149
FXUS61 KPBZ 061220
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
820 AM EDT Sun Apr 6 2025

.SYNOPSIS...
Advancing cold front has ended the threat for heavy rain today.
Snow/Wintry mix chances increase early tomorrow morning. Below
average temperatures are expected through late week.

&&

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

- Late rain/drizzle chances continue this evening
- Below average temperatures expected
-------------------------------------------------------------------

With weak rainfall rates in the wake of a cold front, the Flood
Watch was cancelled early this morning. However, Flood Warnings
remain in effect near river gauge forecast points for areas that
received 2-3 inches of rain over the past 3 day in eastern Ohio.

Weather observations from the 12Z PIT sounding indicate increase
sinking air above 700mb, which reduces the likelihood of
moderate to heavy rainfall this morning and into the afternoon.
Despite this, there is still plenty of moisture within the
boundary layer, so light rain and drizzle will continue across
the region and into the late evening. Areas north of Morgantown,
WV depict elevated probabilities (above 70%) of only a trace to
0.10 inches total through 6pm today. Higher elevations,
especially in Tucker/Preston County, may receive up to a quarter
of inch of additional rain due to rising air associated with
upsloping.

The combination of widespread clouds, lingering rain, and
approaching cold air aloft will lead to below-average
temperature across the region. Probability of afternoon high
temperatures remaining in the 40s are elevated north of
Morgantown, WV; above 80%. The cold front has yet to reach some
portions of northern West Virginia this morning, keeping
temperatures in the low-50s.


&&

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

- Precipitation ends late tonight.
- Below-normal temperatures continue with late day/Monday night
  rain and snow showers.
- Cold air mass peaks on Tuesday.
-------------------------------------------------------------------

Shortwave trough will move southward over the region tonight.
This will continue to drive the surface front further south,
most likely into the Carolinas. The upper level wave could
develop additional light precipitation overnight as it moves
southeastward. Precipitation tonight should end before dawn on
Monday as much drier air spreads southward behind the wave.
Snow/sleet possibilities expand to most of the region tonight.
Any accumulation will likely be light and limited to grassy
areas.

Most of Monday will be dry before a cold front, dropping
southeast from the Great Lakes, could bring scattered showers
to the region late Monday afternoon and night. Precipitation
would start as rain with daytime temperatures mainly in the
upper 40s/lower 50s, but a quick mix with and change to snow is
likely Monday evening, with scattered snow showers continuing
into early Tuesday with the strong cold air advection. Minor
accumulation of less than an inch is possible during the
nighttime hours. Widespread low temperatures in the 20s are
forecast, representing well-below normal values.

850mb temperatures reach their minimum values of -11C to -13C on
Tuesday as the 500mb trough axis reaches the Atlantic Seaboard. By
this point, most snow showers should be confined to areas north of
Pittsburgh, and these will end during the day as low-level ridging
arrives.  High temperatures some 15 to 20 degrees below normal can
be expected.

&&

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

- Dry weather briefly returns midweek before additional
  precipitation chances by late week.
-------------------------------------------------------------------

Dry on Wednesday as surface high pressure crosses, with a brief
bout of quasi-zonal mid-level flow pointing to some temperature
moderation back to around 10 degrees below normal Wednesday.

By Thursday, it appears likely that the upper trough will be
reinforced by a potent shortwave dropping across the Upper Midwest.
Ensembles differ on the exact details, but rain chances do ramp up
for Thursday and Friday as an associated surface low and maturing
frontal system may cross the Upper Ohio Valley. How quickly the
500mb trough axis crosses the region is in question, as some model
solution close off an upper low in the base of the trough, slowing
system progression. That could keep some threat of precipitation in
the forecast into Saturday.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Broad ascent east of the upper trough axis will maintain areas
of light precipitation through much of the TAF period despite
the region sitting in a post-frontal environment. High
confidence exists in IFR through much of the morning that will
give way to MVFR then VFR at most terminals amid low level north
to south dry advection.

Uncertainty increases aft 00z as ascent continues with the upper
trough axis positioned west of the region while area thermal
profiles cool. Some model soundings suggest potential for a
brief period of ice pellets between 01z-06z before a more
natural rain to snow transition occurs. Probabilities peak along
a line from ZZV through PIT (roughly between 30-50% chance of
occurrence), with more limited chances outside this axis. Areal
precipitation may also influence timing and degree of MVFR/IFR
cig restrictions, especially in its NW extent.

Outlook...
Brief drying between upper waves is expected for most of the
daylight hours Monday, with mixing/lift aiding VFR conditions
at most terminals by 18z.

A reinforcing cold front and upper trough axis passage Monday
night into Tuesday morning will provide a narrow band of
precipitation, with cold advection increasing cig restriction
probabilities amidst low probability snow shower potential. The
next low pressure system will arrive late Wednesday into
Thursday with widespread precipitation/restrictions.

&&

.HYDROLOGY...
Heavy rainfall potential continues through Sunday. An
additional 0.5 to 1.00 inches is expected through Sunday
evening, with heavier rain tapering off behind a cold front.
The Flood Watch currently continues through 8 AM Sunday, and
may need to be extended depending on where the heavy rainfall
threat is likely to linger.

Precipitable water is expected to remain elevated through
Sunday, with some periodic jet enhanced ascent. Even after the
heavy rain potential ends, river levels will likely remain
elevated for a few days. Several River Flood Warnings are
already in effect for expectations of minor flooding, and many
other river forecast points will reach action stage.

&&

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

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan
SHORT TERM...22/CL
LONG TERM...CL
AVIATION...Frazier
HYDROLOGY...