Area Forecast Discussion
Issued by NWS State College, PA
FXUS61 KCTP 260927
Area Forecast Discussion
National Weather Service State College PA
527 AM EDT SUN JUN 26 2016
High pressure will bring one more dry day before a frontal system
enters the region Monday. High pressure will return by midweek.
.NEAR TERM /THROUGH TONIGHT/...
Other than some high cloud convective debris from upstream
thunderstorms, skies are clear. High pressure will bring one more
dry warm day after the some local fog patches burn off following
For tonight clouds will begin to increase over the west after
midnight with showers likely reaching my northern mountain
counties before sunrise. Lows a couple of degrees either side of
60 will be well above normal over the northwest, ranging to near
normal around Harrisburg-Lancaster-York.
.SHORT TERM /MONDAY/...
A cold front will move into the forecast area Monday, but guidance
continues to indicate it will be losing vigor as it moves well out
ahead of the main shortwave aloft into the slowly receding upper
ridge. Ensembles show a narrow ribbon of anomalously high PWATs
moving into the area with the front with the SREF also developing
some moderate CAPE. The 00Z deterministic guidance develops more
modest CAPE in the GFS, but a bit more on the order of 800-1500J
in the Canadian and ECMWF. So while the front looks like it will
fairly weak, weak convergence and eroding stability should lead to
at least some scattered showers and thunderstorms as the front
traverses the region. Clouds and showers will knock a few degrees
off high temperatures, compared to today.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
After the cold front moves east of PA Monday night, a more
vigorous secondary shortwave will slide through the region Tuesday
helping to kick off additional scattered showers and
Mid week looks mainly dry as weak mid level shortwave ridging is
made to bring a break in the precip chances. The GFS was an
outlier bringing some showers up into central Pa by Thursdayafternoon.
The GEFS reflected this with very small chances while the ECMWF
and Canadian were dry, so I chose the more optimistic solutions
leaving the mention of showers out of the forecast.
By Friday the upper low bottoms out south of James Bay. Models are
having a hard time resolving individual shortwaves rotating around
this system, but with increasing cyclonic flow aloft there is
some consensus in reintroducing the chances for
showers/thunderstorms for Friday into the weekend.
Daytime highs by midweek will be near to slightly below normal,
but still very pleasant for late June.
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
A few spots have some fog. Most areas still VFR. Less haze
and more blue sky since yesterday.
Dewpoints not that high for mid to late June. Days are long.
Thus held off on any mention of fog in the 06Z TAFS.
Earlier discussion below.
High pressure over Pennsylvania will provide the region with
widespread VFR conditions and light wind through late today, with
just a chance of some minor vis reductions from fog arnd sunrise
Mon...Sct pm tsra impacts, mainly west.
Tue...AM fog possible. Isold PM tsra impacts possible east.
Wed-Thu...No sig wx expected.
NEAR TERM...La Corte
SHORT TERM...La Corte
LONG TERM...La Corte