Friday, July 20, 2018, 4:57 AM EDT
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Area Forecast Discussion
||Wed, Dec 31, 7:00pm EST
FXUS61 KCTP 200554
Area Forecast Discussion
National Weather Service State College PA
154 AM EDT Fri Jul 20 2018
High pressure will move to the east today. Moisture will then
increase for the weekend. Low pressure over the midwest will
near, and another area of low pressure will slide up the East
Coast. The coastal low could make heavy rain for the eastern
half of PA. Saturday may be chilly with a southeast wind and a
chance of rain. A chance of rain is then in the forecast into
the middle of next week.
.NEAR TERM /THROUGH TODAY/...
Looks like the start of the valley fog in the upper West Branch,
and this should expand across the northern valleys and some
patches in the south. Diurnal cu will pop up at first as the
moisture starts to increase in the central mtns, but these could
mix out/lift. A better increase in moisture will occur over far
western PA, and there is a very small chc of a shower touching
Warren and/or Somerset counties. But, it is almost not worth
mentioning. Expect maxes to be very close to normals, perhaps
even a bit higher in the NW.
.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
A moistening south-southeast flow should result in low clouds
expanding to cover a good portion of the CWA by Saturday
morning. The model RH progs put the thickest clouds over the
central mountains. This seems like a good start, but the ridges
perpendicular to the SE flow over the east will also have a high
chance of getting very cloudy. The clouds will likely keep the
heating down to only a meager rise for the day. Maxes may
struggle to get to 70F in lots of places. There is even a chc
of a shra - or perhaps drizzle - over the central mtns.
The bigger trouble in the forecast is the complicated sfc
pattern and resulting rainfall from the coastal low and the
broad low over the Midwest. Models still differ on timing and
location of the coastal low. The dynamics around this storm will
have a direct influence on the area, keeping it either fair or
making it miserable this weekend. This is all still too muddy to
make more than an increase in PoPs for the east through all the
weekend. It may actually warrant a decrease in PoPs for the
west, where it could influence the weather by providing
subsidence and suppressing convection.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
By the weekend, inverted low centered over Lake Michigan will be
channeling tropical-like moisture northward into PA as our
weather becomes unsettled. A compact wave of low pressure forms
near the Carolinas and slides northward toward NJ by Sat night,
enhancing rain/convection chances further. EC and GFS differ
slightly on the intensity of the coastal low. Will need to keep
an eye on this feature as could focus heavier rains over eastern
portions of the state. Sat and Sat PM could be dry over most of
the CWA with us in-between this system and the upper low off to
Upper low begins to fill in Sun into Mon but high PWATs will
keep mention of daily convection in the forecast through much
of the week - peaking in the afternoons - as a tropical feel
persists. An approaching cold front for mid/late week will
enhance precip chances further before weather becomes more
settled for first part of next weekend. Have peaked the bell
curve of PoPs in mid-week.
Temperatures will be a bit below normal Sat/Sun with thicker
cloud cover, then highs return close to normal for next week
while lows look to remain on the muggy side.
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Good VFR will continue through this forecast period as high
pressure slowly slides east across Pennsylvania. Winds will
increase to around 10 knots after 15Z.
Sat-Tue...Occasional SHRA/TSRA with associated MVFR/IFR