ACUS01 KWNS 071240
SWODY1
SPC AC 071239

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0739 AM CDT Sun Apr 07 2024

Valid 071300Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MAINLY
ADJACENT PORTIONS OF WESTERN KENTUCKY AND TENNESSEE AND SOUTHEAST
MISSOURI...

...SUMMARY...
Widely scattered severe thunderstorms are possible during the late
afternoon to mid-evening in the lower/mid Mississippi Valley.

...Lower/Mid Mississippi Valley vicinity...
Early morning surface analysis places the northern rim of 60+ deg F
surface dewpoints across the Arklatex in advance of a cold
front/dryline located in the Ozarks. The deep-layer cyclone located
over the north-central Great Plains will move little during the
period. Low-level moistening in advance of the cold front will
allow for weak to moderate destabilization across parts of the
lower/mid MS Valley, with MLCAPE generally increasing into the
500-1000 J/kg range this afternoon. A belt of strong midlevel
westerly flow will support effective shear of 45-55 kt, more than
adequate for updraft organization. Only weak large-scale ascent is
expected across the region with the stronger forcing for ascent
displaced to the north-northwest over IA/upper MS Valley, which
lends some uncertainty on storm coverage/intensity. Nonetheless,
model progs show isolated to scattered storm development during the
late afternoon through the mid evening across the lower/mid MS
Valley. Adequately enlarged hodographs (200 m2/s2 0-3 km SRH)
beneath strong west-southwesterly mid to high-level flow, coupled
with seemingly sufficient low-level moisture/buoyancy, suggest a few
supercells may evolve near the confluence of the MS/OH Rivers into
far western TN during the 22-02z period. A tornado risk may develop
with one or two sustained supercells, in addition to large hail
potentially accompanying the stronger storms. The loss of
instability will lead to a decreasing severe threat by late evening.

...Iowa...
The latest model guidance indicates at least isolated storm
development this afternoon arcing along the occluded
front over IA. Low-level moisture will likely remain limited with
surface dewpoints in the mid to upper 40s. However, cold mid-level temperatures associated with the mid-level low centered over the
NE/SD border, will aid in weak instability developing by midday. A
narrow corridor of overlapping large 0-3 km MLCAPE (100-150 J/kg)
and low-level vorticity may yield a couple of storms capable of an
isolated severe risk during the afternoon.

..Smith/Mosier.. 04/07/2024

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