060
FXUS61 KCTP 120511
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
111 AM EDT Wed Jun 12 2024

.SYNOPSIS...
* High pressure will build over Pennsylvania through Wednesday.
* As the high drifts east of the region, heat and humidity will
  ramp up for Thursday and Friday, followed by a cold frontal
  passage with scattered thunderstorms during the day Friday.
* A ridge of high pressure will bring an increased risk of
  excessive heat early next week with highs in the 80s and 90s
  and heat index values possibly exceeding 100F.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A stubborn deck of stratocumulus continues to ever so slowly
erode from southwest to northeast this evening as high pressure
continues to build into the region. These low clouds should
clear out by midnight in northeast PA. Meanwhile, some high
clouds associated with a weak front north of PA underneath a
subtle shortwave will stream in by daybreak. The arrival of high
pressure should support light and variable winds overnight.

Biggest question for tonight`s forecast is the formation and
extent of radiation fog. Dewpoint depressions in the northern
tier are only 5-7F, which is easily attainable with a full night
of radiational cooling. If clouds hang on a bit longer tonight,
fog extent could be limited before the arrival of higher clouds.
Have included the chance for patchy fog in deepest valleys in
the northern mountains where confidence is highest. By daybreak
Wednesday, low temperatures will range from the upper 40s
northwest to mid 50s southeast.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
Wednesday will be a transition day between much below normal
temps to start the week and warmer weather for Thursday and
Friday. Variable amounts of mid and high clouds on Wed will
have only a minimal impact on the otherwise abundant sunshine
with highs ranging from the low to mid 70s over the Northern
Mtns to the low 80s throughout the Valleys of Central and
southern PA. These readings will be just a few deg F shy of
climo. Winds will be light from the west. PWAT values will
start out around 0.8 inch and will increase to around 1 inch
Wed afternoon, but it won`t feel humid given sfc dewpoints
remaining in the 40s and 50s.

We`re still expecting a warm up for the second half of the
week, with many locations seeing their warmest temps on
Thursday, except perhaps southeast PA seeing temps a few
degrees warmer on Fri. Temperatures on Friday will depend on the
timing of clouds and convection associated with an approaching
cold front. Over the past 24 hours, models have generally sped
up the arrival time and southward progression of the
aforementioned front, now bringing a chance of showers and
thunderstorms to the northern Alleghenies as early as Thursday
night, and then dropping south across central PA during the day
Fri with more numerous showers and thunderstorms.

Despite forecast high temps near 90 across southern zones Thu-
Fri, relatively low levels of humidity (dewpoints 55-65F) will
hold the heat index to just a couple deg above the air temp.
Thus not anticipating heat products at this time. However, the
+15-20 degree swing from temps well below normal early this
week to the warm weather late this week will be noteworthy.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Next weekend looks dry, as a northerly flow of drier air from
Canada is advected into our area. Plenty of sunshine and fair
weather is expected for Saturday and Sunday with a beautiful
weekend in store. Any slight cool down on Saturday will be
short- lived, with warmer temperatures progged to build back
into the area Sunday into Monday. A few isolated sprinkles could
be possible in the northern tier of PA with weak diurnally
driven updrafts on Monday afternoon.

By Tuesday, the risk for excessive heat will increase as a
large ridge builds over the eastern US. There remains quite a
bit of spread in model guidance, but potential exists for heat
index values topping 100F in southeast PA Tuesday - Thursday
next week. The ECENS is more bullish with the strength and
northern extent of the ridge of high pressure into PA, which
would result in higher temperatures and heat index values. The
GEFS is a bit cooler with a weaker high and potential convection
associated with a shortwave moving along the ridge, but still
indicates the potential for excessive heat.

Based on this anomalous pattern, the Climate Prediction Center
has placed much of eastern PA in a Moderate Risk for Excessive
Heat for the middle of next week (Wednesday - Friday).

&&

.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
06z update... Patchy fog has developed early this morning across
the northern tier river valleys of the Commonwealth, as per
satellite imagery and surface observations. Thus, we expect
KBFD to see conditions as low as IFR through about daybreak. We
have a high degree of confidence (90+%) that fog and low clouds
will burn off quickly later this morning, generally by 12-13z.

Otherwise, VFR will prevail, with a very dry air mass traversing
the region over the next 24 hours or so.

Surface winds look light, generally 5 kt or less.

Outlook...

Thu...Predominantly VFR w/ no sig wx expected.

Fri...Restrictions possible in CB/TSRA.

Sat-Sun...Predominantly VFR.

&&

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

&&

$$

SYNOPSIS...Banghoff
NEAR TERM...Banghoff/Colbert
SHORT TERM...Banghoff/Colbert
LONG TERM...Banghoff/Evanego
AVIATION...Jurewicz/Martin