ACUS01 KWNS 210531

SWODY1

SPC AC 210529



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1229 AM CDT Sat Mar 21 2026



Valid 211200Z - 221200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE

SOUTHERN APPALACHIAN REGION...



...SUMMARY...

Isolated strong to severe thunderstorms may produce hail to near 1

inch diameter this afternoon and evening across the southern

Appalachian region.



...Southern Appalachians...



Very strong midlevel anticyclone remains anchored over the

southwestern CONUS. This is forcing meaningful short waves across

the northern Rockies/high Plains before digging southeast toward the

eastern portions of the United States. Early this morning,

water-vapor imagery depicts one of these features digging southeast

across eastern SD/NE. By the start of the period this short wave

will extend across IL/southeast MO/northeast AR, then it will

advance into KY/TN by early afternoon.



At the surface, a weak boundary that is draped across VA-northern KY

will gradually lift north and become somewhat diffuse west of the

higher terrain. South of this wind shift, modest boundary-layer

heating will be noted across the Carolinas into the TN Valley such

that 0-3km lapse rates should exceed 7 C/km by peak heating.

Forecast soundings suggest convective temperatures will be

approached, or breached by 21z as temperatures rise through the

upper 70s to near 80F across southeast KY/eastern TN. While

low-level convergence is expected to be somewhat weak, orographic

influences will contribute to the potential for isolated

thunderstorm development ahead of the short wave. Forecast midlevel

flow is expected to be around 30-35kt across this region at 500mb,

so deep-layer shear may prove adequate for a few supercells. If

robust convection develops in this environment then hail on the

order of 1 inch could be noted with the strongest storms. This

activity will spread southeast into the western Carolinas as the

short wave advances downstream. The primary concern for hail will be

during the afternoon/evening hours.



..Darrow/Wendt.. 03/21/2026



$$