Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 260025
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
825 PM EDT THU AUG 25 2016

.SYNOPSIS...
A weather disturbance will bring showers and thunderstorms to
western portions of the area into early tonight. These storms
will diminish as they more into east. A seasonably warm and humid
late-summer weather pattern will continue across Central
Pennsylvania into next week.

&&

.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
Current radar mosaic over the NW seems rather benign at this time.
However, there have been a few cells with 50kft+ tops and
persistent rotation. So far, those nastier cells have stayed away
from the CWA. Have refined the timing just slightly with this
update. But, the main shot of precip is associated with a short
wave trough that is moving through wrn NY and wrn PA. Dewpoints
ahead of the line/s of showers are still in the l70s, and
inflow/source dewpoints are in the m70s from SWrn PA. Thus, these
showers (and the few tsra) should continue for a little while, but
near-term models still indicate significant weakening/scattering
as it moves through the c mtns.

Prev...
HRRR runs show convection entering nw cwa this evening. A few of
these storms will be quite strong with frequent lightning...gusty
winds and brief heavy downpours accompanying them as the move east
and southeast. Convection will weaken after sunset with loss of
heating...somewhere close to Centre County and points north
south...likely not making it much further east. After convection
diminishes look for another warm and humid night.

&&

.SHORT TERM /7 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Ridging will bring warm temperatures aloft to limit threat of
convection. Slight less surface moisture will make things feel more
comfortable though temperatures will once again top out well
above average.

Sfc high will build over the region Friday night, resulting in a
fair and mild night. Will have to watch for the possibility of
patchy valley fog over the northern mtns late.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Medium range guidance is in good agreement in keeping an anomalous ridge
aloft in place over the region into the early days of next week.
This will assure we remain warmer than normal with daytime highs
in the mid to upper 80s, low to mid 90s over southeastern areas,
at least into Tuesday.

By mid week week, weak troughing rippling through southern Canada
and the Great Lakes is made to erode the northern portion of the
northeastern ridge a bit, but only to the extent that upper
heights and temperatures fall back closer to normal values.

The NAEFS and GEFS end up carving out a weak mean trough by the
end of the week, but once again heights and temps are forecast to
be near seasonal norms so it should remain quite pleasant with
the biggest chance being a break in the humidity.

Chances for rain will be generally limited to scattered diurnal convection
each day, but with warm air aloft the chances should remain small
in the absence of well defined forcing. There is a period later
Sunday into Monday morning as we come under the northern edge of
the subtropical ridge and a weak cold front approaches, which
could be the first hints at the development of a more significant
MCS upstream. But with such a strong ridge aloft it`s hard to be
confident at this range.

Main item of difference is the tropical system the ECMWF blows
up over the southeastern Gulf of Mexico early next week that the
GFS doesn`t do much with at all. Both model suites agree with
the northern stream trough mentioned above to be enough to keep
any possible tropical developments well south of the local area.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR conditions continue this evening across Central Pennsylvania.
Broken convection in far northwest Pennsylvania and Southwest New
York slowly making progress towards KBFD. Included mention of
VCTS in KBFD from 01z to 03z.

Short range models continue and try and carry convection into
Central Pa this evening, with activity reaching a KIPT-KUNV-KJST
line between 03z and 05z. At this point, have held off mention of
SHRA/TSRA in any of the other TAF locations...because of lower
confidence /30 POPs/. Will continue to monitor evolution of
activity for possible inclusion in TAFs.

For Friday, some morning restrictions should give way to VFR
conditions.

Outlook...

Fri...Morning restrictions in fog and lower ceilings, then VFR.
Sat...Patchy morning fog...otherwise VFR.
Sun...Mainly VFR...but isolated TSRA western 1/3 airspace in the
afternoon.
Mon-Tue...Isolated/Scattered thunderstorms possible.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Ross
NEAR TERM...Ross/Dangelo
SHORT TERM...Ross
LONG TERM...La Corte
AVIATION...Jung



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