MIL-OSI USA: SPC Oct 28, 2021 1300 UTC Day 1 Convective Outlook

1

Source: US National Oceanic and Atmospheric Administration

SPC AC 281237

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0737 AM CDT Thu Oct 28 2021

Valid 281300Z – 291200Z

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FLORIDA TO
THE CAROLINAS…

…SUMMARY…
Severe thunderstorms will be possible across Florida and southern
Georgia today, and into the Carolinas tonight. Damaging winds and a
few tornadoes are possible.

…Southeast States including Florida to Carolinas…
A prominent upper low/trough centered over the Ozarks will continue
eastward today toward the Tennessee Valley, with a very strong
(70-100 kt at 500 mb) and diffluent cyclonic belt of westerlies
overspreading the coastal Southeast States through tonight. Multiple
corridors of thunderstorms are ongoing this morning near/ahead of an
eastward-moving cold front over the east-central Gulf of Mexico,
with a preceding warm front draped near the coastal Gulf of Mexico
portion of northern Florida, southeastward into the central/southern
Florida Peninsula.

An increasingly moist air mass will continue to spread
north-northeastward across much of the Florida Peninsula in tandem
with the advancing warm front, an air mass that will become
increasingly conducive to surface-based storms over inland areas
into mid/late morning and afternoon. For additional short-term
details, see Mesoscale Discussion 1921. Pre-existing clouds and
precipitation will tend to hinder overall destabilization,
especially across the far northern Florida Peninsula into southern
Georgia, with somewhat stronger heating and destabilization expected
across the middle/southern part of the Florida Peninsula by
afternoon.

Strengthening deep-layer winds will support a combination of some
semi-discrete supercells as well as organized bands of convection
across much of the Florida Peninsula, and possibly nearby portions
of southern/coastal Georgia. Damaging winds and a few tornadoes will
be possible through around sunset in these areas.

Farther north, as the warm front moves inland along the coastal
Carolinas, wind profiles will become increasingly supportive of
supercells as very strong surface-6km shear and SRH will be present
across this region by early evening. Although the inland extent of
warm-sector destabilization is a bit uncertain (especially into
Piedmont areas), damaging winds along with a tornado risk will be
possible with line segments/supercells, particularly for coastal
areas of the Carolinas tonight.

..Guyer/Kerr.. 10/28/2021

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