PBZ issues Area Forecast Discussion (AFD) at Jan 3, 4:52 PM EST084
FXUS61 KPBZ 032152
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
452 PM EST Fri Jan 3 2025
.SYNOPSIS...
Snow showers and squalls will continue through the evening. The
snow showers will taper off Saturday as high pressure briefly
builds in. Strong low pressure will bring more widespread snow
to the region late Sunday and Monday, with a wintry mix possible
in some locations south of I-70. Cold weather and scattered
snow showers are then expected through much of next week.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
KEY MESSAGES:
- Snow showers and squalls continue
- Additional snow of 1-3 inches possible where multiple bands
pass over a region in the lowlands; higher in the terrain.
--------------------------------------------------------------------
Several snow squalls are crossing the upper Ohio valley this
afternoon, with reduced visibility and quick accumulation on
roadways. This is a result of a pivoting shortwave energy
diving southeastward across the region. The squall activity
should wane over the next couple of hours as we lose some of
the synoptic forcing, though lake enhanced snow will continue.
CAMs are not handling the exact location of any band well but
expect additional accumulation in the counties north of I-80 as
well as the terrain as NW slow continues overnight. Have bumped
up snow accumulations a bit areawide to reflect what is being
reported and with additional info from the CAMs.
Temperatures will continue to fall in cold advection overnight
and with wind gusts continuing, apparent temperatures will be in
the single digits, with values below zero in the highest
terrain toward morning.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH MONDAY/...
KEY MESSAGES:
- Winter weather headlines continue through Saturday morning
east of I-77
- Snow showers diminish Saturday
- Widespread snow returns late Sunday through Monday
- Impactful snow accumulations likely late Sunday and Monday,
with a wintry mix possible south of Pittsburgh
- Additional winter weather headlines likely
--------------------------------------------------------------------
Lake enhanced snow/upslope should diminish as we go into
Saturday as wind direction backs to westerly and surface ridging
builds. With fresh snow on the ground and the potential for some
of the region to be cloud free Saturday night, temperatures
could fall well below guidance. At this point, will err on the
warmer side with incoming clouds from the next low pressure
system.
All eyes then turn toward the system tracking through the
central CONUS as we head into Sunday. A digging trough will
begin to move into the mid-Mississippi valley during the day on
Sunday, with warm advection and moisture increasing out ahead of
it. This will help to spread light snow into the area by late
Sunday/Sunday night through at least Monday morning. Models and
ensembles continue to struggle with the evolution of this
system as it approaches the upper Ohio Valley. As of todays
ensemble guidance, a more southern track is favored, which could
decrease the potential for mixed precipitation but also put into
question overall snowfall totals, as the speed of the system
also varies. At this time, with the shift in the track, do not
feel as comfortable at hoisting headlines as far north as PIT
and will opt after collaboration with our neighbors and the
Weather Prediction Center to stay along a line from I-70
southward. Additional watches may be needed if a northward shift
returns.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
KEY MESSAGES:
- Widespread snow ends Monday night
- Cold NW flow and periodic snow showers through the remainder
of the week
--------------------------------------------------------------------
Steady snow on the western side of the surface low will end
Monday night as the low exits the East Coast. Model ensembles
then indicate a longwave trough/low will persist across the NE
CONUS and Canadian Maritimes region through the remainder of the
upcoming week. Cold NW flow off of the Great Lakes, and periodic
shortwaves rotating through the main trough, will maintain
scattered snow showers across the region. In addition to the
snow, cold temperatures will continue. 850 MB temperatures are
progged to drop to -15 to -17 deg C by Wednesday and Thursday,
with highs only near 20 (teens in the higher terrain), and lows
in the single digits to the teens.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
Mostly scattered convective snow showers favoring all of western PA
this afternoon. Expect predominantly MVFR conditions but passing
heavier snow showers could cause brief and rapid vsby reductions
to 1SM or less (hinting at up to 0.5-1"/hr snowfall rates in these
showers that may last ~ 30 minutes). This afternoon, instability is
expected to fuel some of the lake effect snow bands entering our
region which is why there are TEMPOs at BVI, PIT, AGC, and LBE.
In addition, cold advection behind the front and steepening lapse
rates will foster NW wind gusts between 20 to 25kts with higher
gusts possible in the higher terrain.
Subsidence and dry advection from the west will limit snow
shower activity after 00z but cold NW flow should maintain
localized bands of lake enhanced snow showers across northwest
PA. Exact location of these bands is too difficult to forecast
and thus include TEMPOs in the TAFs beyond FKL/DUJ. but even sites like
KPIT could see brief heavy snow with IFR vsbys if they cross
the terminal.
Outlook...
Though lingering cold advection in NW flow may continue
scattered light snow showers over northwest PA into the day
Saturday, subsidence will limit intensity and coverage as well.
Brief VFR is possible as a result of high pressure building from
the southwest, but uncertainty remains in extent of those
improvement.
The brief reprieve will be short lived before the next winter
system arrives Sunday afternoon into Monday. Impacts are likely
highest south of KPIT either due to heavy snow or a
moderate probability for mixed precipitation.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory until 10 AM EST Saturday for
PAZ007>009-013>016-020>022-029-031-073-075-077.
Winter Storm Watch from Sunday afternoon through Monday
evening for PAZ031-074>076.
Winter Storm Warning until 10 AM EST Saturday for PAZ074-076-
078.
OH...Winter Weather Advisory until 10 AM EST Saturday for OHZ040-
041-049-050-059-069.
Winter Storm Watch from Sunday afternoon through Monday
evening for OHZ057-068-069.
WV...Winter Weather Advisory until 10 AM EST Saturday for
WVZ001>004-012-021-509.
Winter Storm Watch from Sunday afternoon through Monday
evening for WVZ004-012-021-509>514.
Winter Storm Warning until 10 AM EST Saturday for WVZ510>514.
&&
$$
SYNOPSIS...34
NEAR TERM...34
SHORT TERM...34
LONG TERM...WM
AVIATION...Lupo
Source:
PBZ issues Area Forecast Discussion (AFD) at Jan 3, 4:52 PM EST---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
