559
FXUS61 KCTP 061136
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
736 AM EDT Thu Jun 6 2024

.SYNOPSIS...
*Muggy this morning with showers then breaks of sun with a
 gusty shower or thunderstorm in spots during the afternoon
*Cooler and showery pattern Friday through Monday with
 temperatures below average for early June

&&

.NEAR TERM /THROUGH TONIGHT/...
730AM/1130Z: MCV continues to track across NW PA located near
KDUJ. This should keep bulk of shower activity across the
northern tier early this morning before focus shifts farther to
the east. Overall, little to no change from previous fcst.

Previous Discussion Issued: 458 AM EDT Thu Jun 6 2024

MRMS radar mosaic shows main batch of showers limping into the
western Alleghenies at 08Z along/ahead of leading cold front and
MCV/weak sfc low curling to the north of KPIT. There are a few
light showers drifting across the middle and lower Susq Valley,
but overall this region will be in a predawn precip "lull" due
to sinking air or subsidence in between MCV north of KPIT and
another one well downstream near NYC.

Hires model data shows ongoing shower activity weakening over
south central PA through the remainder of the morning and
becoming more concentrated across the northern mtns into the
Poconos through midday. The primary focus for showers and
potentially strong/severe t-storms will shift to the east of
the Susquehanna River after 16-17Z with the D1 SPC MRGL risk
clipping the eastern periphery of the CWA. The best deep layer
shear lags behind the instability axis that will reside over
eastern PA this afternoon, but increasing WSW mid level flow
should be sufficient for some organization with gusty winds the
primary hazard. The stronger storms could form just to the east
of the CWA so frontal placement and CI location early this
afternoon will be important.

Clouds are likely to break for some sun by the afternoon across
most of CPA based on HREF cloud cover and extrapolation of
upstream dry/clearing slot on IR/WV satellite imagery. A
westerly breeze will advect drier air into the region by late in
the day with max temps trending ~5 degrees warmer vs. yesterday.

Shower activity moves east/fades through tonight along with a
noticeably drop in humidity/dewpoints. This will result in a
cooler and more comfortable (less humid) night with min temps in
the 50-60F range. Shower risk does begin to ramp up downwind of
Lake Erie toward daybreak Friday as upper low and cooler temps
aloft begin to impinge on NW PA.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Upper troughing is forecast to extend from the Canadian Prairie
Provinces southeastward through the Mid Atlantic region early
Friday morning, anchored by a pair of closed lows, one over
central Saskatchewan/Manitoba and the other near Lake Huron.
The setup looks favorable for diurnal showers and storms Friday
afternoon as vortmax rotates through northern PA. This feature
exits to the northeast Friday night with a modest rebound in
500mb heights Friday night into Saturday -- suggesting a mainly
dry 12-24 hour period. Another shortwave embedded in the large
scale trough pattern should spread showers back into the
northwest half of the area Saturday night into Sunday.

High temps in the 65-80F range will run near to several degrees
below early June climo with the largest departures (5-10F) over
the western mtns.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Reloading of the mean Glakes/NE U.S. upper trough by a few
shortwave troughs dropping Southeast will maintain the chc for
mainly diurnal showers/isolated to sctd TSRA through Monday.

Current indications are that by the end of the weekend into
early next week, the upper tough becomes positively tilted and
the low may retrograde slightly and stall over the Great Lakes
region, especially considering the additional energy helping to
deepen the trough. This will continue the unsettled pattern of
diurnally driven showers and thunderstorms through at least
Monday afternoon. Long range ensembles currently show the trough
lifting after Tuesday morning with lower pops for showers/TSRA
as we head into the middle of next week.

Temperatures are likely to average somewhat below climatology
for early to mid-June, with daily highs in the upper 60s and
70s, and overnight lows in the 50s to lower 60s.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A variety of conditions exist this morning with high end
MVFR/low end VFR prevailing for most sites. BFD remains LIFR
this morning as the center of a mesoscale convective vortex
moves overhead. This complex will continue to generate showers
through mid morning and bring MVFR conditions to many sites.

Improving flying conditions are anticipated later this morning,
as a trailing cold front comes through followed by the arrival
of a drier southwest flow. Model RH profiles support
predominantly VFR conditions Thursday afternoon and evening.
West winds will occasionally gust to 15 to 20 kts.

A few thunderstorms could form on the cold front as it crosses
the Lower Susq Valley early Thu afternoon, bringing the chance
of a brief vis reduction in vicinity of KMDT/KLNS. Also, latest
HREF indicates a brief shower/vis reduction will remain possible
across the Allegheny Plateau (KBFD/KJST) through early evening.
Later tonight, VFR conditions will prevail with only a few
scattered clouds.

Outlook...

Fri...Slight chance of a brief PM shower/vis reduction, mainly
NW Mtns.

Sat-Mon...AM low cigs possible NW Mtns. Slight chance of PM
shower/vis reduction NW Mtns.

&&

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

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Lambert/Fitzgerald/Bowen
AVIATION...Banghoff