Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 230706
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
206 AM EST Sat Feb 23 2019

.SYNOPSIS...
Fair weather will hold through tonight thanks to high pressure
tracking north of the region. The high will move off the
Southern New England Coast on Saturday with clouds thickening
up during the day followed by rain late Saturday into early
Sunday.

Gusty and potentially damaging westerly wind gusts will develop
in the wake of cold front late Sunday morning and will continue
through Midday Monday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A fairly thick cirrus layer observed across central Pa late
this evening, the result of waa aloft ahead of southern plains
shortwave. Satellite imagery shows the high clouds being
advected northeast along axis of upper jet, which is progged to
remain over the region tonight. Therefore, expect skies to
remain mostly cloudy overnight, with some thinning of the cirrus
likely over the northern half of the state based on model
400-200mb rel humidity fields.

Surface high pressure directly over Pennsylvania will ensure a
dry night with very light winds. Have zeroed out POPS across the
entire area.

Lows will likely be a couple degrees above climatology due to
cloud cover. Expect daybreak readings ranging from the low 20s
over the northern mountains, to the upper 20s in the south.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
Thickening cloud cover is expected Saturday from south to north,
as high pressure drifts off the Mid Atlantic coast and a warm
front approaches from the Ohio Valley. By afternoon, some spotty
light overrunning rain appears likely over the southern counties
and possible over the northern half of the state, as a southerly
flow overruns cool, stable airmass over central Pa.

Where rain falls, evaporational cooling could drop temperatures
to near the freezing mark over the high terrain, so continue to
include mention of possible fzra over elevations above 2000ft.
No headlines planned at this time, as any light freezing rain
would likely be confined to the ridgetops of central/northern
Pa. Also, road surfaces will likely remain above 32F during the
daytime due to increasing sun angle and nearly all roads
surfaces still have residual treatment from the recent winter
storm.

Superblend/NBM max temps range from the mid 30s over the Laurel
Highlands to the low 40s across the Lower Susq Valley.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Higher PWAT air (between 1-1.25 inches) will spread in from the
Ohio River Valley Saturday night and a soaking rainfall for 7 to
9 hours will ensue as uvvel increases at the nose of a 55 to 65
kt swrly LLJ. Consensus rainfall amounts are between 0.6 and 1.0
inch by around sunrise Sunday, which should be very manageable
regarding stream levels since a significant percentage of the
snow from the midweek storm melted on Thursday, and most will be
gone and flowing into the larger tribs and rivers before the
bulk of the rain arrives late Saturday into early Sunday.

Focus shifts toward the potential of strong winds Sunday PM, as
trailing cold front sweeps through the area, allowing strong
winds associated with Grt Lks storm to mix to ground level. This
scenario of a powerful low passing north of Pa fits the pattern
we see with our strongest winds across central Pa and a quick
look at model 850mb winds suggest >50kt gusts are possible.

High Wind Watch for our Entire Area from Late Morning Sunday
into Monday afternoon, with strongest winds over the west
several hours before they expand into eastern areas.

As the Temperatures continue to warm aloft, expect a likely
surge to springlike readings Sunday. The shallow cool air should
mix out then there should be a return to seasonal readings for
next week.

Med range guidance points toward dry weather early next week,
as high pressure builds across the region. However, model spread
and forecast uncertainty ramps up by the middle of next week
concerning the track, timing and strength of a fast moving
shortwave approaching from the midwest. Given when the
instability is for the storm next midweek, have changed precip
type to mostly snow.

GFS forecasting potential for another system next weekend, with
ECMWF developing a weaker coastal low by Sunday. Much uncertainty
through this portion of the forecast so low confidence equals
low pops.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions  today will trend MVFR to IFR this evening
through tonight. Light rain or misty drizzle will develop from
south to north this afternoon as low level flow increases from
the southeast, with a steadier period of moderate rain expected
overnight into Sunday morning. Light freezing rain is possible
at highest elevations and may impact KJST/KBFD. LLWS is likely
late tonight into Sunday morning and plan to add to 12Z TAFs.

Outlook...

Sun...Scattered rain showers early, then strong FROPA/windshift.
Turning very windy with gusts 40+KT from ~260 degrees. MVFR/IFR
conditions in snow showers possible western 1/3 into Sunday
night.

Mon...MVFR/-shsn western 1/3 trending VFR. Windy with gusts
40+KT from ~290 degrees early; decreasing late.

Tue...Mainly VFR. Chc of snow late across the northwest
airspace.

Wed...MVFR with chc of light rain/snow.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Sunday afternoon through Monday afternoon
for PAZ028-036-037-041-042-046-049>053-056>059-063>066.
High Wind Watch from Sunday morning through Monday afternoon
for PAZ004>006-010>012-017>019-024>027-033>035-045.

&&

$$
SYNOPSIS...Lambert
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Lambert/RXR
AVIATION...Steinbugl



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