LFG
...New England to the Mid Atlantic...
At the start of the forecast period, scattered thunderstorms are
likely to be ongoing near the warm front from southern Quebec
southeastward to southern New England. Insentropic ascent along the
front from a 30-40 kt LLJ will continue to support scattered storms
near the frontal zone through the morning hours as rich
boundary-layer moisture (dewpoints in the upper 60s to low 70s F)
are advected northward. In the wake of the early morning convection,
filtered solar heating will allow for moderate destabilization over
much of New England. Most guidance shows 1500-2000 J/kg of MLCAPE
developing by early to mid afternoon despite only modest low and
mid-level lapse rates. More than sufficient for strong updrafts,
scattered storm development is expected first near the warm front
and subsequently along the trailing surface trough. Deep-layer shear
profiles of 45-60 kt support both supercells and short line
segments. With a favorable parameter space for organized storms,
damaging winds, isolated hail and a few tornadoes are possible.
Confidence in a corridor of locally greater severe risk remains
highest across portions of southern ME, VT, NH and west-central MA.
Here, area model soundings show large curved hodographs with ESRH of
250-350 m2/s2 and STP values of 1.5-3, near the climatological
maximum for the region. With the potential for a mix of supercells
and line segments, the risk for tornadoes appears somewhat higher.
Eventual upscale growth into a linear cluster may also support a
locally greater risk of damaging winds toward the coast later this
evening. Additional storms are possible as the cold front moves
through later this evening, though multiple rounds of prior
convection may limit the severity of any subsequent convection later
this evening.
