Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
325 am EDT Wednesday Oct 22 2014
shower potential will continue to diminish as upper low pressure
exits eastward. A strengthening high will dry and warm the upper
Ohio Valley region into next week.
Near term /through today/...
maturation of low pressure is still model prognosticated over the coast by days
end and ovrall subsidence will gradually suppress convective potential
over most of the upper Ohio Valley area...although slight shower chances may
linger into evening over the ridges with the sharper upslope
Cold temperatures will linger though as cold...to neutral advection continues on
the rear flank of the exiting low. Temperatures about 10 degrees undr the
avgs were massaged using sref means and bias corrected GFS MOS.
Short term /tonight through Saturday/...
shortwave ridging is forecast to suppress remaining precipitation chances tonight...and
Thereafter...NAM...GFS...and European model (ecmwf) have consistently depicted the
approach...and passage of a weak shortwave in northwest flow on Friday. Given
depictions of a limited middle level moisture field...capped low levels aftr middle
level warming...and an absent precipitation spprtg Omega field...have decided
to eliminate the already slight pop forecast in favor a strengthening
Another such disturbance is projected for a Saturday crossing...but
the rain potential lakes equally slim given similiar limitations as
Friday as well as a more northward track of the low center.
Short term temperatures feature moderation toward the seasonal avgs...forecast
for was tweaked again using bias corrected GFS MOS and sref means.
Long term /Saturday night through Tuesday/...
ridging across the central Continental U.S. Will move to the eastern Continental U.S. Through Erly
next weak keeping dry weather in the forecast. A weakening trough is prognosticated for a
middle weak passage as the ridge shifts east. Seasonally cool weekend temperatures
are experimental to increase to above average levels by Erly next weak.
Aviation /06z Wednesday through Sunday/...
widespread IFR conds and scattered showers are expd through Erly this morning with
low level moisture in place under an upper low across the region. While conds
should improve to MVFR later in the morning...the proximity of the upper
low will keep MVFR conds into tonight.
Aviation /Thursday through Sunday/...
rstrns are expd into Thursday morning before the upper low exits the region.