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ACUS02 KWNS 261732

SWODY2

SPC AC 261730



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1230 PM CDT Fri Apr 26 2024



Valid 271200Z - 281200Z



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

THE SOUTHERN/CENTRAL PLAINS...



...SUMMARY...

Numerous severe thunderstorms are likely Saturday into Saturday

night. The greatest severe threat is currently anticipated across

parts of the central and southern Plains, where very large hail,

damaging winds, and multiple strong tornadoes will be possible. A

broader area of potential threat will extend from south-central

Texas north-northeastward to the Great Lakes.



...Synopsis...

A shortwave trough over the Upper Midwest Saturday morning should

further de-amplify as it moves across the Great Lakes through the

day in tandem with a weakening surface low. A large-scale upper

trough over the Southwest will eject across the southern/central

Plains through the period, while an attendant 50-70 kt southwesterly

mid-level jet overspreads these same regions. At the surface, lee

cyclogenesis is expected to occur over western KS through Saturday

afternoon, before the low eventually develops towards central KS

Saturday night. A dryline will extend southward from this low across

the southern/central High Plains, and a warm front will extend

northeastward from the low across the central Plains into the Upper

Midwest.



...Southern/Central Plains...

Most guidance develops thunderstorms early Saturday morning across

northwest TX into central OK. This activity will likely be related

to a subtle mid-level shortwave trough ejecting northeastward across

the southern High Plains, along with ascent along a westward

retreating dryline and warm/moist advection attendant to a southerly

low-level jet. Steep lapse rates aloft fostering moderate to strong

MUCAPE, along with sufficient deep-layer shear, should support some

large hail threat with this early day convection. The potential for

these morning thunderstorms to continue into the afternoon across

central/eastern OK and eastern KS remains uncertain. Even so, some

severe threat may persist with this activity as it spreads eastward.

Fairly meridional flow at low/mid levels suggests a messy mode may

develop, with numerous thunderstorm mergers/interactions possible.



In the wake of this activity, it still appears likely that

substantial destabilization will occur along/east of the dryline and

south of the warm front, with daytime heating of a moist low-level

airmass supporting MLCAPE of 2000-3500 J/kg from north-central KS

southward into parts of western OK and northwest TX. As ascent with

the ejecting upper trough overspreads this warm sector, multiple

attempts at supercell development will likely occur both along the

dryline and warm front, as 40-50 kt of deep-layer shear promotes

robust thunderstorm organization. Any supercells that can form and

persist will be capable of producing very large hail in excess of 2

inches in diameter. With time Saturday evening, a steadily

strengthening low-level jet will foster increased low-level shear,

and greater tornado potential. Multiple strong tornadoes appear

possible during the late afternoon to early evening time frame, as

effective SRH of 150-250+ m2/s2 supports low-level updraft rotation.

Locally greater low-level shear will probably be realized along/near

the warm front Saturday evening, and the Enhanced Risk has been

expanded slightly northward to include more of

south-central/southeast NE. It remains unclear how long a discrete

mode will be able to be maintained, as a tendency for convection to

grow upscale into one or more bowing clusters appears likely

Saturday evening/night. As this mode transition occurs and

convection spreads eastward, a greater threat for severe/damaging

winds will probably be realized across the southern/central Plains.



Due to the influence of the morning convection and potential for

messy storm modes/convective evolution Saturday afternoon,

confidence was not high enough to include greater tornado and/or

hail probabilities across the southern/central Plains at this time.



...Northwest Kansas into Southwest Nebraska and Northeast

Colorado...

Low-level easterly flow will maintain modest low-level moisture

within the post-frontal regime from northwest KS/southwest NE into

northeast CO. Steep midlevel lapse rates will support MLCAPE

increasing to around 500 J/kg, with veering wind profiles with

height through mid levels supporting some potential for organized

convection. A supercell or two could evolve within this regime, with

an attendant threat of large hail and possibly a tornado.



...Upper Midwest/Great Lakes...

A mostly separate regime of at least isolated severe thunderstorm

potential remains evident along/ahead of the front from eastern IA

into parts of the Great Lakes region. While the influence of the

weakening shortwave trough initially over the Upper Great Lakes may

remain mostly displaced to the north of the warm sector, diurnal

heating/destabilization and gradually lessening convective

inhibition may support isolated storm development by late afternoon

along the front. Deep-layer shear will remain sufficient for updraft

organization, supporting a potential for supercells and/or stronger

clusters capable of producing severe hail, damaging gusts, and

possibly a tornado or two. Some increase in storm coverage will be

possible into the evening as the cold front moves southeastward.

Thunderstorms should weaken overnight across this region, though a

stronger cluster to two could move from eastern portions of the

central Plains toward the upper MS Valley before the end of the

forecast period.



..Gleason.. 04/26/2024



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