806
ACUS01 KWNS 100601
SWODY1
SPC AC 100559
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT WED JUN 10 2026
VALID 101200Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MISSISSIPPI VALLEY AND MIDWEST...
..SUMMARY
SCATTERED TO NUMEROUS SEVERE THUNDERSTORMS WITH POTENTIAL FOR LARGE
HAIL IN EXCESS OF TWO INCHES IN DIAMETER, A FEW STRONG TORNADOES AND
DAMAGING WINDS WITH GUSTS OVER 75 MPH ARE EXPECTED THIS AFTERNOON
AND EVENING ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND
MIDWEST.
..UPPER MISSISSIPPI VALLEY/MIDWEST
AT MID-LEVELS, A TROUGH WILL MOVE EASTWARD INTO THE CENTRAL AND
NORTHERN PLAINS TODAY, AS THE EXIT REGION OF A JET STREAK
OVERSPREADS THE UPPER MISSISSIPPI VALLEY AND MIDWEST. AT THE
SURFACE, A COLD FRONT WILL ADVANCE EASTWARD ACROSS THE NORTHERN
PLAINS WITH A WARM FRONT MOVING INTO THE WESTERN GREAT LAKES.
BETWEEN THESE TWO FRONTS, A VERY MOIST AIRMASS WILL BE IN PLACE WITH
SURFACE DEWPOINTS IN THE LOWER TO MID 70S F. EARLY IN THE DAY, A
LINE OF STRONG THUNDERSTORMS IS EXPECTED TO DEVELOP IN WESTERN IOWA
NEAR THE WESTERN EDGE OF THE MOIST AIRMASS. A POTENTIAL FOR SEVERE
WIND GUSTS WILL BE POSSIBLE WITH THIS LINE. EASTWARD ACROSS THE
MOIST SECTOR, MODERATE TO STRONG INSTABILITY IS EXPECTED TO DEVELOP
BY MIDDAY AS SURFACE TEMPERATURES WARM. THIS WILL HELP THE LINE TO
GROW UPSCALE, POTENTIALLY INTO A LINEAR MCS, AS IT MOVES ACROSS
SOUTHERN WISCONSIN AND NORTHERN ILLINOIS EARLY THIS AFTERNOON.
SEVERE WIND GUSTS AND QLCS TORNADOES WILL BE POSSIBLE ALONG THE
STRONGER PARTS OF THIS LINE SEGMENT.
IN THE WAKE OF THE INITIAL LINE SEGMENT, INSTABILITY IS EXPECTED TO
INCREASE AS MOISTURE ADVECTION AND SURFACE HEATING TAKE PLACE. AN
INSTABILITY AXIS IS FORECAST TO DEVELOP IN THE AFTERNOON FROM
EASTERN MISSOURI NORTHWARD INTO EASTERN IOWA, WHERE MLCAPE SHOULD
INCREASE INTO THE 3000 TO 3500 J/KG RANGE. THUNDERSTORM DEVELOPMENT
WILL BE LIKELY DURING THE MID TO LATE AFTERNOON ALONG A ZONE OF
LOW-LEVEL CONVERGENCE FROM NORTHERN MISSOURI INTO CENTRAL AND
EASTERN IOWA. ADDITIONAL STORMS ARE EXPECTED TO FORM FURTHER NORTH
INTO PARTS OF FAR EASTERN MINNESOTA AND WESTERN WISCONSIN. RAP
FORECAST SOUNDINGS IN THE LATE AFTERNOON FROM EASTERN IOWA INTO
SOUTHWEST WISCONSIN HAVE CURVED HODOGRAPHS, WITH 0-6 KM SHEAR NEAR
40 KNOTS, AND 0-3 KM STORM-RELATIVE HELICITY AROUND 225 M2/S2. THIS
ENVIRONMENT WILL SUPPORT SUPERCELLS WITH TORNADO POTENTIAL. A STRONG
TORNADO OR TWO WILL BE POSSIBLE AS SUPERCELLS MOVE EASTWARD IN A
STRENGTHENING LOW-LEVEL JET DURING THE LATE AFTERNOON AND EARLY
EVENING. LARGE HAIL AND WIND DAMAGE WILL ALSO BE POSSIBLE WITH
SUPERCELLS. FROM THIS CLUSTER, A SECOND SEVERE LINE SEGMENT WITH
DAMAGING WIND GUSTS IS EXPECTED TO DEVELOP. THIS LINE WILL LIKELY
IMPACT PARTS OF NORTHEAST MISSOURI AND NORTH-CENTRAL ILLINOIS.
FURTHER SOUTHWEST ACROSS PARTS OF NORTHWEST/NORTH-CENTRAL MISSOURI
AND NORTHEAST KANSAS, SCATTERED THUNDERSTORM DEVELOPMENT IS EXPECTED
DURING THE LATE AFTERNOON AND EARLY EVENING. THESE STORMS WILL BE
LOCATED NEAR AN AXIS OF STRONG INSTABILITY, ALONG WHICH RAP
FORECASTS SUGGEST THAT 0-6 KM SHEAR WILL BE IN AROUND 40 KNOTS. IN
ADDITION 700-500 MB LAPSE RATES ARE FORECAST TO BE NEAR 7.5 C/KM.
THE ENVIRONMENT SHOULD SUPPORT LARGE HAIL AND SEVERE WIND GUSTS.
..OHIO VALLEY/CENTRAL APPALACHIANS
A MOIST AND UNSTABLE AIRMASS WILL BE IN PLACE TODAY ACROSS MUCH OF
THE REGION, WITH SURFACE DEWPOINTS IN THE LOWER TO MID 70S F.
ALTHOUGH LARGE-SCALE ASCENT WILL BE WEAK, ISOLATED THUNDERSTORMS
APPEAR LIKELY TO DEVELOP IN AREAS WHERE LOW-LEVEL CONVERGENCE
BECOMES MAXIMIZED. FORECAST SOUNDINGS ACROSS THE OHIO VALLEY SHOW
STEEP LOW-LEVEL LAPSE RATES DURING THE AFTERNOON AND HAVE ENOUGH
DEEP-LAYER SHEAR FOR A LOCALIZED SEVERE THREAT. A FEW OF THE
STRONGER CELLS COULD PRODUCE ISOLATED SEVERE GUST AND HAIL.
..BROYLES/LYONS.. 06/10/2026
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