Valid 061200Z – 071200Z
…THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE
FLORIDA PANHANDLE TO NORTH CAROLINA…
Severe thunderstorms are expected to spread from the northeast Gulf
Coast this morning to the Carolinas by early evening. Damaging winds
could be common with this activity, and a few tornadoes are also
…Northeast Gulf Coast to the Carolinas…
Strong low-latitude trough is beginning to shift east across the Big
Bend of TX/northeast Mexico as a pronounced mid-level speed max
approaches the base of this feature. By mid day, 500mb speed max in
excess of 100kt will translate into the lower MS Valley, then
strengthen to near 140kt over the Carolinas by 27/12z. In response,
intense 12hr mid-level height falls (200m) will spread across the
northern Gulf States into the western Carolinas.
LLJ is forecast to strengthen across the northern Gulf Basin into
southern AL by sunrise Thursday. This will encourage boundary-layer
moistening with upper 60s surface dew points expected to advance
inland across southern AL/GA, with near 70F dew points across the FL
Panhandle. This moistening will be more than adequate for
substantial SBCAPE ahead of the surging cold front. Latest thinking
is scattered-numerous thunderstorms will be ongoing along the front
at the start of the period. As large-scale forcing approaches this
region, a sharpening band of frontal convection should evolve. Given
the strengthening wind fields there is increasing confidence that a
potentially damaging squall line will race northeast across the ENH
Risk area. In addition, a few pre-squall line supercells may also
develop as minimal forcing will be needed to initiate convection.
Tornado threat will be most concentrated with these more discrete
structures, though embedded squall-line circulations are also
expected given the shear.
A well organized squall line should progress across GA/northern FL
into the Carolinas during the evening hours. This linear MCS should
advance off the NC Coast shortly after midnight.