LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1153 PM CST Sun Feb 26 2023
Valid 271200Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE OHIO VALLEY...
...SUMMARY...
Thunderstorms may produce damaging gusts across the Ohio Valley
today. At least a few tornadoes are also possible, especially across
Ohio this afternoon.
...Synopsis...
A potent mid-level trough will quickly overspread the OH Valley as a
986 mb surface low traverses the Great Lakes region today. A narrow
line of thunderstorms should be ongoing at the start of the period
along the cold front near the MS River and is poised to rapidly
progress eastward through the day. During the first half of the
period, a 50+ kt low-level jet will advect a marginally
moist/buoyant airmass into the OH Valley ahead of the surface
low/line of storms. Strong westerly flow atop the southerly
low-level jet will promote strong vertical wind shear, that in
tandem with the marginal buoyancy will promote a risk for severe
thunderstorms across the OH Valley during the afternoon.
...OH Valley...
Widespread clouds and at least scattered thunderstorms are
anticipated across the warm-sector in association with the warm-air
advection regime, hampering more robust low-level instability from
materializing through at least early afternoon. Nonetheless, latest
guidance consensus shows a brief period of diurnal heating across
the OH Valley in advance of an approaching band of low-topped
storms. Ahead of the storms, temperatures may warm to 60 F amid
upper 50s F surface dewpoints, contributing to short, thin MLCAPE
profiles. However 850 mb southwesterly winds at 50+ kts overspread
by 60-70 kts of west-southwesterly flow will contribute to
relatively long and curved hodographs, suggesting that both
deep-layer and low-level shear will be abundant. As the low-topped
line of storms progresses eastward through the afternoon, small
bowing segments and transient supercell structures may develop, with
damaging gusts possible. The best chance for low-topped supercells
and associated tornadoes would be across OH during the mid to late
afternoon hours, where an optimal overlap of strong low-level
shear/moisture may take place. Should greater than expected diurnal
heating and moisture return occur, a locally higher tornado threat
may materialize. Storms should weaken by early evening as they
approach the Appalachians and outpace any surface-based buoyancy.
..Squitieri.. 02/27/2023
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