Valid 281200Z – 291200Z
…NO SEVERE THUNDERSTORM AREAS FORECAST…
Severe thunderstorms are unlikely today, but an isolated strong
storm cannot be ruled out over coastal parts of southern New England
and also across the higher terrain of New Mexico and West Texas.
A seasonably strong upper trough is forecast to move from the Great
Lakes into New England by Thursday morning, as an upstream trough
begins to amplify over the upper Midwest. A deep cyclone will drift
northward toward Hudson Bay, as a smaller-scale surface wave and
attendant cold front move across the northern Plains. NHC is
forecasting Tropical Storm Erin to move northward and then turn
northeastward well off of the New England coast by Thursday morning.
…Southern New England…
As the upper trough and attendant cold front move eastward into the
Northeast later today, a tropical moisture plume extending north of
T.S. Erin will spread northward into southern New England. Buoyancy
inland should remain very limited given poor midlevel lapse rates
and widespread precipitation, but a modest increase in low-level
shear/helicity may support a few weakly rotating cells this
afternoon into the early evening across near-coastal areas of
southern New England. At this time, the potential for appreciable
surface-based destabilization appears too limited for the
introduction of any severe probabilities.
…New Mexico/West TX…
Strong thunderstorms are possible across the higher terrain of NM
and west TX this afternoon into the early evening. Midlevel flow
will remain weak across the region, but light southeasterly surface
flow veering to northwesterly aloft will support effective shear of
20-25 kt, sufficient to support a few weakly organized cells given
the presence of moderate to locally strong instability. The severe
threat appears too limited in coverage and magnitude for the
introduction of any probabilities at this point.