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000
FXUS61 KCTP 230838
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
438 AM EDT Tue Apr 23 2024

.SYNOPSIS...
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-Frost this morning; then breezy & warmer with low humidity
-Periods of rain showers tonight through Wednesday afternoon
-Rain-free late week with renewed frost/freeze risk Thu & Fri
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Another chilly start today with a frost advisory in effect
until 8AM for active growing season counties from the eastern
Alleghenies into the middle and lower Susquehanna Valley.

Sensible weather for the rest of today will feature low
humidity and breezy conditions (wind gusts 20-30 mph from the
south/southwest) with increasing high/mid clouds and mild
temperatures in the 60-70F range. The gusty wind+low RH combo
does raise some fire wx concerns (see fire wx section).

Hires ensemble guidance brings rain showers associated with
leading cold front/sfc trough into the far NW mtns by this
evening before expanding coverage across the rest of central PA
overnight into early Wednesday morning. QPF remains on the light
side (a few hundreths in the LSV up to ~0.25" in the NW) given
rather unimpressive moisture return evidenced by mean pwat
values below 1 inch.

Low temps tonight in the low 40s/50s are +10-15 degrees warmer
than the last two nights (no frost) thanks to an active
southwest to westerly breeze along with clouds/rain showers.
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&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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The main upper level shortwave trough swings through the area
early Wednesday, followed by a secondary cold frontal passage
during the afternoon. Latest hires model guidance shows
scattered low-topped diurnal convective showers developing thru
the afternoon with the potential to produce locally gusty winds.
SPC continues to indicate non-severe t-storm probs over the
southeastern portion of the CWA for Day 2 where HREF shows a few
hundred J/kg of CAPE. Highs on Wednesday will trend cooler and
range from the upper 40s in the northern tier to mid 60s in the
southeast. Expect rain shower activity to fade quickly toward
sunset/into early Wednesday night or shortly after 00Z Thu.

1030+mb Canadian high pressure building over the region
Wednesday night through Thursday night with below normal pwats
will bring dry wx/rain free conditions into late week. The main
focus will return to potential for frost/freeze conditions
which remain highlighted in the HWO.
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&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
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The next chance of rain will come Friday night into Saturday
associated with low pressure lifting into the Grt Lks and the
associated warm front approaching PA. Medium range guidance
indicates large scale forcing will be weak, with upper level
ridging over PA. Therefore, any rainfall should be on the light
side.

Both the EPS and GEFS indicate the warm front will lift north
of the region by Sunday and Monday, resulting in markedly
warmer and more humid conditions with scattered PM convection
possible. Mean progged 850mb temps south of the warm front are
around 12C, supportive of highs in the 75-80F range.
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&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
VFR conds are expected to prevail through 00Z Wednesday with
high (>90%) confidence. A SCT-BKN high-level (20,000ft+ AGL)
cloud deck will move into the area in the 00Z-02Z Tuesday
timeframe with some breaks of SKC expected to overnight. Winds
overnight will be light/variable with any sustained winds
expected to drop below 5kts sustained after 01Z Tuesday.

Later in the TAF period (after 18Z Tuesday), some lower clouds
will begin moving into central PA. At this time, model soundings
and the bulk of guidance suggests all airfields to stay above
VFR thresholds. If any airfields do manage to drop towards high-
end MVFR cigs, KBFD will be the most likely after 22Z within
stratiform rain. Highest confidence in MVFR cigs will be near
06Z Wednesday behind the passage of a cold front.

Outlook...

Wed...RA early with some MVFR cigs possible, Cloudy PM with
lingering showers and periods of MVFR Cigs and Vsbys.

Thu...Clearing as high pressure builds into the area.

Fri...Mainly dry, but increasing clouds late.

Sat...Rain moves in W early AM and continues throughout the day
with restrictions possible. TSRA possible W PA in PM hours.

&&

.FIRE WEATHER...
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Low humidity (20-30% minRH) and breezy conditions (20-30 mph wind
gusts from the south/southwest) could result in an elevated risk
of wildfire spread this afternoon. However, dead fuel moisture
values per latest PABOF/DCNR sitrep and ongoing Spring green-up
are both limiting factors offsetting the wind+RH fire wx risk
to a large extent in CPA.
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&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM EDT this morning for PAZ019-025>028-
034>036-045-046-049>053-056-057-059-063>066.

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Fitzgerald/Steinbugl
SHORT TERM...Lambert/Fitzgerald/Steinbugl
LONG TERM...Fitzgerald/Banghoff
AVIATION...NPB/Bowen
FIRE WEATHER...Steinbugl