868
ACUS01 KWNS 241243
SWODY1
SPC AC 241242

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0742 AM CDT Tue Sep 24 2024

Valid 241300Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
KENTUCKY INTO SOUTHERN OHIO AND WEST VIRGINIA...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible mainly this
afternoon across portions of the Ohio and Tennessee Valleys into the
central/southern Appalachians.  A few strong/severe storms are also
possible across portions of the southern Plains.

...Ohio and Tennessee Valleys to southern Appalachians...
Water-vapor imagery this morning shows a mid-level vorticity maximum
moving across the middle MS Valley and into the OH Valley.  A belt
of moderate to strong southwesterly 500-mb flow (25-50 kt) will
overspread KY and the surrounding states, with the strongest flow
generally within the Slight Risk bounds.  Bands of showers/weak
thunderstorms are ongoing this morning from middle TN into OH, and
in a separate area over eastern IL immediately ahead of the surface
low.  This low will migrate east-northeast into southern Lower MI by
early evening with a frontal zone extending south-southwest into the
Mid South.  In wake of the early morning convection, some cloud
breaks/destabilization is forecast with upwards of 750-2000 J/kg
MLCAPE from the southern Great Lakes into the southern Appalachian
states.  Ample deep-layer speed shear (via mostly southwesterly flow
through the troposphere) will aid in storm organization into
organized multicells and probably several supercells.  Only notable
change this outlook update was to include portions of the southern
Great Lakes in low-severe probabilities for potential activity
near/ahead of the surface low.  The primary concern across the
general region will likely be damaging winds with the stronger
storms.

...OK vicinity...
An amplifying large-scale trough over the MS Valley will feature a
60-kt 500mb speed max moving southward into the central Great Plains
by early evening on the backside of the upper trough.  Left exit
region of this feature will encourage large-scale ascent, and a weak
surface wave/low should evolve over southwest KS/northwest OK by
early afternoon.  Strong heating will contribute to 750-1250 J/kg
MLCAPE by mid afternoon across OK with flow veering and
strengthening with height.  Elongated hodographs will support the
potential for hail growth with a few of the stronger/sustained
updrafts that evolve.  An isolated threat for large hail (1 to 1.75
inches in diameter) and/or severe gusts (60-70 mph) will probably
peak during the 23z-03z period before storms weaken during the late
evening.

..Smith/Broyles.. 09/24/2024

$$