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ACUS02 KWNS 291733

SWODY2

SPC AC 291731



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1231 PM CDT Mon Apr 29 2024



Valid 301200Z - 011200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHWEST

MN...WESTERN IA...FAR NORTHWEST MO...EASTERN KS...EASTERN NE AND FAR

SOUTHEAST SD...



...SUMMARY...

Severe thunderstorms will be possible on Tuesday from parts of the

mid/upper Mississippi Valley into the central/southern Plains. The

greatest threat is expected from eastern Nebraska into parts of

western Iowa and southwest Minnesota, with a risk of very large

hail, severe wind gusts, and a few tornadoes.



...Synopsis...

An upper cyclone is forecast to be centered over southeastern

British Columbia/southwest Alberta early Tuesday morning. A series

of shortwave troughs are expected to traverse the moderate mid-level

flow is extended throughout the base of this cyclone. The lead wave

in this series will likely move from the central High Plains

northeastward across the northern/central Plains into the Upper

Midwest throughout the day, accompanied by gradually strengthening

mid-level flow. A weak cold front and associated surface troughing

will precede this shortwave, with consolidation into more prominent

low anticipated from the Mid MO Valley into the Upper Midwest during

the afternoon and evening. Northern portion of this front near the

surface low will remain progressive, continuing eastward through the

Upper Midwest overnight. However, southern portion of the front will

slow and eventually stall across KS, with additional surface

cyclogenesis possible along the western portion of this boundary

over western KS and the eastern TX/OK Panhandles.



Farther east, a shortwave trough is expected to gradually shift

eastward from the Lower OH Valley/Mid-South across the TN Valley and

Southeast states, reaching the Mid-Atlantic States by early

Wednesday morning. Some phasing between this wave and a separate

low-amplitude shortwave farther north over the Lower Great

Lakes/southwestern Ontario is possible. Isolated thunderstorms are

anticipated ahead of both of these waves across much of the eastern

CONUS (i.e. from the Upper OH Valley/Northeast States into the

Southeast). However, limited buoyancy and weak shear should temper

the overall severe potential across the majority of the area,

although a locally increased risk is possible from central NY

through eastern PA and from eastern GA through SC.



...Mid MO Valley into Eastern KS...

Low-level moisture is expected to advect quickly northward

throughout the day, ahead of the approaching shortwave trough and

associated surface trough/cold front. Consensus among the guidance

brings low 60s dewpoints into the northeastern KS/northwest

MO/southeastern NE border vicinity by the mid afternoon, with upper

50s  northward along the NE/IA border. This low-level moisture

combined with modest daytime heating and steep mid-level lapse rates

will support moderate buoyancy (i.e. 1500 to 2000 J/kg).

Thunderstorm development is anticipated along the front during the

afternoon, beginning across eastern SD/southwestern MN then

extending southwestward across eastern NE. Given the moderate

buoyancy, robust updrafts should develop quickly, and vertical shear

will be strong enough to support organized storm structures. Large

to very large hail is likely with initial development before the

storms undergo a relatively quick upscale growth, with the

transition to a more linear mode favoring strong gusts. Some gusts

to 75 mph are possible. The tornado threat is a bit more complex.

There is enough low-level curvature to support tornadogenesis, but

the overall potential may be limited by the quick upscale growth and

relatively short time duration storms will be in a discrete mode.

That being said, some tornado threat is possible within the line as

well, particularly across western IA during the early evening (i.e.

around 00Z) as the low-level jet increases. 



...Central KS southwestward across Western OK into Southwest TX...

Most of the stronger large-scale forcing for ascent is anticipated

farther north, but persistent low-level convergence along the

dryline could result in isolated to widely scattered thunderstorm

initiation. Any storms that mature could produce large to very large

hail and damaging downbursts. Guidance has trended towards a bit

more thunderstorm coverage from northwest into southwest TX, but the

lack of stronger large scale forcing limits forecast confidence,

precluding the introduction of higher probabilities with this

outlook.



..Mosier.. 04/29/2024



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