Heavy Rain and Flooding Concerns in Hawaii; Severe Weather this Weekend in the Plains; Pacific Storm in the West

A storm system near the Hawaiian Islands is expected to bring periods of heavy rainfall, strong winds, and isolated strong to severe thunderstorms through Friday. Several rounds of severe thunderstorms are forecast to impact parts of the Great Plains into the Midwest this weekend into next week. Moderate to heavy rainfall and high elevation snow is expected this weekend over California and Oregon. 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.

920
FXUS61 KCTP 100146
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
946 PM EDT Thu Apr 9 2026

.WHAT HAS CHANGED...
* Tweaks in near term for ongoing and future weak convection
across the nrn tier

&&

.KEY MESSAGES...
0) Made minor adjustments to near term to better reflect
convection.

1) Frost concerns return tonight with lower chances for
widespread frost formation across southeastern Pennsylvania.

2) Fire weather concerns continue through Saturday with lower
relative humidities and breezy winds. Little precipitation will
exacerbate drought across southern Pennsylvania.

&&

.DISCUSSION...
KEY MESSAGE 0: Made minor adjustments to near term to better reflect
convection.

Gust front moved through the NW counties and produced a 38KT
gust at BFD, despite having only shallow convection and no CG in
our CWA thus far this evening. Cooling, more-stable air is now
in place there, but dewpoints are into the U40s after the rain.
We expect there to be additional convection move across the nrn
tier overnight. Current batches of TSRAs over LE are headed
this way. It also should diminish in intensity and carry only
light rain as it moves through.

-------------------------------------------

KEY MESSAGE 1: Frost concerns return tonight with lower chances
for widespread frost formation across southeastern
Pennsylvania.

A sneaky set-up for frost exists across portions of southern
and southeastern Pennsylvania overnight tonight, mainly for
areas along and east of the I-81 corridor. The exact coverage of
frost will remain extremely dependent on the presence of the
low-level cloud deck that is expected to form late tonight into
Friday morning. This low-level cloud deck would allow for
temperatures to not radiate (temperatures get cooler) which
could nix almost all mentions of frost in these regions. A
secondary area of concern is that there could be a light breeze
continuing throughout the hours where clear skies are most
progged by model guidance with winds trending calm after the
low-level deck clears the region.

Most of the zones in the aforementioned region have had their
growing season activated due to the recent warm temperatures and
looking at current growing degree days (GDDs) compared to
climatology, so we`ll need to continue watching near-term trends
in these zones over the next couple of hours for any hazard
mentions. Dewpoints are expected to rise late this
afternoon/evening and are forecast to rise into the mid-to-upper
30s based on a combination of HREF/NBM model guidance. Recent
hi-res model guidance also supports this idea with model
guidance also keeping onto a light breeze throughout much of the
overnight period. RH cross-sections at MDT/LNS do indicate
increasing low-level moisture, with HREF model guidance (which
typically performs fairly well with respect to cloud cover)
indicating the potential for low-level cloud deck formation
after midnight and into the early morning hours on Friday.
Joint probabilities from HREF indicate that the potential for a
favorable environment for frost formation (T <= 36, Gusts <= 5)
as achievable; however, only a 10-20% chance for this to occur.

-------------------------------------------

KEY MESSAGE 2: Fire weather concerns continue through Saturday
with lower relative humidities and breezy winds. Little
precipitation will exacerbate drought across southern
Pennsylvania.

Relative humidities this afternoon have dipped into the upper
20% to lower 30% range, with southerly flow allowing for warming
temperatures this afternoon. A similar set-up exists for Friday
ahead of the cold frontal passage with recent model guidance
indicating that portions of southwestern Pennsylvania could dip
into the low-to-mid 20% range Friday afternoon. Low-level dry
air above a weak inversion has been noted on model soundings on
Saturday as well; however, the best chances for this low-level
air to mix down across portions of southeastern Pennsylvania
with some model guidance outlining 850mb Tds pushing closer to
the -20C mark at LNS on Saturday afternoon. This area will also
be compounded by lack of rainfall with the upcoming system, as
recent NBM model guidance has dropped nil in terms of
measurable rainfall south of the Turnpike through Saturday
evening. This lack of rainfall, in areas that are currently
under D1-D2 (moderate to severe) drought will continue to be dry
in the mid-range with no precipitation mentions coming until
the middle of next week.

The main concern with respect to the forecast will be minimum
relative humidities over Friday and Saturday where recent HREF
model guidance indicated a fairly wide spread in the 25th and
75th percentiles for RHs. The highest spread in these RHs on
Friday will be across the central third of the area, where
spreads pushing 30% area possible. Current forecast trends
closer to the 25th (mixed in with NBM model guidance) given dry
air in place across the region; however, there is a situation
where these might still be slightly too high. Reasonable floor
for Friday ranges between 25%-30% across the central third of
the Commonwealth with slightly higher east and much higher west
closer to the cold front. Much drier air in the lower levels
behind the cold frontal passage will also allow for undercutting
of NBM Tds on Saturday; however, the cold front is not notably
strong so winds might not be as robust and could limit fire
weather concerns; however, this will need to be monitored in
future forecast packages.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
A gusty line of showers moved across Bradford just before 00Z
and proceeded to fall apart as it moved east. A few more rounds
of showers are expected there late tonight, but VFR conditions
should persist. The main area of concern in the first 12-15
hours of this TAF package will be at KLNS and KMDT as southeast
winds usher in a marine layer of low clouds after midnight.
Similar to last night, a low-end MVFR deck is favored but its
extent and duration will likely exceed that of Thursday morning.
IFR is favored at LNS, MVFR is favored at MDT, and MVFR is
possible (~30% prob) at IPT. If a low deck of clouds develops at
those airfields, it will likely be slowest to erode at IPT,
perhaps lingering until 15 or 16Z.

Gusty winds will develop again on Friday afternoon across the
entire area, perhaps gusting as high as 25 or 30 knots at KBFD,
and KJST. By Friday afternoon, another round of rain will begin
to encroach on northwest PA, with lowering clouds ahead of the
rain. Restrictions should arrive at KBFD between 20-22Z with
subsequent lowering to IFR ceilings. Additional restrictions are
expected at KJST, KAOO, KUNV, and KIPT along and behind the
front, but any impacts will occur after 00Z (beyond the current
TAF period).

Outlook...

Friday Night...Lingering restrictions northwest

Sat...Restrictions possible early, then trending VFR.

Sun...Mainly dry. Maybe a shower near the NY border.

Mon-Tue...Chance of showers, mainly N/W later in the day.

&&

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

&&

$$

WHAT HAS CHANGED...Dangelo/Beaty
KEY MESSAGES...Dangelo/Beaty
DISCUSSION...Dangelo/Beaty
AVIATION...Banghoff

Forecaster's
Discussion: