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ACUS01 KWNS 280602

SWODY1

SPC AC 280600



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0100 AM CDT Sun Apr 28 2024



Valid 281200Z - 291200Z



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

EAST TEXAS...NORTHWEST LOUISIANA...FAR EASTERN

OKLAHOMA...WESTERN-CENTRAL ARKANSAS AND SOUTHWEST TO SOUTH-CENTRAL

MISSOURI...



...SUMMARY...

Severe thunderstorms are likely today from parts of east Texas and

northwest Louisiana north-northeastward into southwest Missouri.

Damaging winds and a few tornadoes are expected along the stronger

parts of the line. A couple of strong tornadoes could occur from

southwest Arkansas into east Texas. A more isolated severe threat is

expected today over parts of the lower to mid Missouri Valley.



...East Texas/Ark-La-Tex/Ozarks...

A large linear MCS will move eastward across the Ozarks and

Ark-La-Tex early in the period. The line is expected to become

unorganized after daybreak and dissipate by late morning. A moist

and unstable airmass is likely to remain mostly undisturbed across

much of east Texas and Louisiana. This airmass is forecast to advect

northward across the Ark-La-Tex during the afternoon. On the

large-scale, a negatively tilted mid-level trough will move across

the southern and central Plains today. As surface temperatures warm,

thunderstorms will reform along the western edge of the warm sector

by mid-afternoon. The convection is expected to organize into a

line, producing wind damage and hail, moving eastward across the

Ark-La-Tex and Ozarks during the late afternoon. The greatest severe

threat will likely be along the southern half of the line, from

southwest Arkansas and far southeast Oklahoma south-southwestward

into east Texas.



RAP forecast soundings at 00Z/Monday across far southwest Arkansas

and in northeast Texas have MLCAPE ranging from 1500 to 3000 J/kg,

with 0-6 km shear generally from 35 to 45 knots. Also, 0-3 km

storm-relative helicity is forecast to increase into the 200 to 300

m2/s2 range during the late afternoon and early evening, as a 50 to

60 knot low-level jet strengthens. This environment will be

favorable for tornadoes with embedded supercells, and with rotating

elements near the leading edge of the line. A couple of strong

tornadoes will be possible, mainly in the Ark-La-Tex and in east

Texas, where instability is expected to be greatest. Hailstones

greater than two inches in diameter could occur near the southern

end of the line, if a couple supercells can remain semi-discrete.

The more intense bowing segments will likely be accompanied by wind

damage. Although a substantial severe threat is expected as far

south as southeast Texas, there could be a gap in the line across

part of east Texas where the severe threat is locally minimized. On

the northern end of the line in the Ozarks, the magnitude of the

severe threat will be conditional upon destabilization in the wake

of the morning MCS. The severe threat associated with the line

should persist into the late evening as the new MCS approaches the

Mississippi River.



...Lower to Mid Missouri Valley/Mid to Upper Mississippi Valley...

An upper-level trough will move eastward across the lower to mid

Missouri Valley today. Ahead of the trough, a moist airmass will be

in place across much of Missouri northward into southern Iowa. As

surface heating takes place today, thunderstorms are forecast to

develop along the western edge of the moist sector from east-central

Kansas into southeast Nebraska. The storms will move eastward into

Missouri and southern Iowa during the afternoon. RAP forecast

soundings near Kansas City by 21Z have MLCAPE near 1200 J/kg, with

0-6 km shear around 60 knots. This, combined with steep low to

mid-level lapse rates should support a severe threat during the

afternoon. The primary hazards should be wind damage and hail. As

convective coverage increases during the late afternoon and early

evening, a line is expected to organize. Wind damage should become

the primary threat as it approaches the Mississippi River during the

evening.



..Broyles/Thornton.. 04/28/2024



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