Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 220338
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1038 PM EST Sun Jan 21 2018

.SYNOPSIS...
A warm front pushing slowly northward across the area will
bring occasional light rain or drizzle into early Monday. A
potent area of low pressure moving across the Great Lakes will
push a trailing cold front through Pennsylvania on Tuesday.
Temperatures will rise above normal and stay there through early
Tuesday, before falling back to near or slightly below normal
Wednesday and Thursday. A rebound to above normal temperatures
will occur again by next weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Warm front approaching overnight, keeping things rather murky
and damp for much of central PA. Light rain, drizzle and patchy
fog are expected, although any rainfall should be light. Temps
will remain relatively mild for late-January.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
Best upper-level forcing will pass through in the morning, and
warm front will attempt to lift northward across the area. POPs
drop off nicely by aftn, with all but perhaps the northern
border seeing some drying.

Maxes will be a function of both sun (or lack there of) and
warm advection. Will hold in the 40s across the northeastern
portion of the CWA, with most everyone else topping 50 degrees.
Again, not bad for January.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Another January thaw underway that will keep relatively mild
weather ongoing into Tuesday. Departures should reach +10 to
+15 degrees above average, peaking Monday in the NW and Mon
into Tues in the SE. The progressive pattern will keep the
mid/late week cool down rather brief before temperatures
moderate/trend warmer into next weekend.

By Monday afternoon, warm front will have lifted north of the
region, bringing a period of mainly dry weather ahead of
approaching low pressure area. Cold front crosses central PA
Monday night with weak secondary low forming in the lee of the
Appalachians supporting a period of enhanced rainfall over the
eastern 1/2 of PA as front occludes into Tuesday morning on the
order of 0.50-0.75". Not too shabby SW 50kt LLJ could also
generate a rumble of thunder. River ice concerns are addressed
in the hydrology section.

Winds look rather blustery from later Tuesday into Wednesday on
the backside of the low pressure system as colder air filters
back in. Snow showers are likely downwind of Lake Erie into Wed
night but should only amount to light accums. Dry wx under high
pressure Thu-Fri with chilly starts to the day (especially in
the east) with moderating temperatures heading into the weekend
as the next (weaker) low pressure system lifts across the Great
Lakes bringing chances for rain on Sat increasing into Sunday.

&&

.AVIATION /04Z MONDAY THROUGH FRIDAY/...
An increasingly moist southerly flow will overspread the area
tonight in advance of low pressure across the Miss Valley.
Orographic lifting of this moist flow will continue to yield
LIFR cigs across the northern mountains (KBFD) overnight, while
progressively higher cigs are expected further south. LIFR
conditions noted at KUNV at 03Z, but a developing southerly
breeze is expected to cause low level moisture to mix out and
result in modest improvement there later tonight. VFR conditions
noted across southeast Pa (KMDT/KLNS) at 00Z, but latest model
soundings and MOS guidance support the idea of a possible
period of MVFR cigs/vsbys roughly between 10Z-14Z. Expect
predominantly MVFR cigs at KJST overnight, where a southerly
flow results in drying/downsloping off of adjacent higher
terrain.

Warm front is progged to lift through western Pa on Monday,
resulting in a return to VFR conditions along the spine of the
Alleghenies, including KJST and possibly KBFD/KAOO. Elsewhere,
modest improvement will come slowly across the eastern half of
Pa on the cold side of the front.

LLWS problem will become a concern Monday evening, as a very
strong low level jet overspreads the area ahead of an
approaching cold front.

Outlook...

Tue...AM rain/low cigs poss, then windy with PM shsn poss w mtns.

Wed...AM shsn possible w mtns.

Thu-Fri...No sig wx expected.

&&

.HYDROLOGY...
Marietta gage /MRTP1/ pretty much steady right now, although ice
effects continue. The Flood Watch for this area lasts into
Monday afternoon. Due to the mild temperatures, there is a
potential for ice movement, but also deterioration/thinning with
time. All locations along rivers and streams that have
significant ice buildup should monitor water levels closely for
the next several days.

The anticipated rainfall totals of 0.5 to 0.8 inches over the
next 48 hrs is much less than we had a few days ago, and the ice
is less pervasive/extensive due to our relatively mild temps
(versus the period leading up to our previous significant
rainfall).

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Monday afternoon for PAZ065-066.

&&

$$
SYNOPSIS...Dangelo/Evanego
NEAR TERM...Evanego
SHORT TERM...Dangelo/Evanego
LONG TERM...Lambert/RXR
AVIATION...Fitzgerald
HYDROLOGY...


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