972
ACUS11 KWNS 091504
SWOMCD
SPC MCD 091503
WIZ000-IAZ000-MNZ000-091630-
MESOSCALE DISCUSSION 1912
NWS STORM PREDICTION CENTER NORMAN OK
1003 AM CDT SAT AUG 09 2025
AREAS AFFECTED...PARTS OF EXTREME NORTHEAST IOWA INTO SOUTHERN AND
CENTRAL WISCONSIN
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 091503Z - 091630Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...SCATTERED DAMAGING WINDS GUSTS ARE POSSIBLE IF THE ONGOING
STORMS CAN INTENSIFY THROUGH MID-AFTERNOON. CONVECTIVE TRENDS ARE
BEING MONITORED FOR THE NEED OF A SEVERE THUNDERSTORM WATCH
ISSUANCE.
DISCUSSION...AN ELONGATED MCS CONTINUES TO GRADUALLY PROGRESS
EASTWARD ALONG A STATIONARY SURFACE FRONTAL BOUNDARY. SMALL BOWING
SEGMENTS ALONG THE IA/MN BORDER HAVE RECENTLY PRODUCED SUB-SEVERE
WINDS, WITH THE MASON CITY, IA ASOS RECENTLY REPORTING RAPID SURFACE
PRESSURE RISES AND A 43 KT GUST. THOUGH SOME ANVIL CIRRUS HAVE
OVERSPREAD SOME OF THE PRECEDING WARM SECTOR, SURFACE TEMPERATURES
ARE WARMING INTO THE 80S F AMID AT LEAST LOW 70S F DEWPOINTS,
YIELDING 1500+ J/KG MLCAPE. DESPITE THE AFOREMENTIONED BUOYANCY, THE
STRONGER DEEP-LAYER SHEAR IS PRIMARILY CONFINED TO THE POST-FRONTAL
ENVIRONMENT, AND IS ORIENTED ROUGHLY PARALLEL TO THE ELONGATED MCS
LEADING LINE. AS SUCH, THERE ARE QUESTIONS REGARDING HOW INTENSE
THIS MCS MAY BECOME THROUGH MID-AFTERNOON, WITH REGIONAL RADAR
IMAGERY SHOWING CONVECTIVE OUTFLOW GRADUALLY UNDERCUTTING THE MCS.
NONETHELESS, GIVEN PRECEDING BUOYANCY, IT IS PLAUSIBLE THAT AN
UPTICK IN DAMAGING GUST POTENTIAL MAY INCREASE PENDING FAVORABLE
SELF-ORGANIZATION OF THE MCS. SUCH CONDITIONS ARE BEING MONITORED
FOR THE SUBSEQUENT NEED OF A SEVERE THUNDERSTORM WATCH ISSUANCE.
..SQUITIERI/HART.. 08/09/2025
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...GRB...MKX...DVN...ARX...DMX...
LAT...LON 42579149 42649188 42769225 42919257 43009272 43139278
43259270 43529205 43849123 43819114 44698903 44738779
43958751 43058784 42778806 42578867 42508961 42579149
MOST PROBABLE PEAK WIND GUST...55-70 MPH
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