED...Lambert/Steinbugl
KEY MESSAGES...Lambert/Dangelo/Steinbugl
DISCUSSION...Lambert/Steinbugl
AVIATION...Beaty
CLIMATE...Steinbugl

Forecaster's
Discussion: