465
FXUS61 KCTP 130540
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
140 AM EDT Mon May 13 2024

.SYNOPSIS...
A warm front will brush northern PA on Monday before a cold
front pushes through on Tuesday. A wave of low pressure
tracking south of the Commonwealth will continue showery
conditions on Wednesday with drier conditions expected
Thursday and Friday.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
Clouds and precip continue to diminish as expected with only a
small patch of WAA mid-clouds drifting in to make the sky fcst a
little different for a few hours. That may impact some Aurora
peeking. Fog is seen in the valleys of Tioga/Potter and other
nrn tier counties already and should expand as advertised. No
very-low clouds have yet developed, but these are still
expected (70% confidence) over the east as the clouds in place
over the east diminish and fog and light SErly wind combine.

Prev...
SHRA and clouds are dwindling as we lose the heating of the
day, which is right on track with the going fcst. Surface
ridging building into the region will help to diminish the cloud
cover even more over the next few hours. But...the eastern half
of the area will have recently-wetted ground. The winds should
go light and promote fog development. Some drier air/lower sfc
dewpoints in the west should keep the fog more patchy there vs
more- widespread in the east. Ensemble prob charts continue to
indicate that the eastern part of the state is likely to see the
reprisal of low clouds and/or fog shortly after the rain and
clouds diminish. Given the low certainty/confidence of either
fog or low cloud development (could be either - or both), we
won`t be posting a fog advy just yet. However, be prepared for
foggy conditions for the morning rush, especially in the eastern
valleys. The western half of the CWA *may* be able to glimpse
the waning aurora tonight, but given latest space weather
forecasts that window appears to be closing quickly with the
best Aurora conditions expected to stay a little farther north
tonight than the past nights.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
Upper level ridging building over PA should result in a warmer
and drier Monday overall. However, a weak area of low pressure
and its attendant warm front lifting through the Eastern Grt Lks
could produce a few morning showers or afternoon tsra across
the northern half of PA. Partly sunny skies and a developing
southwest flow should push readings into the low to mid 70s.

A wave of low pressure will approach from the Ohio Valley
Tuesday before crossing the area Tuesday night, accompanied by a
renewed chance of rain and perhaps some thunder.

Low pressure slides off of the Mid Atlantic coast on Wednesday
with decreasing showers expected by Wed aftn and evening. We may
see our best drying period in over a week arrive Wednesday
night and potentially last into Friday.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Late evening update holds no big changes to the long range fcst.
Thursday-ish still has the possibility of being dry for most
locations. The S may have isold diurnal convection - but
shortwave ridging will likely keep it dry. Left the 20-30 PoPs
in for Thurs given by the National Blend respecting the low
predictability of timing and strength of mesoscale features,
like the aforementioned small ridge aloft, at this range.

Prev...
Lingering unsettled weather is possible into Wednesday, as
upper-level low pressure passes overhead.

Medium range models diverge a bit late this week. The ECMWF
continues to show unsettled weather persisting into Thursday,
as the upper- level low pressure very slowly pulls to our east.
The GFS/GEFS is a bit more optimistic, showing an upper- level
ridge bringing a period of dry weather from Wednesday night
through early Friday.

Both medium range models are in agreement in bringing our next
weather maker into the area later Friday into Saturday with
another round of showers and thunderstorms. The result would be
another Saturday with rain, easterly winds, and below average
temperatures - a beloved tradition over the last couple months
in Central PA.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
High pressure, clearing skies, and light winds will be the story
of the night across much of Pennsylvania. Given the conditions
for efficient radiational cooling fog has already begun
developing in the valleys across the north east and the Lower
Susquehanna Valley. Fairly strong signal for IFR conditions due
to low clouds or fog at MDT, LNS, and IPT. It`s possible these
sites could see 1/2 mile visibility restrictions in the pre dawn
hours. UNV has a small chance (~10%) of lowered conditions
toward daybreak.

After fog lifts/mixes out, VFR conditions prevail for everyone
on during the day on Monday. High pressure riding will become
dominant; however, a few light showers will impact northern
airfields Monday (BFD, UNV, and IPT), but no restrictions are
expected at this time.

Outlook...
Tue...Showers/tstms and reductions developing.

Wed...Showery weather and reductions continue.

Thu...Slow improvement, with a few lingering showers possible.

Fri...Deteriorating conditions with showers increasing.

&&

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

&&

$$

SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...Dangelo/Banghoff
AVIATION...Bowen