PBZ issues Area Forecast Discussion (AFD) at Nov 29, 8:03 PM EST
183
FXUS61 KPBZ 300103
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
803 PM EST Fri Nov 29 2024
.SYNOPSIS...
Scattered snow showers will largely taper off overnight,
although a few may persist in the ridges into Saturday morning.
A prolonged cold period sets in with occasional snow shower
chances likely through the beginning of December.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
KEY MESSAGES:
- Scattered snow showers mostly ending this evening, although
they may persist along the ridges overnight.
- Wind chills dropping into the single digits in many areas by
Saturday morning, and below zero on the higher ridges.
-------------------------------------------------------------------
With the loss of modest instability and a shortwave trough
departing, coverage and intensity of snow showers has dropped
off over the past couple of hours. Expect this trend to continue
tonight, with the ridges perhaps holding on to scattered snow
showers after midnight, while snow showers largely cease
elsewhere. Think that the potential for the main Lake Erie
lake- effect band to wobble into Forest/far northern Venango is
a bit less now given the continued W/WSW flow, but will continue
to monitor.
The more notable overnight impact will be wind gusts and wind
chill values tonight into Saturday morning. Wind gusts of
20-30 mph (and higher gusts in the terrain to near 45mph) will
bring wind chill values into the single digits through Saturday
morning. Latest ensemble probabilities suggest >60% chance of
wind chills below 0 in the higher elevations, with the highest
ridge tops potentially approaching -10.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
- Well below-normal temperatures for the weekend, with near-zero
wind chills Saturday and Sunday morning.
- Clipper system will bring snow to the region south of
Pittsburgh Sunday
-------------------------------------------------------------------
Broad 500 mb trough will remain the in place through the rest of the
weekend, though height rises are expected Saturday with surface
ridge nudging into the upper Ohio valley. Even with the potential
for sunshine, the probability of highs above freezing is around
10- 40% (highest over east central Ohio).
The next system will approach on Sunday, which is a fast moving
clipper-type system moving through the base of the trough. At this
time, the best lift is progged south of Pittsburgh with upslope
continuing with the systems passage. While deep moisture through the
DGZ will be present, the fast track of the system should be a
limiter on accumulation. At this juncture, the NBM had the
probability of greater than 3.0" around 40% through Monday
morning. Will continue to monitor the trend in this system as
some guidance suggests a stronger system than others.
Kept the temperatures for the weekend period below the deterministic
NBM due to its warm bias as we enter the cold season. Steep lapse
rates will promote continued mixing of wind gusts with a 60-80%
chance of >30 mph gusts Saturday relaxing some on Sunday.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
KEY MESSAGES:
- Much colder temperatures remain into next week.
- Rounds of shortwaves maintain snow chances.
-------------------------------------------------------------------
Eastern CONUS troughing will generally prevail during the long
term, with some flattening possible midweek before additional
shortwaves dig the trough across the NE for the end of the week.
With a more northwesterly component to the wind by late Monday,
some lake enhanced snows may be possible across the region
through Tuesday. This will be followed quickly on the heels of a
reinforcement in the trough by a low pressure system Wednesday
into Thursday. There are differences in the strength and timing
of the system during that time frame which could lead to some
precipitation type challenges. After that system, yet another
push of cold air is expected with lake enhanced snow showers to
end the week.
At this time, temperatures look to remain below seasonal
averages for the entire period, with the brief "warm up"
happening mid week before we once again struggle to go above
freezing.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
Scattered snow showers will taper off this evening as an upper
trough axis moves east of the area, and as moisture/lapse rates
in the dendritic growth zone diminish. Otherwise, VFR stratocu
cigs are expected overnight into Saturday morning with moisture
under a temperature inversion, and cold advection aloft. FKL and
DUJ could briefly see a few lake effect snow showers overnight
as the boundary layer flow veers slightly to the west after the
passage of the trough, though the flow is expected to back to
the SW again late tonight pushing any snow activity back north
of the area.
Gusty W-WSW wind will persist, especially during the daytime
hours, with a tight surface pressure gradient in place, and
mixing. Stratocu should clear from SW-NE Saturday as weak
surface ridging builds in.
Outlook...
Restriction and light snow chances return Sunday with another
crossing shortwave trough. Additional potential restrictions and
snow chances are expected through Wednesday as a series of
shortwave troughs cross the Upper Ohio Valley region, and
lake/terrain enhancement occurs.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...34
NEAR TERM...34/CL
SHORT TERM...34
LONG TERM...34/MLB
AVIATION...WM
Source: PBZ issues Area Forecast Discussion (AFD) at Nov 29, 8:03 PM EST (https://mesonet.agron.iastate.edu/p.php?pid=202411300103-KPBZ-FXUS61-AFDPBZ)
---------------
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!