STWatches coming in a few hours
https://www.spc.noaa.gov/products/md/md1825.html
Mesoscale Discussion 1825
NWS Storm Prediction Center Norman OK
1031 AM CDT Wed Aug 21 2019
Areas affected...Northern Mid Atlantic Coast region through southern
New England
Concerning...Severe potential...Watch possible
Valid 211531Z - 211730Z
Probability of Watch Issuance...60 percent
SUMMARY...Intensifying thunderstorms posing a risk for potentially
damaging wind gusts and, perhaps, an isolated tornado or two, appear
increasingly possible by 2-4 PM EDT. This could require the
issuance of one or two severe weather watches.
DISCUSSION...Convective development appears to be undergoing at
least some gradual intensification, within a narrow band now
overspreading the Champlain and Hudson Valleys, and as far south as
northern New Jersey. This appears to be occurring on the leading
edge of mid-level forcing for ascent associated with a remnant
convectively generated or enhanced perturbation, which is forecast
to progress into and through western and northern New England by mid
to late afternoon. This may be trailed to the southwest by another
area of mid-level forcing for ascent spreading northeastward across
the northern Mid Atlantic Coast region into southern New England.
Based on latest observational data, seasonably moist boundary layer
air may mostly remain confined to the south of a weak surface front,
reinforced by rain-cooled air associated with weakening convection
preceding the main ongoing band. This extends roughly from the
leading edge of the convective band across northern Massachusetts,
though this boundary could shift northward some into and through the
afternoon.
To the south of the front, insolation during the next few hours is
expected to contribute to moderate mixed-layer CAPE of 1000-2000
J/kg, coincident with strengthening of west-southwesterly flow in
the 700-500 mb layer. This may contribute to an environment
increasingly conducive to organized convection by 18-20Z, which
could include further intensification of the ongoing line and
perhaps additional discrete storms, with supercell structures
possible. Although low-level hodographs may be somewhat modest in
size, a tornado or two might not be out of the question, mainly near
the surface boundary across southern New England. Otherwise,
strongest storms probably will pose a risk for potentially damaging
wind gusts.
..Kerr/Guyer.. 08/21/2019
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP...
LWX...