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ACUS01 KWNS 010607

SWODY1

SPC AC 010606



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0106 AM CDT Mon Apr 01 2024



Valid 011200Z - 021200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE

SOUTHERN PLAINS TO THE OZARKS AND INTO FAR WESTERN INDIANA....



...SUMMARY...

Severe weather is expected to occur over a broad region from the

southern Plains, the Ozarks, portions of the Ohio Valley, and into a

small part of the Mid-Atlantic. Large to very large hail, damaging

winds, and tornadoes (some strong) are possible. The severe threat

will peak this afternoon/evening in the southern Plains with the

greatest threat for the Ohio Valley vicinity being the

evening/overnight period.



...Synopsis...

A large, positively tilted upper-level trough will shift east from

the Southwest to the central Plains today. A mid-level shortwave

trough, currently rounding the base of the large scale trough, will

advance quickly northeast through the day today within a strong

mid-level jet. This strong flow will overspread a broad, very moist

warm sector and lead to severe weather across a large portion of the

Southern Plains into the Midwest.



A surface low is present across eastern Colorado this morning with a

stationary front extending eastward across Kansas and Missouri and

into the Ohio Valley. This surface low will drift slowly east

through the day and the front is expected to lift north across

Missouri as a warm front during the afternoon. 



...North Texas, central and eastern Oklahoma, southeast Kansas, and

the Ozarks...

Mid 60s dewpoints are expected across much of the warm sector east

of the dryline by mid-day today with temperatures warming into the

70s to low 80s. Moderate to strong instability is expected to

develop by the time ascent associated with the approaching trough

overspreads the dryline. Once this occurs, expect rapid storm

development along the dryline from southern Kansas to north Texas.

Very strong shear, and mostly straight hodographs will support

splitting supercells initially capable of large to potentially giant

hail across a broad region from southwest Missouri to north Texas.

Storm evolution off the dryline is still somewhat uncertain. Some

guidance depicts more discrete development off the dryline and the

potential for multiple rounds of supercells, while other CAM

guidance waits until closer to 00Z to convect and leads to upscale

growth and significant storm interaction within the first few hours.

This evolution will have a significant impact on the longevity of

the giant hail threat, but even with a messy storm mode, very large

hail will remain a threat.



Low-level shear is expected to be very weak for much of the day,

which will limit the tornado threat. However, by the evening, the

low-level jet is expected to strengthen with the ejecting wave and

low-level shear will improve. The most favorable hodographs are

expected across northeast Oklahoma into southeast Kansas and

southwest/central Missouri in a region where mature supercells will

likely be ongoing. Therefore, a more favorable period for tornadoes

and potentially strong tornadoes may exist from 23-03Z as the

low-level shear improves.  



...Eastern Missouri into southern Illinois...

At least isolated supercells are expected to develop along the warm

front from northern Missouri into central Illinois this afternoon

and evening. Strong instability and very strong shear will support

large to very large hail. In addition, storm motion is expected to

be parallel to the surface front. Therefore, any supercells which

can latch onto the warm front will have a higher tornado threat.

However, more isolated storm coverage and uncertainty regarding

storm evolution preclude higher tornado probabilities in this

region. 



Later in the evening and into the overnight hours, storms from the

west will move into the region with a threat for large hail, a few

tornadoes, and severe wind gusts. 



...Ohio River Vicinity...

Supercells from Illinois may continue east along the warm front into

the evening across southern Indiana and potentially southern Ohio.

Additional storms may also develop along this frontal zone with a

primary threat of large hail. Weaker instability/shear should limit

the overall threat from these storms compared to farther west.

However, moderate instability and strong shear will support a threat

for large hail, damaging wind gusts, and perhaps a tornado. 



Overnight, a cluster of storms is expected to approach from the

west. The overnight environment will continue to support a severe

threat with 1500 J/kg MLCAPE and effective shear in excess of 50

knots. There is still considerable uncertainty how this cluster will

evolve. A cluster of supercells would pose a threat for all severe

weather hazards, while a more organized MCS may support a greater

severe wind and QLCS tornado threat. 



...Central Texas...

Strong instability is expected to develop ahead of a dryline across

central Texas this afternoon. Confluence along the dryline and weak

height falls should provide ample support for isolated to scattered

storm development. Any storms which develop will be capable of very

large to giant hail, given very strong instability and shear an

expected supercellular storm mode.



..Bentley/Darrow.. 04/01/2024



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