616
FXUS61 KCTP 151114
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
714 AM EDT Tue Oct 15 2024

.SYNOPSIS...
An upper level trough will pivot through Pennsylvania
today into Wednesday.

Ridging at the surface and aloft will follow for late this
week and maintain influence on our weather right through
early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Variable amounts of cloud cover and light wind were creating a
a marginal risk for frost/freeze conditions early today.

A fairly potent shortwave rotating southeastward through the
mean trough over eastern Canada and the NE US will be
accompanied today by the left exit region of a 130 kt upper jet
max. Enhanced large scale deep lift and near orthogonal llvl
flow to the Laurel Highlands and NW Mtns will bring an extensive
depth of layered low/mid level clouds that will intersect the
favorable dendritic growth zone (between 8-12 KFT AGL)
today/tonight. This will lead to increasing coverage of rain
showers (mixed with or falling as high elevation wet snow
showers today with the Zero C wet bulb level slowly descending
from around 2 KFT AGL to 1 KFT AGL tonight).

In the wake of the aforementioned shortwave, large scale
subsidence should result in brightening skies by late afternoon
over much of the Ridge and Valley region Central PA and the
Susquehanna Valley.

No snow accumulation is expected during the daylight hours
today with mixing down forecast 850mb temps of around -2C
yielding expected high temps Tuesday from the mid 40s over the
higher terrain of the Alleghenies, to the mid 50s across the
Lower Susq Valley.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Tonight looks similar to Monday tonight with a deepening,
moistening boundary layer expected ahead of the main upper level
trough. This scenario should promote an increasing chance of
orographically enhanced rain/snow showers over the W Mtns as the
night progresses. Thermal profiles look just cold enough for a
rain/snow mix over the higher ridgetops of the Alleghenies,
where a light coating to 0.5 inch is possible on colder, non-
paved surfaces is possible by early Wed AM.

Concerning the frost/freeze threat, a similar dilemma will
likely arise late tonight/early Wednesday as is occurring
early this morning with increasing clouds and a light breeze
making a frost unlikely over the W Mtn, but the higher terrain
could see min temps just below freezing. Further east, skies
should remain mostly clear, but a persistent light breeze could
result in only patchy frost, despite min temps in the mid 30s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
All medium range guidance supports fair and warmer weather late
this week into next weekend, as the upper trough lifts out and
is replaced by a building ridge over the Eastern CONUS. Surface
high pressure and associated dry air mass building into PA
should result in efficient radiational cooling into next
weekend, with frost/freeze concerns through at least Friday
morning. Abundant sunshine and moderating temps aloft should
result in progressively warmer days with highs getting back
above average by Friday. GEFS 2m temp anomalies indicate max
temps should be 5-10 degrees above average by next weekend,
translating to 65-70F over most of the region with additional
warming likely into early next week.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected across Central PA today, though
there may be brief drops to MVFR at BFD and JST in any showers
that move through. Mostly cloudy skies will persist across the
north and west, while cloud cover will decrease into the
afternoon for the southeast. Winds won`t be nearly as gusty as
yesterday, but a few 15 to 20 knot gusts will be possible. MVFR
ceilings are expected to develop at BFD and JST overnight and
rain and snow showers appear likely.

Outlook...

Wed...A chance of showers, mainly across the north and west.

Thu-Sat...VFR/no sig wx.

&&

.CLIMATE...
A record high temperature of 82 degrees was set at Altoona on
Sunday. This breaks the old daily record of 81 degrees set Oct
13, 1954.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 9 AM EDT this morning for PAZ004>006-
010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066.

&&

$$

SYNOPSIS...Fitzgerald
NEAR TERM...Lambert/Fitzgerald
SHORT TERM...Lambert/Fitzgerald/Steinbugl
LONG TERM...Fitzgerald
AVIATION...Bauco
CLIMATE...Colbert