506
FXUS61 KPBZ 251700
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
100 PM EDT Tue Jun 25 2024

.SYNOPSIS...
Remnants of a mesoscale convective system may impact the region
after 1pm today. Heavy rain showers and sub-severe wind gusts
may occur. The threat for strong storms increases Wednesday
with a new disturbance.

&&

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

- An upstream disturbance is expected to impact the region early
  afternoon into the early evening.
- Periods of heavy rain and lightning may occur after 1pm for
  eastern Ohio.
- Wind gusts along the line of showers and storms may range
  from 30mph to 40mph.
-------------------------------------------------------------------

A mesoscale convection system (MCS) continues to dive south,
within an elongated ridge, across the Great Lakes early this
morning. Noted impacts over northern Indiana and northwest
Ohio include small hail and wind gusts ranging from 30mph to
45mph. Velocity measurements from surrounding radars over the
Midwest indicate a low-level jet of 35mph to 40mph between
1,000ft to 2,000ft.

Remnants of this MCS will likely start to impact our region over the
next 2 to 4 hours. However, the overall intensity will rapidly
dissolve with time given warm air associated with the ridge. A
quick period of heavy rainfall rates (1 to 2 inch per hour
rates) and 30mph to 40mph wind gusts may observed with the
downdrafts.

With increasing cloud coverage from outflow of the MCS and
precipitation chances, temperatures north of I-70 will likely
trend near average. Areas south may trend 5 degrees above
average.

&&

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

- Showers and thunderstorms are more likely Wednesday with a
  crossing front.
- Severe storms and flooding will be possible.

-------------------------------------------------------------------

A trough and associated cold front cross the region Wednesday,
with a late afternoon/evening FROPA. 25th to 75th percentile QPF
for KPIT ranges from 0.20" to 0.8", and with convection there
will always be a rather large range so this seams reasonable.
Similar to Tuesday, the Wednesday convective setup will be
modulated by the evolution of Tuesdays convective cold pools. In
any case, showers and storms are more likely. SPC is currently
carrying a slight risk as far west as PGH and marginal
elsewhere, with the primary risk being damaging winds. SPC also
shows a 5% and 2% for hail and tornados respectively which lines
up fairly well with the latest 00Z CSU machine-learning
probabilities. WPC has the entire region under a marginal for
flooding.

&&

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

- Dry weather Thursday through Friday.
- Near normal temperatures Thursday, before a late week warmup.
- Shower and thunderstorm chances return for the weekend.
-------------------------------------------------------------------

In the wake of Wednesday`s front, temperatures return to normal
and dry conditions resume as high pressure builds in across the
region. A warming trend in temperatures is forecast Friday and
into the weekend as heights gradually rise, reaching about
590-592dm by Saturday. Ensembles show about a 50% chance in
general of highs hitting 90F on Saturday. There`s a good chance
most locations will see apparent temperatures back in the 90s
with Tds back up in the upper 60s / low 70s.

Showers and thunderstorm chances return with the increased
instability and another frontal system Saturday and Sunday.

Dry conditions and near to slightly above normal temperatures
are forecast early next week as high pressure resumes control.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
An MCS will continue to weaken/move SSW of the region this
afternoon, with low probability for thunderstorm and moderate
rain shower impact at ZZV. Convective cirrus and VFR condition
is favored the rest of the afternoon and evening period as
subsidence maintains a stable environment.

An upper level shortwave will approach the area late tonight
into Wednesday with an associated surface cold front. Confidence
is high that this wave will help foster increased shower and
thunderstorm coverage between 15z-00z Wednesday. Confidence is
significantly lower on timing and progression of convection
starting as early as 09z. Available convective modeling shows a
large range of storm evolutions through this period as they
struggle to handle the altered environment the current Ohio MCS
is causing. TAF leans a bit into HRRR and HRW ARW modeling given
better handling on current weather; but variability in outcomes
for both storms and area restrictions is high.

.Outlook...
Showers and thunderstorms will taper off (with longer delay in
restriction improvements) with cold FROPA Wednesday evening.
High pressure and rising heights aloft is favored to support VFR
and dry weather Thursday/Friday.

The next upper level shortwave and surface cold front will
increase thunderstorm and restriction chances Saturday.

&&

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

&&

$$

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