490
AWUS01 KWNH 170351
FFGMPD
IAZ000-NEZ000-170700-
MESOSCALE PRECIPITATION DISCUSSION 1098
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1150 PM EDT TUE SEP 16 2025
AREAS AFFECTED...WESTERN/CENTRAL IA
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 170349Z - 170700Z
SUMMARY...A FEW SLOW MOVING THUNDERSTORMS WILL CONTINUE AT LEAST A
LOCALIZED FLASH FLOOD THREAT OVER WESTERN IA OVER THE NEXT FEW
HOURS WITH HOURLY RAINFALL OF 1 TO 2+ INCHES.
DISCUSSION...GOES EAST INFRARED IMAGERY WAS CONTINUING TO SHOW
COOLING CLOUD TOPS OVER THE PAST 30-45 MINUTES OVER WESTERN IA
WHERE AN OUTFLOW BOUNDARY WAS BEING OVERRUN BY A 10-20 KT LOW
LEVEL JET. ALOFT, DEEPER LAYER MEAN WIND SPEEDS WERE WEAK,
SUPPORTING SLOW CELL MOTIONS OVER IA WITH MRMS DERIVED RAINFALL
RATES OF 1 TO 2+ INCHES IN AN HOUR SINCE 00Z. WHILE THE STRONGER
UPPER LEVEL FORCING AND LOW LEVEL JET MAGNITUDE WERE LOCATED TO
THE WEST ACROSS NE, A WEAKER BRANCH OF THE LOW LEVEL JET EXTENDED
OVER EASTERN NE INTO WESTERN/CENTRAL IA INTO THE UPPER MS VALLEY,
PROVING SUFFICIENT FOR OVERRUNNING AND SCATTERED LOW MOVING STORMS
WHERE MLCAPE RANGED FROM 500-1500 J/KG VIA 03Z SPC MESOANALYSIS
DATA. CONTINUED AREAS OF SLOW MOVING THUNDERSTORMS WILL CONTINUE
AT LEAST A LOCALIZED THREAT OF FLASH FLOODING OVER THE NEXT 2-4
HOURS WITH INCREASING CONVECTIVE INHIBITION POSSIBLY LOWERING THE
THREAT AFTER 07Z.
OTTO
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...DMX...FSD...OAX...
ATTN...RFC...KRF...MSR...NWC...
LAT...LON 43439448 43189370 42369300 41269400 40999576
41349626 42109652 42559627 43019587 43379520
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