280
ACUS11 KWNS 091031
SWOMCD
SPC MCD 091031
IAZ000-091200-
MESOSCALE DISCUSSION 1910
NWS STORM PREDICTION CENTER NORMAN OK
0531 AM CDT SAT AUG 09 2025
AREAS AFFECTED...CENTRAL IOWA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 091031Z - 091200Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...THUNDERSTORMS MAY INCREASE IN COVERAGE AHEAD OF A SURFACE
FRONT THROUGH THE MORNING HOURS. DAMAGING WINDS AND ISOLATED LARGE
HAIL WILL BE POSSIBLE.
DISCUSSION...AN INTENSE HYBRID SUPERCELL/SMALL BOW OVER SOUTHEAST NE
WILL CONTINUE TO TRACK EAST/NORTHEAST THIS MORNING AHEAD OF A
SOUTHEASTWARD SAGGING SURFACE COLD FRONT. IF THIS CONVECTION IS
MAINTAINED, IT WILL MOVE INTO PORTIONS OF WESTERN/CENTRAL IA IN THE
NEXT COUPLE OF HOURS. ADDITIONAL STRONG STORMS ARE ALSO ONGOING
ACROSS PARTS OF NORTHWEST IA AND SHOULD GRADUALLY SHIFT NORTHEAST
TOWARD NORTH-CENTRAL IA.
A VERY MOIST AIRMASS BENEATH STEEP MIDLEVEL LAPSE RATES IS
SUPPORTING A CORRIDOR OF STRONG INSTABILITY AHEAD OF THE SURFACE
FRONT. EFFECTIVE SHEAR MAGNITUDES WILL INCREASE THROUGH THE MORNING,
AIDING IN CONTINUED STORM ORGANIZATION. WHILE THIS CONVECTION WILL
BE MOVING INTO THE REGION DURING A CLIMATOLOGICALLY UNFAVORABLE TIME
OF DAY, WIDESPREAD SEVERE GUSTS HAVE BEEN NOTED WITH THE ONGOING
STORM ACROSS SOUTHEAST NE OVER THE PAST COUPLE OF HOURS, LIKELY IN
PART DUE TO THE LARGE RESERVOIR OF INSTABILITY IN PLACE. A NEW WATCH
DOWNSTREAM FROM WW 579 MAY BE NEEDED IN THE NEXT HOUR IF CURRENT
TRENDS UPSTREAM CONTINUE.
..LEITMAN.. 08/09/2025
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...DMX...FSD...OAX...
LAT...LON 41119483 41109528 41389561 41869576 42719509 43449422
43429348 42969311 42219311 41579326 41259398 41119483
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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