Area Forecast Discussion
Issued by NWS -- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KPBZ 250540
Area Forecast Discussion
National Weather Service Pittsburgh PA
140 AM EDT MON JUL 25 2016
A weak and slow moving cold front will pass through the area later
today, bringing the risk for more showers and storms. Area dries
out by mid week. Above normal temperatures will remain for most
of the week.
.NEAR TERM /THROUGH TODAY/...
For the overnight, not much change needed. Minor adjustments to
pops late and cloud cover. Temperatures have been updated with a
blend of hires guidance.
A weak cold front will try and cross the region late today, before
losing most of its structure as the evening approaches. Expect
activity to re-fire today, but timing and coverage remain an
issue. Much will depend on what happens with the MCS over the
upper midwest and how its large scale outflow will be maintained
and what convection may fire with the crossing of the wind shift.
Additionally, debris clouds from the aforementioned complex will
play a role by restraining max heating potential and in turn
overall instability. Plenty of moisture already in place with most
locations reporting surface dewpoints near or just above 70
degrees. This would mean today`s convection will be very efficient
rain makers, allowing for a high risk for heavy downpours. Models
are showing different stories on when and where convection may
erupt, as they are attempting to decipher the effects of the
western complex and where its energy will eventually travel. Since
questions remain on location and timing, have left pops in the
Temps were constructed using the Bias-Corrected blend of hires
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
Front will fizzle out tonight and do little to eject the humid
airmass in place. Models are in pretty good agreement that any
convection will die out tonight. Noticeably drier air does move
in from the north in the mid and upper levels, however humidity
levels look to remain rather high through Tuesday with the lack of
low level dry advection.
It will take until Tuesday night and then finally into Wednesday,
when the juicy low level air is shoved to the south.
Both Tuesday and Wednesday look dry with a good deal of sunshine.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
- Continued above normal temperatures
- Best shot at rain arrives Thursday night into Friday
Overall no real change to synoptic pattern for much of the week
as a broad H5 anticyclone dominates the southern 2/3rds of the
CONUS. Our mid level height values will fall a few decameters,
but not enough to usher in temps where they should be for this
time of year. Based on H8 temps progs...do not see a stretch of
90F+ weather like this weekend. However, would not be surprised
for eastern Ohio to be right around 90F for daytime highs most of
Baroclinic zone that crosses Monday night weakens and washes out
over the central Appalachians Tuesday as flow become parallel to
the boundary and it encounters increased subsidence. In its
wake, slightly cooler weather than what we have experienced
takes hold for mid week. By weeks end, another shortwave trough
traverses the region sweeping a cold front through. Timing
differences reside with ECMWF and GEFS, but ECMWF keeps the
recent summer trend going of shortwaves passing outside peak
heating hours. GFS opts for a Friday afternoon passage. Either
way, the next shot of widespread precipitation appears to be
Thursday night into Friday. Zonal flow re-establishes for the
weekend with temperatures near the climo average of lower to mid
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Fairly widespread MVFR conditions will be likely overnight
periodically as low level moisture pools and transient fog forms.
CIGS will likely periodically run IFR at KFKL and KDUJ as well. A
system moving in from the NW for Monday will increase the chances
of showers and thunderstorms as is slowly drifts through the area,
which also may locally restrict conditions on Monday. After this
system drifts through, low level moisture will remain in its wake,
which could again mean the return of low clouds and fog for Monday
.OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/...
After the passage of the cold front Monday night, no widespread
IFR conditions are expected at this time.