Area Forecast Discussion
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FXUS61 KPBZ 171749
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1249 PM EST Tue Jan 17 2017

.SYNOPSIS...
A warm front will lift north across the area with occasional rain
expected today. A crossing cold front will keep shower chances
through Wednesday before high pressure returns dry weather for
Thursday.

&&

.NEAR TERM /UNTIL 10 PM THIS EVENING/...
Precipitation with a warm front should clear the forecast area by
the afternoon. Although synoptic models suggest that more rain
will occur across most locations through the afternoon, the HRRR
agrees more with current radar trends, and have decided to leave
most locations with a chance of rain. The one exception will be a
line of showers along the cold front itself, and have tried to
time likely pops with the expected frontal passage. Most locations
should warm well into the 50s during the daytime.

&&

.SHORT TERM /10 PM THIS EVENING THROUGH FRIDAY/...
Shower chances should continue tonight and Wednesday as the
surface low`s associated cold front passes, and subsequent upper
troughing crosses the area. The rain could mix with snow in cold
advection Wed especially N of I 80 and in the ridges, though no
accumulation is expected. Building high pressure should result in
a return of dry weather to the forecast Wednesday night and
Thursday. Temperatures should cool behind the front, but are
still expected to average around 10 degrees above seasonal levels
by mid week.

A deep upper trough across the Plains is progged to advance NEWD
Thursday night and Friday, and is expected to be situated from
the Upper Midwest to the OH Valley region by Friday. With decent
model agreement on deep layer moisture, ascent and upper support
increased POPs to likely for rain. Temperatures should continue to
average around 15 degrees above seasonal levels to end the week.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The upper trough should slowly exit the region through Saturday
with decreasing rain chances. Unsettled and relatively warm
weather is expected through the rest of the period as operational
and ensemble model progs indicate the development of a closed low
advancing from the Southern Plains to the Ohio Valley region from
Sunday through early next week. Tweaked Superblend guidance output
was used for much of the period to depict the general trends and
smooth out operation model differences.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Restrictions likely through the day as a frontal system continues
to migrate across the region. Precipitation will be widely
scattered outside of the vicinity of the crossing cold front and
have timed frontal passage of TAFs based on latest radar trends
and guidance. Lower cigs and rain chances will return early in the
morning as the parent upper trough moves overhead. Not much
improvement expected during the day on Wednesday with plenty of
low level moisture trapped under the subsidence inversion.
Conditions may improve by late afternoon as the boundary layer
depth decreases.

The LLWS threat will lessen tonight as winds decrease above the
inversion.

.OUTLOOK...
Restrictions are likely through Wednesday with crossing low
pressure. Thereafter, expect general VFR until the next system
moves in on Friday.

&&

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

&&

$$



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