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205
FXUS61 KCTP 022318
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
718 PM EDT Thu May 2 2024

.SYNOPSIS...
-Warm/dry weather with lower humidity continues for Friday as
 high pressure slides to the northeast.

-Unsettled starting Friday night with occasional showers and
 thunderstorms. The heaviest rain will be Friday night in the
 west and Saturday in the southeast.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --
Previous discussion... Dry air covers the entire CWA, now with
Td 33F at BFD and readings nearing 50F in the far SE. The upper
high is right overhead and keeping even the high clouds at bay
for now. There will be some high clouds move in from the west
overnight, but not thick enough to affect the sfc temps. Expect
mins in the m40s at BFD to the m50s in the SE as the wind goes
calm in lots of places.

715 pm update... All remains quiet this evening, with very dry
boundary layer air in place across the Commonwealth. Upstream
satellite imagery and near-term model guidance shows a gradual
influx of higher-level cloudiness later tonight into Friday
morning, but that looks like about it. Some of our guidance is
suggesting that an area of maritime low cloudiness could impinge
on NJ and far eastern PA, but we think this lower cloud mass
will very likely stay east of the Susquehanna Valley overnight
and early Friday.

By daybreak, low temperatures should range from the mid 40s over
the northern mountains, to the mid 50s over south-central PA.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Sfc ridge slides E/NE on Fri, and moist return/srly flow brings
dewpoints back into the u50s W and l50s E. Stability dips over
the western mtns with TSRA popping by mid-aftn in the highest
elevation of the Laurels and in the ANF/far NW. These should
multiply and spread to the east through the night. Some of these
could be moving slowly and PWAT will be 1.25" over the west by
sunset. FFG is 1-1.5"/1hr in the west, and slightly higher
east. Thus, there is a MRGL risk for excessive rainfall over the
western third/half of the CWA due to potential for heavy
rainfall. Have increased PoPs to likelies and low-end catg for
Fri night for the SWrn half of the CWA.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
-Noticeably cooler this weekend with periods of rain
-Trending warmer/above climo but remaining unsettled next week

A slow moving frontal system combined with anomalous pwats will
bring periods of rain to central PA this weekend. A few non-
severe thunderstorms are possible, most likely along and west
of the Alleghenies on the edge of warmer air surging into the
upper Ohio Valley. The eastern slopes of the Alleghenies into
the Susquehanna Valley will noticeably cooler with rain, low
clouds and moist southeast flow. We trimmed max temps on
Saturday due to the CAD pattern setup. Rain/showers continue on
Sunday with highs recovering ~10F on the western and southern
periphery of the CWA. Despite the relatively high moisture
available, overall stability should limit rain rates especially
east of the mtns and preclude flooding risk. 48hr blended mean
QPF ranges from 0.50-0.75" with spot amounts up to 1 inch
possible.

The front stalls near or south of the MD line before lifting to
the northeast (as a warm front) into midweek. The favors the
best chance for rain the SW zones on Monday before POPs increase
to 50-70% Tuesday into Wednesday. After a weekend cooldown,
temps are forecast to trend warmer/back above climo into the 70s
to low 80s next week.

&&

.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
An upper ridge has crested overhead, keeping the sky clear. WNW
sfc winds are gusting into the teens. Tranquil weather will
persist through tonight with diminishing winds thanks to the
high pressure aloft and to our NE. Expect a return/srly flow to
develop in the morning on Friday. This will help generate more
cu, and decrease stability, esp in the W. SHRA/TSRA are expected
late aftn/evening Friday at JST and BFD. A warm front will rise
into wrn PA on Friday, but stall out there until Sat when a
cold front catches up and pushes it eastward. This will push the
SHRA/TSRA to the east and across the rest of Central PA.
Widespread SHRA/TSRA are expected Friday night into Sunday. The
heaviest rain will be Fri night over the W and Saturday
aftn/evening in the SE. IFR restrictions will be possible Fri PM
into Sunday.

Outlook...

Sat PM-Sun...Widespread restrictions across the central and
western mountains due to low cigs. SHRA likely with a chance of
TSRA.

Mon-Tues...AM fog/clouds poss. PM -SHRA possible areawide.

&&

.CLIMATE...
Several records were tied or set on Thursday May 2nd:
SITE       OBSERVED TEMP      PREVIOUS RECORD
Altoona         87F             87 in 1954
Harrisburg      90F             88 in 1913
State College   ??*             86 in 1938
Williamsport    89F             89 in 2018

*Official report from State College will be available Friday
 morning.

May 2nd was also the first 90F day at Harrisburg. It is the
13th earliest 90F day on record. The earliest 90F day occurred
on April 17th in 1896 and 2002. The average first 90F day is
June 1st.

&&

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

&&

$$

SYNOPSIS...Dangelo
NEAR TERM...Jurewicz/Dangelo
SHORT TERM...Dangelo
LONG TERM...Steinbugl
AVIATION...Jurewicz/Evanego/Colbert
CLIMATE...Steinbugl/Banghoff