Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kpbz 231737 

Area forecast discussion
National Weather Service Pittsburgh PA
1237 PM EST Thu Feb 23 2017

warm weather will continue until the passage of a Saturday cold


Near term /until 6 PM this evening/...
with 11am update, kept isolated showers in the forecast to the
southeast of Pittsburgh, but backed off from scattered coverage
as radar has gone quiet across that area. Still expect showers
this afternoon to be mainly limited to northern zones, as a
frontal boundary is progged to stall in in the vicinity of the
I-80 corridor before lifting back to the north as a warm front.
Model guidance continues to suggest the possibility of a few
thunderstorms in the mix as well, however, chances are too low
to include in the forecast as warm air aloft is more likely to
keep any activity capped off.


Short term /6 PM this evening through Saturday/...
any remaining shower activity that develops across northern
zones will diminish this evening as the warm front lifts north.
With the forecast area well withing the warm sector,
temperatures on Friday look to be the warmest yet since
beginning this prolonged period of well above normal
temperatures. The current forecast includes record breaking
temperatures at all climate locations and dry conditions.

Friday night southerly winds will increase as the cold front
approaches and this along with plenty of cloud coverage will
likely result in record high minimums overnight.

There is higher confidence in timing of frontal passage...not
pushing it back later and keeping the inherited forecast as-is
as the modtrends tool is finally showing a flat linear
regression slope regarding the eastern Continental U.S. Trough.

The front will cross Saturday morning into early afternoon with
the timing of the passage would still not seem to favor much of
a severe threat given the expected lack of buoyancy, but with
strong flow and plenty of shear to enhance updrafts, any storms
may need to be monitored for wind gusts.

In any case winds will be strong ahead and behind the front
through early Sunday...with isolated gusts up to 40mph possible.


Long term /Saturday night through Wednesday/...
behind the cold front, wraparound showers will drop in coverage
Saturday night, with snow showers possible. Sunday will likely
be the only completely dry day in the extended forecast. Model
guidance is then a little uncertain with timing of a system on
Monday before having surprisingly good agreement on Wednesday.
Have stuck close to the superblend through this portion of the
forecast. After slightly below normal temperatures on Sunday,
high temperatures will increase through the period, with 60s
once again a possibility by the first day of March.


Aviation /18z Thursday through Tuesday/...
MVFR ceilings will linger into tonight with abundant low level
moisture associated with a frontal boundary. Scattered showers
are possible this afternoon, mainly north of pit. Ceilings may
fall a bit after sunset, with areas near and north of I-80
possibly sinking to IFR levels. Once the front lifts north and
the region gets into the warm sector, ceilings will begin to
rise back to VFR levels late this evening and overnight, with
fkl/duj possibly that level shortly after sunrise. VFR
conditions will then continue through Friday with thinning
clouds by afternoon. Cannot rule out patchy MVFR fog overnight
but elected not to include for now as the boundary layer should
remain mixed.

widespread restrictions are likely with the approach and passage
of a cold front on Friday night and early Saturday.


record high temperatures for climate sites:

Thu Fri
-------- --------
pit 70 (1922) 70 (1875,1906)
zzv 64 (2000) 70 (1961)
mgw 68 (1996) 75 (1975)
duj 63 (1985) 60 (1985)
hlg 62 (2000) 63 (2016)
phd 69 (1975) 66 (1985)


Pbz watches/warnings/advisories...

National Weather Service Glossary of Abbreviations