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000
FXUS61 KPBZ 140700
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
300 AM EDT Sun Apr 14 2024

.SYNOPSIS...
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 /THROUGH TONIGHT/...
KEY MESSAGES:

- Thunderstorm chances return today with potential for strong to
  severe with a larger portion of the area outlined in an
  Enhanced Risk (3/5).

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

With high pressure in place, expect a mainly clear sky with a
few middle/high clouds arriving towards dawn on NW flow aloft.
Warm advection with southwest flow ahead of a warm front will
hold lows a couple degrees above normal.

Heading into the coming day, the strong southerly flow allowing
for decent warm air advection will keep temperatures well above
normal. To boot, with the passage of the warm front, only
looking at some mid and high level cloud cover passing overhead.
As daytime heating gets underway, will begin to see cu
development by midday. Any shower or thunderstorm development
should hold off until after 19Z/20Z where storms should begin to
initiate north of I-80 and begin to intensify as they track
south across PA and OH and eventually WV during the overnight
period. The latest hi-res models suggest the best instability
setting up across western PA and into eastern OH with NBM probs
showing around 50% to 60% of greater than 1500 J/Kg surface
based CAPE and only 30% to 40% into western PA and event less
into central PA. With this in mind, the HREF is similar. Getting
into shear, most deterministic feature indicate roughly 30 to 40
knots of 0-6 km bulk shear. The probs of surpassing 40 knots
stems around 30% to 40% according to the HREF. Its also worth
mentioning that according to the NBM probs on the CWASP, there
is a 90% to 100% likelihood of crossing 50 on the parameter in
eastern OH and just crossing into western PA. Nevertheless,
parameters in place and model sounding indicating right curved
hodographs, expect to see all hazards today as the convection
begins to materialize. All models continue to show an initial
development of a broken line of discrete cells as the line dives
south into the forecast area. There is a chance that the line
further organizes under the better shear into a more squall line
situation as SPC did continue with their 30% wind in the
outlook. As the line tracks south, it is possible that a tornado
could occur with the line or with a broken discrete cell. There
are some indications that the line could hang up a bit given the
line of storms will be parallel to the predominant flow aloft.
This could lead to a few hampering flood issues again but
further analysis will be need on that threat. A marginal risk of
excessive rainfall is on tap issued by WPC.

The convection should begin to wane as it reaches the PA/WV
border and further slides south-southeast. Into Sunday night,
some lingering showers/storms are likely but the severe threat
should be over by 04Z if not earlier. Lows on Sunday night will
be a bit warmer as the cold front struggles to push south with
mid 50s likely. Clearing out and drying is likely by 12Z Monday.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
KEY MESSAGES:

- Dry weather returns Monday with moderating temperatures.
-------------------------------------------------------------------

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. Temperatures will then
rebound nicely for Tuesday with warm southerly flow and highs
reaching the mid 70s. There is a possibility of a fire weather
issue but this depends on rainfall on Sunday.

&&

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

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

Brief upper ridging slides overhead by Tuesday night 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.

The Friday and Saturday timeframe with highlight another wave
forming on the trailing cold front of the previous exiting low.
A lot of uncertainty here so will just mention low chance pops
for Friday and Saturday.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
VFR is expected through early this afternoon as a ridge of high
pressure moves east across the region. An approaching low level
jet should also result in a LLWS potential at ZZV overnight,
with the jet reaching most other airports as mixing begins.
This should result in gusty SW wind up to 30kt through the day.

The ridge will slide east of the region by afternoon, as a cold
front tracks southeast out of the Great Lakes region. A broken
line of thunderstorms is expected to develop along the front by
mid afternoon, as diurnal instability builds and shear
increases. Southwest wind at the surface, and northwest wind
aloft, will enhance the directional shear also resulting in a
severe thunderstorm potential. The most likely timing for
thunderstorms at PIT appears to be 22Z-01Z. Included TEMPOs for
now with still some uncertainty in thunderstorm timing.

A wind shift the W/WNW is expected after FROPA, with VFR cigs
continuing.

.Outlook...
VFR is expected under high pressure Monday and most of Tuesday.
Restriction potential returns late Tuesday and Wednesday with
approaching low pressure. Restrictions are possible into
Thursday under a subsequent upper trough.

&&

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

&&

$$

SYNOPSIS...Shallenberger
NEAR TERM...Shallenberger
SHORT TERM...MLB/Shallenberger
LONG TERM...MLB/Shallenberger
AVIATION...WM