Area Forecast Discussion
Issued by NWS Pittsburgh, PA

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FXUS61 KPBZ 290950 AAA
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
550 AM EDT Fri Mar 29 2024

.SYNOPSIS...
Remaining rain and snow showers south of Pittsburgh will end
this morning. Otherwise, building high pressure will result in
dry weather through this evening. Low pressure will cross the
region Saturday and Saturday night, with showers and a few
thunderstorms. A series of crossing low pressure systems will
bring additional showers and thunderstorms to the region later
Sunday through Tuesday, with heavy rain and severe storms
possible.

&&

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

- Weak shortwave exits this morning
- Dry and seasonable weather the rest of the day

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

A crossing shortwave trough will continue to support scattered
rain showers south of I 70 early this morning. Areas across the
higher terrain should see scattered snow showers with colder
air in place, though any accumulation is expected to be less
than an inch. There is a slight potential of a brief instance of
light freezing rain in eastern Tucker county as the moisture
depth decreases and exits the dendritic growth zone.

Otherwise, high pressure will build in behind the exiting
shortwave, with dry weather expected. A tight pressure gradient
and mixing should result in NW wind gusts from 25 to 30 mph
today for most of the area. The higher terrain areas across
eastern Tucker county WV could see gusts up to 50 mph, where the
wind advisory remains in effect through 8 PM. High temperatures
are expected to be within a couple of degrees of seasonable
levels.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
KEY MESSAGES:

- Showers and isolated storms return late tonight and Saturday
- Lull in precipitation later Saturday night through early Sunday
  morning
- Warm front advancing north returns showers/storms later
  Sunday and Sunday night
- Marginal potential for severe storms Sunday afternoon and
  evening across portions of OH and WV
-------------------------------------------------------------------

A shortwave trough, and associated surface low pressure, will
track out of the Central CONUS, approaching the Upper Ohio
Valley and Great Lakes region late tonight. Showers will
overspread the region with increasing moisture and ascent as
the low tracks across the region. The region is also expected to
be in the left front quadrant of an upper jet, enhancing the
ascent. A rather fast progression of the low should help to
limit rainfall amounts, with a quarter to a half inch expected.

SREF/HREF progs indicate the low will track across northern Ohio
and NW PA. Limited instability south of the low could result in
a few thunderstorms mainly Saturday afternoon. Gusty wind will
be possible if any storms become organized with a strong wind
field aloft and shear in place.

The low is expected to exit eastward Saturday night, as it pulls
a surface cold front across the region. This front is then
expected to stall across the Ohio Valley region late Saturday
night, before lifting back northward later Sunday and Sunday
night in advance of another surface low across the Midwest. A
band of more significant rainfall is expected Sunday night as
the front continues to advance northward. Elevated instability
could also support scattered thunderstorms Sunday afternoon and
overnight, which would enhance precipitation rates. In addition,
SPC has placed a portion of SE OH and northern WV in a marginal
risk for severe thunderstorms, with moderate instability and
increasing shear in the vicinity of the Sunday afternoon and
evening.

The rainfall Saturday, and Sunday night, could set up a potential
for flooding early in the week.

&&

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

- Potential for heavy rain and thunderstorms Monday and Tuesday
  with with a strong low pressure system
- Severe thunderstorms possible Tuesday
- Colder and windy Wednesday and Thursday with rain and snow
  showers
-------------------------------------------------------------------

The warm front is expected to stall across the Upper Ohio Valley
region again on Monday as the flow aloft becomes parallel to the
front. Heavy rain will be possible where the front stalls,
though uncertainty exists in its exact location. Thunderstorms
will also be possible, especially south of the front.

An upper trough is progged to advance out of the Midwest Monday.
Southwest flow ahead of the trough should push the warm front
northward Monday night. Additional showers and thunderstorms are
expected. A low level jet will also enhance rainfall rates, with
elevated instability maintaining a few thunderstorms. This would
bring an increased flood potential. Additional showers and
thunderstorms are expected to continue Tuesday as the low tracks
across the Lower Great Lakes region. Increasing shear and
instability could result in a potential for strong to severe
storms again on Tuesday. SPC has placed roughly the southern
half of the forecast area in the day 5 severe weather outlook.

The surface low is expected to become nearly stationary through
Wednesday, as it pulls a cold front across the region. Cold
advection behind the front, and a crossing upper low, will
maintain rain and snow shower chances Wednesday and Thursday.
The upper low should begin to exit the region late Thursday.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
A weak wave will pass south of PIT through dawn. Some light
precip will be likely but VFR conditions should remain.
Probabilities of MVFR remain below 20% for ZZV and MGW. Some
isolated showers are possible through dawn, though coverage is
not anticipated to be large enough to justify a prevailing or
tempo group.

Clear skies will prevail heading into the day. Daytime mixing
will allow winds to gust up to 20kts, peaking during the
afternoon. VFR conditions will prevail through the rest of the
TAF period.

.Outlook...
VFR is expected through Friday night under high pressure.
Widespread restrictions and showers return Saturday with
crossing low pressure. VFR briefly returns Sunday under high
pressure, before restrictions in showers/possible tstms return
Sunday night and Monday with a warm front.

&&

.HYDROLOGY...
Widespread rounds of rainfall are expected beginning Saturday
and continuing into the middle part of next week. The initial
rounds should eventually saturate the ground, resulting in an
increased flood potential as additional showers and
thunderstorms occur. Ensemble probabilities for >2" of total
rainfall have increased (40-70%) areawide, but especially across
West Virginia, with high end amounts of 3-4" not out of the
question there. This may result in areas of flooding or flash
flooding, especially on Monday into Tuesday, when our area has
been placed in a Marginal Risk (1/5) for excessive rainfall.

Rises on area rivers from prolonged excessive rainfall are also
looking increasingly possible as ensemble probabilities
continue to trend higher by the beginning of next week.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...Wind Advisory until 8 PM EDT this evening for WVZ514.

&&

$$

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


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