Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
124 PM EDT sun Aug 30 2015
weak low pressure will bring shower chances today across the
upper Ohio Valley region. Warm and humid conditions expected
through the upcoming week.
Near term /through Monday/...
shower/isolated thunderstorm chances are expected to continue
through this evening with the approach of a slow moving upper
trough...though observed morning soundings show warming middle
levels should help limit instability and precipitation coverage.
Temperatures a few degrees above average are expected using the
latest GFS MOS.
A vorticity lobe will lift from the southern Appalachians towards
the midatlantic coast on Monday. The southern portion of the County Warning Area
will be skimmed by this. Moisture and instability will be barely
sufficient for slight chance probability of precipitation from pit on south. Proximity to
vorticity lobe plus terrain effects may allow for a bit better
coverage along the southeastern ridges. Departure of disturbance
plus loss of heating will end precipitation chances by 00z
Short term /Monday night through Wednesday/...
ridging will take control of the eastern part of the country and
hold on for an extended period. Midlevel capping appears more
likely on Tuesday...and for now have only kept slight chance probability of precipitation
along the ridges. For Wednesday...a weak shortwave over the Ohio
Valley...embedded in the general ridging pattern...may allow
capping to be overcome sufficiently for isolated convection. Each
nighttime period should be mostly dry.
Temperatures will of course be above normal in this pattern.
Generally blended mosguide with previous values for the forecast.
Would expect some readings at or just over the 90 degree level by
Long term /Wednesday night through Sunday/...
no changes to the overall pattern are expected...with the eastern
ridge holding firm. With the ridge axis still to the west on
Thursday...an areawide slight chance still looks appropriate. The
sprawling upper high will drift eastward with time though...such
that the ridges would be favored mainly for diurnal activity for
Friday and Saturday. By Sunday...with the center of the ridge just
to the east...an improved moisture feed may support activity
areawide once again. Little organization is foreseen throughout
the extended period...with overall precipitation totals remaining
fairly low. Above normal temperatures in the 80s to around 90 will
be featured each day.
Aviation /17z Sunday through Friday/...
continued general VFR through the first half of the taf period
with ridge building aloft. Before daybreak areas of mfvr and some
IFR fog should develop with increasing low level moisture and
weak flow. This should burn off toward 14z Monday. Winds will be
light westerly except for variable winds overnight.
Outlook...Monday night through Friday...
general VFR except for patchy morning fog the remainder of the