Area Forecast Discussion Issued by NWS Pittsburgh, PA
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 180002
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
802 PM EDT Sun Mar 17 2024
.SYNOPSIS...
-- Changed Discussion --
Scattered snow showers are expected on and off through Tuesday
morning with a crossing upper trough. Dry weather is then
expected as temperatures will gradually warm mid to late week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
-- Changed Discussion --
KEY MESSAGES:
- Lake enhanced showers continue mainly north of Pittsburgh
- Colder temperatures arrive tonight, especially over the
southern half of forecast area
-------------------------------------------------------------------
Deep and cold trough over the Great Lakes will gradually move south
overnight. 500 mb heights will fall another 70 meters or so as
a result. The column will continue to cool and especially the
boundary layer, with 850 mb temps falling from about -4C this
evening to -11C in the PIT area by 12z Monday.
Coverage of snow showers is expected to become more sparse
overnight with the loss of diurnal heating. However, cooling
temperatures and the loss of insolation will increase the
possibility of light accumulations overnight, especially along
and north of I-80. A light dusting to perhaps a brief half inch
is possible for those locations.
Hourly temperatures, PoPs, and sky cover were refreshed with the
latest hi-res blend, but otherwise, no significant changes were
needed for the overnight period.-- End Changed Discussion --
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
KEY MESSAGES:
- Cold and unstable under upper trough with showers of snow and
graupel.
- Potential for light snow accumulation, mainly north of I 80
and in the higher terrain
-------------------------------------------------------------------
Upper trough will start the day over northwest Ohio and Lake
Erie, moving to western PA and WV by the late afternoon.
Strongest height falls of 150 meters will be over VA.
A very cold and unstable airmass is expected given we have mid
March sun angle. 850 mb temps will be around -10C, 700 mb -18C,
and 500 mb dropping to around -35C. RAP soundings show moist and
unstable situation with diurnal heating under trough with
increasing moisture and even 100-300 j/kg of CAPE. Cloud tops
will be in the -20 to -25C range, so vigorous convective snow
showers are expected which certainly could produce brief heavy
snow bursts and graupel. Accumulations outside of ridges will be
limited by March sun angle. However, with convection continuing
into the evening, there is certainly the potential for
accumulations north of I-80 and over the ridges Monday night.
CIPS analogs indicate that the WV ridges have a 30-50% chance of
4" or more in patterns like this. At this point expect 2-3" in
those areas so expect a sub-advisory event especially during the
daylight hours.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
KEY MESSAGES:
- Near normal temperatures expected Tuesday through Friday
- Mainly dry weekend with moderating temperatures
----------------------------------------------------------------
As heights gradually rise and flow turns from northwest
to westerly aloft, a low pressure area over the Great Lakes
will skirt mainly north of the forecast area as it heads toward
Ontario/Quebec/New England Tuesday into Wednesday. Certainly
could be snow in the northern half, especially Tuesday morning,
but the system will have limited moisture so the precipitation
shield is more likely to impact New York and far northern PA.
Flow gradually tilts from westerly to southwesterly as the week
progresses with gradually rising heights and moderating
temperatures. While near normal readings are expected most of
the week, moderation begins over the weekend with highs in the
50s Saturday and Sunday.-- End Changed Discussion --
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
General VFR forecast with the exception of FKL and DUJ which
will see occasional MVFR conditions with snow showers. Gusty
winds will continue through the night, but should weaken as the
night progresses.
Snow showers will become more prevalent and widespread on
Monday. Difficult to pinpoint when and where they will hit, with
FKL and DUJ having the highest probabilities to see restrictive
vis/cigs. Winds gusts are again possible on Monday, but not as
strong as today.
.Outlook...
VFR returns Wednesday and Thursday as a ridge of high pressure
builds in-- End Changed Discussion --
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...Rackley
NEAR TERM...Craven/Rackley
SHORT TERM...Craven
LONG TERM...Craven
AVIATION...Craven