Flash Flood Guidance
Issued by NWS

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000
AWUS01 KWNH 220346
FFGMPD
WIZ000-MNZ000-IAZ000-220615-

MESOSCALE PRECIPITATION DISCUSSION 0530
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1145 PM EDT FRI JUL 21 2017

AREAS AFFECTED...NERN TO E-CNTRL IA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 220344Z - 220615Z

SUMMARY...FLASH FLOODING RAINS WILL CONTINUE TO AFFECT NERN TO
E-CNTRL IA FOR AT LEAST ANOTHER 2-3 HOURS. TRAINING WITH RAINFALL
RATES AS HIGH AS 3 IN/HR WILL BE POSSIBLE.

DISCUSSION...TRENDS IN KARX RADAR REFLECTIVITY SHOWED A WWD
EXPANSION OF TRAINING RAINFALL ACROSS NERN IA...OVERLAPPING SOME
OF THE SAME AREAS WHICH RECEIVED HEAVIER RAINFALL EARLIER IN THE
DAY ON FRIDAY. THIS AXIS IS OCCURRING ALONG THE WRN EDGE OF
MODERATELY STRONG SWLY LOW LEVEL MOISTURE TRANSPORT ATOP A
QUASI-STATIONARY FRONT DRAPED WNW TO ENE ACROSS S-CNTRL IA.
INDIVIDUAL CELLS WITHIN THE GROWING CLUSTER OF ELEVATED CONVECTION
ARE PROPAGATING ESE AT 20-30 KT...PARALLEL TO VERY MOIST 700 MB
FLOW OF SIMILAR MAGNITUDE WITH DEWPOINTS NEAR 8C PER NEARBY
SOUNDINGS FROM 00Z AND RAP ANALYSES.

GIVEN ANOMALOUS MOISTURE WITH PWATS NEAR 2 INCHES AND LARGE
UPSTREAM INSTABILITY OF 3000-5000 J/KG...THE CONVECTION IS
EXPECTED TO CONTINUE FOR AT LEAST THE NEXT COUPLE OF HOURS
ADJACENT TO THE WRN EDGE OF MPD #528 WHICH IS VALID UNTIL 06Z.
BOTH THIS CURRENT MPD AND MPD #528 WILL BE REEVALUATED AND UPDATED
IN A COUPLE OF HOURS AS TRENDS DICTATE. UNTIL THEN...ADDITIONAL
RAINFALL TOTALS OF 3-5 INCHES WILL BE POSSIBLE ACROSS PORTIONS OF
NERN IA WITH THE AXIS POTENTIALLY SHIFTING SOUTH BY 06Z INTO
N-CNTRL TO E-CNTRL IA.

OTTO

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

ATTN...WFO...ARX...DMX...DVN...MPX...

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

LAT...LON   43639253 43419137 43279083 43049083 42639119
            42119142 42179279 42519387 43079432 43569404




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