ACUS01 KWNS 161632

SWODY1

SPC AC 161630



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1130 AM CDT Sat May 16 2026



Valid 161630Z - 171200Z



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

THE CENTRAL HIGH PLAINS AND CENTRAL PLAINS...



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF

THE OHIO VALLEY...



...SUMMARY...

Severe thunderstorms capable of producing large to very large hail,

severe/damaging winds (some 75+ mph), and a few tornadoes should

occur this afternoon and evening across parts of the central Plains

into Iowa.



...Central High Plains into Mid MO Valley...

Recent surface analysis placed a low over southwest KS, with a warm

front extending through a low over far southeast NE to a third low

over southern WI. The low over southwest KS is forecast to fill

while another low develops back farther west across southeast CO

today. As it does, low-level moisture advection will persist across

the central Plains, while a deeper upper trough traverses the

Intermountain West. Combination of low-level convergence east and

north of the surface low and increasing large-scale ascent will

favor thunderstorm development during the late afternoon/early

evening across northeast CO. This initial activity is expected to be

supercellular, with large to very large hail as the primary risk.

This initial activity should be high-based, with strong downdrafts

resulting in a quick transition to a linear mode. Even so, some

tornado risk is still apparent, particularly with the southernmost

supercells that persist through the early evening when a

strengthening low-level jet will lengthen low-level hodographs

considerably. 



Most guidance continues to suggest that an intense bowing cluster,

with significant wind gusts over 75 mph possible, will develop and

spread eastward along/near the warm front from along the southern

NE/northern KS border vicinity through the evening. Given the

organized nature of this line, it should persist throughout most of

the night, and an eastward expansion has been made to the Enhanced

Risk to account for increased probability of strong gusts into more

of southeast NE.



A separate area of intense thunderstorms is anticipated farther east

this afternoon/evening along/near the warm front. Given the ongoing

thunderstorms across northern MO, there is some question to where

the front consolidates this afternoon. Consensus within the guidance

places it from far southeast NE across southern IA, but there is

some chance it ends up a bit farther south in far northern MO.

Robust thunderstorm development is expected along this boundary this

afternoon amid strong low-level moisture advection and heating, and

persistent low-level convergence. Environmental conditions support

supercells capable of all severe hazards, including large to very

large hail (isolated 2"+ inches in diameter) and tornadoes, but a

messy convective mode and related storm interference could disrupt

updrafts and may limit discreteness. Tornado risk will be focused

along/near the front where backed low-level easterly winds may

locally enhance 0-1 km SRH. Some clustering is possible, with an

attendant threat for more damaging gusts wherever this clustering

occurs.



...Mid Mississippi Valley into the Midwest/Ohio Valley...

With the primary shortwave trough well west of the region, mesoscale

features will dominate the severe potential across the region today.

One such feature is the MCV currently moving through southeast MO.

This feature is expected to result in a localized increase in

mid-level flow along its eastern periphery as it progresses

eastward/northeastward along the OH River vicinity. Filtered heating

and/or outflow from the ongoing showers and thunderstorms could

result in a baroclinic zone ahead of this vorticity maximum from

north-central KY into far southern IN. Expectation is that ascent

attendant to the MCS coupled with low-level convergence along this

boundary will result in additional thunderstorm development this

afternoon.



The locally enhanced mid-level flow coupled with modest low-level

southerly flow should result in moderate vertical shear, with

effective bulk shear values from 30 to 40 kt. This is sufficient for

updraft organization, but the mixed boundary layer will likely

support strong downdrafts. The general expectation is for an early

mostly multicell/isolated supercell mode to transition quickly to a

more linear mode with one or more bowing line segments. Isolated

hail is possible early in the convective cycle, with a trend towards

more damaging gusts with time. Given the modest and veered low-level

flow, the tornado potential will be low, but the presence of a

boundary suggests that there remains a low-probability tornado risk.





...Southern High Plains...

Isolated thunderstorms may initiate this afternoon along the surface

dryline from southwest KS into the eastern OK/TX Panhandles and

western OK. While deep-layer shear will be weaker with southward

extent across the southern High Plains, a narrow zone of minimal

MLCIN along/east of the dryline may support isolated convection

capable of producing both locally severe hail and wind gusts.



..Mosier/Bunting.. 05/16/2026



$$