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000
FXUS61 KCTP 240541
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
141 AM EDT Wed Apr 24 2024

.SYNOPSIS...
-Periods of rain showers tonight through Wednesday afternoon
 (mainly across the NW Mtns tonight)
-Rain-free late this week with a renewed frost/freeze risk early
 Thursday and Friday mornings

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
Rain did manage to make it to the ground at BFD. Dewpoint rose
into the u30s-l40s across the N where it did rain more than a
sprinkle. However, the very dry (20s) dewpoints continue for
much of the rest of the CWA> The next volley of showers moving
across wrn PA does have some gusty wind with it, as it is
probably mixing the wind down as the rain-cooled air reaches the
ground, too. Our local stability/dry air will break down some,
but not across the entire CWA. The SE/Lower Susq is more likely
to go without getting the ground wet overnight. Will leave
20-30 PoPs there.

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.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM THURSDAY/...
Looking at the accumulated Growing Degree Days (base 50F), it
appears that more of the CWA has hit the growing season. Thus,
we`ve expanded the Freeze Watch for Wed night/Thu morning into
more of the area - despite keeping the minT forecast as is. We
have kept the Laurels (Cambria/Somerset/Bedford) out of the
watch for the time being since current fcst is for mins in a
general 32-36F span. Note: Cambria and Somerset have been deemed
to be "in" the growing season, now. The areas not yet in the
growing season in Central PA are Schuylkill, Potter, Tioga,
Sullivan, northern Clinton and northern Lycoming Counties.

Prev...
The main upper level shortwave trough swings through the area
early Wednesday, followed by a secondary cold frontal passage
during the afternoon leading the way for a pool of slightly
anomalously cold air aloft (about -25C at 500 mb or about -1
sigma).

Latest hires model guidance shows scattered low-topped diurnal
convective showers developing during the late morning (Mainly
over the NW Mtns) and through the afternoon across the Central
and SE zones 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 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.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
We will have a chilly but tranquil start to the extended period
Thursday morning, with widespread freeze/frost expected courtesy
of sprawling Canadian high pressure ridging into the
northeastern United States. Plenty of sunshine is expected
on Thursday, helping temps rebound through the 50s to low 60s.

Another chilly night is expected Thursday night (especially
over eastern areas), before moderating return flow on the
backside of departing high pressure begins on Friday and brings
milder temperatures and increasing high cloudiness.

The weekend appears somewhat unsettled, with a warm front
approaching Friday night and the warm sector struggling to
overspread central PA. It won`t be raining all the time, but
periods of rain or showers cannot be ruled out from the Friday
night through Sunday.

Upper ridging may eventually win out by Sunday night and Monday,
allowing for drier wx and warmer temps with highs surging
through the 70s and perhaps topping 80F across the south on
Monday.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Rain showers have moved into the western portions of the area;
however, due to very dry conditions at the surface precipitation
is struggling to reach the surface. The rain that is reaching
the ground will remain light into the morning hours. The south
to southwesterly breeze has diminished a bit, but we continue to
see occasional gusts of 15-25 kts in some locations.

Cigs will continue to gradually lower overnight, with the
western highlands (BFD, JST) dropping to MVFR, if not IFR, by
daybreak on Wed. Low probability (<20%) of LIFR exists for BFD
in the afternoon, bit cigs are more likely to remain MVFR/IFR.
The central mtns will likely drop to borderline MVFR/VFR by
daybreak, with the Lower Susq Valley remaining VFR.

We should eventually see light rain showers make it to the
ground across the western highlands, but this activity is likely
to diminish as it progresses eastward overnight. There could
also be some LLWS during the early overnight hours, with a
35-45 kt southwesterly wind a couple thousand feet above the
sfc.

Surface winds will become northwesterly overnight, and become
gusty again by Wed afternoon. Spotty showers remain possible on
throughout the day as well before completely diminishing by the
early evening.

Outlook...

Wed...Spotty -SHRA with MVFR cigs west and predominantly VFR
east.

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

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

Sun...Scattered SHRA/TSRA possible.

&&

.FIRE WEATHER...
Low humidity (20-30% minRH) and breezy conditions (20-30 mph wind
gusts from the south/southwest) will result in an elevated risk
of wildfire spread late 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.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Freeze Watch from late tonight through Thursday morning for
PAZ004-005-010-011-017>019-025>027-045-046-049>053.

&&

$$

SYNOPSIS...Lambert
NEAR TERM...Lambert/Dangelo
SHORT TERM...Lambert/Dangelo
LONG TERM...DeVoir/Evanego
AVIATION...Evanego/Bowen
FIRE WEATHER...Lambert