National Weather Service Raw Text Product

273 
FXUS61 KPBZ 130500
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1200 AM EST Thu Feb 13 2025

.SYNOPSIS...
Freezing rain chances will diminish before dawn Thursday. Rain 
will change to snow late Thursday morning before ending 
Thursday evening. Dry weather is expected Friday, before active 
weather returns over the weekend with strong low pressure.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
KEY MESSAGES:

- Freezing rain threat expected to end before dawn amid rising
  temperature
- Isolated heavy snow showers possible late Thursday; the
  evening rush hour may be impacted

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

11:45PM Update: 

The center of low pressure system currently resides in western
Ohio this evening. With south/southeast flow, warm air 
continues to advance into the region and temperatures have 
climbed into the 40s/mid-30s for a large portion of the area. 
However, along the ridges and near I-80, the threat for freezing
surface temperatures remains for the next 6 hours and icy 
conditions may continue along roadways and along elevated
surfaces. Counties will likely be trimmed from west to east 
from the Advisory as surface winds shift from the southwest. 

A dry slot, noted on GOES-16 low-lvl water vapor, is currently 
advancing into eastern Ohio. Reflectivity returns will likely 
be scattered to isolated for the next few hours. 

With the passing cold front expected late morning, the warmest 
time period for Thursday will likely be between 4am to 6am
opposed to late afternoon. 

In the wake of the cold front, expected an uptick in snow
shower/snow band activity between 4pm to 7pm from the west with
a passing shortwave. Hi-Res models depict reflectivity returns
of 20DBZ to 30DBZ with snow bands which could create hazardous
travel and visibility concerns. The snow squall parameters is
also maximized between 20Z Thurs to 00Z Friday over western PA
due to steep lapse rates and instability values between 40J/kg 
to 75J/kg. Short-fused Special Weather Statements (SPS) or Snow
Squall Warnings may be needed this evening. 

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
KEY MESSAGES:
 
- Dry Friday
- Wintry precipitation returns Friday night and Saturday

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

Dry weather is expected Friday as the high moves east across 
the region. The next shortwave trough is expected to track east 
out of the western CONUS Friday night, as a surface low develops
across the southern Plains. Wintry precipitation is expected to
overspread the region late Friday night into Saturday in warm, 
moist advection in SW flow ahead of the low/trough, and with a 
crossing surface warm front. Some jet enhancement should also 
increase ascent during the day Saturday.


Model soundings and critical thicknesses indicate the precip
should begin as snow, with a changeover to rain from S-N under
the warm advection. At this time, it appears most of the snow
accumulation should be north of PIT, with near advisory levels
possible near and north of I 80. Most areas should transition to
rain through the afternoon. Locally heavy rain will then be 
possible, especially south of PIT, beginning later in the day.

&&

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

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

The surface low mentioned above is progged to take a similar
track to tonight's/Thursday's system, reaching eastern
Ohio/Western PA Sunday morning. A cold front will then cross the
region after the low tracks further northeastward, with rain
changing to snow after FROPA. Locally heavy rain Saturday night
and Sunday morning could result in localized flooding. Elevated
river and stream levels are also possible. 

An upper trough is then progged to approach and cross the 
region late Sunday and Sunday night, with snow chances 
continuing. Cold NW flow across the Great Lakes should maintain
some snow showers across the region on Monday, before high
pressure returns dry weather for Tuesday. Another shortwave
trough is progged to advance our of the central CONUS by
midweek, returning snow chances to the region. 

Much colder temperatures are expected Sunday night into Tuesday,
as 850mb temps are progged to drop to -20 to -22 deg C.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
Rain showers have become more widespread over the past few
hours, although visibilities are still mainly VFR. The freezing
rain threat is now confined to locations north of I-80 and along
the higher ridges, and have TAF mention at only FKL and DUJ
through 03Z or so, before warmer air arrives.

Still expect a 40 to 50 knot low-level jet to arrive later this
evening, with a threat of low-level wind shear where surface
wind decouples and prevents gusting at the surface. Ceilings are
forecast to float down to IFR levels areawide as the low levels
saturate underneath a lowering inversion. HREF probabilities of
such are 50 to 90 percent areawide by 12Z. A cold front arrives
in eastern Ohio after 09Z and swings through during the morning.
This will bring gusty westerly winds, an end to widespread 
precipitation, and a gradual improvement in ceilings.

After 18Z, ceilings will remain at MVFR, with wind gusts of 30
to 30 knots continuing out of the west. There is some risk of
scattered snow showers that could bring brief visibility
impacts especially after 21Z. Used VCSH for this threat for now
as timing/placement of said snow showers remains low 
confidence.

Outlook... 
High pressure will promote a brief period of VFR Friday (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...Hefferan
NEAR TERM...Hefferan
SHORT TERM...WM
LONG TERM...WM
AVIATION...CL