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000
FXUS61 KPBZ 171925
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
325 PM EDT Sun Sep 17 2017

.SYNOPSIS...
Unseasonably strong high pressure centered over the region will
bring a prolonged period of dry weather, along with unseasonably
warm temperatures through the coming week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...

Stagnant high pressure will remain anchored over the region
through tonight, with seasonably high boundary layer moisture
content remaining in place despite the lack of recent rainfall.
With the dissipation of diurnal cumulus, clear skies and calm
winds should again allow temperatures to fall toward saturation.
Once again, expect a repeat performance of late night/early
morning dense fog in the river valleys.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...

Very little weather of interest is expected through the early
week period locally. A narrow high amplitude ride will remain
anchored from the western Gulf northeastward through western
Pennsylvania, framed by Hurricane Jose to the east and an upper
level trough to the west. The approaching trough will rapidly
shear out as it approaches Tuesday, with the surface boundary
never reaching the area. Given strong mid level capping and the
subsidence west of Jose, any threat of afternoon showers would
be extremely isolated either afternoon.


&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...

Once the nor`easter formerly known as Hurricane Jose departs
the eastern seaboard, mid level heights will continue to rise
over the eastern CONUS. 500mb heights exceeding 590dm are an
almost certain bet by Thursday, and will continue through the
weekend. Such values would be several standard deviations above
climatology for late September. Using today`s high temperatures
as a baseline (14.5C 850mb, calm winds, significant Cu
coverage), see no reason why forecast highs Thursday through
Sunday won`t be at least several degrees warmer than those
advertised by the model blends, in the mid to perhaps even a few
upper 80s. Have made upward adjustments, and this beginning to
calendar autumn may end up being one of the warmest stretches
of the year. Additionally, there is a near zero chance of
rainfall through the balance of the forecast period. This
becomes noteworthy as some areas (including locally here at NWS
PBZ) are abnormally dry over the past month and will likely be
heading into early drought conditions. Also, for those who have
noticed an accelerated (nearly 1 month) head start to the
foliage change in the local area, this will undoubtedly be
halted by the stretch of much above normal temperatures.

Bookbinder

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Persistence forecast is expected into Monday. A brief period of
MVFR ceilings is possible early this afternoon with diurnal cu
eventually rising to VFR. Clouds should clear out this evening
with another round of IFR/LIFR fog early Monday.

.Outlook...
Patchy morning fog restrictions are possible through Thu with
ridging in place.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.

&&

$$