Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 230259
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1059 PM EDT Wed Mar 22 2017

.SYNOPSIS...
One really cold night tonight before a more seasonable spring
pattern returns. The temperatures will rise back to near or
above normal levels through the end of March. A wintry mix
remains possible early Friday morning before changing to rain.
The weekend starts off very mild with rain likely by Sunday, and
continued chances for showers early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
All is well. The air is cold. We may actually be a tiny bit
colder with the forecast than the current trend would play out
if the temps were linear, but weather is never linear. Mainly,
the air has not yet calmed down. We`ll just give it time.

Prev...
Interesting to watch the dry air expand southward on the
satellite pics, especially the Ozone IR band (9.6microns).
Dewpoints are very low with most of the CWA w/in a few degs of
0F. Clear skies, and the wind has only recently become a little
lighter. By morning, it may be calm in many places. Record lows
anyone? See below in climate section.

Prev...
Subsidence and drying clearly evident on the WV imagery with
strong high pressure building in. Dewpoints over much of PA also
have fallen into the single digits this afternoon.

Cold/dry air continues to push into Central PA via gusty NNW
winds (generally in the 25-30 mph range) in strong low level
CAA. Temps peaking only in the mid 20s north to around 40
south, and when adding in wind chill effects today will feel on
the order of 40 to 50 degrees colder relative to yesterday!

The cold air is being supplied by a strong 1035+mb modified
arctic high pressure system that is drifting across the Great
Lakes to a position centered over Central PA by daybreak
Thursday. The abnormally dry air coupled with clear skies and
winds becoming light will result in a very cold night with
minimum temperatures falling to near-record territory with
single digits likely in the northern mountains and teens across
the south. See the climate section for 3/23 minimum
temperatures records.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
After a cold start, temperatures will begin to rebound as low
level flow veers to the south/southwest by midday Thurday across
the west and mid afternoon in the east. Highs Thursday will be
below average but it should feel noticably warmer with very
light surface winds and plenty of late March sunshine bringing
peak temps in the 40s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
WAA pattern ramps up quickly Thursday night into Friday via
anomalous west-southwest low level jet. Model solutions all keep
on with temperature profiles/low-level temps favorable for
freezing rain. The cold air might be deep enough for a little
sleet at first, but just enough to mention. Will keep the
p-type to R or ZR after sunrise over the NE. As we are finding
today, the heat from the late March sun does wonder. But, there
is still snow on the higher elevation, esp in the NE where the
threat for ZR is higher. Will keep on with mentions of just a
few hundreths of ice for now. Overall impact appears minimal
but it only takes a small amount of ice to cause problems
especially during the early morning commute. Temps should climb
above freezing everywhere by mid morning Friday ending the risk
for ice.

Rain focus should shift north into NY Friday afternoon into
Friday night as baroclinic zones sets up in upper level
confluence zone downstream of deep cyclone moving through the
Southern Plains. The boundary placement will be key to the fcst
but it looks for now that most of the area will be in the mild
warm sector.

The models and ensembles continue to show a series of upper
troughs progressing onshore from the Eastern Pacific and across
the Southwest/South-Central Plains before deamplifying as they
move east of the MS River. The first of 3 upper troughs emerges
from the Southern Plains and crosses into the MS Valley Sunday
and continues to weaken as surface frontal wave translates
downstream crossing the OH Valley/Great Lakes into the northern
Mid Atlantic states by Monday. Blend of NBM/ECENS/WPC still
indicating max POPs in the Sunday-Sunday timeframe.

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 also be mild but a bit
cooler due to the likelihood of rain. Fcst issues pertaining to
a backdoor cold front appear to be confined to New England early
next week with temperatures remaining near or or above climate
averages into early next week.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
For 00Z TAFS, no big changes.

Very dry air in place, with no clouds as of late aft.

Winds will die down after sunset.

VFR and light winds continue through Thursday, with high clouds
increasing late.

Outlook...

Fri...Showers/reduced CIGS possible, mainly BFD.

Sat-Sun...Showers/reduced CIGS possible.

Mon...Showers/reduced CIGS possible west.

&&

.CLIMATE...
Minimum temperature records for 3/23 at select sites:

MDT: 14 in 1934
IPT: 8 in 1906
BFD: 5 in 1959
AOO: 15 in 1960

&&

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

&&

$$
SYNOPSIS...RXR/Steinbugl
NEAR TERM...Dangelo/RXR
SHORT TERM...RXR
LONG TERM...Ceru/Steinbugl
AVIATION...Martin
CLIMATE...



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