526
ACUS11 KWNS 202235
SWOMCD
SPC MCD 202235
MAZ000-NHZ000-CTZ000-210030-

Mesoscale Discussion 1348
NWS Storm Prediction Center Norman OK
0535 PM CDT Thu Jun 20 2024

Areas affected...much of Massachusetts and adjacent southern New
Hampshire

Concerning...Severe Thunderstorm Watch 438...

Valid 202235Z - 210030Z

The severe weather threat for Severe Thunderstorm Watch 438
continues.

SUMMARY...A developing cluster of thunderstorms may still pose
increasing risk of producing damaging wind gusts while spreading
southeastward across Massachusetts, perhaps including much of the
Greater Boston vicinity, by 8-9 PM EDT.

DISCUSSION...The boundary layer remains strongly heated (including
surface temperatures near 90F) and characterized by seasonably high
moisture content supportive of mixed-layer CAPE in excess of 2000
J/kg, along pre-frontal surface troughing inland of the southern New
England coast.  This is beneath prominent mid/upper ridging, but
north of the ridge axis, where deep-layer westerly mean flow may be
on the order of 15-20 kt.  Aided by southerly low-level inflow of
the unstable air, strengthening ongoing storms along a corridor
southeast of Albany NY into the Keene NH vicinity may still undergo
further intensification and upscale growth during the next hour or
two.  As this occurs, consolidating southeastward propagating
outflow may be accompanied by increasing risk for potentially
damaging wind gusts into the 00-01Z time frame.

..Kerr.. 06/20/2024

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

ATTN...WFO...GYX...BOX...ALY...

LAT...LON   42427332 42777227 42807188 42827119 42117069 42037161
            41987249 42077327 42427332