Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
307 PM EDT Monday Aug 31 2015
warm and humid conditions will continue through the week with
isolated daytime showers and thunderstorms possible.
Near term /through tonight/...
a few showers and thunderstorms have popped up in the high terrain
and further west along a weak convergence zone this afternoon.
While nothing has been able to maintain itself with weak shear and
lift...continued development is expected until the loss of
heating this afternoon.
Clear skies and light wind should promote fog development
tonight...especially in the river valleys. Low temperatures will be
warmer than average based on a blend of model guidance.
Short term /Tuesday through Thursday/...
the models continue to build the upper ridge Tuesday before the
weak upper shortwave over the Ohio Valley finally gets absorbed
back into the upper level flow Wednesday. Thus...probability of precipitation were
constructed with the best chance for showers and thunderstorms
across the entire region Wednesday afternoon. Working against any
probability of precipitation higher than chance values are the warm temperatures in the
middle-levels both days. Generally expect coverage to be mainly
Summer airmass/diurnal convection that will dissipate each evening
with the loss of heating.
Another weaker disturbance will pass across the region on
Thursday as the ridge rebuilds. Again...will keep probability of precipitation rather low
at this time.
The warm air in the middle-levels will translate to very warm
temperatures at the surface with highs expected to get very close
to 90 through the entire time period.
Long term /Thursday night through Sunday/...
no major changes to the extended period as the impressive eastern
Continental U.S. Ridge further amplifies reaching into eastern Canada. Cannot
rule out diurnal rain chances...especially in the higher terrain
as the center of the upper high moves north of the area and return
flow establishes a moisture feed from the middle- Atlantic.
Still...largely dry conditions will persist into and through the
weekend. Temperatures will stay several degrees above average
through the period.
Aviation /19z Monday through Saturday/...
general VFR into Tuesday with light southwest winds. Isolated
showers and thunderstorms will be possible late afternoon and
evening...but coverage not enough for mention at any port. Patchy
MVFR to IFR fog expected before sunrise overnight...burning off by
Outlook...Tuesday night through Saturday...
general VFR except for patchy morning fog the remainder of the week.