836
FXUS61 KCTP 082110
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
510 PM EDT Wed May 8 2024

.SYNOPSIS...
- A mainly dry cold front pushing through the Susquehanna Valley
  this afternoon will stall out just south of PA tonight.

- A strong wave of low pressure will move across southern PA
  Thursday evening bringing periods of rain, with some
  potentially gusty thunderstorms over the southwest third of
  the state.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Surface cold front, marked mostly by a moderately sharp dewpoint
drop, extended from the Poconos of NEPA to the Lower Susq Valley
at 1830Z.

Negative LLVL Theta-E advection and increasing wind/shear aloft
will continue to negate the chance for any cu to develop
vertical enough to produce precip along or ahead of this
boundary.

For the rest of this afternoon, look for good weather for most
outdoor activities with abundant sunshine and above normal high
temps by around 10 deg F. However, a gusty West-Northwest wind
(between 30-35KTS) will create good kite-flying weather, but
challenging conditions for the gold and Frisbee football
courses.

Temps are right around their fcst highs, varying from mainly the
mid 70s across the higher terrain of the north and west to the
mid 80s throughout the Southern Valleys and Lower Susq Region.

Sfc dewpoints have plunged to the U30s to L40s across the
Northern Mtns in the wake of the aforementioned front and
enhanced by deep subsidence beneath the right exit region of a
130 kt upper jet over Lake Erie.

West winds and gusts will steadily decrease around and shortly
after sunset before veering around to a lighter NW then
northerly direction between midnight and daybreak.

After an initially clear sky, high clouds will increase from
the SW.

Min temps will dip into the mid 40s across the north and mid to
upper 50s in the south.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Frontal boundary stalls near or just to the south of the
Mason/Dixon line late tonight/Thursday morning, and model
ensembles indicate a consensus sfc low track across SW PA then
likely across the Mason Dixon line or the Panhandles of MD and
WVA. SFC and elevated instability is minimal for all but
Somerset County Thursday.

Blended in the colder members of the NBM and NAM based on the
timing of increasing clouds later Wed night/early Thursday and
the showers/periods of steadier rain spreading north and cutting
off heating in the morning.

A flat/no-diurnal T curve is strongly in play for Thursday.

Max temps could struggle to reach 60 across much of Central and
northern PA and may hold in the mid 50s over the N Mtns.

Periods of chilly rain continue Thursday afternoon and night
with low clouds/fog shrouding the ridges.

Storm total rainfall for Thursday into early Friday are between
0.50 and 1.00 inch with some locally higher amounts possible.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
The aforementioned low moves off the coast on Friday and will
allow for relatively cool temperatures across central PA with
lingering showers as the unsettled pattern continues into the
weekend with an upper low crossing the region. The best chances
of precipitation tapering off will be in the overnight Saturday
morning period with chances increasing into the latter half of
the weekend.

Drier period will continue into the first part of next week, the
rest of the long term period, as upper level ridging
builds/moves across the eastern U.S. thanks to long wave
troffing being reconstituted across the Plains/eastern Rockies.
This will likely mean more rounds of strong to severe
thunderstorms for the Plains, but a more settled pattern and
milder temps in the East, at least for few days.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
Late afternoon discussion.

Minor adjustments made to the TAFS late this afternoon.

I did back off the timing of the rain a bit on Thursday, given
recent trends of the models to hold the main bands further
south, compared to recent days.

Earlier discussion below.

A cold front from the Poconos to the Lower Susq Valley this
afternoon will move southeast to the Mason Dixon line tonight
then stall out there through Thursday.

A drier westerly flow behind the front will maintain the
current, widespread VFR conditions for the rest of today and
tonight.

Winds will generally gust in the 20-30KT range behind the cold
front, but a few gusts in the mid-upper 30KT range are possible.

Periods of rain with lowering CIGS (and a few T-storms across
SW PA) will impact flight operations beginning during the mid
morning hours Thursday and continuing through Thursday night
(and likely Friday) as low pressure at the surface and aloft
moves east from the Ohio Valley.

Outlook...

Thu/Thu night...Periods of rain/low cigs possible, mainly from
Thu afternoon on.

Fri...Low cigs/drizzle possible, especially in the morning.

Sat...PM showers/low cigs possible, mainly W Mtns.

Sun...AM low cigs possible W Mtns. Sct afternoon showers/brief
vis reductions possible.

Mon...Still a chance of a shower.

&&

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

&&

$$

SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Gartner/NPB
AVIATION...Lambert/Martin