883
ACUS11 KWNS 170736
SWOMCD
SPC MCD 170736
IAZ000-MNZ000-SDZ000-171000-
MESOSCALE DISCUSSION 1160
NWS STORM PREDICTION CENTER NORMAN OK
0236 AM CDT WED JUN 17 2026
AREAS AFFECTED...IOWA...FAR SOUTHERN MINNESOTA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 170736Z - 171000Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...A SEVERE THREAT IS EXPECTED TO DEVELOP OVER PARTS OF IOWA
AND FAR SOUTHERN MINNESOTA EARLY THIS MORNING. LARGE HAIL AND
ISOLATED SEVERE WIND GUSTS WILL BE POSSIBLE. WATCH ISSUANCE WILL
LIKELY BE NEEDED, PROBABLY BETWEEN 08Z AND 09Z.
DISCUSSION...A MID-LEVEL SHORTWAVE TROUGH AND AN ASSOCIATED 65 TO 75
KNOT MID-LEVEL JET WILL MOVE EAST-SOUTHEASTWARD INTO THE MID
MISSOURI VALLEY EARLY THIS MORNING. AHEAD OF THE TROUGH, AN 850 MB
JET WILL SHIFT EASTWARD ACROSS IOWA AND STEADILY STRENGTHEN. AS THE
MID-LEVEL JET APPROACHES, LIFT ASSOCIATED WITH THE NOSE OF THE
LOW-LEVEL JET WILL SUPPORT SCATTERED THUNDERSTORM DEVELOPMENT OVER
PARTS OF WESTERN AND CENTRAL IOWA INTO FAR SOUTHERN MINNESOTA. THIS
CONVECTION IS EXPECTED TO BECOME MORE ORGANIZED AS IT MOVES INTO
EASTERN IOWA TOWARD DAYBREAK. AS THE LOW-LEVEL JET STRENGTHENS,
MOISTURE AND INSTABILITY WILL RAPIDLY INCREASE OVER IOWA. MUCAPE
OVER MUCH OF IOWA IS EXPECTED TO REACH THE 2000 TO 3000 J/KG RANGE
JUST PRIOR TO DAYBREAK. THIS, COMBINED WITH 700-500 MB LAPSE RATES
AROUND 8 C/KM, EVIDENT ON FORECAST SOUNDINGS, WILL BE FAVORABLE FOR
SUPERCELLS WITH LARGE HAIL. ALTHOUGH THE STORMS WILL REMAIN
ELEVATED, A FEW STRONG WIND GUSTS WILL ALSO BE POSSIBLE, MAINLY WITH
ANY SUPERCELL THAT CAN BECOME ROBUST.
..BROYLES/GUYER.. 06/17/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...DVN...ARX...MPX...DMX...FSD...OAX...
LAT...LON 43949431 43849299 43649223 43129152 42569125 41509108
41009137 40769205 40749371 40869501 41559583 42689638
43199646 43639624 43869572 43949514 43949431
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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