673
FXUS61 KCTP 240817
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
417 AM EDT Mon Jun 24 2024

.SYNOPSIS...
An upper level trough will swing over Pennsylvania today, then
high pressure will build over the state tonight. A relatively
zonal flow will remain in place through the rest of the week,
with cold front passages likely late Wednesday and either late
Saturday or early Sunday next weekend.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
Early morning satellite imagery shows breaking clouds downwind
of the mountains, as a drier northwest flow overspreads the
state behind last evening`s cold front passage. However, low
level moisture ascending the Alleghenies will continue to
produce sct-bkn stratocu across the the northern and western
part of the forecast area. Low level cold advection will push
readings steadily downward this morning, with daybreak readings
likely ranging from the mid to upper 50s over the N Mtns, to
around 70F across the Lower Susq Valley.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH WEDNESDAY/...
The arrival of the upper trough will bring markedly cooler
weather to the region today, with 800mb temps supporting highs
from just the lower 70s over the mountains north of KIPT, to
the mid 80s across the Lower Susq Valley.

Low level instability associated with the passage of the upper
trough should result in a considerable amount of cu/stratocu
today over the N Mtns, where a stray shower is possible. A
tight pressure gradient and steep lower tropospheric lapse rates
should result in breezy conditions by late June standards.
Latest Bukfit soundings support afternoon wind gusts of 20-25kts
over the western part of the forecast area and 25-30kts in the
east, which is several knots higher than NBM guidance.

The arrival of very dry air aloft above a weak inversion a signal
that reliably results in afternoon dewpoints dropping below NBM
guidance, so have leaned toward the drier MAV guidance.

Fair and seasonable weather with diminishing winds are
anticipated tonight, as high pressure builds into the state.
Latest NAMNest and SREF prob charts target the Alleghenies for
late night valley fog.

The surface high is progged to pass off of the Mid Atlantic
coast Tuesday, resulting in a warmer return southwest flow.
Ensemble mean 850mb temps rising to near 17C supports highs
mostly in the 80s, to near 90F in the Lower Susq Valley.
However, dewpoints remain moderate in the 50s.

A warm front lifting through the Eastern Grt Lks may result in
a shower or tsra Tuesday night, mainly over the NW Mtns. Surging
PWATs and falling heights ahead of an upstream cold front will
bring a much better chance of widespread showers/tsra Wednesday
afternoon. A ribbon of relatively strong mid level winds,
combined 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
around a half inch.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Late evening update holds very minor changes to the long range
fcst. Did knock out PoPs totally from Thurs-Fri as we dry nicely
behind the mid-week front. Before the front, Wed could be just
muggy and hot enough to need a heat advy in the SE, but only
for Wed.

Prev...
Showers and storms will gradually exit to the the southeast on
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 and Sunday as a warm front lifts across the region.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR conditions are occurring across most of Central PA as of 05Z.
Some low clouds have been developing across the west behind the
cold front and MVFR ceilings are being observed at BFD. They
will likely remain MVFR through the rest of the night. Most
guidance suggests that these lower ceilings make it to JST
within the next hour or two, though confidence is lower in MVFR
ceilings lasting as long as they will at BFD. Not expecting any
fog formation tonight as westerly winds stay around 5 to 10
knots and drier air works its way in from the north

All TAF sites will likely be VFR by 14z. Northwest winds will
gust in the 20-30 kt range through much of the day Mon before
diminishing Mon evening.

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.

&&

.CLIMATE...
No temperature records were set on Sunday. The following
records have been set during this stretch of heat:

MDT:
* A record high temperature of 99 degrees was set at
  Harrisburg, PA on Saturday, Jun 22, breaking the old record of
  97 degrees set in 1988.

IPT:
* A record high temperature of 98 degrees was set at
  Williamsport on Friday June 21st, breaking the old record of
  97 degrees set in 1923 and tied in 1933.

BFD:
* A record high temperature of 89 degrees was tied at Bradford
  on Friday June 21st, tying the record set in 2022.
* A record high temperature of 90 degrees was set at Bradford on
  Thursday June 20th breaking the old record of 88 degrees set
  in 2012.
* A record high temperature of 88 degrees was set at Bradford on
  Wednesday June 19, breaking the old record of 87 degrees set
  in 1987.

AOO:
* A record high temperature of 96 degrees was set on Saturday,
  Jun 22, breaking the old record of 91 degrees set in 1988.

Highest Max Temperatures for Central Pennsylvania Observing
sites for June (date of occurrence is in parentheses:

State College 96 in 1952 (26th) and 1933 (29th)
Harrisburg 100 in 1966 (27th), 1952 (26th), and 1934 (29th)
Williamsport 104 in 1925 (5th)
Altoona 97 in 1971 (28th) and 1953 (21st)
Bradford 93 in 2022 (22nd)

Longest run of consecutive days with max temp >=90 in June:

State College 6 (24-29th 1966)   /current streak=2/
Harrisburg 10* (19-28th 1943) /current streak=7/
Williamsport 9 (18-26th 1923)   /current streak=7/
Altoona         8 (13-20th 1994)   /2024 streak=6 (ended Sat)/
Bradford        1 (23rd 2024)      /2024 streak=1 (Sat)/

*Harrisburg had a run of 11 days with temperatures greater than
 90 degrees that started on 26th and ended on July 6th in 1901.

&&

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

&&

$$

SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Dangelo/Banghoff
AVIATION...Colbert/Bauco
CLIMATE...Evans/Steinbugl/Colbert