Area Forecast Discussion
Issued by NWS State College, PA

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406
FXUS61 KCTP 240753
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
353 AM EDT Fri Mar 24 2017

.SYNOPSIS...
A warm front will drift northeast from the Ohio River Valley
today, and we could see a brief period of freezing rain this
morning followed by a rapid warm up. The frontal boundary will
sag back south to near the Mason-Dixon line by Saturday night,
then remain stationary from near Cleveland...to the
Baltimore/Washington area Sunday night. Mid-tropospheric heights
and temperatures over the Commonwealth will be slightly above
normal into next week. A few week systems should bring showers
to the region, but at this time the pattern does not suggest any
significant rain events.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
High clouds overspreading the SE half of the state, while
thicker/layer clouds capable of supporting some rain were edging
east across the PA/OHIO border.

Under mainly clear skies early on, temperatures dipped into the
mid and upper 20s. The mercury is beginning to rebound back
above freezing in many locations as a light wind develops and
stirs up the near-sfc layer. However, with the sfc T/Td spread
on the order of 10-20 deg F, expect significant boundary layer
cooling and a fairly good chance at seeing some very light
freezing rain (and even some sleet pellents) through about
14-15Z today.

Satellite imagery shows a larger area of deep cold cloud tops
over Michigan and leading cirrus over Ohio. Clouds are coming
and behind them some rainfall is coming.

Due to the cold air in the boundary layer the rain will likely
start as freezing rain over northern and some central areas.
Farther south less QPF is forecast and later in time so less
likely they will see freezing rain.

The HRRR and its coarser twin the RAP show the precipitation
coming in slower with each run. Likely, most areas will not see
any precipitation before 6 AM. In with 0.01 to about 0.10
inches of QPF a light glaze is possible before 9 AM (especially
in northern and central areas).

Most of the region in the advisory for freezing rain could see a
light glaze this morning.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
There will be a lingering threat for isolated freezing rain in
the 8 AM to 10 AM timeframe today in some locations and perhaps
11 AM in colder areas of our northeastern areas. But the
forecast rapid warm up and the March sun angles should help
reduce this fast. One might not see the sun but the shortwave
energy will reach roads and walks.

The chance of rain diminishes during the day.

There should be a very rapid warm up by late morning and into the
afternoon. Winter will have exited stage East and it may be
along time before we see any significantly cold weather again.

High temperatures should range mainly from the 50 to the lower
60s. Warmest in the south/southwest.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
At the outset of the longer term period the models are in fair
agreement in timing and strength. All are indicating a boundary
just to the north of Pennsylvania with a large upper level low
moving through the central midwest. A negatively tilted ridge
over the mid Atlantic will allow for stable but cloudy weather
into Saturday. Lows Friday night into Saturday should range from
the upper 40s to low 50s. There could be light rain showers on
Saturday but warm and stable. A cooler moist boundary should
move into the region Sunday out ahead of the approaching low.
Have adjusted POPs for timing and intensity. QPF remains
variable but possible wet period Sunday into Monday.

Above average temperatures are expected over the weekend with
the warmest day likely on Saturday with some sites approaching
70F over southern PA. Sunday should be markedly cooler behind
a backdoor cold front and a likelihood of rain. However, above
average temperatures (especially nighttime) appear very likely
through early next week, as 12Z GEFS indicates Pa remains
beneath a mean upper level ridge and plume of anomalous PWATs.
The chance of showers will spike with passage of next shortwave
Tuesday into Wednesday.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
VFR conditions under thickening high-mid level clouds will trend
lower with MVFR most likely between 09-15z as quick shot of
light precip moves across the airspace. Thermal profiles remain
marginally supportive of brief/light ice mix (FZRAPL) across the
northeast 2/3 of the airspace before changing to rain. A strong
low level jet from 230-260 degrees will produce LLWS thru mid
morning. The precip exits the airspace to the east by 18z
leaving behind mainly dry VFR/MVFR conditions through tonight.
Guidance is less optimistic at KBFD suggesting a more prolonged
period of IFR conditions.

Outlook...

Sat...Mainly VFR. Chance of rain northern 1/2 airspace.

Sun-Tue...Sub-VFR with periods of rain.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 11 AM EDT this morning for
PAZ005-006-010>012-017>019-026>028-037-041-042-045-046-049>053-
056>059.

&&

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



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