Flash Flood Guidance
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757
AWUS01 KWNH 212351
FFGMPD
MOZ000-IAZ000-KSZ000-NEZ000-220550-

MESOSCALE PRECIPITATION DISCUSSION 0710
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
751 PM EDT MON AUG 21 2017

AREAS AFFECTED...NERN KS/SERN NE INTO NRN MO/SRN IA

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

VALID 212350Z - 220550Z

SUMMARY...CONVECTION IS EXPECTED TO BECOME MORE WIDESPREAD ALONG
PORTIONS OF THE MISSOURI RIVER VALLEY INTO THE IA/MO BORDER WITH
POSSIBLE FLASH FLOODING. 2-4 INCHES OF RAIN WILL BE POSSIBLE
THROUGH 06Z.

DISCUSSION...23Z SURFACE OBSERVATIONS PLACED AN OUTFLOW BOUNDARY
NEAR I-70 STRETCHING FROM NERN KS INTO CNTRL MO. WHILE RAINFALL
FROM EARLIER TRAINING THUNDERSTORMS NORTH OF THIS BOUNDARY
PRODUCED ABOUT 2-3 INCHES OF RAIN JUST NORTH OF KANSAS CITY AROUND
20Z AND LIKELY SOME DEGREE OF ENHANCED CIN LOCALLY...AREA GPS
OBSERVATIONS SHOWED NEARLY 2 INCHES OF PRECIPITABLE WATER ALONG
I-70 ON EITHER SIDE OF THE MO/KS BORDER AMID AN ESTIMATED
1500-3000 J/KG MLCAPE PER THE LATEST SPC MESOANALYSIS PAGE. THESE
PWAT VALUES ARE ABOUT 0.2 INCHES HIGHER THAN 2-3 HOURS AGO. AREA
RADAR IMAGERY HAS SHOWN A RECENT INCREASE OF CELL DEVELOPMENT
ACROSS PORTIONS OF ERN KS.

WATER VAPOR IMAGERY SHOWED A VORTICITY MAXIMUM OVER N-CNTRL
KS...EMBEDDED WITHIN A LARGER-SCALE MID-LEVEL TROUGH AXIS
EXTENDING FROM NM INTO THE UPPER MS VALLEY. THIS VORTICITY MAX IS
PROGGED BY THE RAP TO REACH S-CNTRL IA TO ERN KS BY 06Z ALONG WITH
SLIGHTLY ENHANCED 850-700 MB FLOW FROM THE SOUTHWEST.
UNIDIRECTIONAL SWLY FLOW ABOVE 850 MB AHEAD OF THE MID-LEVEL
SHORTWAVE SHOULD PROMOTE TRAINING OF CELLS AS FORCING AHEAD OF THE
VORTICITY MAXIMUM LIKELY AIDS IN ADDED CONVECTION ACROSS ERN KS
INTO MO.

FARTHER NORTH...CONVECTION WAS OBSERVED NEAR ANOTHER OUTFLOW
BOUNDARY STRETCHING WEST-EAST FROM E-CNTRL NE INTO S-CNTRL IA AT
23Z AHEAD OF A LONG-LIVED MCS. A THIRD AREA OF CONVECTION WAS
OBSERVED OVER NERN NE AHEAD OF A SLOW MOVING COLD FRONT. AS THE
CONVECTION CURRENTLY OVER CNTRL IA CONTINUES TO MOVE SEWD...ADDED
UPPER LEVEL DIVERGENCE TIED TO THE RIGHT ENTRANCE REGION OF A 250
MB SPEED MAX OVER IA SHOULD AID IN VERTICAL LIFT OVER NRN MO/SRN
IA EARLY TONIGHT LEADING TO ADDITIONAL CONVECTION.

GIVEN INCREASED MOISTURE FLUX INTO THE ENTIRE REGION...PLENTY OF
MOISTURE...INSTABILITY AND THE FORCING MECHANISMS DESCRIBED
ABOVE...AN ADDITIONAL 2-4 INCHES OF RAIN IS EXPECTED THROUGH 06Z
IN AND AROUND THE MISSOURI RIVER VALLEY STRETCHING EAST ALONG THE
IA/MO BORDER WITH RAINFALL RATES PEAKING NEAR 2 IN/HR. SOME
OVERLAP IS EXPECTED WITH HEAVY RAIN OVER WRN IA WHICH FELL OVER
THE PAST 24 HR WHICH WOULD ENHANCE THE THREAT FOR FLASH FLOODING.

OTTO

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

ATTN...WFO...DMX...DVN...EAX...LSX...OAX...SGF...TOP...

ATTN...RFC...ABRFC...MBRFC...NCRFC...

LAT...LON   41329507 41289334 40919245 40059199 39169207
            38659311 38589448 38429604 39179643 40229615
            41019601



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