Flash Flood Guidance
Issued by NWS

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000
AWUS01 KWNH 260909
FFGMPD
WIZ000-MNZ000-261400-

MESOSCALE PRECIPITATION DISCUSSION 0566...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
508 AM EDT WED JUL 26 2017

CORRECTED FOR LOCATIONS IN HEADER

AREAS AFFECTED...SRN MN INTO WRN WI

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 260901Z - 261400Z

SUMMARY...LOCALIZED FLASH FLOODING WILL BE POSSIBLE FROM PORTIONS
OF SRN MN INTO WRN WI THROUGH 14Z. TOTAL RAINFALL OF 2-4 INCHES IS
EXPECTED IN ONE OR TWO LOCATIONS ACROSS THESE LOCATIONS.

DISCUSSION...REGIONAL RADAR IMAGERY AT 0830Z SHOWED A SMALL
CLUSTER OF INTENSIFYING RAIN CORES SOUTHWEST OF MSP WITH RADAR
ESTIMATED RAIN RATES NEAR 1 IN/HR WHERE BRIEF TRAINING HAD
DEVELOPED. REFLECTIVITY FROM KFSD HELPED IDENTIFY A WEAK MCV NEAR
LYON COUNTY IN SWRN MN...TRACKING ENE. WHILE PRECIPITABLE WATER
VALUES OVER NWRN IA/SWRN MN WERE AS LOW AS 1.2 INCHES EARLIER IN
THE NIGHT...MOISTURE ADVECTION TO THE NORTH AND EAST...SEEN VIA
CIRA LAYERED PW PRODUCT IMAGERY...HAD INCREASED THESE VALUES INTO
THE 1.5 TO 1.9 INCH RANGE...HIGHEST BENEATH CURRENT RAINFALL. A
SIZABLE PLUME OF INSTABILITY...MUCAPE OF 2000-3000+ J/KG PER
RECENT SPC MESOANALYSIS PAGE...WAS OBSERVED SOUTH OF THE COLD
FRONT ALONG THE MN/IA BORDER.

AS A 700 MB SHORTWAVE TROUGH...CURRENTLY OVER N-CNTRL
NE...CONTINUES TO MOVE EAST OVER THE NEXT 3-6 HOURS...A CONTINUED
INFLUX OF MOISTURE/INSTABILITY WITH 30-40 KT 850-700 MB FLOW
SHOULD NOSE INTO SWRN MN BY 12Z AS SEEN IN THE 08Z RAP. DOWNSTREAM
ACROSS CNTRL/ERN MN INTO WRN WI...LFC-EL MEAN FLOW IS EXPECTED TO
PARALLEL LOW LEVEL INFLOW FROM THE W OR WSW AMID MODERATELY
DIFFLUENT FLOW ALOFT AND LINGERING INSTABILITY IN EXCESS OF 100O
J/KG. IN ADDITION TO ONGOING CONVECTION SW OF MSP...ADDITIONAL
CELLS CANNOT BE RULED OUT TO THE WEST OVER S-CNTRL MN WHICH WOULD
HAVE THE POTENTIAL TO TRAIN TOWARD THE EAST INTO WI THROUGH THE
EARLY MORNING HOURS. FLASH FLOODING WILL BE POSSIBLE IF THIS
OCCURS...ESPECIALLY HEAVY RAIN OVERLAPS LOCATIONS WHICH RECEIVED
HEAVY RAINFALL EARLIER IN THE WEEK WHERE SOIL MOISTURE IS STILL
RUNNING HIGH.

OTTO

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ARX...FSD...GRB...MPX...

ATTN...RFC...NCRFC...

LAT...LON   45399123 45189013 44449003 43869098 43629210
            43589397 43709472 44069523 44519534 44909463
            45049336



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