Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 251106
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
706 AM EDT WED MAY 25 2016

.SYNOPSIS...
A ridge of high pressure will build over the northeastern U.S.
bringing a noticeably more summer-like pattern into the first
part of the holiday weekend. Slightly cooler weather may arrive
for Memorial Day.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Atmosphere is pretty dry for the summer-like temperatures coming
up again today. Diurnal ranges may be 30 to 40 degrees in some
places today with highs more like mid-July. Afternoon RH`s will be
into the 20 to 30 pct range. Thus, it will be tough to get any cu
to pop. If they do, it will be over the ridges and very sparse
coverage. One exception may be over the NE as some deeper
convection could make a weak shower over central NY and drop it
down through the Endless Mountains late in the day. Otherwise,
POPs will be nil. Max temps should be 1-3 degrees warmer than
Tuesday thanks to the sunshine and a slightly milder start to the
day in most places.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Clouds start to increase from the west late tonight. But, it
should remain clear in the eastern half of the area all night. The
wind never quite dies off, so very mild mins are expected. The low
level moisture/dewpoints should be on the rise. A spot or two in
the southern tier may not go below 60F. Will keep POPs low for the
overnight, but a stray shower is possible by sunrise in the
Laurels.

Muggy is the word for Thursday. Most guidance brings dewpoints
into the 60s all over the region. The limiting factors for
convection will probably be the presence of a capping inversion
around 12kft at the top of some morning mid-level clouds. But,
the clouds may slide to the east a bit and allow the heating to
bring the W/NW into the 80s. This results in CAPE near/over
1000J/kg. All the convection should be diurnally-driven, but the
GFS does ride a very weak short-wave trough right overhead at peak
heating time, too. Thus, it is more bullish on the QPF/POPs than
the NAM and ECMWF which make very little precip. POPs will be
held at 50 pct over the Alleghenies and 20-40 pct in the rest of
the region for the afternoon and early evening. These numbers may
be too a few pct points too high, but the cap may seriously limit
deep convection.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The extended guidance continues to show a strong ridge over the
mid Atlantic and the Great Lakes region through the weekend. This
will bring the arrival of the first extended period of summer-
like temperatures and humidity.

By Thursday we will be embedded in a broad WSW flow aloft.
Slightly above normal PWATS support the idea that humidity will
become noticeable over most of the area for the first time this
warm season. It also means we will be susceptible to mainly
afternoon convection pretty much on a daily basis into the
weekend. However the strong ridge should provide enough subsidence
to keep any convection at bay Thursday and Friday. The GFS is
very aggressive poking the Bermuda ridge strongly up over the
eastern U.S. Saturday while the ECMWF is a little flatter. However
given the southerly flow of moisture, the warmer temperatures and
the possibility of a mid level trough advecting through, Saturday
should have a decent chance for some afternoon convection. The
trend is for the ridge to break down late in the weekend and for
cooler air to move into the region early next week. This could
bring temperatures to slightly below normal.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
No fog as of 7 am. No big changes for 12Z TAFS.

High pressure will provide the region with a warm and
sunny day with just a few clouds. VFR conditions will
prevail.

Interesting feature about yesterday when I came in early
afternoon was the gusty NW winds. Winds became quite gusty
as winds shifted to the NW. Dewpoints fell into the 30s in
some spots.

500 mb heights come up some today and pressure gradient
weakens some this aft...so I am not expecting winds to be
that strong. Still with the high late May sun angle...the
airmass will likely still mix to about 7000 feet.

There could be a few showers and thunderstorms late Thursday.
Not totally sold on this...as dewpoints are low and have to
come up a lot higher. Somewhat a better chance on Friday.

OUTLOOK...

Thu-Sun...Isold...mainly pm tsra impacts possible.

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Ceru
AVIATION...Martin



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