Area Forecast Discussion
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FXUS61 KCTP 291800
Area Forecast Discussion
National Weather Service State College PA
200 PM EDT FRI JUL 29 2016
An upper level trough will influence the region through early
next week...bringing daily chances of scattered showers and
thunderstorms. Most of the time will be dry in any one location
however. high pressure will build over the northeastern united
states by mid to late next week.
.NEAR TERM /THROUGH TONIGHT/...
Mostly sunny skies with temperatures in the 80s this afternoon.
There are a few showers around the most organized areas are in
northwestern PA with a few rogue showers in central PA.
CAMS forecasts allowed for depicting convection in northwest where
PoPs are highest in forecast. Did not try to forecast rogue
showers in central areas.
Most activity should die off this evening as we lose the
instability. Then patchy fog, favored in areas of recent rainfall.
Low mainly in the 60s some warmer spots in southeast and cooler in
.SHORT TERM /SATURDAY/...
Most guidance continues to show the plume of high PW air coming
into PA Saturday. This favors increased chance of showers and
thunderstorms. Each hydrostatic model and it`s convective
parameterization scheme (CPS) have a different idea on the
evolution. The high PW air and SW flow favors the chance of rain.
The 12Z NAM maybe a excessive later Saturday into Sunday.
At this time the GEFS 0.5 degree data implies the chance of rain
increases rapidly after 11 AM Saturday and keeps climbing. It of
course has a big wet bias in convective cases. The GEFS and all
the blends imply lowest PoPs in northwest and west and higher
central to eastern areas. GEFS is basically showing rain over all
of eastern and central PA by 21Z.
Expect showers and thunderstorms with areas affected by intense
cores to see some better rainfall amounts. Most areas should not
see the widespread 0.5 to 1.0 inch amounts.
The rainfall peaks in the SREF/GEFS shortly after the CAPE peaks.
This implies mostly convective and CPS is biasing forecasts.
The most intense rainfall is forecast mainly after 21Z and early
overnight Saturday which is mainly in the next forecast period.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A second wave moves through in cyclonic flow Saturday night and Sunday
keeping the POPs in the 50-70 range with highest chances over the
eastern counties. Short-wave moves to the coast Sunday night with
ridging building in across Central PA helping clear things
out.Monday should be a drier day with sunshine and temps in the
80s.Hi pres ridge should hold through Wednesday though the GFS
tries to indicate maybe an isolated afternoon/evening shower or
thunderstorm over the Laurel Highlands both days.
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR all about the air space. Issues this afternoon include some
very isolated rogue showers in central PA and more organized
showers in northwestern PA. Check radar before takeoff as some of
these showers will develop into thunderstorms.
Models imply rain and showers move in Saturday into Saturday
night. Shower with lower visibility and ceilings along with
isolated thunderstorms will be an issue from about midday Saturday
through midnight. Then more IFR in patchy fog where it rains.
SAT...Showers and isolated TSTMS IFR/MVFR then overnight fog.
SUN-Mon...Scattered showers and isolated thunder.