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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