136
FXUS61 KPBZ 230756
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
356 AM EDT Thu May 23 2024

.SYNOPSIS...
Showers and storms are possible today mainly south of
Pittsburgh. Seasonably warm highs today. Periodic thunderstorm
chances are expected through the holiday weekend as a series of
upper level disturbances cross the region.

&&

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

-Showers and storms are possible today, mainly south of PIT as a
 cool front stalls just south of the region.
-Cooler temperatures today, but still seasonable.
 _____________________________________________________________

A cool front will drift south and east of the forecast area
this morning, stalling over the northern reaches of the Mid-
Atlantic region. This will allow for a break from convection for
a portion of the morning hours. The question for the afternoon
is the path of a shortwave trough which will move eastward in
the vicinity of the quasi-stationary front this afternoon.
Seeing some differences in model solution with the track of the
wave. This is due to the influence of a second, albeit weaker,
shortwave that will move across northern Ohio/PA this afternoon.
Some of the operational models want to almost phase the two
waves allowing for rainfall to spread further north. While,
other models want to keep them separate and focus on the
northern wave pushing the southern wave further south. Latest
blended guidance is trying to find a happy medium, but is
focusing the higher PoPs mainly south of I-70 this afternoon.
The latest CAM models are leaning toward a more southern track
of the wave, keeping much of the area dry. With so much
uncertainty for this afternoon will lean heavily on the blended
guidance.

The resting place of the front and track of the shortwave will
also play a role in how much convection can re-fire this
afternoon. Obviously a further south placement would keep the
higher levels of instability/buoyancy further south, limiting
storm development.

Cloud cover will also depend upon how far south things settle,
as drier air will be spreading southward behind the front. There
is a good chance that the I-80 corridor could see plenty of
sunshine today.

Temperatures will cool a few degrees, but still remain
seasonable.

&&

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


- High pressure and brief ridging should keep the area dry
  Friday.
-A crossing shortwave will return the risk for showers and
 storms Saturday.
 _____________________________________________________________

Confidence is increasing that dry weather will develop Thursday
night into Friday as shortwave ridging crosses the region with
high pressure at the surface. Minimal airmass change with
slightly higher heights should promote above normal temperature
again.

Ensembles are leaning toward a wave crossing the region
Saturday producing showers and thunderstorms; timing varies,
but potential exists for convection to exit east of the area
before evening activities. That variability leads to an
inconclusiveness on severe potential but note that analogs for
the pattern and machine-learning analysis suggests at least a
low probability for hazardous weather that day.

&&

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

- Variability remains high on long term forecast and may be
  predicated on prior day`s convective outcomes.
- Overall, periodic showers and thunderstorms with slightly
  above normal temperature is favored through the holiday
  weekend and into next week.
  ____________________________________________________________

A more well-organized low pressure system is becoming the
favored pattern development to end the holiday weekend as it
lifts through the Great Lakes. Higher probabilities for showers
and thunderstorms are expected during this time frame but it is
unlikely to be "all day" rain type of events. Early analogs for
this pattern also suggest at least a low probability for
hazardous weather, but much variation in that potential remains.

Long range suggests a shift to a cooler, dry pattern by the
middle of next week as upper troughing develops over the Great
Lakes. Expect temperature to fall below the seasonal average,
with Tuesday potentially being the transition day from shower
activity to dry weather.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A general VFR forecast for the period. Showers and
thunderstorms may redevelop this afternoon primarily south of
PIT which could return associated chances for restrictions later
this afternoon and into the evening. At this time, the activity
looks to be scattered, so will leave out the mention as the
probabilities are too low for any confidence that a storm will
hit a port.

.Outlook...
Periodic thunderstorm chances and restrictions are likely
through the weekend as an active weather pattern continues.

&&

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

&&

$$

SYNOPSIS...22
NEAR TERM...22
SHORT TERM...22/Frazier
LONG TERM...Frazier
AVIATION...22