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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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