SPC AC 201624
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1024 AM CST Thu Jan 20 2022
Valid 201630Z - 211200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not forecast across the contiguous United
States today.
...Synopsis...
In the mid-levels, a positive-tilt shortwave trough initially over
the Midwest/Mississippi Valley will consolidate with a weaker
southern stream perturbation across the Mid-South as they move east
toward the coast today. Apart of the broader central/eastern US
troughing, they should remain behind a surface cold front analyzed
from the central Carolinas to the western Florida Panhandle and
southern Gulf Coast. The airmass ahead of the front is of poor
quality given prior frontal intrusions into the Gulf of Mexico in
the preceding days. The poor phasing of synoptic lift combined with
limited surface moisture ahead of the front suggests thunderstorm
potential onshore will be limited.
...Gulf Coast...
Model soundings show MLCAPE values of less than 250 J/kg across much
of the FL Panhandle, southern MS/AL and the LA Delta. As the front
continues southeast this afternoon, surface moisture and buoyancy
should continue to be removed farther away from the influence of the
approaching mid-level troughs. While a few clusters of weak storms
are expected to move onshore through the early afternoon near the
front, issues with onshore moisture return and poor synoptic lift
suggest overall severe potential will remain negligible.
...Southern Florida...
Isolated thunderstorms will also be possible across far southern
portions of the FL Peninsula and Keys today and tonight. Ahead of
the approaching synoptic front, weak onshore flow across the eastern
shore has allowed some moisture recovery inland. Despite poor lapse
rates and very limited synoptic forcing for ascent, a few
thunderstorms may develop along sea-breeze boundaries through the
afternoon. Displaced from the approaching upper troughs, deep-layer
shear will remain weak, generally below 25 kts. The limited shear
and buoyancy suggests little potential for storm organization.
..Lyons/Grams.. 01/20/2022
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