686
FXUS61 KPBZ 242355 AAA
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
655 PM EST Sun Nov 24 2024

.SYNOPSIS...
Rain chances return Monday and Monday night, followed by rain
and snow on Thanksgiving and much colder and unsettled weather
heading into the weekend.

&&

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

- Dry and partly to mostly cloudy.
------------------------------------------------------------------

Warm air advection aloft has eroded a large chunk of the low
clouds that have blanketed the area. This process is expected to
continue overnight. However, the low clouds are being replaced
by high cirrus clouds that are rushing eastward ahead of the
next system. Overnight period is in good shape, just needed to
make adjustments to the sky cover.


&&

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

- Rain returns Monday and Monday night with a cold front
-------------------------------------------------------------------

Flat upper level ridging, ahead of an approaching central CONUS
trough, will maintain dry weather through most of Monday
morning as the surface high slides eastward.

The trough will continue to advance eastward on Monday, as
surface low pressure develops across the Great Lakes region. The
low is expected to track through southern Ontario Monday
evening and overnight, pulling a cold front across the region.
Rain chances will escalate through the afternoon and evening as
moisture and ascent increase in southwest flow ahead of the
front.

Rain will continue until the front completes its passage Monday
night. Scattered areas of rain and snow in cold advection behind
the front, mainly along and north of the I-80 corridor. Any
precipitation should taper off Tuesday night as high pressure
begins to build across the region.

Temperature on Monday are expected to be 5 to 10 degrees above
average ahead of the cold front, before returning to seasonable
levels after FROPA.

&&

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

- Mainly dry Wednesday
- Rain and snow chances return Wednesday night and Thanksgiving
- Much colder and unsettled pattern by late week
-------------------------------------------------------------------

Model ensembles indicate a trough will begin to advance eastward
from the central CONUS Wednesday, as low develops across the
Southern Plains. Increasing moisture and ascent in southwest
flow ahead of the trough, and on the northern side of the
developing low, will return rain and snow to the region
Wednesday night.

Operational models differ in the positioning of the low by
Thanksgiving, with some keeping it further south, and others
further north. This will affect both the amount and type of
precipitation across our region. At this time, ensemble tracks
favor a more northern positioning of the low, though plenty of
uncertainty exists in the details. Stayed close to the ensemble
blend guidance, which results in rain and snow across the region
on Thanksgiving. Snow is more probable north of PIT, with rain
to the south.

A significant pattern change is then expected, as the initial
trough deepens into a long wave trough across the Eastern CONUS
through the remainder of the long term period. Much colder
temperatures and periodic rounds of snow are expected as
individual shortwaves rotate through the trough, and some lake
and terrain enhancement occurs.

Seasonable temperatures are expected early in the forecast
period, before readings drop to between 15 and 20 degrees below
average after Thanksgiving.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Dry advection from the southwest has returned VFR conditions to
all but FKL/DUJ this evening. FKL cigs should erode by around
03z, with DUJ restrictions continuing through 12z as limited
lake moisture linger.

Clearing sky and radiational cooling may initially allow a few
pockets of fog to form, but increasing cirrus should limit this
threat overnight. Ceilings are expected to lower once again
Monday afternoon in advance of a cold front. MVFR is likely
by/after 18z, with further degradation to IFR expected after
00z Tuesday. Light, scattered showers are expected in the
afternoon and evening, though probabilities are initially low.
Have covered with Prob30s in the afternoon until better chances
arrive overnight.

Outlook...
Widespread restrictions will likely continue into Tuesday with
showers. Skies will begin to scatter Tuesday afternoon with dry
advection. Additional showers and restriction chances are
expected mid to late week with a new large-scale disturbance.

&&

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

&&

$$

SYNOPSIS...88
NEAR TERM...88
SHORT TERM...WM/88
LONG TERM...WM
AVIATION...Rackley