Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 190847
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
447 AM EDT Tue Mar 19 2024

.SYNOPSIS...
A weather season mismatch across central PA this week with a
brisk and chilly winter-like pattern bringing rounds of snow
showers for the first few days of Spring. Temperatures should
bottom Thursday night and trend seasonably warmer over the
weekend and into next week. A period of rain (or wet snow at
higher elevations) is likely Friday night into Saturday morning.

&&

.NEAR TERM /THROUGH TONIGHT/...
Expect ongoing CAA/lake effect snow showers and flurries to
continue to fade/dwindle this morning as the llvl wind
trajectory backs or shifts from the NW to SW in advance of a
clipper low pivoting eastward just north of Lake Superior. Most
of the higher terrain in the western and northern Alleghenies
should wake up to a fresh coating of snow.

As the lake effect connection tapers off, low-mid lvl warm
advection and isentropic lift should generate some light snow
developing across the northern tier based on the latest hires
ensemble guidance. WPC/NBM qpf amounts favor <1 inch along and
to the north of US-6.

The brief shift in the llvl wind trajectory to a WAA regime will
help temperatures trend higher by as much as 10 degrees day/day
over the Laurel Highlands. Despite the neutral to positive 24hr
maxTchange, fcst highs ranging from the mid 30s in the northern
tier to mid 40s in the lower Susquehanna Valley are still 5 to
10 degree below daily climo.

Snow showers are most likely to linger over the western
Alleghenies tonight into AM Wed. as a progressively colder
westerly flow ramps up into Wednesday morning. Cloud cover and
active breeze will hold temps in the 30s tonight across the
majority of the area or about +5F above climo give or take.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
-A winter-like pattern for the first full day of Spring 2024-

The passage of the cold front trailing the aforementioned
clipper low early Wednesday should be accompanied by scattered
rain/snow showers. A few of the showers could survive into the
Susq Valley, due to strong forcing ahead of the upper level
shortwave. Steep lower tropospheric lapse rates indicate the
potential of some heavier snow squalls across the north central
mtns and we added chance SW+ to the wx grids. The snow squall
parameter fcst from CIPS deterministic models is also generally
supportive of a squall risk Wednesday with timing and marginal
air/road temps suggesting sharp visby reductions as the primary
impact. We continue to highlight the snsq threat in the HWO.

Deep cold advection and passage of an isallobaric/pressure rise
couplet signal the strongest northwest wind gusts Wednesday
afternoon/evening. Peak bufkit mtum transfer and ensemble data
indicate peak gusts 35-45 mph range or just shy of advisory
criteria.

The cold NW flow continues into Thursday with snow showers and
flurries downwind of Lake Erie and over the Alleghenies
gradually diminishing by Thursday night as high pressure builds
into the area. Temps likely bottom on Thursday with daytime
highs 10 to 20F below average and what could be the coldest
night until next winter (teens and 20s).

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Medium range guidance suggests a period of light precipitation
is likely Friday PM associated with warm advection ahead of a
weak northern stream shortwave. Thermal profiles point to mainly
rain, but the N Mtns could be cold enough for a light snow
accumulation. Most guidance keeps a more significant southern
stream shortwave well south of the area. However, there remains
a small chance of phasing of two branches of the jet, resulting
a heavier rainfall across Eastern PA Friday night into Sat.

Fair and cool weather looks likely the second half of next
weekend, as upper troughing exits the east coast and high
pressure builds in from the Grt Lks. Rising heights noted in the
model guidance early next week, but a cold air damming
signature with strong high pressure over the Canadian Maritimes
suggests the warmup will be tempered.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
There will be occasional to persistent MVFR across PA`s
northern and western mtn airfields tonight and even some brief
periods of MVFR Cigs at KUNV and KAOO in -SHSN this into this
evening. These snow showers are currently marching their way SE
as the overhead trough moves through. Lake effect snow behind it
will continue to impact BFD into the early morning hours.

West-northwest winds will be moderately gusty this evening and
tonight for all TAF sites.

A dual or multi-layered cloud shield (mainly VFR) will spread
across the region Tuesday as the low level flow backs a bit more
to the west-southwest, helping to confine most of the snow
showers across the far NW zones, with generally mostly cloudy
skies and breezy and dry conditions elsewhere.


Outlook...

Tuesday-Saturday...Periodic snow showers and reductions,
primarily across the higher terrain of northern and western PA.
This will be enhanced by reinforcing shots of unseasonably cold
air and gusty W/NW winds. West to northwest wind gusts could
peak in the 35 to 40 mph range on Wednesday.

&&

.CLIMATE...
Astronomical Spring (vernal equinox) begins today at 11:06 PM
EDT.

&&

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

&&

$$

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


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