Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
129 am EDT sun Jul 31 2016
periodic showers and storms will continue through the weekend.
High pressure brings the return of dry conditions for much of
Near term /until 6 am this morning/...
shower and thunderstorm activity has ended across the region. Have
removed overnight chances of showers from the forecast as latest
trends lead towards continued stabilization and 00z models all
show agreement in a weak ridge at 700 transitioning over the area
the remainder of the night.
As deeper moisture exits to the east mid-level cloud coverage will
lessen and allow for additional late night radiational cooling to
result in widespread stratus and fog development.
Short term /6 am this morning through Monday night/...
yet another short wave trough will translate southeast toward the
area on Sunday. With abundant low level moisture still in place,
the left exit of a northeastward translating upper jet streak, as
well as some mid-level cooling as the 500 mb wave tracks through the
area, scattered showers and thunderstorms will again develop on
Sunday. However, the coverage is unlikely to be as widespread as
was seen today.
Much drier air follows the exits of the Sunday system to the east.
The only exception to this may be a stray shower in the ridges on
Monday as low-level moisture may linger in the ridges a bit longer
than other areas. This may just barely manage to allow for a bit
more unstable profile and a shower or two during the peak heating
Northwesterly flow then encompasses the area by Monday night. This
will bring in much cooler and drier air for the overnight, which
could very well mean a night during which we can all shut off the
air conditioning and open the windows! Fries
Long term /Tuesday through Saturday/...
shortwave ridging will maintain dry and benign weather on Tuesday.
The shortwave ridge flattens a bit for the remainder of the week
as ripples rotate around the broad upper ridge over the Southern
Strong advection of warm, moist air is expected late in the coming
week. As a result of the arrival of this warm air, temperatures
will climb into the upper 80s-near 90 on Thursday and Friday. The
combination of the moist airmass and the weakening upper ridge
will support increasing chances for thunderstorms late in the
week, especially on Friday as a frontal boundary invades the
region from the northwest.
Aviation /06z Sunday through Thursday/...
a crossing shortwave should maintain areas of MVFR ceilings
through the evening. A band of showers and isolated thunderstorms
is also expected to cross the region this evening with additional
MVFR/local IFR conditions. Showers should end as shortwave support
exits tonight, though widespread IFR fog and stratus is expected
for most ports with low level moisture in place.
The fog should mix out Sunday morning as the stratus lifts and
transitions into a cumulus layer. VFR should return by afternoon as
mixing lifts the ceilings, though upper troughing should maintain
shower and thunderstorm chances for the afternoon.
Outlook /Sunday night through Thursday/...
broad upper troughing should maintain the potential for periodic
restrictions in showers and thunderstorms through Monday.