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ACUS01 KWNS 070558

SWODY1

SPC AC 070557



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1257 AM CDT Sun Apr 07 2024



Valid 071200Z - 081200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF

FAR EAST TEXAS INTO THE LOWER/MID MISSISSIPPI VALLEY...



...SUMMARY...

Isolated strong to severe thunderstorms appear possible during the

late afternoon to mid-evening from parts of far east Texas into the

lower/mid Mississippi Valley.



...Synopsis...

A deep mid/upper-level cyclone initially centered over the Nebraska

Sand Hills vicinity is forecast to gradually weaken and move

northeastward through the day. A related surface low will also

gradually weaken as it moves from eastern NE toward

northwest/north-central IA. A trailing front will move eastward

across parts of the mid MS Valley into the ArkLaTex region. 



...Lower/Mid Mississippi Valley vicinity...

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. Moderately strong midlevel flow will support

effective shear of 45-55 kt, resulting in a conditionally favorable

supercell environment. However, with stronger large-scale ascent

displaced to the north of the better instability, and only weak to

modest midlevel lapse rates expected regionwide, storm coverage and

intensity will likely be limited to some extent. 



While it may take some time for storms to mature, a couple of

supercells could evolve by late afternoon into early evening across

parts of the lower/mid MS Valley, with more isolated development

eventually possible into far east TX and western LA. Low-level

shear/SRH will be sufficient for a tornado or two, if mature

supercells can be sustained. Otherwise, isolated hail and

strong/damaging gusts could accompany the strongest storms, before

the threat wanes by late evening. 



...Iowa/northern MO...

Low-topped convection may develop this afternoon along an occluded

front that will extend across parts of IA into northern MO/western

IL. Guidance varies regarding the extent of diurnal heating and

destabilization near this front. If sufficient heating and

steepening of low-level lapse rates can occur, then there could be a

nonzero threat for a brief tornado where vorticity is maximized near

the boundary. Confidence in this scenario remains too low to include

probabilities at this time.



..Dean/Bentley.. 04/07/2024



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