Severe Thunderstorm Warning 99, NWS Pittsburgh, PA

Area Forecast Discussion
National Weather Service Pittsburgh PA
205 PM EDT Tue Jul 7 2020

.SYNOPSIS...
Well above normal temperatures and scattered showers and
thunderstorms mainly during the afternoon and early evening will
persist through the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Showers and thunderstorms expected to persist until early evening
with greatest coverage over Ohio zones where sfc dewpoints are
currently in the lower 70s. The severe threat is low with minimal
shear, but there is potential for isolated flooding with longer lived
convection.

Convective activity will wane after sunset with loss of heating.
Warm overnight lows in the upper 60s to near 70 are expected.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Ridging will build on Wednesday leaving the best chance for
showers/storms over the ridges during the afternoon. High
temperatures in the low 90s will persist.

Higher pressure returns on Thursday as the upper ridge axis crosses
the region. This will lower, but not eliminate, afternoon convection
chances. Have maintained slight chance thunder for much of the area,
with higher chance PoPs across the WV/MD ridges.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
The long term period marks an eventual transition to cooler
temperatures and more unsettled weather as upper troughing digs
across the Great Lakes and Upper Ohio Valley into the weekend.
Friday/Saturday will feature better organized and more widespread
rain chances with crossing shortwaves in advance of a frontal
passage on Saturday.

At least one of these weekend days may need to be monitored for a
severe or flash flood threat given the abundant moisture present
ahead of the approaching disturbances.

Temperatures will moderate back towards average through the weekend
into early next week, with highs in the lower 80s by Sun/Mon.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Visible satellite imagery suggests the development of a cu field
across the region as convective temperature is met, with scattered
thunderstorms increasing in coverage through the duration of this
afternoon in conjunction with a passing shortwave trough. With dry
air evident aloft, gusty wind and cloud to ground lightning will be
the main hazards before convection wanes after 0Z.

Otherwise, increased sfc moisture may lead to areas of MVFR fog
development early Wednesday morning, with additional thunderstorm
development expected Wednesday afternoon.

.Outlook...
VFR will prevail with exception for increasing convection chances as
the week progresses, with intermittent restrictions expected in
afternoon / early evening thunderstorms.

&&

.CLIMATE...
Based on the 30-year climatological average, here is the "normal"
number of 90-degree days per year at each of the local climatic
sites:

Pittsburgh: 6.9 days
Morgantown: 8.0 days
Wheeling: 5.0 days
Zanesville: 10.0 days
Dubois: 1.0 day

90F+ temperatures are still forecast through Friday, barring
interference from well-timing thunderstorms. Based on historical
stretches of 90F days, here is a summary of the most-recent such
stretches at each site:

Pittsburgh (7/3-7/10/2020): prior 8-day stretch ended 8/20/1995
Morgantown (7/2-7/10/2020): prior 9-day stretch ended 8/4/1995
Wheeling (7/4-7/10/2020): prior 7-day stretch ended 7/27/2016
Zanesville (7/4-7/10/2020): prior 7-day stretch ended 7/8/2012
Dubois (7/5-7/10/2020): would be longest 90F stretch at DUJ.

Dubois most recently had a 5-day stretch of 90F days ending
7/23/2011. Dubois also is the site with the greatest potential
variability in the forecast maximum during this forecast period, and
therefore the most likely not to reach 90F on any given day.

&&

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

&&

Hazardous Weather Outlook
National Weather Service Pittsburgh PA
316 AM EDT Tue Jul 7 2020

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021-509>514-080730-
Garrett-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-Westmoreland Ridges-
Fayette-Fayette Ridges-Hancock-Brooke-Ohio-Marshall-Wetzel-Marion-
Monongalia-Ridges of Eastern Monongalia and Northwestern Preston-
Preston-Eastern Preston-Western Tucker-Eastern Tucker-
316 AM EDT Tue Jul 7 2020

This Hazardous Weather Outlook is for western Maryland, east
central Ohio, northwest Pennsylvania, southwest Pennsylvania,
western Pennsylvania, northern West Virginia and the northern
panhandle of West Virginia.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.