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fxus61 kpbz 212318 
afdpbz

Area forecast discussion
National Weather Service Pittsburgh PA
618 PM EST Tue Feb 21 2017

Synopsis...
shower chances are expected through early Wednesday as a weak
front crosses the area. Warm weather is expected to continue
until the passage of a late Friday night and Saturday morning
cold front.

&&

Near term /until 6 am Wednesday morning/...
a weakening cold front is expected to dissipate as it crosses
the area tonight. Shortwave support and ascent fields are
progged to be limited, so continued with only chance pops
overnight for showers. Lows are expected to be around 25
degrees above the seasonal average.

&&

Short term /6 am Wednesday morning through Thursday night/...
generally zonal flow continues into this period, with more
amplified flow towards the end ahead of the strong system
approaching Friday night. A few showers may linger along the
dying boundary Wednesday morning, before flat ridging provides a
dry interlude Wednesday afternoon through much of Wednesday
night.

Flow begins to amplify Thursday as a strong shortwave begins to
dig over the plains. The increasing southwest flow will push
moisture and a warm front towards the region with time.
Modest isentropic lift at 300/305k will also support chance pops
for showers. Some modest instability of 300 j/kg or less is
noted on model soundings, but elected to hold off on thunder
mention for now.

The unseasonable warmth continues through this period, with high
temperatures consistently running 20-25 degrees above average.
Made only minor modifications to numbers using bias-corrected
guidance. See climate section for details on record high
temperatures this week, some of which could be in jeopardy.

&&

Long term /Friday through Tuesday/...
warm front will lift north of the area Friday increasing
southerly flow into the area. 12z GFS continues the trend of
slowing down the progression of the strong cold front late
Friday into early Saturday. Delayed timing should allow for
enhanced clearing in the warm sector, and as a result,
temperatures will soar. Have kept with the trend of bumping up
friday's highs, although not quite to the mex numbers.

Will continue with likely pops for this boundary, with a chance
for thunder, though the overnight passage may be a bit of a
limiting factor. Temperatures should return to near normal
values, with snow showers as the system departs.

Very broad troughing is then expected through early next week,
with another system progged for passage in the deterministic
guidance.

&&

Aviation /00z Wednesday through Sunday/...
a weakening cold front should result in lowering, but still VFR,
ceilings tonight as it crosses the area. A few showers are
possible but upper support is limited. Enough low level moisture
could move in behind the dissipating front Wednesday morning to
result in MVFR ceilings from zzv to fkl to duj, though VFR
stratocu is expected elsewhere.

Outlook...
restrictions are possible with a Thursday night warm front.
Restrictions are likely with a Friday night/early Saturday cold
front.

&&

Climate...
record high temperatures for climate sites:

Wed Thu Fri
--------- -------- --------
pit 70 (1922,30) 70 (1922) 70 (1875,1906)
zzv 67 (1992) 64 (2000) 70 (1961)
mgw 70 (1980) 68 (1996) 75 (1975)
duj 60 (1983) 63 (1985) 60 (1985)
hlg 57 (1949) 62 (2000) 63 (2016)
phd 73 (1997) 69 (1975) 66 (1985)

&&

Pbz watches/warnings/advisories...
Maryland...none.
Ohio...none.
PA...none.
WV...none.

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