681
FXUS61 KCTP 171518
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1118 AM EDT Sat May 17 2025

.SYNOPSIS...
* Breezy and warm today with a mix of clouds and sun; scattered rain
  showers focused over the northern tier
* Partly to mostly cloudy, windy and cooler end to the weekend
  with isold rain showers downwind of Lake Erie
* Nice start to next week before trending cool and wet Wed-Fri

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
Ample moisture in the 60s at the sfc. BUt, a warm cap aloft
should limit vertical development of most cells that start up
this aftn. Timing may be a little quicker than earlier
expectations, but not more than an hour. Nearest SHRA is KCLE
w/no TS yet. Have kept thunder chcs lower then straight PoPs
due to the cap. SPC has us out of even general thunder today.

Prev...
The latest model data suggests the cold front pushing eastward
through the Upper Ohio Valley traverses CPA with little more
than scattered rain showers through the afternoon. The 17/06Z D1
initial convective outlook from SPC even removed general
thunder. There is a strong signal for measurable rain showers
focused across the northern tier later today as the upper low
tracks across the eastern Great Lakes. Dewpoints trend lower
throughout the day behind a gusty (25-35 mph) west-southwest
wind. Max temps this afternoon will likely be the warmest over
the next week with highs near 70F in the far NW mtns to the
lower 80s in the lower Susquehanna Valley.

The synoptic pattern takes on more of a cool season cyclonic NW
flow regime tonight into Sunday with cloud cover and periods of
showers concentrated over the NW Alleghenies. The clouds and NW
breeze will limit the diurnal range with min temps generally in
the 50-60F range or about +5-10F above climo (-10F lower
night/night).

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SUNDAY/...
The weekend will end partly to mostly cloudy and noticeably
cooler with a gusty west wind 25-35 mph adding to the relative
cool down. Max POPs for light QPF rain showers/sprinkles remain
focused downwind of Lake Erie and across the northern tier.
Daytime temps trend 10 to 15 degrees lower vs. Saturday in the
upper 50s NW to ~70F in the southeast. Canadian high pressure
starts to nose into the area Sunday night providing cooler temps
45-55F and a declining WNW breeze.

All signs point to a nice start to next week as ridging
sfc/aloft gets pinched in between another blocky pattern taking
shape over the eastern CONUS. Look for a seasonably mild day
with more sun than clouds and highs in the 60-75F range. Monday
night looks chilly and potentially frosty under a mainly clear
sky and light wind. Areas of frost are most likely across the
northern tier with below normal PWs and min temps in the low-mid
30s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
GEFS 850T anomaly shows a slight downward T trend for Monday
into Tuesday with neutral/warming and ridging aloft. This will
help day time temps reach the mid 60s to low 70s while allowing
for mainly clear and chilly conditions Monday night with a
potential for frost over central and northern PA with PWAT
values dipping to well below normal - or 0.3 to 0.4 of an inch.

The wet and disturbed weather pattern makes a return for the
middle of the week. The mid to late week period is highlighted
by another fairly sharp trough axis moving across the region on
Wednesday- Thursday, preceded and accompanied by numerous
showers and a chance for afternoon TSRA. The trough will also
bring in notably cooler air for the second half of the work week
as both the GFS and EC are in fairly good agreement on yet
another closed low moving over or just to the north of PA
(though the EC is about 12 hours or so slower with this
feature). Expect highs for the end of the week to struggle to
reach the mid 60s across the southeast and remain in the upper
50s to the north.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Winds will become gusty in the east shortly. MVFR clouds in the
N/W should lift some as the sfc heats up. VFR conditions should
rule elsewhere until SHRA move in from the NW. The timing for
these showers is early to mid-aftn in BFD and mid-aftn to early
evening in IPT/UNV/AOO/JST. The cold front pushing through will
be undercutting some pretty warm air aloft. That should keep
vertical depth of the convection below where lots of ice/graupel
should form, thus reducing the chc for TS. Reductions in flight
cat due to the SHRA are limited with fairly light and moving
SHRA expected. Just a small (20 pct or less for most terminals)
chc of TS as these SHRA move through, so no mentions yet. BFD
may have a 30-40pct chc TS, so will prob add a prob30 to them
for the 17-20Z timeframe.

Outlook...

Sun...Mainly VFR. Isold SHRA NW (BFD).

Mon-Tue...VFR.

Tue PM-Wed...Ocnl SHRA/TSRA.

&&

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

&&

$$

SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo/Colbert
LONG TERM...Bowen
AVIATION...Dangelo