769 
FXUS61 KPBZ 180300 AAB
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
1100 PM EDT Sat Jul 17 2021

.SYNOPSIS...
After a dry start to the week, periodic rain chances can be expected
by mid-week with near-normal temperature.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Scattered showers supported by frontogenesis coincident with cold-
frontal passage are moving sely through the ridges this evening. Bulk
shear has moved eastward with jet propagation, and little buoyancy 
remains so the opportunity to organize or develop with height will 
not be given.

Isallobaric acceleration post frontal passage will allow temperature
to drop to a comfortable level, and nwly wind to remain elevated
overnight. This will mitigate any chance of widespread fog formation.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
A mostly dry day is expected Sunday due to subsidence and an influx 
of drier air. Residual cool air advection and a sct/bkn aftn cu cloud
deck will cause area temperature to be a few degrees below normal.

A similar pattern is expected Monday, with mostly dry conditions
due to sfc ridging though an iso aftn shower can't be ruled out as
the upper trough shifts slightly east, and vorticity advection
briefly propagates through the Ohio Valley. Increased insolation 
will allow for seasonal average temperature.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Periodic precipitation chances are expected to return by mid-week as
the upper pattern will transitions to northwest flow with embedded 
shortwaves over the eastern Great Lakes in response to building 
central U.S. ridging.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Deeper saturation within the boundary layer and modest ascent will 
support drizzle for a couple more hours in the wake of today's main 
shortwave trough until drying from above leaves only bkn cigs 
remaining for the rest of tonight.

With recent rainfall and cold advection from today's frontal 
passage, MVFR-IFR stratus will prevail for most sites through 
tomorrow morning. However, intruding dry air and subsidence could 
create breaks in the deck, most likely at ern-OH terminals.

Daytime heating will return VFR conditions for all sites late 
morning Sun into the evening. 

.Outlook...
Despite deep NW flow aloft, warm/moist conditions will prevail and a
stratus deck/isolated fog will likely form Sun night into early 
Mon morning.

Periodic precipitation chances are likely to return by mid-week.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

$$

Update...Kramar