SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Wed May 25 2022
Valid 252000Z - 261200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL GULF COAST STATES AND MIDWEST...
...SUMMARY...
Isolated strong to severe thunderstorms remain possible from the
central Gulf Coast states into parts of the lower/mid Mississippi
Valley, Midwest, and Ohio Valley.
...20Z Update...
The Slight Risk has generally been trimmed behind a line of
thunderstorms ongoing across eastern MS and southeastern LA.
Occasional strong to damaging wind gusts should continue to be the
main threat with this convection as it spreads into parts of
northeastern MS and western AL over the next few hours. See
Mesoscale Discussion 915 for more information.
Low severe probabilities and a corresponding Marginal Risk have been
maintained over much of the lower MS Valley behind the ongoing
activity. Most guidance suggests that additional convection will
form this evening/tonight along and ahead of a cold front as
large-scale ascent associated with an upper low overspreads this
region. Low-level shear appears strong enough for a brief tornado or
two, and isolated strong to damaging winds may also occur if
convection can grow upscale into a line.
No changes have been made to the Slight Risk across parts of
IL/IN/OH and Lower MI. The environment along/south of a warm front
appears conditionally favorable for a mix of multicells and
supercells capable of producing both damaging winds and perhaps a
few tornadoes. But, it remains unclear whether robust convection
will develop across this area through the rest of the afternoon.
..Gleason.. 05/25/2022
.PREV DISCUSSION... /ISSUED 1120 AM CDT Wed May 25 2022/
...IL/IN/OH...
Water vapor imagery shows an upper low over OK, with a
negatively-tilted shortwave trough rotating northward across the mid
MS Valley. Widespread dewpoints in the 60s to lower 70s are present
south of diffuse warm front lifting northward across northern IL/IN,
with broken clouds allowing pockets of daytime heating and
destabilization. However, mid-level lapse rates are not very steep,
limiting afternoon MLCAPE values to generally below 1500 J/kg. The
combination of sufficient CAPE and modest large scale support will
likely lead to widely scattered thunderstorms by mid/late afternoon.
Local VAD profiles and model forecasts show some increase in low
and mid level winds through the day, along with sufficient low-level
shear for a few rotating storms and bowing structures. While the
parameters are subtle, there appears to be some risk of a few
tornadoes across this area later today, prompting the addition of a
SLGT risk.
...MS/LA/AL...
A line of strong/severe storms is tracking eastward across western
MS into a moist and unstable air mass. This line may continue to
pose a risk of locally damaging wind gusts through the afternoon.
Please refer to WW #273 and recent MCD #912 for further details.
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