027
FXUS61 KPBZ 140610
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
210 AM EDT Sun Jul 14 2024

.SYNOPSIS...
A more active weather pattern featuring increased thunderstorm
chances and the potential for severe weather will return later
tonight through Wednesday, followed by dry and seasonable
weather after the passage of a cold front.

&&

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

- Well above normal temperatures and largely dry conditions
  through the afternoon.
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Shortwave ridging transitioning over the region will maintain
dry conditions and daytime highs around 10F above normal on
average across the region today. Winds will veer slightly as as
the surface ridge subtly shifts southeastward.

Uncertainty remains with the evolution of an MCS crossing out
of the upper Midwest and into the Ohio Valley this afternoon.
CAMs continue to hint at a weakening trend as this feature
pushes southeast into our region, owing to continued warm air
aloft and a relatively dry environment. It is possible that
Sunday evening may remain dry or see little more than light rain
showers with increased cloud cover. However, significant
variations exist in how quickly these storms fall apart and the
timing. The SPC Day 1 Outlook has maintained a marginal risk
(1/5) into our eastern Ohio counties.

&&

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

- Active weather with the potential for severe hazards will be
  possible possible during the period until the passage of a
  cold front on Wednesday.

- Heat risks continue but will be dependent on convective
  evolution and resultant cloud cover.

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The mentioned shortwave/decaying MCS is pegged by models to
help erode/cool the warm air aloft and prime the region for
additional shortwave movement overnight into Monday. Ensembles
are trending toward higher probabilities for showers and
thunderstorms ahead of that wave Monday, but much variation
remains (and will be tethered, in part, to upstream convective
evolution). General consensus still favors an afternoon timing
where mean SBCAPE values will range from 2000-3000 J/kg, weak
shear and DCAPE values around 1000 J/kg. These would indicate a
damaging wind (and lower probability hail threat) environment
via either individual storm clusters or a secondary MCS.
However, at least one CAM favors morning convection across the
area before a more robust MCS Monday evening. Morning/early
afternoon convection could certainly throw a wrench in more
organized evening storms.

Timing and presence of convection will also greatly determine
the extent of potential heat risks. The lack of convection and
cloud cover through a portion of the afternoon could foster mid
90s highs with rising dewpoints, creating fairly widespread
heat indices above 100F; early convection and/or lingering
cloud cover may make it difficult to even hit 90.

Ensembles favor additional shortwave movement south of a
deepening upper level trough north of the Great Lakes Tuesday
into Wednesday. The more well developed trough is then favored
to push a cold front through the region Wednesday
afternoon/evening and position broad upper troughing over the
Great Lakes to end the work week. In a broad sense, this pattern
lends to a peak in hot/humid conditions and potential severe
weather Tuesday; peak shower/thunderstorm chances Wednesday with
frontal passage.
&&

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

- Dry weather and seasonable temperature return Thursday through
  the end of the week.

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High pressure moving in behind the cold front and cool sfc
advection will return dry conditions to the region Thursday.
Thursday`s highs are forecast to dip several degrees below
normal, before a warming trend begins Friday and into next
weekend.
&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
There is high confidence in IFR/LIFR fog at FKL through 12z
given its positioning near the river valley, with satellite
imagery already showing fog development.

The rest of the region will experience VFR conditions under the
influence of high pressure that will extend through 00z. Expect
a few/sct CU with diurnal heating and potential for an
occasional SW wind gust to 20kts.

A decaying MCS is expected to approach from the NW near to just
after 00z, though model depiction on its
strength/location/coverage varies widely. Probabilities favor
northwest PA (FKL/DUJ) for possible tstm impact, with lesser
chances for terminals south and west.

.Outlook...
Periodic shortwave movement will lend to thunderstorm chances
through mid week, peaking Wednesday with the approach and
passage of a cold front. Timing and coverage will be difficult
to ascertain even a day out due to the strong impact of prior
days convective evolution.

High pressure is favored by Thursday and ensure another period
of VFR and dry weather.

&&

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

&&

$$

SYNOPSIS...88
NEAR TERM...88
SHORT TERM...88
LONG TERM...88
AVIATION...Frazier