Area Forecast Discussion
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FXUS61 KCTP 261716
Area Forecast Discussion
National Weather Service State College PA
116 PM EDT Wed Apr 26 2017
A moist east-northeast inflow from the Atlantic Ocean will
provide a cloudy and misty start today, followed by clearing
through the afternoon. A few strong to severe storms are
possible across the Northwest Alleghenies Thursday afternoon and
evening. Warmer temperatures are expected through the end of the
.NEAR TERM /THROUGH TONIGHT/...
We can see some funny blue stuff above the stratocumulus clouds
locally. The GOES-16 0.64 channel shows most of the high clouds
are in our easternmost areas and points east. Still some low
clouds trapped in the valleys but mainly just strato-cu.
The clouds will slowly erode and the temperatures will slowly
climb this afternoon. Most areas should approach if not top 70F.
The extreme southeast will likely be the last area to see the
sun so they may not quite get to 70F in some locations.
One of those days where northwestern PA will be warmer than our
southeastern areas. Enjoy the late afternoon and evening pleasant
Due to weak flow and increasing moisture there could be some
patchy fog. But a relatively warm overnight.
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Nice start to the day Thursday and it should be a warm day. Many
areas will top 80F.
The POP, CAPE, and PWAT fields all suggest a front approaches
from the west in the afternoon. Noted the 12Z GFS is slower and
our superblend is drier than previous runs. No real QPF in our
region until around 2100 UTC and by 0000 UTC it gets to central
PA and dies. The GEFS is not in yet. Clearly any
showers/thunderstorms will most likely be in the late afternoon
or evening hours. Only modest CAPE where the LLJ is the
strongest. In the 600-900JKG-1 range. Better CAPE in some
models/members to southeast where there is less lift and weaker
The front is moving into a strong ridge and it is a bit moisture
Overnight Thursday into Friday showers end or die out in central
areas. A bit cooler and drier overnight Friday into Friday AM.
The PW is normal to below normal and the 850 hPa temps are
closer to normal to a tad above normal. There is no CAPE to
speak of. Friday looks potentially like a really nice warm late
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Model and ensemble guidance remained in good agreement with
large scale pattern amplification this period with a vigorous
closed H5 low ejecting northeast from the southern Rockies into
the upper Great Lakes/Canada and deep surface cyclone expected
to lift out of the MS Valley. Meanwhile, an anomalous upper
ridge centered over the Southeast U.S./western Atlantic will
gradually weaken and shift east.
The details of weekend forecast are still uncertain with rain
risk likely focusing along/north of quasi-stationary frontal
zone progged to shift south of PA by early Sunday before lifting
back to the north as warm front. Therefore continued to utilize
a NBM/ECENS/WPC blend for max/min temps and POPS which
maintained good continuity with previous fcst. While unsettled
with a period of rain likely at some point, the fcst does not
look like a washout. Temperatures should remain above late-
April climo but could be too warm/cool depending what side of
the boundary you are on.
Max POPS remain centered on Monday/May 1st as the aforementioned
cold front crosses the Appalachians and continues toward the
Atlantic seaboard. A severe weather threat may evolve downstream
from the OH Valley into the Mid Atlantic, but at this time it is
unclear whether instability will be sufficient to support severe
Temperatures will decline to near normal behind the cold front by
next Tuesday May 2nd.
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
Lots of clouds and low clouds around this AM. Some isolated
bands of light rain too. Most areas are MVFR only patchy IR.
Conditions should slowly improve later this morning and
afternoon from west to east as the low to our east drifts away
Model RH profile support VFR conditions at BFD/JST by midday,
while more gradual clearing takes place across the eastern half
of the state during the afternoon. Poorest flying conditions
will likely hang on the longest (perhaps until 16-17Z) across
the Lower Susq Valley invof KMDT, KLNS and KMUI.
Patch MVFR/IFR overnight expecting areas of fog. We also
anticipate late afternoon/eve showers and thunderstorms over
western areas spreading into eastern areas. Highest probability
in the 21 UTC to 03 UTC range.
Thu...AM fog possible. Isolated PM tsra impacts possible west.
Fri...No sig wx expected.
Sat...Rain/low CIGs possible NW Mtns. Isolated tsra impacts
Sun...Low CIGs possible east. Isolated PM tsra impacts possible