Mesoscale Discussion 1059

Issued

Jun 21, 2021, 9:23 PM EDT (01:23 UTC)

Expired

Jun 21, 2021, 11:00 PM EDT

In force

97 min

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 300...303...304

Counties Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Worcester County, MA, Cheshire County, NH, Passaic County, NJ, Albany County, NY, Columbia County, NY, Dutchess County, NY, Greene County, NY, Orange County, NY, Putnam County, NY, Rensselaer County, NY, Rockland County, NY, Ulster County, NY, Bennington County, VT, Windham County, VT

The Albany radar (KENX), 85 km from the middle of the area, began a volume at 01:25 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.

329 
ACUS11 KWNS 220124
SWOMCD
SPC MCD 220123 
MAZ000-NHZ000-CTZ000-VTZ000-NYZ000-NJZ000-220300-

Mesoscale Discussion 1059
NWS Storm Prediction Center Norman OK
0823 PM CDT Mon Jun 21 2021

Areas affected...Portions of New England and the Northeast.

Concerning...Severe Thunderstorm Watch 300...303...304...

Valid 220123Z - 220300Z

The severe weather threat for Severe Thunderstorm Watch 300, 303,
304 continues.

SUMMARY...Radar and satellite trends suggests ongoing convective
line will gradually weaken over the next couple of hours with the
loss of diurnal heating. Isolated severe wind gusts will remain
possible with the strongest storms through 0200-0300z. A downstream
watch is unlikely given weakening trends and stabilizing surface
conditions.

DISCUSSION...Ahead of a broad upper trough over the northern US,
0120z observations show a loosely organized squall line stretching
from northeastern PA through eastern NY into western VT. Infrared
satellite trends over the last hour show cloud-top temperatures are
slowly warming with the loss of diurnal heating. Surface obs
indicate temperatures ahead of the ongoing storms across southern NH
and portions of MA and CT have fallen into the 70s F, as the
boundary layer has begun to separate. With weakening buoyancy and
rapidly increasing inhibition, severe storm potential will diminish
as storms track eastward. Isolated damaging wind gusts will likely
remain possible with the strongest convective cores, particularly
over southern NY, east of current active weather watches. However,
widespread severe potential is rapidly decreasing. Convective trends
will be monitored, but no downstream watches are currently planned
owing to the limited nature of the severe threat with eastward
extent.

..Lyons/Grams.. 06/22/2021

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

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

LAT...LON   40937446 41677465 42507429 43297334 43407232 43257197
            42877183 42487179 42167207 41497317 40937446

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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.