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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 021325
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
825 AM EST Sat Dec 2 2023

.SYNOPSIS...
Several waves of low pressure will slide along a slow moving
frontal boundary located over Lake Erie and western NY. These
waves will each bring a period of showers. Cooler conditions
will arrive later on Monday through midweek. Milder conditions
are expected for the later part of next week.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
-- Changed Discussion --
Issued dense fog advisory until 15Z/10AM for much of the middle
and lower Susquehanna Valley based on multiple RWIS stations
reporting visibility less than 1000ft (<0.2 miles).

SPS for a broader area of central PA east of the Alleghenies will
continue to highlight the locally dense fog and associated travel
impacts outside of the advisory area.

Prev...
Weak but persistent front just to the north of the CWA. The
130KT jet overhead will continue to bring moisture into the
area, but weak subsidence today will help build the pressure
overhead just a little. This should bring some improvement to
the overall murkiness. Some breaks are already in the sky cover
at this early hour in the south. Expect some showers to linger
for a good part of the day along the NY border. Temps should get
back into the u50s across the south while the north will stay
below 50 - but that is still 10F above normal for early Dec.
-- End Changed Discussion --

&&

.SHORT TERM /7 PM THIS EVENING THROUGH MONDAY NIGHT/...
A wave sliding across the plains will help develop a sfc low
which will slide into the area from the SW on Sunday. Timing of
precip arrival Saturday evening/night looks similar to the past
few runs. It should start around 00Z in the SW and spread N & E
overnight. The far NW/Warren Co may not get wet until later in
the day on Sunday after the low deepens to our north.

Temps will dip only a few degrees tonight as dewpoints rise
along with the precip. They`ll only rise a little (4-8F) on
Sunday thanks to the same cloud cover and precip. QPF looks
higher than the last one, with many places getting between
half of an inch and one inch.

A cool shot of air will then arrive after the sfc low passes
our latitude. Expect fairly seasonable temps for Monday.
Current PoPs for Monday may be a little too high, but any
showers should be confined to the west, esp the NW. We`ll take a
little closer look there in a bit.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Late evening update.

For the period late next week, models show a small chance of
mainly rain, perhaps mixed with show early on. Pattern would
suggest mainly dry weather, but went with low POPS, given
models and other nearby offices.

Early evening update.

Inverted trough could bring some snow to the far southwest
early on, as already noted in the fcst.

A southwest milder flow of air expected after wed.

Earlier discussion below.

Clipper system diving southeast from the Great Lakes across
southwest PA Tuesday PM remains in focus with potential for
accumulating snow at higher elevations. We continued to take
POPs higher particularly over the Laurel Highlands. The upper
trough is slow to depart which could linger rain/snow well into
Wednesday over the favored upslope areas.

Northerly flow behind the departing Clipper under a deep upper
trough will continue colder temp trend (near to below climo)
through the middle of next week.

Another shot of rain/snow is possible later next week
particularly across northern PA as low pressure tracks through
southeastern Canada. Temps are currently projected to rebound
slightly above average into next weekend.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
The widespread LIFR to VLIFR conditions impacting many
airfields across Central PA and the Susq Valley this mid morning
hour will very slowly improve through 13-15Z before some breaks
in the clouds move overhead and cause enough warming of the sfc
and vertical mixing to lift categories to IFR and MVFR. Still,
weak low to mid-level ridging drifting over much of Central PA
and the Susquehanna Valley today won`t be sufficient to
significantly break up a dual-layered cloud deck (containing
a several KFT layer of dry air in between) with winds remaining
fairly light.

The best conditions to start the day will be found across the
Laurel Highlands where a light to moderate swrly breeze and the
strongest subsidence/deepest dry air at low to mid levels will
be found - leading to IFR and areas of MVFR.

Slow improvement to MVFR or even low-end VFR cigs and vsbys
will occur for this afternoon into early this evening before a
second round of rain arrives from the southwest tonight and
lowers conditions dramatically to IFR and LIFR once again.

Model soundings currently indicate the potential for BFD to
remain IFR through 21Z before some slight improvement occurs.

Outlook...

Tonight-Sun...Periods of light rain/reduced cigs expected.

Mon-Wed...Chance of light rain/snow.

&&

.CLIMATE...
Williamsport Monthly (November) and Seasonal (Fall) Climate
Summary:
-------------------------------------------------------------
 The average temperature for November was of 41.3F or -0.6F
 below the 30yr mean. The average maximum temperature was 51.4F
 or +0.8F above normal while the average minimum temperature was
 31.3F or -1.9F below normal. The most notable callout last
 month was the -1.74" departure from normal in precipitation
 with only 1.51" (24th driest). For the Fall/Autumn season
 spanning the 3-month period from September to November, it was
 a rather mild and dry ranking as T-20th warmest (54.9F mean
 temp) and 23rd driest (7.15" total precip or -4.56" below
 normal).

Harrisburg Monthly (November) and Seasonal (Fall) Climate
Summary:
--------------------------------------------------------------
 The average temperature for November was of 44.7F or -0.2F
 below the 30yr mean (T-50th warmest). The average maximum
 temperature was 55.0F or +1.1F above normal (T-30th warmest)
 while the average minimum temperature was 34.4F or -1.4F below
 normal. The total precipitation last month was 2.49" or -0.48"
 below normal. For the Fall/Autumn season spanning the 3-month
 period from September to November, it was a quite mild ranking
 as 15th warmest (57.6F mean temp). The total precip was 9.39"
 or -2.22" below normal.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
Dense Fog Advisory until 10 AM EST this morning for PAZ027-028-
036-049>053-056>059-063>066.
-- End Changed Discussion --

&&

$$

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