598
FXUS61 KCTP 300744
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
344 AM EDT Sun Jun 30 2024

.SYNOPSIS...
A cold front will push through central Pennsylvania on Sunday.
A large high pressure system will build into the region early
in the upcoming week, followed by a dying cold front pushing in
from the Great Lakes and stalling out over the area late next
week by the middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Lingering convection over parts of the south central and
southeast late this evening should continue to decrease in
coverage after midnight. Can`t drop POPs altogether overnight as
850 mb thermal ridge is overhead and additional isolated showers
can still pop up overnight, but most areas will remain dry. We
expect there to be areas of fog give current dewpoint depressions
of 1-3F and dewpoints in the lower 70s. Some areas of fog are
very likely given high surface dewpoints and light winds ahead
of the cold front that will be approaching from the GLAKS and
Ohio Valley overnight. With thermal trough in place and 850
temps around +18 to +19 across much of central PA, lows tonight
will be warm, ranging from the mid 60s to mid 70s, which is
10 to 15 deg F above normal for late June.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Passage upstream surface cold front will bring the chance for
another round of convection Sunday. Locations most likely to see
potential strong/svr t-storms are over the southeastern part of
the CWA due to a fropa coinciding with peak heating of the late
afternoon.

Max temps Sunday will be a few to several deg F higher than
today (Sat) in all locations.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Dewpoints drop off rapidly by Sunday evening with another
comfortable few days of weather in store to start the month of
July. Canadian high pressure builds to southern Ontario by
Monday night, bringing a fair and cool night with the high
moving directly overhead. This will result in efficient
radiational cooling and min temps several degrees below normal.
Fair and warmer weather is expected Tuesday into at least the
first half of Wednesday, as upper level ridging builds over the
state and surface high drifts offshore.

All medium range guidance tracks a weakening shortwave well
north of PA late Wednesday into Thursday. The dying cold front
is likely to sag into the state Thursday and stall out in the
vicinity of PA through Friday. Falling heights/surging low level
moisture ahead of the front could support scattered convection
as early as Wednesday afternoon over the northwest half of PA.
However, a better chance of showers/tsra areawide will come
with the arrival of the front Thu into Friday. Early best guess
of late week rainfall based on ensemble plumes ranges from 0.25
to 0.75 inches, with the highest amounts over the N Mtns and
least in the south.

Heat and humidity should peak ahead of the front Wed-Thu.
Ensemble mean 850mb temps surging to near 20C indicate max temps
could reach the low to perhaps mid 90s in the Lower Susq Valley
Thursday, with high humidity pushing heat indices into the mid
and upper 90s. Ensemble plumes suggest slightly cooler daytime
temps late week, due to more clouds/showers. However, high pwats
in the vicinity of the stalling front should result in muggy
nights and above normal min temps the entire second half of next
week.

Models begin to diverge as we head into the weekend. Most
guidance suggests that rain chances stick around through at
least Saturday as another cold front approaches the area.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
Given ample low level moisture beneath a thermal inversion, low
cigs have developed across the northern Alleghenies and Laurel
Highlands. BFD dropped to IFR shortly after 06z, and will likely
remain IFR through sunrise. Farther to the east, restrictions
have generally been limited to the higher elevation airfields
north of MDT. High clouds blowing off of convection to our south
has kept fog development to a minimum, but fog may expand if
higher clouds become thinner towards daybreak.

Much of Sunday will be mostly cloudy with MVFR cigs persisting
across central and western airfields through early afternoon.
A cold front will slide south through the day. Scattered
SHRA/TSRA are expected along and ahead of this boundary mainly
during the afternoon and early evening hours, with MDT and LNS
having the highest chance of seeing vsby restrictions in brief
downpours.

Conditions are expected to improve later Sunday, as the winds
shift to the northwest and much less humid air moves into the
area. The HREF does suggest MVFR cigs are possible at BFD into
Sunday night given upslope flow off Lake Erie.

Monday and Tuesday look dry at this point with VFR conditions,
as high pressure builds into the area. Some valley fog is
possible in the north both mornings.

Outlook...
Wed...PM TSRA moving across from W-E.

Thu...A chance of showers and storms.

&&

.CLIMATE...
At the Altoona Airport, a daily record rainfall of 0.77 inches
was set on Sat, Jun 29. This total breaks the old record of
0.53 inches set back in 1972.

&&

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

&&

$$

SYNOPSIS...Lambert/DeVoir/Fitzgerald
NEAR TERM...Lambert/DeVoir/Fitzgerald/Dangelo/Martin
SHORT TERM...DeVoir/Fitzgerald/Steinbugl
LONG TERM...DeVoir/Fitzgerald/Bauco
AVIATION...Martin/Colbert
CLIMATE...Evans/Steinbugl