Area Forecast Discussion
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FXUS61 KCTP 241832
Area Forecast Discussion
National Weather Service State College PA
232 PM EDT FRI JUN 24 2016
A nearly stationary front will linger just south of the Maryland
border today. High pressure will dominate for the weekend before a
cold front approaches the area Monday. High pressure should return
.NEAR TERM /THROUGH TONIGHT/...
Two main clusters of shra at this point and just a few ltg strikes
in each of them. The action near the front to our south is well-
handled by any model you wish to pick but... The cluster in the
central mountains is not captured by the HRRR or RAP at this point
- despite existiung in that general area for at least 3 hrs. Gotta
go off the (guidance) grid(s) here and allow persistence and
conceptual model to work their best.
Upper short wave trough is swinging through right now - a little
early to catch peak heating to be coincident with the best lift.
Lower dewpoints in the north should limit the spread of shra to
the north of the current cluster between IPT-UNV. Lowest POPs will
be there for the rest of the daylight hours. Higher numbers will
follow in the vicinity of those current clusters of convection.
Not much cu in the SE yet, but expect some increase there with
best heating and higher dewpoints in that area. Will keep POPs on
the higher-end of the chance range there.
As the upper trough slides eastward in the next few hours, a
slight increase in the areal coverage will occur before a
commesurate decrease in shra coverage for the remaining few hours
before sunset. Most of the convection should be done by sunset.
After sundown, a period of clearing is expected, except perhaps
right along the southern border. This will allow for rapid cooling
without any gradient wind. Patches of fog should start to develop
before midnight and may become more widespread later tonight. Low
clouds may develop in the SC/SW mountains with the flow in the
lower 5 kft from the east providing lift. Mins will range from the
L50s N to the L60s SE - almost exactly normal for late June.
.SHORT TERM /SATURDAY/...
After any fog burns away, the moisture will lift and could form a
scattered cu field along the spine of the mountains. But, the
large-scale subsidence and suppression of rising upper heights
should keep any cu flat. There is the smallest chance of a
sprinkle, but nothing worth putting in the grids. Overall, a
wonderful June day with maxes into the 80s and only a very light
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
The large scale pattern will feature a 588+DM ridge on Sunday
before an upper trough becomes established from the Great Lakes
into the Northeast through the remainder of the period. A frontal
boundary/surface trough at the leading edge of the upper trough
will press southeastward on Monday followed by the main synoptic
cold front on Tuesday. The front becomes stalled along the East
Coast back into the TN valley, while high pressure migrates
eastward from the Upper Midwest into the North-Central
Appalachians Wednesday into Thursday.
The models and ensembles are in pretty good agreement with the
overall flow pattern through the end of June. There are some minor
timing differences concerning the early week FROPAs with larger
spread by July 1 concerning a potential wave of low pressure
tracking east along the aforementioned stalled frontal zone.
Temperatures should peak on Sunday and trend gradually cooler
through the middle of next week, as heights remain suppressed.
Convective precipitation will focus along the fronts with maximum
POPs on Mon-Tue.
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
So far, the shra are staying in between the terminals. Two main
clusters around MGW/LBE and between UNV-IPT. Cu rather short at
this point with heating limited by persistent low-mid cloud
cover. Wind light and variable but generally N-E. Upper flow
westerly. Enhancement in lift from weak upper trough will pass
through this afternoon. This should keep shra going into the very
early evening. With less heating than yesterday and lower moisture
on the whole, the shra should wind down faster, mainly before 00z.
Overnight will hold fog and low clouds in the SW-SC with a light
easterly llvl flow and remnant moisture from shra. Will go for a
brief period of IFR at most locations as those that do not have
the low deck will likely clear out and radiational cooling will
allow for fog there as no significant change in dewpoint is
expected. The Nrn tier - esp BFD - is the least likely place to
have fog due to low dewpoints. Any AM fog should burn away
quickly at most sites, with KJST stuck the longest. Moisture lifts
to eventually developinto a sct cu field over the spine of the
Alleghenies. NW flow and general subsidence should keep the cu
very short and no mention of shra necessary.
Sun...No sig wx expected.
Mon...CFROPA. ocnl shra/tsra.
Tue...Sct pm tsra impacts poss, mainly east.