Mesoscale Discussion 1908

Issued

Sep 1, 2019, 7:26 PM EDT (23:26 UTC)

Expired

Sep 1, 2019, 9:00 PM EDT

In force

94 min

Issued by

the Storm Prediction Center

Chance of a watch

5%

The Pittsburgh radar (KPBZ), 41 km from the middle of the area, began a volume at 23:27 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

007 
ACUS11 KWNS 012326
SWOMCD
SPC MCD 012326 
PAZ000-NYZ000-WVZ000-OHZ000-020100-

Mesoscale Discussion 1908
NWS Storm Prediction Center Norman OK
0626 PM CDT Sun Sep 01 2019

Areas affected...Parts of eastern Ohio...western Pennsylvania...far
southwest New York

Concerning...Severe potential...Watch unlikely 

Valid 012326Z - 020100Z

Probability of Watch Issuance...5 percent

SUMMARY...A brief increase in convective coverage and perhaps
intensity may occur over the next few hours. The stronger storms may
produce isolated damaging wind gusts, marginally severe hail, and
possibly a brief tornado. The isolated nature of the risk precludes
a WW issuance.

DISCUSSION...Scattered storms have been developing for much of the
afternoon along a axis of a passing mid-level shortwave trough.
Recently, mosaic radar and lightning trends have depicted a slight
uptick in convective coverage and intensity. Recent CAM guidance
also depicts a short-lived increase in storm coverage along the
OH/PA/NY borders, before weakening in association with nocturnal
cooling. Should storms organize and mature further, modest but
adequate buoyancy (1000 J/kg MLCAPE, or 2000 J/kg MUCAPE) and
deep-layer shear (30 knots bulk-effective shear) suggest that
multicellular and transient supercellular structures may be
achieved, with isolated, marginally severe hail and wind gusts
possible. In addition, low-level speed and directional shear are
present, with modest veering in the sfc-850 mb layer contributing to
sickle-shaped hodographs and corresponding 150-200 m2/s2 effective
SRH (per latest RAP forecast soundings), especially in western
Pennsylvania. As such, a brief tornado cannot be ruled out in the
near term, despite the slowly stabilizing environment.

Nonetheless, given the expected isolated nature of the severe
threat, a WW issuance is not anticipated.

..Squitieri/Edwards.. 09/01/2019

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...BUF...CTP...PBZ...RLX...CLE...ILN...

LAT...LON   39838278 40258181 41498066 41948042 42277969 42427908
            42187817 41677801 40627858 40047917 39698053 39448180
            39838278

Mesoscale Discussions in Pennsylvania, 2019Mesoscale Discussions in Ohio, 2019Mesoscale Discussions in West Virginia, 2019Every mesoscale discussion in 2019

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.