Valid 121300Z – 131200Z
…NO SEVERE THUNDERSTORM AREAS FORECAST…
Severe thunderstorms are not expected today or tonight.
The dominant upper-air feature over the CONUS will remain a large,
stacked, occluded, deep-tropospheric cyclone, now centered over
northwestern MN. Its low will move slowly eastward to
east-northeastward through the period, reaching the northwestern
“Lakehead” region of Lake Superior by 12Z. The associated surface
cold front — analyzed at 11Z from near BUF across western PA,
eastern TN, south-central AL, and the northwestern Gulf — should
reach the eastern Mid-Atlantic region, central Carolinas,
northern/central GA, and western FL Panhandle by 00Z. The
southeastern CONUS segment of the front should decelerate/stall
through tonight, while the northern part proceeds offshore from the
Mid-Atlantic and offshore from most of New England.
Isolated thunderstorms have been evident near the front across the
Gulf coast region of southwestern AL, extreme southeastern MS, and
the southeastern LA river mouth region during the last few hours.
This potential will shift southward and weaken gradually through
today, as frontal lift diminishes, amidst modest deep-layer lapse
rates. Overnight, strengthening/elevated low-level warm advection,
moisture transport, and isentropic lift will foster scattered
showers and perhaps isolated, weak thunderstorms in a corridor
located mainly on the cold side of the front, from eastern AL to
parts of the western Carolinas. Isolated thunderstorms also are
possible in a weakly forced but favorably moist/buoyant air mass
over and near the southern Straits of Florida.