086
FXUS61 KCTP 191926
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
326 PM EDT Sun May 19 2024

.SYNOPSIS...
High pressure is building into the region. Generally rain-free
conditions, light wind and warmer temperatures are expected to
hold through the middle of the upcoming week. A storm system
should arrive later Wednesday into Thursday bringing the next
chance of showers and thunderstorms to the area.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Subsidence in the wake of the upper trough is keeping the
vertical development of the diurnal cu to a minimum. There could
still be a few very light SHRA across the SE and Laurels where
some taller cu are seen on vis pics at 19Z.

The sky should become mostly clear out over most of the CWA for
a short time this evening/early tonight. But, there is still a
light easterly flow in the llvls to bring in Atlantic mstr
tonight. We do expect stratus to return to the ern half of more
of the CWA. There could also be fog around tonight, but lack of
rainfall during the day will argue against it. Dewpoints are
still near 60F, and we should dip to near the dewpoints
overnight. The more likely places to get fog will be in the
valleys. But, stratus could kill the chc for fog to form by
keeping it milder. Have kept mins 55-60F.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
As with Sunday AM, the low clouds which are expected to be over
the ern half or so of the CWA will have to burn away before we
realize the nice-ness potential of the day. The light SSE sfc
winds will not bring in much warmer air, but the lack of or
earlier dissipation of the stratus will help temps rise 5-8F
higher over the Allegheny Plateau vs Sunday. The rest of the
area will be within 2-3F of Sunday`s maxes. Just enough
instability develops across the nrn tier of counties in the aftn
to pop a lonesome SHRA/TSRA. Left PoPs in the 20-30pct range
for now. NBM and NAM are the most aggressive in making precip
there. The support aloft is tough to find except for perhaps a
short wave trough rolling over the Upper Great Lakes. The
heights do dip a little overhead. But, the NAM breaks the cap at
10kft around BFD in the aftn, while most other mdls (incl HRRR)
do not, or make only the thinnest of CAPE.

Mon night looks similar to the last few nights, but less of
(not as extensive of) a reprisal of the nighttime stratus. There
could still be some fog, but we`ve only mentioned patchy fog
for the time being. Mins will probably be 1-2F milder than Mon
AM.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Confidence is increasing in the timing of the frontal passage to
be Wednesday afternoon and evening. The surface low is currently
progged to be positioned north of the great lakes and track well
north of PA into central Ontario and eventually into Quebec. The
resulting cold front will track across the Ohio Valley and into
the Mid-Atlantic region. This will bring showers and
thunderstorms across PA late Wednesday into early Thursday,
however uncertainty remains as to the extent of these storms.
Southerly flow ahead of the front will bring warm air advection
and instability, but medium range guidance suggests these
storms could breakup as the front crosses into central PA.
Therefore PoPs have been capped at 60% for now.

After the front moves through, considerable uncertainty still
exists in terms of how much and how frequent rain will be. A
chance of showers remains in place through the end of the week
despite zonal flow aloft providing little in the way of synoptic
forcing. The next chance for a widespread soaking rain will
come during the weekend with a center of low pressure developing
across the Ohio Valley by Friday afternoon, and even the latest
guidance is suggesting these weekend showers could be scattered
to isolated given a lack of significant forcing and some ridging
building in Friday to Saturday.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Mainly VFR conditions prevail across the airspace for the early
afternoon; however a few sites are still stubbornly holding onto
MVFR low clouds. All sites should improve to VFR later this
afternoon. Can`t rule out a spotty shower this afternoon,
however very sparse coverage, low confidence (<20% POP) and
minimal operational impact will preclude mention from TAF. Focus
for tonight will shift back to fog (west/central) and low
stratus restrictions (east) into early Monday morning. Areas
that have mostly cleared will dry out making confidence in
widespread fog low, but a mention of IFR fog conditions have
been made in the TAFs for the eastern sites.

Outlook...

Mon...Patchy AM fog possible, then VFR.

Tue...VFR/no sig wx.

Wed-Thu...Chance of t-storms.

Fri...Mainly VFR, slight chance of showers.

&&

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

&&

$$

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