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FXUS61 KPBZ 231247

Area Forecast Discussion
National Weather Service Pittsburgh PA
847 AM EDT Wed May 23 2018

High pressure provides dry weather through Friday. Seasonable
temperatures today will give way to well above normal values by
Friday. Another unsettled weather pattern may arrive during the
holiday weekend.


No major changes for the morning update. The issue of the day
will be the advance of dry air from the north and timing the
clearing that will take place.

Previous discussion...

Plenty of stratus lingers behind the front. Mixing later this
morning will break up the stratus, with mostly sunny skies
foreseen by afternoon. Temperatures will remain a few degrees
above normal.

A mostly clear sky and light wind will dominate tonight as the
surface high center builds in. Despite the recent rain, models
do not seem too keen on fog development tonight. This is likely
due to the drier afternoon dewpoints int the lower to mid 50s,
which may set crossover values that may not be breached
significantly overnight. Low temperatures will be around those
aforementioned seasonal values.


The dry pattern will continue through this period for the most
part as a flattening upper ridge arrives. Thursday will feature
wall-to-wall sunshine with a dry overall column. Enough low-
level moisture may creep back in by Friday to allow for some
afternoon flat cumulus, but another mostly sunny day is
foreseen. Temperatures will commence a warming trend, climbing
back to well above normal values by the end of the week.

Deeper moisture will start riding up the back side of the ridge
Friday night, with a few isolated showers possible by sunrise
on Saturday. This will represent the first hints of another
active weather pattern to follow.


As hinted in the previous section, the holiday weekend will
feature a return of unsettled weather. Moisture will continue to
pump northward behind the departing ridge on Saturday, leading
to some scattered showers and thunderstorms. As a potential Gulf
of Mexico tropical system rides north into the southeast states,
a continued moisture feed around it may interact with Great
Lakes/northeast U.S. troughing to provide shower and
thunderstorm chances right on through Memorial Day and into
Tuesday. Given the several rounds of precipitation expected,
rainfall totals may have to be monitored for at least an
isolated flooding potential. However, ensembles/GEFS QPF
M-climate continue to point to a relatively unremarkable pattern
overall, and thus a widespread flood threat is not yet foreseen.

Temperatures will continue to run several degrees above normal,
with tightening diurnal ranges due to the bouts of clouds and


MVFR to IFR stratus is expected to continue this morning before
mixing out/dissipating under building high pressure and dry
advection. VFR is then expected through the rest of the TAF
period under the high.

Restriction potential returns with weekend low pressure.




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