-- Discussion containing changed information from previous version are highlighted. --
437
FXUS61 KPBZ 230749
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
349 AM EDT Mon Sep 23 2024

.SYNOPSIS...
An active weather pattern is expected through most of the week.
Even with the clouds and threat of rain, temperatures will
remain warm through the week.

&&

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

- Showers, isolated thunderstorms expected through the morning.
- Temperatures remain above normal.
-------------------------------------------------------------------

A shortwave trough, ahead of a surface cold front, will swing
through the region late tonight. Most of the rain associated
with the upper level wave will be light. Seeing some convection
firing just ahead of shortwave, but it is weakening as it moves
eastward. Overnight PoPs have been updated to better reflect
current conditions and latest model data.

A cold front will slowly progress eastward through the region
this morning. Most of the deep moisture and best upper level
support will be ahead of the front. With this setup, would
expect much of the rain to be light. The atmosphere will not
destabilize very much ahead of the boundary, but there will be
increasing wind shear so thunderstorms cannot be completely
ruled out.

The front will exit to the east early this afternoon, and there
will be brief ridging aloft as the early morning shortwave moves
over eastern PA. Would expect the rain threat to lessen this
afternoon, and we may dry out enough to lose the lower clouds
during the afternoon.

Above normal temperatures are anticipated today.

&&

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

- Rain chances continue through mid-week.
- Temperatures remain warm.
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Height falls are expected on Tuesday as another shortwave trough
swings through the region during the afternoon. This wave looks
to be stronger than today`s and with southwest flow aloft, ahead
of an upper low that will dig into the midwest, gulf moisture
will stream in over the region. Another round of showers and
possibly thunderstorms is expected Tuesday.

Temperatures Tuesday will be above normal again.

Little change on Wednesday as a large trough settles in over the
Midwest. The area will remain on the eastern side of the upper
level system, meaning gulf moisture will continue streaming
northward over the region. Upper level waves will swing through
the trough and eject northeastward in the southwest flow aloft.
This will mean the threat for showers and possibly storms will
continue through Wednesday.

Temperatures Wednesday remain above normal.

&&

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

- Uncertainty increases greatly for the latter half of the week with
  potential tropical low interaction.
- Rain chances will continue through the end of the week.
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A weak boundary may pass through the area sometime Thursday,
but seeing significant spread in the ensembles on the timing
which will impact when we lose the rain chances. The central
CONUS trough digs deeper on Thursday and looks to cut off from
a northern stream trough, but ensemble clusters exhibit quite a
bit of disagreement here. A faster solution cuts off rain
chances overnight Wednesday night while others suggest a slower
progression and maintain the rain all the way through Thursday
night. Meanwhile, the remnants of a potential tropical system in
the Gulf may interact with the trough.

The highest probability scenario is that the northern stream
trough is through by late week. A few ensembles still lag the
passage, with some higher QPF totals possible across the
southeastern half of the forecast area. Another cluster of
ensembles has the system moving into the Midwest behind the
trough. Will stick with NBM given all of the uncertainty.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Light rain rates are expected to continue through dawn. The
main exception is MGW, where some instability is evident.
Correspondingly, a brief thunderstorm is possible early in the
TAF period. Elsewhere, light rain will gradually saturate and
lower ceilings into the morning. Most sites are favored for MVFR
cig minimums in the AM hours with roughly a 50% chance or
greater of IFR in northwest PA and eastern OH.

Cigs are forecast to lift to VFR throughout the day, save DUJ,
but coverage is expected to remain broken. Weak forging may
allow for isolated shower and storm development in western PA
and northern WV, but confidence was to low to note as a tempo or
precialing group save LBE. Ample low moisture and reinforced
saturation tomorrow night likely means another night of at least
MVFR restrictions are ahead for most ports. More rain arrives
Tuesday.

.Outlook...
Rain and restriction chance continues into Tuesday with another
low pressure center. Unsettled weather is then possible through
mid-week.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...22
NEAR TERM...22
SHORT TERM...22
LONG TERM...MLB/Milcarek
AVIATION...Milcarek