495
FXUS61 KPBZ 121534 AAA
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
1034 AM EST Wed Feb 12 2025

.SYNOPSIS...
Another storm system will bring a wintry mix to the area today
that will change to rain, with an extended period of freezing
rain possible in some areas north of Pittsburgh and in the
ridges. Dry weather returns Friday before active weather returns
this weekend.

&&

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

- Wintry mix/freezing rain today and tonight, especially N of
  PIT and in the ridges

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Update...
Made some adjustments to POPs and hourly temperatures based on
the latest radar, surface observations, and near term model
data. Increased POPs where an area of snow has increased along
the leading edge of warm advection. The 12Z PIT sounding shows
saturation through the lower portion of the dendritic layer.
This should keep most of the precip in the form of light snow
this morning. As warm advection occurs by mid to late morning,
some patchy freezing rain is possible south of the current
advisory area. Confidence in occurrence is low, so will monitor
the trends through the morning.

Previous discussion...
Developing low pressure will move toward the Midwest today and
drive a warm front through the region. Strengthening southwest
flow will push warmer air northward behind the surface boundary.
Rain will begin to overspread the region late this morning and
during the afternoon. Latest NBM probs of measurable
precipitation remain generally less than 20%. However, in the
ridges of WV and into SW PA, probs for measurable precip jump to
30-40% this morning. For the most part, the warmer surface air
should out race the precipitation meaning most locations will
see all rain. However, over the ridges, and the I-80 corridor,
the colder surface air should hang on longer, increasing the
threat for a period of freezing rain. Thus all current headlines
will continue. It will likely take until late this evening for
temperatures above freezing to reach the far northeast corner of
the forecast area. Probs for freezing rain remain mainly over
the advisory areas. Will need to monitor counties north of PIT,
but south of I-80 as some low probs <20% for freezing rain are
showing up in the northern portion of those counties this
afternoon.

&&

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


- Rain changing to snow before ending Thursday
- Dry Friday

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The surface low is progged to track across western Ohio into NW
PA tonight into Thursday morning. The low will continue
advancing northeastward Thursday, pulling a cold front across
the region. Rain will likely change to snow in the cold
advection, and as the upper trough crosses the Upper Ohio Valley
region.

Building high pressure should return dry weather to the region
later Thursday night and Friday.

&&

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

- Snow changing to rain Friday night and Saturday
- Locally heavy rain possible
- Rain changing to snow Saturday night and Sunday
- Much colder late Sunday and Monday
-------------------------------------------------------------------

Model ensembles indicate a digging trough will track across the
central CONUS Saturday into Sunday. A surface low is progged to
develop across the MS Valley region again on Saturday, tracing
across the Upper Ohio Valley region on Sunday. Strong warm,
moist advection in SW flow ahead of the trough will result in
precip overspreading the region late Friday night, continuing
through Sunday. There is a potential for locally heavy rain as a
strong jet enhances ascent, though plenty of uncertainty in the
details exists. Rain is expected to change to snow on Sunday as
the low tracks NE and pulls a cold front across the region.

Upper troughing and cold NW flow off of the Great Lakes will
maintain snow shower chances at least through Sunday night.
Much colder temperatures are expected behind the front, with
readings 10 to 20 degrees below average by early next week.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Ongoing snow showers along a ZZV-AGC-LBE line this morning
gradually depart to the east through roughly 15z. Could see some
FZRA mix in with the snow at places like ZZV and MGW before it
departs, though confidence is too low to warrant mention in the
TAFs. Once the morning precip departs, expect a brief reprieve
from late morning into early afternoon before rain overspreads
the area again after 19z and lasts through the remainder of the
TAF period. Most likely terminals to see FZRA at the onset this
afternoon are FKL and DUJ, though lower probabilities do exists
for BVI as well. Other terminals should see temperatures warm
enough before rain begins to avoid any notable ice accrual.

Ceilings start the morning mostly VFR, with a few select sites
sitting at MVFR already. Gradual lowering to widespread MVFR is
expected by late morning, with IFR mixing in as rain begins this
afternoon.

A southerly low-level jet sets up tonight ahead of the main low
passage. The most likely scenario for now is for enhanced winds
to remain elevated, providing wind shear probabilities that
increase after 02Z for most. Should mixing be more prolific in
any rain showers, or surface warm advection trend stronger,
there is a chance this could materialize as localized gusts up
to 30kts. Some temporary cig improvement is possible with this
push, but will likely be short lived.

Outlook...
MVFR to IFR conditions in light rain will continue overnight
into Thursday. Additional rain showers are expected ahead of an
advancing cold front Thursday morning. There remains potential
for afternoon isolated lake-enhanced snow showers after the
frontal passage, though these are most likely to remain limited
to areas closer to the lakefront. Expect drier conditions and
veering winds to the west with 20 to 30kt gusts outside of these
restrictions.

High pressure will promote a brief period of VFR by Friday
afternoon (near 100% probability) before the next low pressure
system brings multiple rounds of a wintry mix of conditions plus
restrictions Saturday into early next week.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory until 4 AM EST Thursday for PAZ007>009-
     015-016-074-076>078.
OH...None.
WV...Winter Weather Advisory until 4 AM EST Thursday for WVZ512.
     Ice Storm Warning until 4 AM EST Thursday for WVZ514.

&&

$$

SYNOPSIS...WM/22
NEAR TERM...WM/22
SHORT TERM...WM/22
LONG TERM...WM
AVIATION...Cermak/Frazier/Milcarek