LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1250 AM CDT Tue Jun 20 2023
Valid 201200Z - 211200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...AND PARTS OF THE LOWER MISSISSIPPI VALLEY AND
SOUTHEAST...
...SUMMARY...
Isolated to scattered severe thunderstorms appear possible across
parts of the Southeast and northern Plains today. Damaging winds and
large hail should be the main threats.
...Synopsis...
A highly amplified flow field aloft will prevail across the U.S.
today, with a sharp trough over the West and a low over the
Southeast, flanking a ridge extending from Texas to the Upper Great
Lakes.
At the surface, a weak baroclinic zone is progged to lie in an
east-to-west manner across the Southeast/Gulf Coast states, and then
turning northwestward across Texas to the central High Plains area.
Meanwhile, a second cold front will make very gradual eastward
progress across the Dakotas/Wyoming through the period.
...Northern Plains...
Afternoon thunderstorm development is initially expected over the
central Wyoming vicinity, with isolated storms then moving quickly
northeastward. These storms would be accompanied by some potential
for strong/gusty winds locally. By early evening, additional storm
development is expected farther east, within the more unstable
airmass along the surface cold front. With the eastern fringe of
stronger mid-level southwesterlies expected to extend east atop the
surface frontal zone, and a southerly low-level jet increasing
through the evening, shear will support organized/rotating storms,
accompanied by risks for severe-caliber hail/wind. While convection
should diminish somewhat in coverage by late evening and into the
overnight hours, local severe risk may persist through Wednesday
morning, with lingering convection.
...Arklatex and Sabine River Valley east to southern Georgia and
Florida...
Widespread storms are expected once again today across portions of
the Southeast and lower Mississippi Valley, as a very moist boundary
layer -- destabilizing through the afternoon -- persists near and
south of a weak surface baroclinic zone. While some risk for severe
weather will exist as far east as Georgia/Florida, the greatest
potential -- mainly in the form of damaging winds -- will likely
occur from the Louisiana vicinity east to the Mobile Bay area.
Here, stronger northwesterly cyclonic flow aloft -- around the back
side of the upper low parked over the Mid South -- is expected.
Episodes of strong/locally severe storms through much of the period.
..Goss/Wendt.. 06/20/2023
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