539
FXUS61 KCTP 241857
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
257 PM EDT Mon Aug 24 2026

.WHAT HAS CHANGED...
* Kept adding to the PoPs for the area N of rte 22 for the next
  several hours.
* Bumped up sky and PoPs a little for Tues in the far N.

&&

.KEY MESSAGES...
1) Upper level low pressure near Toronto Ontario early today
will drift northeast and diminish its influence on our cool
temps and occasionally showery conditions through the midweek
period with a gradual warmup in temperatures Tuesday through
Thursday.

2) Showers and thunderstorms return Wed night or Thursday as a
cold front approaches from the west.

&&

.DISCUSSION...
KEY MESSAGE 1: Upper level low pressure near Toronto Ontario
early today will drift northeast and diminish its influence on
our cool temps and occasionally showery conditions through the
midweek period with a gradual warmup in temperatures Tuesday
through Thursday.

Update 230 PM...

Have seen the forecast play out as advertised thus far. Main
change in this time frame was to bump up the sky and PoPs (10
pct) for Tues, too - but only for the N. Best day for the entire
CWA looks like Wed with high pressure sliding east. Did add fog
in for Tues night/Wed AM.

Previous discussion...

Left exit region of an upper level jetlet rounding the base of
the upper trough combined with a CFA and sfc reflection in the
form of a weak trough has led to areas of showers advecting
into South-Central PA and the Lower and Mid Susq Valley early
today (and even a few low- topped TSRA a few hours ago near and
to the North of KIPT).

Expect a fair amount of morning sunshine across the bulk of
Central PA after this current, embedded shortwave trough exits
to the east and NE later this morning. However, unseasonably
cool temps aloft (850 temps mainly +8 to +9C today) will lead
to the sunshine taking on a self destruct form with plenty of
MDT CU/Thickening strato cu developing /advecting ESE from the
NW Mtns twd the central ridge and valley region. The next
compact shortwave and mid/upper level speed max will rotate
through a bit further to the north today, focusing the vast
majority of any showers near and to the north of the RT 6
corridor in northern PA.

As noted in previous discussions and based on current high res
ensembles and its members, it`s unlikely that any precip will
get south of I-80, but there will be plenty of clouds. Some
showers will linger into the night and possibly early Tuesday
before drier air works in as the upper trough departs.

Vertical mixing depth increasing to 4-6 kft after 14Z today will
lead to a quick increase in the West to West-Southwest breeze
with moderate gusts into the upper teens at times. There will be
nearly a 20 deg delta in max temps from North to South today,
with reading struggling to reach 60F across the highest terrain
near and north of RT 6, while the Lower Susq Valley sees
afternoon highs in the mid to upper 70s. These high temps will
be 10-13F below normal across the Northern Tier counties and
just a few degrees below normal in the Lower Susq Valley.

  -------------------------------------------------------

KEY MESSAGE 2: Showers and thunderstorms return Wed night or
Thursday as a cold front approaches from the west.

Return flow around the high will bring more moisture up through
the Mid-Atlantic and into the Susq Valley late Wed night. This
will touch off a few showers. A cold front will be approaching
from the west at the same time. Diurnal heating will combine
with upper energy to kick off numerous SHRA/TSRA on Thursday.
The front probably won`t fully pass thru the CWA until Friday
morning. So, Thursday night (Lunar Eclipse time) probably won`t
be clearing enough for much of the CWA to be able to see it
well. The west has the best chance to do so, but confidence is
low in sky cover at this range.


&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
An upper level low over southwestern Ontario will keep a
cyclonic flow of cool air across the Great Lakes into
Tuesday.

Much of the time will be dry with VFR conditions. However
lower CIGS will occur from time to time, mainly at BFD, but
also at other spots late tonight. MDT and LNS the two TAF
sites that are not expected to have lower CIGS late tonight.

Main chance for a shower today and Tuesday will be at BFD.

Outlook...

Wed...Patchy morning fog, otherwise mainly VFR conditions.

Thu...Chance of showers and storms again, mainly later
Thursday.

Fri...Still a slight chance of a shower.

Sat...Clearing.

&&

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

&&

$$

WHAT HAS CHANGED...Dangelo
KEY MESSAGES...Lambert/Dangelo
DISCUSSION...Lambert/Dangelo/Colbert
AVIATION...Martin