|Mesoscale Discussion 1333|
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Mesoscale Discussion 1333
NWS Storm Prediction Center Norman OK
0558 PM CDT Mon Jul 17 2017
Areas affected...Portions of northeastern PA...eastern NY...northern
NJ...CT/MA/VT/NH...and western ME
Concerning...Severe Thunderstorm Watch 417...
Valid 172258Z - 180000Z
The severe weather threat for Severe Thunderstorm Watch 417
SUMMARY...An isolated severe hail/wind threat should continue in and
downstream of remaining valid portions of WW 417 for another hour or
two before diminishing. Additional WW issuance is not anticipated.
DISCUSSION...Ongoing clusters of convection across New England
associated with an upper-level trough have produced sporadic
strong/gusty winds with tree damage and marginally severe hail as
they moved across WW 417 and vicinity this afternoon and early
evening. The airmass downstream of these thunderstorms into eastern
New England is only weakly unstable (MLCAPE generally 500 J/kg or
less), and convective inhibition also increases with eastward
extent. While effective bulk shear values around 30 kt may continue
to support some organization of several ongoing clusters for another
hour or two, the loss of diurnal heating will lead to further
weakening of already marginal instability. The overall severe threat
will therefore continue to diminish this evening, and additional
watch issuance downstream of WW 417 is not expected.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 40907428 40527492 40997606 41417622 42667468 43047386
43407276 43997191 45227066 45797033 45957006 45826961
44447039 42637229 41707329 40907428
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