Mesoscale Discussion 1329
NWS Storm Prediction Center Norman OK
1220 PM CDT Fri Jun 26 2026
Areas affected...northern and central New England
Concerning...Severe potential...Watch possible
Valid 261720Z - 261915Z
Probability of Watch Issuance...60 percent
SUMMARY...The threat for widely scattered severe storms capable of
large hail, damaging winds, and perhaps a brief tornado is expected
to increase this afternoon. Convective trends are being monitored
for a possible Severe Thunderstorm Watch.
DISCUSSION...Forcing for ascent attendant to a short-wave trough
moving along the St. Lawrence Valley coupled in conjunction with a
warming/ destabilizing, pre-frontal air mass is contributing to
deepening cumulus and early thunderstorm development over the
Adirondack Mountains as of 17z. Cloud breaks within the immediate
downstream air mass along and east of the Champlain Valley area
expected to aid in further air mass destabilization this afternoon
with MLCAPE increasing to 1000 J/kg along and south of a subtle warm
front/ differential heating zone lifting north through VT and NH.
Current expectations are for the ongoing storms to gradually
intensify while spreading east into the discussion area with
additional storm development possible along favored terrain and/or
the warm front. Mid/upper-level wind fields are forecast to
strengthen through the afternoon with an associated increase in
deep-layer shear. Forecast hodographs indicate a largely
unidirectional shear profile, suggesting the potential for splitting
supercells capable of marginally severe hail and locally damaging
wind gusts. While ambient low-level shear is expected to remain
modest, some brief tornado potential could materialize with any
supercell that can favorably interact with the warm front.