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ACUS01 KWNS 290113

SWODY1

SPC AC 290112



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0812 PM CDT Sun Apr 28 2024



Valid 290100Z - 291200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PART OF

EAST TEXAS...WESTERN TO NORTHERN LOUISIANA...AND SOUTHERN

ARKANSAS...



...SUMMARY...

Severe storms, capable of wind damage, a couple tornadoes and

isolated large hail are likely this evening across parts of east

Texas, northern/central Louisiana and southern Arkansas. A few

severe storms, associated with wind damage and hail will also be

possible in a broader area from the southern Plains and Lower

Mississippi Valley northward to the Ozarks and Lower Missouri

Valley.



...Sabine River Valley/Ark-La-Tex/Southern Plains/Ozarks...

The latest water vapor imagery shows a mid-level trough over the

southern Plains, with southwesterly flow over the Ark-Latex and

lower Mississippi Valley. A shortwave trough, and an associated 50

to 60 knot mid-level jet, appear to be moving through the

Ark-La-Tex. A large cluster of strong to severe storms is ongoing

near this shortwave trough, and to the east of the jet streak, from

east Texas into far northwest Louisiana. This cluster is expected to

move eastward across the remainder of east Texas, and into northern

and western Louisiana this evening, where linear MCS development

will be possible.



The latest surface analysis shows the moist sector, with backed

southeasterly flow, across the Sabine and Lower Mississippi Valleys.

A mesolow is located in the Ark-La-Tex. Surface dewpoints across the

moist sector are in the mid to upper 60s F, with the RAP/observed

RAOBS estimating MLCAPE generally in the 1500 to 2000 J/kg range.

The instability will sustain a large cluster of storms, as it moves

toward the Mississippi Valley this evening. In addition, regional

WSR-88D VWPs at Fort Polk and Shreveport, Louisiana have 0-6 km

shear around 40 knots, with a lot directional shear from the surface

to 4 km above ground level. This will continue to be favorable for a

severe bowing line segment for several more hours this evening. Wind

damage will be likely along the leading edge of the line. If a cold

pool can become organized, then the wind damage threat could become

more widespread. The Fort Polk, Louisiana WSR-88D VWP also has 0-3

km storm-relative helicity around 225 m2/s2 suggesting a tornado

threat will exist with the line, and with the more intense cells

further to the southwest. The more intense semi-discrete storms in

east Texas should be supercellular, having a large hail and isolated

tornado threat. The severe threat is expected to continue for

several more hours, but should become marginal in the late evening

and overnight period. A severe threat will also be possible further

to the north into the Ozarks and lower Missouri Valley, but should

be isolated due to the airmass largely being overturned.



Further to the north and west into central and eastern Oklahoma,

north-central Texas, RAP analysis show moderate instability in

place, with MLCAPE generally from the 1000 to 2000 J/kg. In

addition, the observed sounding at Oklahoma City, and forecast

soundings further to the east have 0-6 km shear generally in the 30

to 45 knot range. This, combined with steep mid-level lapse rates

should support a severe threat early this evening. Hail and isolated

strong wind gusts will be the primary threats. Large-scale

subsidence behind the exiting shortwave trough should keep any

severe threat marginal this evening.



..Broyles.. 04/29/2024



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