NWS Forecast Discussion

345
FXUS61 KCTP 251016
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
616 AM EDT Tue Jun 25 2024

.SYNOPSIS...
High pressure over the Commonwealth this morning will drift
east and off the Mid Atlantic Coast by this evening.

Heat will build again by Wednesday leading to a chance of
thunderstorms by late in the day and Wednesday night as a cold
front pushes through the state.

Dry weather with comfortable humidity on Thursday and Friday
will be followed by another cold front late Saturday or early
Sunday of next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Mainly clear skies, light wind and surface dewpoints in the low
to mid 50s will lead to a comfortably cool early Summer morning
with valley fog and patchy low clouds across primarily the
Northern Mountains of the state early today.

High pressure ridge sliding across Central and Eastern PA late
this morning will bring abundant sunshine and light wind for
much of the day followed by a gradually freshening southwest
flow and some alto cu and cirrus moving in for the afternoon
hours.

High temps this afternoon, ranging from near 80 over the high
terrain of the north and west to around 90F throughout the
larger metro areas in Southeastern PA will average between 5 and
8 deg F above normal for the date.

Precipitable Water values will be between 0.5 and 0.75 of an
inch this morning before a rather sharp increase in deep layer
moisture occurs this afternoon and evening. PWAT values will
double or more (to around 1.5 inches) statewide by 02Z Wed.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
A warm front will lift northeast across the Eastern Grt Lks
tonight and may spark a few showers or even a TSRA tonight,
mainly over the NW Mtns. Some showers and even a rumble of
thunder are also possible across the Central Ridge and Valley
region of the state during the second half of the night as the
instability axis over Lake Erie, sags to the SE.

The increase in moisture and clouds tonight will result in low
temps 12 to 14 deg F warmer than early this Tuesday morning`s.
Lows will be in the mid 60s across the higher terrain of the
north and west and in the upper 60s to mid 70s respectively
throughout the Central Ridge and Valley region and SE part of
the CWA.

The aforementioned surging PWATs and falling heights ahead of
an upstream cold front will bring a much better chance of
widespread showers and scattered strong to potentially severe
thunderstorms Wednesday afternoon/evening.

There will be little break from looks like two ir 3 rounds
SHRA/scattered TSRA from late Wednesday morning, through
Wednesday afternoon and into Wed the aforementioned axis of
CAPE becomes located over Central PA and the Susq Region.

A ribbon of relatively strong low to mid level (west to
southwest) winds of 50 to 55 kts, combined with moderate
instability, suggests organized convection and locally severe
weather is possible Wed PM. Latest ensemble plumes indicates
most likely aerial average rainfall Wed will be between one half
and one inch.

SPC has outlined most of the CWA in a SLGT Risk area for SVR
with the Northern Tier counties of the state falling within
their MRGL area.

High temps Wed should reach the upper 70s to low 80s across the
Northern Mtns and upper 80s to low 90s respectively across the
Central and SE zones.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
It gets hot again late in the week, but no long-term records
(except perhaps maxi-mins Sat night) should be challenged.
Relief/precip/storms come from a cold front in the middle of the
weekend (timing subject to change slightly).

Prev...
Showers and storms will gradually exit to the the Southeast
counties of PA Wednesday night as high pressure builds in. The
midweek cold front will reset the cycle similar to what today`s
cold front will do and usher in a similar stretch as Monday &
Tuesday. Thursday and Friday will consist of about 48 hours of
lower dewpoints, temperatures closer to average for this time of
year, and plenty of sunshine. Afternoon highs in the 70s and
80s, overnight lows in the 50s and 60s (perhaps even upper 40s
in the northern mountains Friday morning), and dewpoints below
60F will feel especially good with the persistent stretch of
heat.

As high pressure shifts to the east on Friday, southerly flow
will support increasing temperatures and moisture into the
weekend. The chance for showers and storms will also ramp up
Saturday as a warm front lifts across the region. By Sunday, a
trailing cold front will bring additional showers and
thunderstorms and usher in another cooler stretch for the start
of July.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
Mainly VFR conds continue through the TAF period. Any patchy fog
that is present across the northwest will dissipate by 13Z. High
clouds will begin spreading into the area from the west during
the late morning. The clouds will begin to lower into the
evening across the west and MVFR ceilings likely develop at BFD
after 00Z as showers and potentially a thunderstorm or two left
over from convection to our west approach the region. There is
low confidence in how much precipitation occurs overnight as it
will be dependent on the evolution of convection to our west
during the day today. Model soundings support ceilings dropping
to IFR at BFD by 08Z and LIFR ceilings appear possible. These
lower ceilings increase in coverage across the region, with all
sites except MDT and LNS likely seeing MVFR ceilings by sunrise.

A west- southwesterly low level jet moves in to the northwest
as well and will lead to a period of LLWS as winds at 2000 feet
increase to around 45 knots. Confidence is highest that BFD see
LLWS, while it appears more marginal at other airfields.

Outlook...

Tue...VFR, no sig wx expected.

Wed...Restrictions possible in TSRA.

Thu...AM SHRA/TSRA with restrictions possible, drying out late.

Fri...Mainly VFR.

Sat...Restrictions possible in TSRA/SHRA.

&&

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

&&

$$

SYNOPSIS...Lambert
NEAR TERM...Lambert/Dangelo
SHORT TERM...Lambert
LONG TERM...Banghoff
AVIATION...Colbert/Bauco

NWS CTP Office Area Forecast Discussion