982
ACUS48 KWNS 110929
SWOD48
SPC AC 110928

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0328 AM CST Thu Dec 11 2025

Valid 141200Z - 191200Z

...DISCUSSION...
Latest medium-range model output indicates that the amplified
trough, likely digging through the lower Great Lakes and Ohio Valley
at the outset of the period, will continue rapidly digging across
the U.S. Atlantic Seaboard, before pivoting offshore and supporting
strong cyclogenesis through the northwestern Atlantic into early
next week. In its wake, an initially expansive cold surface ridge,
centered near the mid/lower Missouri Valley, may gradually weaken,
but is forecast to continue southeastward into and across the
offshore Atlantic, Florida Peninsula and much of the northern Gulf
Basin.

Thereafter, it still appears that mid/upper flow may trend more
zonal, particularly across the northern U.S. and southern Canada,
downstream of a blocking high that is forecast to be maintained, but
become suppressed to the south of the Aleutians.  Short wave
developments embedded within this regime remain uncertain, but there
is still at least some signal that a developing southerly return
flow may support a modest influx of moisture off the northwestern
Gulf by the middle of next week.  This could contribute to
thunderstorm development across parts of the Mid South through
portions of the lower Ohio and Tennessee Valleys Wednesday into
Thursday, ahead of a modest cold front.  However, at this time, it
appears that some combination of weak/limited destabilization and
modest shear/forcing for ascent will tend to minimize the risk for
severe storms.

..Kerr.. 12/11/2025