700
ACUS11 KWNS 131227
SWOMCD
SPC MCD 131227
IAZ000-ILZ000-131430-
MESOSCALE DISCUSSION 1966
NWS STORM PREDICTION CENTER NORMAN OK
0727 AM CDT THU AUG 13 2026
AREAS AFFECTED...PARTS OF CENTRAL/SOUTHEASTERN IOWA AND ADJACENT
ILLINOIS
CONCERNING...SEVERE THUNDERSTORM WATCH 581...
VALID 131227Z - 131430Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 581
CONTINUES.
SUMMARY...THE CLUSTER OF STORMS HAS UNDERGONE GENERAL WEAKENING, BUT
COULD STILL POSE A RISK FOR STRONG TO SEVERE WIND GUSTS ALONG AND
SOUTH OF THE I-80 CORRIDOR, EAST OF DES MOINES TOWARD THE
MISSISSIPPI RIVER, THROUGH 9-10 AM CDT.
DISCUSSION...COLDEST CLOUD TOPS IN INFRARED SATELLITE IMAGERY AND
PEAK LIGHTNING FLASH RATES HAVE GENERALLY BEEN MAINTAINED INTO THE
DES MOINES VICINITY, BUT THE CONVECTIVE SYSTEM HAS BECOME LESS
ORGANIZED LOOKING IN RADAR LOOPS. THE PRIMARY MCV AND WESTERLY REAR
INFLOW TO ITS SOUTHWEST HAVE UNDERGONE RECENT WEAKENING. HOWEVER,
ANOTHER NOTABLE CYCLONIC CIRCULATION HAS DEVELOPED TO THE
EAST-SOUTHEAST (NOW TO THE NORTHEAST OF DES MOINES), WITHIN
CONTINUING STRONGER THUNDERSTORM DEVELOPMENT FOCUSED NEAR/ABOVE THE
LEADING EDGE OF A DEVELOPING AREA OF 2-HOURLY SURFACE PRESSURE RISES
ON THE ORDER OF 2 MB. THIS MAY CONTINUE POSE THE MOST PROMINENT
RISK FOR A SWATH OF STRONG TO SEVERE SURFACE GUSTS NEAR THE I-80
CORRIDOR EAST OF DES MOINES THROUGH 14-15Z. IT DOES NOT APPEAR OUT
OF THE QUESTION THAT ANOTHER SIMILAR CIRCULATION COULD STILL EVOLVE
WITHIN TRAILING CONVECTION NOW TO THE SOUTHWEST THROUGH SOUTH OF DES
MOINES.
..KERR.. 08/13/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...DVN...DMX...
LAT...LON 42189285 42199165 41779088 41429074 40889130 40659186
40809275 40769373 41139402 41709281 42189285
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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