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ACUS01 KWNS 010102

SWODY1

SPC AC 010100



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0800 PM CDT Tue Apr 30 2024



Valid 010100Z - 011200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE

SOUTHERN PLAINS NORTH-NORTHEASTWARD INTO THE UPPER MISSISSIPPI

VALLEY...



...SUMMARY...

Severe storms, capable of large hail (possibly above 2 inches in

diameter), damaging wind gusts, and a few tornadoes are expected

this evening from the upper Mississippi Valley south-southwestward

into the southern Plains.



...Central Plains/Lower Missouri Valley/Upper Mississippi Valley...

The latest surface analysis has a 1002 mb low over southwest Iowa,

with a narrow corridor of maximized low-level moisture from near the

low southwestward into eastern Kansas. The RAP has moderate

instability along this corridor with MLCAPE estimated to be in the

1500 to 3000 J/kg range. Scattered strong to severe storms are

ongoing along and near the instability axis. These storms will

continue to move eastward toward the upper Mississippi Valley and

Ozarks this evening. In addition to the instability, WSR-88D VWPs

near the instability axis from northwest Missouri southwestward into

southeast Kansas have 0-6 km shear in the 35 to 40 knot range.

Within this area, RAP forecast soundings suggest that 700-500 mb

lapse rates are in the 7 to 7.5 C/km range. This will continue to be

favorable for supercells with large hail over the next few hours.

The more dominant supercells could produce hailstones greater than 2

inches in diameter. Strong low-level shear was also evident on the

WSR-88D VWPs suggesting a few tornadoes could develop. Severe wind

gusts also could occur with supercells or short line segments. The

severe threat is expected to continue through much of the evening,

but should become more isolated and marginal, especially toward late

evening.



...Southern Plains...

Westerly mid-level flow is evident on water vapor imagery over the

southern Plains this evening. At the surface, a moist airmass exists

throughout much of Texas and Oklahoma. Scattered thunderstorms are

ongoing to the east of a dryline, near the western edge of the moist

airmass, from western Oklahoma into west-central Texas. The 00Z

soundings at Norman and Midland are showing MLCAPE in the 2000 to

3500 J/kg range. Regional WSR-88D VWPs show moderate deep-layer

shear over much of the southern Plains, with 0-6 km shear generally

in the 40 to 45 knot range. This, along with 700-500 mb lapse rates

near 7.5 C/km, will support supercell development this evening, with

a potential for large hail. Hailstones of greater than 2 inches in

diameter will be possible with the more intense cells. An isolated

tornado threat could continue in southwest Oklahoma for another hour

or so. A few damaging wind gusts could also occur. The severe threat

should become more isolated during the mid to late evening, as a cap

begins to build in across much of the southern Plains.



...Mid-Atlantic To Far Southwest New England...

The latest radar imagery shows a cluster of strong to severe

thunderstorms located over far eastern Pennsylvania and northwestern

New Jersey. This cluster was located just to the north of a 1009 mb

low, along the northeastern edge of a pocket of maximized low-level

moisture. Within this pocket, surface dewpoints are in the mid to

upper 50s F, an MLCAPE is estimated to be in the 250 to 500 J/kg

range, according to the RAP. This cluster of storms should weak, as

it moves east-southeastward toward the coast this evening. A few

marginally severe wind gusts will be possible.



..Broyles.. 05/01/2024



$$