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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 251112
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
712 AM EDT Thu Apr 25 2024

.SYNOPSIS...
-Rain-free end to the week with low humidity & frost/freeze
-Showers to start the last weekend of April; not a washout
-Major warmup Sunday-Monday with summer-like temperatures

&&

.NEAR TERM /THROUGH TONIGHT/...
650AM/1050UTC: Expired frost/freeze headlines for all but the
NW mtns. Clouds and a light wind held temps above the freezing
mark/prevented frost formation in most areas.

Previous Discussion Issued: 438 AM EDT Thu Apr 25 2024

IR satellite trends at 4AM/08UTC show low clouds holding firm
and expanding in coverage over south central PA early this
morning. Radar is even detecting some spotty light rain/dz to
the southwest of State College. The clouds have been holding
temps above the hourly fcst which casts serious doubt on
frost/freeze potential in some locations. With the NPW headline
expiring at 8AM, we will continue to monitor with reduced
confidence in both sub freezing temps and frost formation early
this morning. The latest hires model guidance and slower
improving remote sensing observational/satellite trends suggest
the sky cover fcst may not be high enough over the southern tier
and will address this with the next forecast update.

Outside of cloud trends, the only other potential concern today
is fire wx given curing fuel moisture and low humidity this
afternoon (see fire wx section for more info). Highest
confidence in clearing tonight is over northern areas with
renewed frost/freeze risk. We will continue to highlight this in
the HWO and allow dayshift to coordinate/post headlines.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The sfc high strengthens to +2SD or ~1035mb as it drifts over
interior New England to Long Island by 12Z Saturday. Rain free
wx conditions will continue Friday with sun mixing with high
clouds and max temps trending warmer into the upper 50s to lower
60s.

Showers along a warm front are likely to move into the western
Alleghenies Saturday morning based on the latest operational
model/ens consensus. The rain will be moving into dry air which
will help keep QPF amounts below 0.25 inch. The second half of
the day Saturday into Saturday night looks increasingly drier
as the warm front lifts to the north of the Keystone State. Max
temp fcst is a little tricky with early day clouds and light
rain falling into a retreating dry low level airmass favoring
cooler solutions; while late day breaks of sun and milder
southerly flow could push temps a bit higher than fcst. Series
of higher nighttime lows continues through the weekend.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Late evening update holds very few changes to the long term.
Have kept the forecast very consistent with a very warm period
coming up.

Prev...
The weekend appears somewhat unsettled, with a warm front
arriving Saturday and warm sector struggling to overspread
central PA. It won`t be raining all the time, but a couple of
showers are likely on Saturday with a t-storm possible on
Sunday.

Upper ridging should eventually win out by early next week,
allowing for drier wx and much warmer temps with highs surging
through the 70s and perhaps topping 80F across the south on
Sunday. The warmest day of the extended period will be Monday as
temperatures soar into the 80s areawide. A bit humid as well
with fcst Td around 60F. This could support overnight lows near
record levels next week (near 60F).

Precipitation will be tough to come by in the extended period
without much gulf moisture sourcing. Decaying systems that bring
severe weather to the Plains will struggle to stay together and
7-day precipitation forecasts show very little rainfall across
southeast PA through the middle of next week with amounts only
approaching 0.75" in northwest PA.

&&

.AVIATION /11Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
The northern extent of the cloud cover continues to decrease
this morning, while clouds have filled in across the southern
tier. Overall, the trend will be towards less cloud cover and
higher ceilings through the day today. JST will likely be the
last location to see these low clouds move out, but they should
see ceilings rise to VFR by 18Z. After that point, there is high
confidence in VFR conditions persisting through the rest of the
06Z TAF period as the area will remain under high pressure.

Outlook...

Thu Night-Fri...Predominantly VFR conds under high pressure.

Fri night-Sat...Patchy rain developing from west to east.

Sun...Isold SHRA/TSRA possible.

Mon...Predominantly VFR.
-- End Changed Discussion --

&&

.FIRE WEATHER...
With fuel moisture potentially falling below 10% over the next
two days, there could be an elevated risk of wildfire spread
during the afternoons across portions of central Pennsylvania.
The dayshift will coordinate with PABOF/DCNR partners on the
possible issuance of a SPS to highlight fire wx risk.

MinRH this afternoon (Thu) is forecast to drop to 15-25% over
the northern half of the area with potential downside to 10%.
MinRH over the southern tier districts along the MD line is
forecast between 30-40%. The wind will <10 mph from the
north/northeast.

MinRH is forecast to recover a bit Friday afternoon bottoming in
the 25-40% range. However, the wind will increase from the south
southeast with gusts to 20 mph at times over the higher terrain
along the southern Allegheny Plateau.

Increasing low level moisture/dewpoints along with some rain will
limit fire weather concerns this weekend.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 8 AM EDT this morning for PAZ004-005-010-
011.

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Banghoff/Evanego
AVIATION...Bauco
FIRE WEATHER...Steinbugl