388
FXUS61 KCTP 060246
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1046 PM EDT Wed Jun 5 2024

.SYNOPSIS...
A warm front extending from Eastern Lake Erie to the Greater
Philadelphia Area will lift slowly northeast overnight, followed
by a cold front pushing east through Western and Central
Pennsylvania on Thursday.

It will turn breezy and less humid behind the front on Thursday
with near to slightly above normal high temperatures.

Friday and Saturday will be cooler and less humid with diurnal
showers that will be most numerous across Northern PA.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Surface warm front extended from near KERI to KUNV and KLNS this
evening with the axis of steadiest and heaviest rain over the
past 6-8 hours being located near this boundary`s current
position.

SFC cold front was slicing through the NW half of Ohio attm and
will push into the Western Mtns of PA during the early to mid
morning hours Thursday and the Central Mtns during the late
morning/early afternoon.

A relative mid in POPS with only isolated to scattered showers
will be found across our Central Zones and Susq Valley between
04Z and 12Z.

The far eastern zones seeing a likelihood of lingering showers
and TSRA, linked to the nose of the Swrly LLJ (ahead of a
compact mid/upper level shortwave) riding up and over the
aforementioned warm frontal boundary and causing highly
efficient showers of varying intensity.

Compensating subsidence in the wake of this meso-B feature and
veering, westerly flow aloft will lead to will mean little
additional QPF overnight over much of the Central third or so of
the CWA and less than 0.75 of an inch in the east as
instantaneous precip rates are below 0.25 of an inch across the
bulk of the region.

Scattered showers/TSRA will move back into the western zones
late tonight, along and ahead of the cfront.

PWATS hovering between 1.5 and 2 inches over the entire CWA will
lead to a muggy /warm night with temps ranging through the 60s,
to near 70F in the SE metro areas. Sfc dewpoint will only be a
few deg F lower.

The threat for any poor drainage and small stream flooding
issues will be steadily decreasing overnight across Central PA
and the Susq Valley.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Primary cold front will be moving into the Central Mtns later
Thu morning/midday hours with PWAT values dropping to between
0.8-1.0 inch for much of the afternoon, prior to the much drier
air pushing in Thur night with PWATS under 0.7 of an inch.

Left <50 PoPs in the east during the morning. Additional
convection is expected, esp in the W) in the aftn as a secondary
cfront moves through and the upper cold pool nears. Thurs night
stabilization should diminish/kill most of the precip, but some
fog is possible as we cool off to near dewpoints. Maxes
Thursday will be similar to today, but humidity should get down
to about 50pct for most of the CWA, much less humid.

Friday should be more typical of a late-spring day under an
upper low. A channel of higher vorticity rolling across the
area should make numerous SHRA/TSRA. The showers should spread
from NW to SE thru the day/aftn, but might not get into the
Lower Susq. Maxes Fri should be much below normal with m60s in
the NWrn Alleghenies and nearer to normal with u70s over the SE.

&&

.LONG TERM /SATURDAY 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 much of the
extended period.

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 /02Z THURSDAY THROUGH MONDAY/...
Deteriorating flying conditions are expected this evening, with
showers, isolated thunderstorms and falling cigs ahead of an
approaching warm front. Latest HREF prob charts support MVFR
cigs becoming widespread this evening, with IFR cigs likely over
the higher elevations, especially over Northern PA. Latest
guidance indicates the warm front will lift into Southern PA
after midnight, resulting in a return to predominantly VFR
conditions over that part of the state, while IFR cigs persist
over the N Mtns of PA.

Improving flying conditions are anticipated late Thursday 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.
However, 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.


Outlook...

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

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

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

&&

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

&&

$$

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