424
FXUS61 KPBZ 081323
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
923 AM EDT Mon Jul 8 2024

.SYNOPSIS...
Dry weather will continue today before active weather returns
midweek, associated with a passing trough and the remnants of
Beryl. Tuesday and Wednesday will be the hottest days of the
week with widespread 90s outside of the mountains.

&&

.NEAR TERM /THROUGH TONIGHT/...
KEY MESSAGES:

- Dry conditions, with temperatures a bit above seasonal norms.

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The forecast is on track this morning as the 12z PIT sounding
shows a good amount of dry air up to above 500 mb save for a
shallow layer of moisture supporting passing upper level clouds.
Efficient mixing after the diurnal inversion breaks will allow
for quick heating and deep mixing likely dropping dew points a
couple degrees this afternoon. Weak southerly flow aloft will
promote modest warm advection and ensemble 850 mb temperatures
in the 17-18C range with ensemble probability of 80-90% chance
for exceeding 90F, highest in the urban areas and south of
Pittsburgh. With dew points mixing out some, heat index values
will remain below advisory criteria.

High pressure will remain in the region through today and
tonight. Heading into the day, the ridge over the Atlantic will
shift a bit allowing moisture influx from the southwest in
conjunction with a weak wave crossing the Middle Atlantic
region. This will highlight the potential for Tucker and Preston
County to see a few showers or storms this afternoon.
Otherwise, above normal temperatures and dry conditions
expected.

A return of the southwest flow through the day will advect
additional moisture into the area. While the area will still be
under the influence of high pressure, the influx of moisture
will allow fog to continue to be possible late tonight. Clear
skies will be the issue here. With the return of moisture, muggy
and warm conditions will also return as lows will be in the low
70s for Tuesday morning.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:

- A combination of a passing trough and the remnants of Beryl
  will make for a flooding potential as well as a severe weather
  potential.

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With quite a few runs of the NBM and other ensembles, trends are
beginning to highlight the slowed approach of the Midwest trough
sliding southeast during the day on Tuesday due to landfalling
Beryl and its track into Mid MS Valley. This is combined with
the stout ridge off the east coast. Thus, the low center of
Beryl will track northeast into the Upper OH Valley and Lower
Great Lakes region by Wednesday afternoon. It is very likely
that the slowed approach of the trough may keep much of the
forecast area dry for Tuesday with only slight instances of
rainfall. Still will keep the slight chance pops for Tuesday as
SPC does keep the area in a general thunder for Tuesday. This
will also work to make the Heat Indices climb into the upper 90s
to around 100 for Tuesday afternoon. The prospect of cloud cover
and a stray shower will add relief to this but a Heat Advisory
may be needed.

By Wednesday, the remnants of Beryl finally track into the
region. The right side of the track will highlight some
rainfall into the Lower Great Lakes and along the southern
shores of Lake Erie. Here a marginal to slight risk of excessive
rainfall is in place. There is some uncertainty here as
ensembles are showing a 40% prob of an inch of rainfall or more
for Wednesday and Wednesday night. Thus, a Flood Watch will not
be needed at this time, but if the track adjusts to the east
more than this may change.

Ample moisture, some destabilization and plenty of shear from a
landfalled tropical system will likely set the stage for a
severe weather potential and so SPC has issued a Marginal risk
of severe weather along the northern PA counties for Wednesday
afternoon and evening. At this time, the main threats will be
damaging winds and a tornado or two. Bowing to a more diurnal
nature, showers and thunderstorms should begin to weaken and
dissipate by Wednesday night with only a few showers through the
overnight.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
KEY MESSAGES:

- Uncertainty remains in the extended with the exit of the
  trough.

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By Thursday, the bulk of the moisture will exit to the east but
some lingering trough will keep the potential for showers and
storms during the day on Thursday with afternoon development.
Trends are difficult to pin down at this time and low confidence
is the take away as the ridge off the coast retreats a bit
allowing the trough to move further east and the trough over
western PA to finally shift to the east. This is quite a shift
in solutions as model runs 24 to 48 hours ago had precip
lingering over the area much longer. Thus pops for Friday and
Saturday will be relatively low chance with Sunday finally
seeing high pressure setting up over the area. The shift shows
the uncertainty in the solutions and thus will keep low chance
in the forecast with Sunday possibly the dry day.

&&

.AVIATION /13Z MONDAY THROUGH FRIDAY/...
Confidence remains high (above 90%) that VFR conditions will
prevail through the forecast period under high pressure. Winds
will be light and variable. Scattered cu field with cigs
between 4-6kft is likely to develop after 15Z with diurnal
heating, dissipating around sunset.

.Outlook...
Isolated thunderstorms with associated local restrictions could
impact terminals west of PIT Tuesday afternoon as the ridge
breaks down.

Impacts from the remnants of Beryl could occur Wednesday into
Thursday.

&&

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

&&

$$

SYNOPSIS...Shallenberger
NEAR TERM...MLB/Shallenberger
SHORT TERM...Shallenberger
LONG TERM...Shallenberger
AVIATION...Cermak/Rackley