400
FXUS61 KPBZ 172108
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
508 PM EDT Wed Jul 17 2024

.SYNOPSIS...
Showers and thunderstorms will continue through the evening with
a crossing front. High pressure will return dry conditions and
seasonable temperatures the remainder of the week and into the
weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:

- Showers and storms expected along and ahead of a cold front
  crossing through this evening.

- A small threat of strong to severe wind gusts remains, as does
  the risk of isolated flooding, although both threats will
  decrease with time.

 __________________________________________________________________

Update focused on minor adjustments over the next several hours
based on radar and observation trends. Outflow moving out ahead from
the main convective line has helped to sap its strength to some
degree, and the overall environment for strong wind gusts
remains poor with lackluster lapse rates and unfavorable DCAPE
values. An isolated strong to severe gust or two cannot be
totally ruled out, mainly in eastern Ohio where slightly more
favorable MLCAPE/DCAPE is located. Also, despite the lingering
high PWAT values, flooding concerns are lessening with time as
well as the overall line becomes more progressive, with urban
areas most likely to see any impact from localized 1-2"/hour
rainfall rates. The cold front itself is just now crossing into
the northwest corner of the CWA, and will continue to slowly
progress to the southeast through the evening.

Once the main line departs the region by 01Z/02Z, a few
scattered showers may linger ahead of the crossing boundary,
which should exit the region shortly after midnight. Partial
clearing is expected overnight, although stratocumulus may
linger particularly in the ridges. Patchy fog cannot be ruled
out as well, although ongoing mixing may limit its extent to
some degree. Dewpoints and temperatures will drop off through
the night as well, although a noticeable difference will likely
wait until daytime mixing on Thursday.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
KEY MESSAGES:

- Dry and cool conditions Thursday with temperatures moderating
  to near normal Friday.

  _________________________________________________________________

Dry and seasonable conditions are expected as surface high
pressure builds eastward over the region. Low- level cold and
dry advection will keep temperatures near or even a few degrees
below average Thursday and Thursday night with valley fog
chances.

Stout mixing into the day on Friday under high pressure will
result in temperatures near normal, and fairly low humidity.
This will leave the area feeling comfortable for the last day of
the work-week.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
KEY MESSAGES:

- Mainly dry weekend with high pressure in control.

- Precipitation chances return for the start of the week.
-------------------------------------------------------------------

Digging trough over the central Plains may lead to a slight
increase in 500mb heights Saturday/Sunday. This may also bring
some moisture return to the upper Ohio Valley but at this time,
precipitation looks to be limited to the ridges south and east
of PGH. With rising heights, temperatures will trend higher to
slightly above normal. Strengthening southwesterly flow will
return precipitation chances into early next week ahead of
approaching low pressure.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
Scattered showers and thunderstorms are ongoing this afternoon
ahead of a cold front which is slowly creeping southeastward
through the area. A mix of VFR/MVFR cu should slowly lift to
more widespread VFR by late afternoon with additional heating
and mixing occurring, though locally lower cigs/vis can still be
expected in and around the heavier showers and storms. The weak
front pushes through by roughly 03Z, followed likely by a
stratocu deck with VFR cigs except along the higher terrain east
and southeast of LBE/MGW where low cigs/vis may linger through
Thursday morning under weak upslope flow. VFR is expected by
Thursday afternoon as cooler and drier air moves into the area
behind the front.

Generally light southwest winds this afternoon ahead of the
front become light and variable overnight, then northwesterly on
Thursday in the wake of the cold front. So far, gusts in storms
have remained weak, around 20 knots, though these could
increase to 30-40 knots in late afternoon and evening as
additional heating and better lift along the front itself
support deeper convection.

.Outlook...
VFR is expected Thursday through Sunday under building high
pressure.

&&

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

&&

$$

SYNOPSIS...34/CL
NEAR TERM...CL
SHORT TERM...34
LONG TERM...34/88
AVIATION...Cermak