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000
FXUS61 KPBZ 132213
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
613 PM EDT Sat Apr 13 2024

.SYNOPSIS...
Dry weather continues into tonight with wind gusts decreasing
after sunset. Thunderstorm chances increase again on Sunday with
a cold front, some potentially strong to severe. A brief bout
of dry weather expected Monday before rain chances return on
Tuesday with moderating temperatures into next week.

&&

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

- Dry with clouds clearing and wind gusts diminishing after
  sunset.

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

No major changes to the forecast as of 6 PM. Did allow the Wind
Advisory in eastern Tucker County to expire in collaboration
with neighbors, with wind gusts slowly diminishing. Otherwise,
a mostly clear and quiet night is forecast.

Previous discussion...

The gradient and mixing into a 30-40 kt low level jet will
continue the wind gusts up to 25-35 mph into early this
evening. Gusts will diminish after sunset areawide with even
the chance for >20 mph gusts dropping off significantly, save
for the ridges with gusts to 30 mph are still possible
overnight. Warm advection with southwest flow in building
ridging will hold lows a couple degrees above normal.

&&

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

- Thunderstorm chances return Sunday with potential for strong
  to severe with part of our area outlined in an Enhanced Risk
  (3/5).
- Dry weather returns Monday with moderating temperatures.
-------------------------------------------------------------------

Come Sunday, a warm front is progged to pass through in the morning
placing our area in the warm sector of low pressure just to our
north. Surface flow backs more southerly and warm, moist advection
pulls temperatures into the 70s with greatest confidence of 80-90%
chance south and west of Pittsburgh. Dew points will rise into the
mid to upper 50s allowing for sufficient destabilization by
afternoon ahead of an approaching cold front. Hi res ensemble joint
probabilities for CAPE exceeding 1000 J/kg and deep layer shear
exceeding 30 kt is 60-90% across much of the area. A belt of 40-50
knot westerly low level flow atop southwest flow at the surface will
support directional shear in the low levels where the majority of
shear and clockwise curvature noted in hodographs will be confined
to the lowest 1-3 km layer. This environment will be supportive of
all hazards including damaging wind, large hail, and tornado
potential. While the environment will be supportive of supercellular
structures, the mean layer flow will have a dominant west-east
component along a similarly oriented cold front which may make it
more difficult for these storms to propagate off of the initiating
boundary and become discrete, rather favoring more of a linear
cluster type mode with embedded supercells. Some question will come
into play with warm advection occurring aloft that may mute low
level lapse rates some as well as how far south the storms can sag
before we lose daytime heating. Convection will likely reach our
northern zones around 3-4pm and sink south through the evening.
Mean precipitable water values will rise up to near 1" and
while the front should be progressive, still can`t rule out a
localized flooding concern given the saturated soils and
parallel component to the front promoting upscale growth.

With the only minimal uncertainty being driven by the progression of
the upper trough into Monday, confidence is high that the cold front
will clear the area by Monday morning and, aside from some low
probability shower chances south of I-70, the day should be dry.
Ensembles aren`t very bullish on intrusion of cooler air in the wake
of the front as an 850 mb ridge quickly builds in its wake and
temperatures take a slight dip but still remain well above
normal.

&&

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

- Temperatures climbing well above average.
- Rain chances return Tuesday and linger into mid-week.
-------------------------------------------------------------------

Brief upper ridging slides overhead Tuesday before breaking down
into Wednesday as an upper trough digs across the Midwest. Primary
ensemble uncertainty stems from the progression of the trough and
surface low, but consensus tracks it through the Great Lakes to our
north and returns rain to our region by Tuesday as a leading
shortwave passes through. Rain chances continue into Wednesday as
the warm front approaches with the cold front following behind as
early as Wednesday night or as late as early Thursday morning, again
owing to uncertainty with the progression of the upper wave.
Ensembles push a secondary reinforcing cold front through by late
week which may tumble temperatures back down towards normal to
close out the week.

Otherwise, above normal temperatures will be the theme into mid-week
as southerly return flow promotes warm advection kicking
temperatures well above average with ensemble probability for >70F
in excess of 70% through Thursday.

&&

.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
Skies will continue to clear from west to east through the
afternoon as high pressure builds in from the west. Gusty WNW
wind will continue through the afternoon with a tight pressure
gradient, and lessen this evening the gradient relaxes under
the building high.

.Outlook...
Restrictions with showers and possibly severe thunderstorms are
expected late Sunday with a crossing cold front. VFR is expected
under high pressure Monday and most of Tuesday. Restriction
potential returns late Tuesday and Wednesday with approaching
low pressure.

&&

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

&&

$$

SYNOPSIS...MLB/Shallenberger
NEAR TERM...MLB/CL
SHORT TERM...MLB
LONG TERM...MLB/Shallenberger
AVIATION...88