Special Weather Statement, NWS Pittsburgh, PA

Area Forecast Discussion
National Weather Service Pittsburgh PA
653 PM EDT Sat Aug 7 2021

.SYNOPSIS...
Scattered showers and a few thunderstorms are possible this evening
and Sunday with a passing trough. Expect warm, humid conditions
through the next week.

&&

.NEAR TERM /THROUGH SUNDAY/...
For the evening update...adjusted Pops to more closely represent
current conditions and latest hires model data. Temperatures were
updated with a blend of model guidance.

Previous discussion...
Upper trough will pivot across the region through tonight. Modest
instability but weak shear will support scattered convection this
afternoon/evening. Despite the trough, the forcing mechanisms present
for organized convection are rather weak. As such, kept PoPs in the
chance category, with the higher values coming as the axis
approaches.

Convection will then diminish with the loss of diurnal heating
overnight. Lingering cloud cover will keep temperatures slightly
elevated.

Upper trough will be east of the region on Sunday but one last
shortwave in northwest flow will support additional showers/storms
across western PA/northern WV, where low-mid level moisture remains.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
Ridge of high pressure will then build over the region through
Monday before yet another trough approaches for Tuesday.
Strengthening southerly flow in advance of the next trough will
support temperatures above seasonal averages, with values potentially
exceeding 90 across much of the region.

Chances for showers and thunderstorms will then increase late Monday
night/Tue morning as the next trough lifts across the Great Lakes.

Temperatures will stay a touch above seasonal averages for both highs
and lows through the period.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Confidence is high that the remainder of the work week will feature
warm and fairly humid conditions, with daily temp averages above
climo, and daily rain chances... but confidence is low in the
details given spread amongst model guidance.

After Tuesday, models significant diverge with the details. However
both the ECMWF and GFS suggests the Upper Ohio Valley gets placed
within or just south of faster flow associated with the northern
stream mean troughing across northeast North America. The evolution
of the longwave pattern and timing of any perturbations remains
nebulous, but the warm/humid conditions will lend itself to a
forecast the favors storm chances most afternoons... at least until a
push of cooler, drier air comes through... which both the GFS and
ECMWF are hinting at for next weekend.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Scattered showers and thunderstorms will continue across the area
through early evening as noted in TAF TEMPO groups. A few showers may
then linger into the overnight.

Lingering llvl moisture and some clearing overnight may lead to areas
of fog before dawn. Otherwise, VFR is expected through Sunday with
light S/SW'ly winds.

.Outlook...
Restrictions in thunderstorms are likely to return Tue with the next,
approaching disturbance.

&&

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

&&

Hazardous Weather Outlook
National Weather Service Pittsburgh PA
307 AM EDT Sat Aug 7 2021

OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-029-
031-073>076-WVZ001>004-012-021-509>514-080715-
Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson OH-
Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest-
Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny-Armstrong-
Indiana-Washington-Greene-Westmoreland-
Higher Elevations of Westmoreland-Fayette-
Higher Elevations of Fayette-Hancock-Brooke-Ohio-Marshall-Wetzel-
Marion-Monongalia-
Ridges of Eastern Monongalia and Northwestern Preston-Preston-
Eastern Preston-Western Tucker-Eastern Tucker-
307 AM EDT Sat Aug 7 2021

This Hazardous Weather Outlook is for east central Ohio, western
Pennsylvania, and northern West Virginia.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
641 PM EDT SAT AUG 07 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0620 PM     FLASH FLOOD      UNITY                   40.49N  79.78W
08/07/2021                   ALLEGHENY          PA   SOCIAL MEDIA

            SEVERAL FLOODED ROADWAYS FROM HEAVY RAINFALL.

&&

EVENT NUMBER PBZ2102066

RACKLEY

Special Weather Statement
National Weather Service Pittsburgh PA
723 PM EDT Sat Aug 7 2021

PAZ021-072345-
Allegheny-
723 PM EDT Sat Aug 7 2021

...A STRONG THUNDERSTORM WILL AFFECT EAST CENTRAL ALLEGHENY COUNTY...

At 722 PM EDT, a strong thunderstorm was located over Munhall, or
near McKeesport, moving east at 10 mph.

Winds in excess of 30 mph and penny size hail are possible with this
storm.

Locations impacted include...
Pittsburgh, Penn Hills, Monroeville, McKeesport, West Mifflin,
Baldwin, Wilkinsburg, Munhall, North Versailles, Swissvale, White
Oak, and Forest Hills.

This includes Interstate 376 in Pennsylvania between mile markers 75
and 81.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4037 7977 4032 7992 4041 7996 4047 7984
      4039 7977
TIME...MOT...LOC 2322Z 248DEG 10KT 4039 7989