252
FXUS61 KCTP 072201
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
601 PM EDT Tue May 7 2024

.SYNOPSIS...
- A warm front will drift northeast across the area this
  evening with scattered showers and a possible thunderstorm
  across southern PA.
- Low pressure moves just north of the area tonight into
  Wednesday morning, brining showers and thunderstorms.
- A stronger wave of low pressure will move across southern PA
  Thursday evening.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A warm front will continue to track northeastward across central
PA this evening, with scattered showers expected mainly along
the spine of the Alleghenies and south of State College. SBCAPE
values generally remains in the 500-1000 J/KG range with
localized maxima across southern PA. Some elevated instability
so have kept in a SChc of thunderstorms across S PA
(Cambria/Blair southward) in showers this evening with highest
chances across the PA/MD border in the next couple of hours.

Temps did slightly overperform today, allowing for slightly
warmer than forecast MinTs this evening with increasing cloud
cover throughout the evening and overnight hours. MinTs will
remain fairly uniform ranging from the upper 50s across the
northern tier to lower 60s across the southern tier.

Low pressure moves toward PA and western NY late this evening
and will cross the area overnight. PWAT values topping out near
1.5" with an increase in CAPE will promote numerous SHRA/TSRA.
It is of note that recent runs of hi-res guidance does indicate
a slightly later arrival time with precipitation entering
central PA after midnight. Models continue to outline that the
area of greatest coverage remains across W PA in the 03-07Z
timeframe overnight as the nose of a moderately strong, 35-45 KT
LLJ approaches the region.

Intense/near-severe storms overnight shouldn`t get much farther
east than a BFD-UNV-AOO line. SPC has the SWrn corner of the
CWA into the MRGL risk for svr wx as a cold front moves through
the area. The period of showers and a few TSRA will peak
between about midnight and 5 AM across Central and Eastern parts
of the CWA.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Model guidance tracks the weak surface low north of PA
Wednesday, with a weak trailing cold front coming through during
the morning hours. Any morning showers should give way to
increasing sunshine, as drier air works in behind the front.
Model 850mb temps near 15C support highs ranging from the mid-
and upper 70s over the N Mtns, to the low and mid-80s in the
valleys of Central/Southern PA. Mixed in lower PWATs via the NBM
25 pctl values for Wed afternoon as sfc dewpoints dive into the
40s (and possibly a few u30s across the Northern Mtns) during
the late afternoon hours.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
While Wednesday will be mainly dry for much of the time, wet
conditions work back into the area for Thursday. A sfc low
still looks like it will track right along the PA, MD border.
High temperatures for the most part will be below 70 degrees,
and extensive cloud cover as well, will limit the chance for
thunder. SPC has slight near the border in the far southeast.
Storm development will depend on the track of the low and
if much in the way of heating can occur during the day on
Thursday.

While rain will not occur all the time on Thursday or be very
heavy, much of the day will feature at least some spotty rain
and drizzle.

While the low moves off the coast on Friday, cooling aloft will
result in a chilly day, along with some showers.

A brief break is likely for early Saturday, but another low
drops southeast later on during the weekend, so looking at no
real dry spells anytime soon. An upper level ridge building
across the western states will aid in keeping more of the same
type of conditions over our area into early next week.

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
Most or all of central PA will see VFR conds continuing through
early tonight with just some spotty, brief MVFR conditions in
isolated SHRA.

A warm front extending from KBFD to KUNV and KMDT at 1830Z will
lift northeast across the remainder of the region late
today/tonight. A potent upper level disturbance and sfc cold
front will push east from the Ohio Valley later tonight and
early Wed, preceded by a 4-6 hour period of LLWS late tonight
and early Wed morning. This southwesterly low level jet causing
the wind shear will also aid in the development of numerous
showers and a few thunderstorms and a higher frequency of MVFR
and brief IFR conditions, especially after 04z Wed.

Drier air will begin to work into the western airfields around
12z Wed, but sfc fog may develop prior to sunrise as the low
level moisture is slow to scour out.

Outlook...

Tue...AM low cigs/showers possible southern tier of PA.
Scattered evening tsra impacts possible W Mtns.

Wed...AM low cigs/tsra possible.

Thu...Periods of rain/low cigs likely. Scattered afternoon
TSRA.

Fri and Sat...Showers with periods of low cigs possible.

&&

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

&&

$$

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