599 
FXUS61 KPBZ 150130
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
830 PM EST Mon Jan 14 2019

.SYNOPSIS...
Several rounds of wintry precipitation will be possible this 
week with much colder weather anticipated for the beginning of 
next week.

&&

.NEAR TERM /THROUGH TUESDAY/..
Changes for the eve update included the addition of some light
snow for the ridges based on some reports - no problems are
anticipated.

Otherwise, swath of stratus that has blanketed areas south and 
west of PIT today is expected to be pulled northward during the 
predawn hours as a shortwave crosses the Great Lakes. No 
measurable precip is anticipated as mid level moisture and 
ascent indications with this system are limited; however, with a
relative-saturated boundary layer, some patchy freezing drizzle
is possible but confidence is not sufficient to mention just 
yet. Overnight lows were projected just a couple degrees under 
the seasonal averages, and Tuesday highs about 5 degrees under 
following passage of the aforementioned disturbance.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Another, and more significant shortwave is forecast to emerge
from the Great Lakes Region early on Wednesday. Relatively warm
and moist advection on the van of that system will support a POP
increase on Tuesday night. Given model sounding indications that
remain below zero in combination with a shallow mixing layer and
model-agreed shallow free convection layer, have opted for precip
type as light snow despite the absence of mid level moisture.
any accumulation will not be problematic. For that systems
frontal passage on Wednesday, boundary layer temperature looks
too warm after the morning warm surge to worry about winter
impacts at this point.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
The next in series of shortwaves is projected for a Thursday
approach and passage. A similiar warm-advection/questionable 
precip type situation is anticipated with models vastly
different in precip-definning temperature profiles.

Given current indications of a northward low track which would
result in stronger warm advection over the Upper Ohio Region,
will stay with a scenario of snow-north of pit, and a change to
rain over the south. Given the potential for several inches of
accumulation, will maintain the HWO mention for this system.

The development of a high amplitude trough and subsequent
encroachment toward Upper Ohio airspace will define the weather
for the weekend. Expect continued precipitation chances followed
by much cold air as that trough digs eastward by early next
week.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
An approaching shortwave will pull MVFR cigs that have blanketed
ports south and west of PIT northward as it approaches tonight.
A high-confidence forecast of deterioration to IFR stratus is 
anticipated for the peridawn hours.

Persistent cig restrictions, primarily MVFR, are expected as the
systems cold front crosses the region on Tuesday. Another 
disturbance will reinforce restrictions and bring the next chc 
for precipitation on Tuesday night.

.Outlook...
Persistent restrictions should be expected as a series of 
disturbances cross the region during the latter half of the 
week.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.

&&

$$