568
FXUS61 KCTP 170625
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
225 AM EDT Wed Jul 17 2024

.SYNOPSIS...
- The last of the thunderstorms from today will continue to
   move south east into the early hours of tonight.

 - A cold front will push through on Wednesday with another
   round of strong to severe thunderstorms.

 - High pressure will build in from the Great Lakes on Thursday
   and bring mainly fair weather with seasonable temperatures
   through the end of the week.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
A line of convection is still present in the far SE corner of
the lower Susquehanna Valley. These storms will likely move out
of the CWA by 10 PM. With temperatures cooling off as sunset
approaches the environment to support thunderstorms will
continue to wane across the SE. Additional storm development is
not anticipated after the current line of storms exits the
area.

Low temps tonight will remain uncomfortably warm across south
central Pennsylvania. The heat advisory remains in effect
overnight as lows in the lower susq will stay in the mid to
upper 70s. Lack of clouds tonight could again make some patchy
valley fog, but lack of rainfall today will be a tick in the
negative column. Developing morning showers may impinge on the
wrn highlands by sunrise.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH THURSDAY NIGHT/...
An upper level trough approaching from the Grt Lks will push a
cold front through the region Wednesday, accompanied by a round
of showers/tsra Wed afternoon into Wed evening. Cloud cover and
an early arrival of the fropa should keep the threat of severe
weather low over the northwest part of the forecast area.
However, the pre-frontal heating of the a very moist/unstable
airmass, combined with a belt of relatively strong mid level
flow, will support a threat of severe weather Wed PM across the
southeastern counties. Cloud cover and convection should hold
temps down a bit Wednesday, even across the Lower Susq Valley.
The Heat Advy currently up for that area for Wed will be allowed
to continue as surging dewpoints ahead of the front could still
yield heat indices near 100F across the southeast counties. PWs
of nearly 2" in the SE could help feed very heavy downpours.
But, the fast storm motions and very high FFG (widespread 4.5"/3
hrs values) keep the threat for flash flooding low. The MRGL
risk in the Day2 ERO was collaborated with WPC, mainly in order
to keep continuity with previous forecasts.

Wed PM looks like the cfropa occurs for all but perhaps a few
towns on the MD border. Thus, the SHRA should press mainly or
entirely to the S of the border well before sunrise. Dropping
dewpoints may keep the threat of fog low, but the temps drop
right along with them. Have not added it into the wx grids at
this point. For Thursday guidance converges towards a return
towards fair and seasonable weather with lower humidity during
the day Thursday and through the end of this week as high
pressure builds from the Great Lakes.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Much drier air will continue to work into the region Friday,
as high pressure builds into the area.

While there could be an isolated shower Saturday afternoon, the
weekend looks dry at this point.

By early to mid week next week, humidity levels will creep back
up. This will result in muggy nights again by mid week and more
in the way of a chance of showers and storms by then.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
MVFR cigs are forecast to develop across the northwest airspace
by 12Z along with some rain showers downwind of Lake Erie. Cigs
could dip into the IFR range, but MVFR is more probable (>60%
chance) at KBFD. Showers and thunderstorms are expected to
develop this afternoon into the evening along and ahead of a
cold front pushing southeast from the Great Lakes. Storms should
decrease in coverage and exit/dissipate over the south/eastern
airspace between 03-06Z. There is decent model signal for post-
frontal upslope low MVFR cigs particularly at KJST and
potential IFR fog impacts at KBFD/KIPT late tonight into early
Thursday morning.

Outlook...

Thu...MVFR cigs psbl northwest 1/2; low VFR elsewhere.

Fri-Sun...AM valley fog. Otherwise, no sig wx/VFR.

&&

.CLIMATE...
The max temperature hit 100 degrees at Harrisburg yesterday
7/16. The last time KMDT hit 100 was back on July 19, 2020.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for PAZ036-056-057-
059-063>066.

&&

$$

SYNOPSIS...Dangelo/Bowen
NEAR TERM...Dangelo/Bowen
SHORT TERM...Dangelo/Bowen
LONG TERM...Martin
AVIATION...Steinbugl
CLIMATE...Steinbugl