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ACUS01 KWNS 170101

SWODY1

SPC AC 170100



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0800 PM CDT Tue Apr 16 2024



Valid 170100Z - 171200Z



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

THE MID TO UPPER MISSISSIPPI VALLEY INTO THE SOUTHWESTERN GREAT

LAKES AND LOWER OHIO VALLEY...



...SUMMARY...

Several clusters of strong to severe storms will continue to impact

the mid to upper Mississippi Valley this evening. The severe threat

will affect the southwestern Great Lakes and lower Ohio Valley later

tonight. Damaging wind gusts, isolated large hail, and a few

tornadoes will be possible.



...Mid to Upper Mississippi Valley/Southwestern Great Lakes/Lower

Ohio Valley...

An upper-level low is evident on water vapor imagery over the mid

Missouri Valley, with an associated 60 to 80 knot mid-level jet

located in the mid Mississippi Valley. At the surface, a 989 mb low

is located in far northwest Iowa, with a corridor of maximized

low-level moisture (surface dewpoints in the 60s F) in the mid to

upper Mississippi Valley. A line of strong to severe thunderstorms

is ongoing along a zone of low-level convergence from northwest

Illinois into southern Wisconsin. This line will likely be

maintained, moving east-northeastward to the western shore of Lake

Michigan by late this evening. Ahead of the line, the RAP has MLCAPE

in the 1000 to 1500 J/kg range. WSR-88D VWPs in central and northern

Illinois have 0-6 km shear around 60 knots suggesting the severe

threat will continue this evening. Wind damage will be likely with

the more intense parts of the line, especially with the faster

moving bowing segments. WSR-88D VWPs across central and northern

Illinois have 0-3 storm-relative helicity generally in the 500 to

550 m2/s2 range. This will likely continue to support an isolated

tornado threat with rotating storms that remain somewhat discrete,

or with circulations within the line itself. Isolated large hail

could also accompany the stronger rotating cells.



Further south into the mid Mississippi Valley, the RAP is analyzing

MLCAPE in the 1200 to 1500 J/kg range across much of eastern

Missouri and Arkansas. The instability combined with 0-6 km shear in

the 60 to 75 knot range will likely support a severe threat this

evening. However, large-scale ascent is weaker this far south

suggesting that storm coverage will be isolated. Any cell that can

intensify near the instability axis this evening, could be

associated with wind damage and hail. A marginal tornado threat will

also be possible.



..Broyles.. 04/17/2024



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