LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0103 AM CDT Sun Jun 18 2023
Valid 181200Z - 191200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM
SOUTHEASTERN ARKANSAS/NORTHERN LOUISIANA SOUTHEASTWARD TO PARTS OF
ALABAMA AND THE FLORIDA PANHANDLE...
...SUMMARY...
Severe thunderstorms are expected on Sunday from The Arklatex area
to the central Gulf Coast states. Damaging gusts and large hail will
be the main hazard with these storms. A severe gust or two may also
occur across eastern Montana.
...Arklatex region across the central Gulf Coast states and
vicinity...
A complex scenario is unfolding for today, as clusters of
strong/severe storms are ongoing across Oklahoma and
southern/western Arkansas which will spread east-southeastward with
time. As this convection continues moving eastward/southeastward
with time, and other storms develop near remnant/associated outflow,
forecasting the timing and location for episodes of strong/severe
storms across the risk area is quite difficult at this time.
With that said, the large-scale setup remains favorable for locally
severe storms, with a very moist boundary layer to become moderately
to strongly unstable away from ongoing storms and associated cloud
cover. This, combined with moderately strong flow through the lower
and middle troposphere, suggests organized/rather fast-moving
storms, including potential for both supercells and linear/bowing
structures.
Given this potential, a 30% potential for wind/hail (i.e. ENH risk)
is being maintained across the lower Mississippi Valley vicinity and
central Gulf Coast region. Again however, details within this
region remain difficult to discern, aside from likelihood for a
primary/early band of storms followed by secondary/later development
later in the period. Various CAMs depict drastically different
convective evolutions -- reflective of the complexity of the
forecast, and thus a more detailed assessment will await later
outlooks.
...Eastern Montana...
As a cold front shifts eastward across Montana during the afternoon,
ahead of a deep upper low drifting slowly southeastward across
Washington state, very weak afternoon destabilization is expected.
The destabilization will result from very deep boundary-layer mixing
through the diurnal peak heating hours. Given this deep/dry
sub-cloud layer, isolated/weak frontal convection that develops may
produce gusty, evaporatively aided outflow winds, before convection
weakens after dark.
..Goss/Flournoy.. 06/18/2023
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