703
FXUS61 KPBZ 270015
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
815 PM EDT Fri Apr 26 2024

.SYNOPSIS...
Dry, seasonable weather today will be followed by showers
tomorrow morning with a slight chance of a rumble of thunder.
There is a low chance of a storms tomorrow afternoon and
Sunday afternoon. A warming trend is expected through Monday
with temperature 10 to 20 degrees above average.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
KEY MESSAGES:

- Day conditions today followed by increasing shower chances
  overnight.

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Warm, moist advection moving toward the ridge axis positioned
over the Upper Ohio River Valley will promote increasing cloud
cover during the overnight period. The insolation plus 850mb
warm advection and a relatively-mixed boundary layer should
promote above normal low temperature, with nocturnal cooling
more modest for the far western zones.

700mb moist advection ahead of mid-level PVA is promoting a band
of light rain showers that will skirt along/north of the eastern
OH forecast area through midnight, with dry lower levels
limiting accumulation/precip reaching the ground. Frontogenesis
along a warm front will maximize beginning early Saturday
morning in response to an incoming jet streak, aiding a more
organized band of showers along the PA/WV east/west border that
will move ENE. Limited elevated instability should keep any
lightning isolated and provide no severe threat.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
KEY MESSAGES:

- Showers with a low chance of storms persist through the
  morning, departing to the east by afternoon.
- Low chance of afternoon storm Saturday.
- Storms Sunday are most likely north of I-80.

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The warm front will continue through during the morning hours,
allowing rain chances to continue with a low probability of a
rumble of thunder. Probabilities of exceeding 0.25" of QPF are
only greater than 50% in western PA and northern WV for now,
with probabilities of exceeding 0.5" low to none. Thereafter, a
building 500mb ridge will prevail, bringing an increase in
daytime highs to above seasonable normals behind the warm front.

There is a low probability of an afternoon thunderstorm with
250 to 500 J/kg of elevated instability in around 20 to 30 kts
of shear as a weak shortwave passes, although guidance is
divergence on the presence of the shortwave forcing. Therefore,
thunderstorm development remains low probability. Should storms
materialize, severe benchmarks remain low, thus no hazards are
anticipated.

Sunday, afternoon storms are possible again, mainly north of
I-80 as mid-level PVA round the top of a ridge axis. Though CSU
MLP has a 5% to 15% severe risk, concerns are low at this point
for organized convection with weak low- level shear. One thing
that will need to be monitored is DCAPE, with models showing
roughly 600 to 900 J/kg at this time with mid to upper level dry
air, which may support a low probability of downburst wind
threats.

Daytime highs are expected to top out 10 to 15 degrees above
normal area-wide on Sunday. Probabilities of exceeding 80
degrees are 50% to 80% in the Pittsburgh metro and points
southwest.

&&

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

- An unsettled pattern continues through next week with above-
  average temperatures favored.

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

There is high confidence in eastern ridging through the
beginning of next week, allowing temperatures to remain well
above normal. Chances of exceeding 80 degrees are even a bit
higher on Monday, with 80s forecast area-wide. This would be
around 10 to 20 degrees above seasonal normals.

A surface cold front is expected to pass during the day on
Tuesday, followed by a flattening of the eastern ridge. By
Wednesday, clusters still vaguely agree on quasi-zonal flow,
but uncertainty spurs from here into late week. Mainly, two
scenarios emerge: the first develops a central CONUS ridge that
enforces an eastern troughing pattern. This would lead to a
drier, cooler pattern. The second scenario keeps quasi-zonal
flow in the central CONUS, which translates to zonal flow to the
east as well. This pattern may lean a bit warmer and more
unsettled.

Both CIPS analogs and the CSU MLP highlight low severe
probabilities into Tuesday through Thursday, so conditions will
need to be monitored as we head into next week.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
High and mid-lvl clouds will continue to filter into the region
as a large scale system over the Great Plains advances north.
Widespread VFR is expected through at least 12Z with lingering
dry within the boundary layer.

MVFR to IFR conditions are expected to develop between 14Z to
16Z, especially north and east of PIT with weak warm advection
and flux of moisture with passing warm front.

Probability of VFR conditions increase between 22Z to 00Z
Saturday with a surge of dry, warm air from the southwest.
However, FKL/DUJ may linger under MVFR/IFR cigs longer if a
potential moisture boundary stalls. If that is the case,
restrictions north of PIT may last through 06Z to 09Z Sunday.

.Outlook...
With the ridge axis situated just north of Lake Erie, there is
the potential for shower/isolated thunderstorm activity Sunday
evening. Areas of potential convection will likely be near
FKL/DUJ due a potential lake breeze.

&&

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

&&

$$

SYNOPSIS...Milcarek
NEAR TERM...Frazier
SHORT TERM...Milcarek
LONG TERM...Milcarek
AVIATION...Cermak/Hefferan