Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
1026 PM EDT Monday Aug 3 2015
a cold front will push southeast and through the state overnight.
High pressure will dominate the midweek before unsettled
conditions return for Thursday and Friday as a slow moving front
moves back into the region.
Near term /until 6 am Tuesday morning/...
10 PM update...
A cluster of storms extends from the northern suburbs of
Pittsburgh to just west of State College...and is tracking east at
a decent clip. Earlier tall cores have come down quite a
bit...with most activity looking sub severe at this hour. Biggest
question for the next 3-6 hours will be how persistent the storms
will be in the face of a stabilizing lower atmosphere. Hrrr
suggests the scattered...not very organized showers and
thunderstorms continue through about 05-06z...when activity
quiets down rapidly region-wide.
Biggest remaining threat looks to be localized heavy rain within
the east-west band that is pretty much tracking due east. The
movement is fairly rapid so flooding threat looks minimal unless a
location manages to get hit several times in a short period of
Lows early Tuesday will range from the middle 50s in the northwest to middle
60s over the southeast.
Short term /6 am Tuesday morning through 6 PM Tuesday/...
a rather strong upper trough and secondary cfront will be diving
southeast from the upper glakes region. Although the low level environment
will be drier and slightly cooler in the wake of Monday night/S
cfropa...strong forcing beneath the l.E. Region of a 95 knots jet will
likely spark at least isolated to scattered thunderstorms and rain across the
central and northern mountains
Maximum temperatures will vary from the 70s across the northwest half of the
County Warning Area...to the 80s in the southeast half. Close to normal for late Summer.
Long term /Tuesday night through Monday/...
the upper low over northern Quebec should continue to drift to
the northeast and zonal to slightly northwest flow is expected to
follow as a quasi-stationary boundary hangs out just to the south
of the state. Uncertainty remains in the placement of the
boundary so will keep some pop in the southern part of the state...but
most locations will be dry until Thursday into Thursday night.
Then a stacked low will slide eastward from the middle Mississippi
Valley and may make a more-or- less constant rain instead of
showery/convective precipitation. The upper level low will finally move
off late next weekend which will be a Herald for quieter weather.
Temperatures should trend cooler later in the week before warming
up into next week.
Aviation /02z Tuesday through Saturday/...
widely scattered showers and thunderstorms will continue across the
airspace through late tonight before gradually weakening/dissipating
after midnight into the predawn hours. The sparse coverage precluded
mention in terminals and will amend as necessary. Jst/aoo should see
the greatest risk for thunderstorm impacts given evolving storms upstream
over pit/btp vicinity moving east-southeastward. The other potential AVN concern is
IFR fog or low ceilings developing during the predawn hours. Guidance
seems to favor western tafs given combo of weak upslope westerly flow and
narrowing dewpt depressions. Any rainfall will also aid in potnl
reduced conds by providing addnl low level moisture. Confidence in
restrictions after 06z is low at this time but something to be aware of for
the 06z scheduled issuance. For Tuesday...look for mainly VFR with
scattered-broken ceilings 050 and surface wind gusts 15-20kts 16-22z.
Wednesday...VFR. No sig weather.
Thu-Fri...VFR/MVFR with rain possible as low pressure tracks south of
Sat...VFR with a low chance of MVFR in isolated afternoon rain showers.
near term...la corte