MESOSCALE PRECIPITATION DISCUSSION 0600
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
206 AM EDT WED AUG 24 2016
 
AREAS AFFECTED...FAR SOUTHEAST MN/FAR NORTHERN IA...SOUTHWEST WI 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 240605Z - 240745Z
 
SUMMARY...AS OF 0555Z...RADAR IMAGERY SHOWED THAT CONVECTION ALONG
THE MN/IA BORDER HAD BECOME ALIGNED WITH THE MEAN FLOW AND THAT
CELLS WERE TRAINING OVER THE SAME AREA.  SOME OF THESE AREAS HAD
ALREADY RECEIVED LOCALLY MODERATE TO HEAVY RAINFALL DURING THE
EVENING.  THIS SUGGESTS FLASH FLOODING IS POSSIBLE.

DISCUSSION...FLASH FLOODING WILL BE POSSIBLE WHERE RADAR SHOWED A
PERSISTENT EAST TO WEST BAND OF HEAVY RAIN THAT CLOSELY PARALLELS
THE MN/IA BORDER.  SOME PLACES IN THIS AREA ALREADY RECEIVED SOME
LOCALLY MODERATE TO HEAVY RAINFALL DURING THE EVENING WHICH MAY
MAKE THE AREA BEING SOMEWHAT MORE PRONE TO FLASH FLOODING THAN
SUGGESTED BY THE 1- AND 3-HOUR FLASH FLOOD GUIDANCE.  

THE SHORT TERM/RAPID REFRESH GUIDANCE SHOWS THAT THIS EAST TO WEST
BAND WAS NEAR THE GREATEST VALUE OF BOUNDARY LAYER MOISTURE FLUX
CONVERGENCE...AND THAT RAINFALL RATES WILL BE DECREASING AS THE
AREA OF GREATEST MOISTURE FLUX CONVERGENCE SAGS SOUTH AND WEAKENS.
 FLOODING WILL BE POSSIBLE UNTIL RAINFALL RATES DIMINISH BETWEEN
0630Z AND 0730Z.  

THE 04Z HRRR SEEMED TO CAPTURE THE GENERAL SENSE OF CONVECTIVE
EVOLUTION WHILE THE ARW AND THE EXPERIMENTAL VERSION OF THE HRRR
WERE BOTH PROBABLY TOO FAR TO THE NORTH. 

BANN

ATTN...WFO...ARX...DMX...MKX...MPX...

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

LAT...LON   44109011 43888940 43328956 43049085 43019150 
            43069240 43209302 43419317 43669282 43899180