Area Forecast Discussion
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FXUS61 KPBZ 061428
Area Forecast Discussion
National Weather Service Pittsburgh PA
928 AM EST Tue Dec 6 2016
Low pressure is expected to spread precipitation across the
region Tuesday. A Thursday cold front will return snow shower
chances and much colder temperatures for the end of the week.
.NEAR TERM /THROUGH TONIGHT/...
An upper level shortwave trough and associated surface low
shifting across the Ohio valley today will support widespread
precipitation over the region while sufficient moisture is
fetched from the Gulf and Atlantic. Strong warm advection aloft
will result in mostly freezing rain where the advisory is. Some
sleet may be mixed in initially as wet-bulbing takes into effect.
Southeast flow will inhibit warming in these areas until the flow
veers southwest later in the evening.
Across the northeast zones, precipitation should be held off long
enough while temperatures warm and allow for rain or snow
showers. This diagnosis is supported by the morning sounding
displaying abundant dry air as this feature is progged to advect
northeast. Later today, however, the northeast zones remain in a
possible favorable area for quick snow accumulation as wet-
bulbing, moisture, and omega fields are enhanced via upper
dynamics. Will closely monitor the area and latest model trends
for any significant changes in the forecast.
The low level jet should allow for gusty winds across the ridges
this evening but are expected to remain below advisory criteria.
Steady precipitation will pull off to the east fairly rapidly
by the late evening as the system shifts east.
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
Dry weather is forecast for Wednesday as surface high pressure
pays a brief visit, although temperatures will remain a touch
below normal. The next cold front is still expected to cross on
Thursday, bringing the coldest air of the season thus far. Kept
the idea of high chance/low likely PoPs for snow showers behind
the front in the developing mid-level trough. Lake enhancement
does not appear likely with generally WSW flow, although some
minor accumulation is possible, especially north of Pittsburgh.
Temperatures will tumble towards values well below normal.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Upper troughing and cold W-WSW flow should persist across the
eastern CONUS through Friday maintaining the chance for lake
enhanced and upslope snow showers. Some accumulation is likely with
a 13+ degree temperature difference between the lake and 850hpa.
But with uncertainty in band placement, have just upped PoPs for
the likely locations through Saturday morning. A less amplified
pattern sets up for the weekend through early next week, with
several crossing shortwaves progged. Differences in the evolution
of these systems prompted the use of the superblend for much of
this timeframe. Much below average temperatures are expected to
moderate by early next week.
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
Condition deterioration to eventual IFR can be expected today as
low pressure spreads precip over the region. Most of that will be
rain, but a wintry mix is anticipated at FKL and DUJ. ESE may also
be problematic on the surface with gusts around 20kt with
gradual veering as the system passes this afternoon and evening.
MVFR cigs are likely to linger tonight in the residual moisture
blanket and cooler flow behind the system, but building surface
high pressure will support improvement to VFR on Wednesday.
Periodic restrictions are likely for the rest of the week as a
strong cold front sweeps the region.
MD...Winter Weather Advisory until 10 PM EST this evening FOR
PA...Winter Weather Advisory until 10 PM EST this evening FOR
WV...Winter Weather Advisory until 10 PM EST this evening FOR