324
ACUS11 KWNS 171627
SWOMCD
SPC MCD 171627
NHZ000-MAZ000-VTZ000-CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-171830-

Mesoscale Discussion 1666
NWS Storm Prediction Center Norman OK
1127 AM CDT Wed Jul 17 2024

Areas affected...Eastern PA/northern NJ into western New England

Concerning...Severe potential...Watch likely

Valid 171627Z - 171830Z

Probability of Watch Issuance...80 percent

SUMMARY...The damaging-wind threat will increase this afternoon. One
or more watches will likely be needed.

DISCUSSION...Relatively strong heating is underway from parts of the
Mid Atlantic into western New England, to the east of an extensive
cloud shield that is moving eastward across western/central NY/PA
and WV. A seasonably deep upper-level trough will move eastward
across the lower Great Lakes and Northeast through the day, while an
MCV embedded in the larger-scale trough will move from WV toward the
Mid Atlantic. Cumulus is gradually building from east-central PA
into southeast NY, and a general increasing in storm development and
coverage is expected with time this afternoon.

Midlevel lapse rates are weak (as noted on regional 12Z soundings),
but continued heating will support MLCAPE increasing above 1000 J/kg
with time. Modestly enhanced midlevel flow will support 30-40 kt of
effective shear, sufficient for some storm organization. Multiple
storm clusters and possibly a couple of supercells may evolve with
time, with steepening low-level lapse rates supporting a primary
threat of damaging wind. Some threat for isolated hail and/or a
brief tornado is also possible if any supercells can be sustained.
One or more watches will likely be needed this afternoon to cover
the damaging-wind threat.

..Dean/Hart.. 07/17/2024

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

ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP...
LWX...

LAT...LON   40317389 39737510 39527769 39867743 41267620 42887433
            43587327 43697258 43467206 42067273 40317389