Area Forecast Discussion
Issued by NWS Pittsburgh, PA

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FXUS61 KPBZ 261650

Area Forecast Discussion
National Weather Service Pittsburgh PA
1250 PM EDT Sun Jun 26 2022

An approaching cold front will bring scattered showers and
thunderstorms to the area this afternoon and evening. Cool and
dry weather will then prevail to start the work week.


A warm and humid day is underway across the Upper Ohio Valley and
Allegheny Mountains. GOES imagery shows an upper-level low digging
across the Upper Great Lakes region and southern Canada. This low
will send a cold front into the forecast area this evening and into
the overnight hours.

The main story of the day will be the threat for showers and
thunderstorms as we head into the afternoon/evening period today.
Cloud cover and some light showers / drizzle continues to cross the
area, though visible sat imagery shows some breaks in the cloud
cover appears likely as we head into the afternoon. Just modest
afternoon heating of this warm and moist airmass should yield an
increase of MLCAPE to between 500 and 1000 J/kg for much of the
area, with perhaps higher values if more insolation is achieved. As
a result, convection will likely develop along and ahead of the
approaching cold front as it moves through the area between roughly
21z (5PM EDT) and 06z (2am EDT).

SPC continues to highlight the area in a marginal risk for severe
thunderstorm. This continues to be just that-- marginal. Despite the
instability, mid-level lapse rates of a meager ~5.5 C/km and limited
shear will keep the severe threat limited to the possible isolated
downburst-type scenario in the strongest of cells today.
Additionally, a limited flash flood threat also remains in place.

Given the fairly dry conditions as of late, rainfall will likely be
more beneficial than problematic. Downpours may be heavy, so a quick
and isolated instance of flash flooding is possible... especially
over urban areas.

Shower coverage will decrease from the west this evening and
eventually clear out of northern West Virginia by the middle of the
night after cool, dry northwest flow comes in behind the FROPA.


Very pleasant weather is expected on Monday and Tuesday as dry
northwest flow prevails behind the departing trough and cold
front. Highs both days will be in the 70s, about 5 degrees below
climatological values. Lows will also be cool, with temps
dropping into the 50s at night... though some typically cooler
spots may very well descend into the 40s on Tuesday night.


Sfc high pressure is expected to remain across the region as
the upper flow becomes more zonal by mid to late week. This
should result in continued dry weather, with a warming trend.

Precipitation chances increase by late week and into the
weekend as warm, humid air returns to the Upper Ohio Valley.


In the wake of an exiting, pre-frontal trough; moisture
advection within persistent, sly flow should trigger additional
shwr/tsra development through this eve, with occasional cig
restrictions to MVFR expected. As convection diminishes tonight,
mainly after 06Z, areas of MVFR/IFR cigs and vis and should
develop, especially where heavier rainfall was realized. This
should eventually be interrupted by dry advection via nwly flow
as a sfc cold front crosses, with lingering restrictions
improving to VFR by early Mon.

VFR is expected to prevail through mid-week under high pressure.




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