364
ACUS48 KWNS 170841
SWOD48
SPC AC 170840

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0340 AM CDT Sat May 17 2025

Valid 201200Z - 251200Z

...DISCUSSION...
...Day 4/Tuesday...
As the primary mid-level trough shifts east on Tuesday, scattered
severe thunderstorms are likely across parts of the Mid-Mississippi
Valley into the Tennessee Valley. Upper 60s to low 70s dewpoints
will be present ahead of a cold front. Convection/cloud cover from
Day 3 convection across the Plains/Ozarks will impact
destabilization across Kentucky and into the Ohio Valley. However,
farther south, strong destabilization is likely as the boundary
layer heats beneath steepening mid-level lapse rates. 50 to 60 knots
of mid-level flow will overspread this unstable warm sector during
the afternoon Tuesday. As this occurs, an uncapped boundary layer
and synoptic scale ascent should combine for scattered severe storm
development. Wherever moderate to strong instability develops, most
likely south of the TN/KY border, supercells are anticipated with a
primary threat for large hail. By later in the evening, storms may
congeal into a MCS with an increasing damaging wind threat.

...Day 5/Wednesday...
A cold front will advance across the Appalachians on Tuesday
night/Wednesday morning. Moderate instability is forecast ahead of
this cold front Wednesday morning/early afternoon. A few strong to
severe storms may develop along the front before it moves into the
Atlantic. However, the limited duration of this threat, and
potential for timing shifts as newer guidance arrives, precludes
severe weather probabilities at this time.

...Day6-8..
A relatively benign severe weather pattern is expected from
Thursday/Day 6 into next weekend as a cold front pushes into the
Gulf. A few storms are possible along the cold front as it moves
south along the Florida Peninsula on Thursday. Otherwise, more
robust moisture recovery will begin Thursday night. Overall,
moisture quality will be low initially, but eventually some threat
may develop across the Plains as low-level moisture advection
continues.

..Bentley.. 05/17/2025