Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
407 am EDT Monday Aug 3 2015
a cold front will bring scattered showers and thunderstorms later
today. Dry weather will return Tuesday and Wednesday.
Near term /until 6 PM this evening/...
focus today will turn to a cold front that will slide southeastward
across the region this afternoon and evening. Expect showers and
thunderstorms to re-fire later today along the front. Models
continue to struggle with the amount of instability the atmosphere
will have to work with...although there is good model agreement
for modest wind shear...which will help to organize storms. The
amount of residual cloud cover that crosses the region from the
early morning mesoscale convective system will be crucial...as this would obviously limit
sunshine and make it difficult to reach convective temperatures.
Short term /6 PM this evening through Wednesday/...
scattered showers and thunderstorms will continue this evening as
the front finally clears the region. Lingering showers are
possible across the southern half of the region late tonight...
dependent upon how fast the surface boundary is able to push south
of my forecast area. It may slow up just a bit with the loss of
any good push in the upper levels.
Tuesday looks to be a dry day with broad high pressure building
into the upper Ohio Valley. A weak shortwave trough could bring a
shower to the north late in the day...but moisture will be
Most of Wednesday day should be dry. Another weak front will cross
the area late in the day...which could spark a few scattered
showers. At this point...confidence is low with how much rain this
feature will be able to produce as moisture and upper level
support are sparse.
Temperatures will remain around seasonal norms through the
Long term /Wednesday night through Sunday/...
there is good agreement in the long term forecast as an upper
trough remains parked over the eastern US. Several waves riding
through the upper flow will maintain the chance for showers and
thunderstorms through the period...with overall better consensus
between the GFS and European model (ecmwf) than in the previous days runs. With the
trough prognosticated to deepen by next weekend...expect temperatures to
trend a few degrees cooler than seasonal averages in northerly flow.
Aviation /08z Monday through Friday/...
VFR conditions will persist through the predawn hours and sunrise.
Cold front is expected to approach and enter forecast area this
afternoon...and exit during the evening hours. A few mainly light
showers will develop mainly north and west of pit by midday...some
leftover from vigorous convective line to the northwest. Further
development is forecast during the afternoon hours with thunderstorms and rain
possible at all terminals. Timing is still a bit tricky and
continue to handle with thunderstorms in the vicinity for now. Brief IFR conditions and
strong wind gusts will be possible with the heavier storms.
Outside of storms...gusty SW winds will develop during the
daylight hours...shifting to west behind the front during the
evening...with VFR conditions redeveloping behind the storms.
Outlook...Monday night through Friday...
the next chance for restrictions is expected with a Thursday