MESOSCALE PRECIPITATION DISCUSSION 0046...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
202 AM EDT SUN MAY 19 2013
 
AREAS AFFECTED...WESTERN IA AND SOUTHWEST MN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 190558Z - 190958Z
 
SUMMARY...A BOW ECHO MOVING IN FROM NE IS EXPECTED TO SLOW
DOWN/STALL ACROSS PORTIONS WESTERN IA AND SOUTHERN MN OVER THE
NEXT SEVERAL HOURS, WHICH SHOULD LEAD TO FLASH FLOODING.

DISCUSSION...THUNDERSTORMS HAVE BOWED OUT SIGNIFICANTLY FROM NE,
ENTERING WESTERN IA AT THE CURRENT TIME. A MESOSCALE CONVECTIVE
VORTEX -- MCV -- NEAR THE EASTERN KS/NE BORDER IS LIFTING
NORTHEAST, WHICH SHOULD SIGNIFICANTLY SLOW DOWN THE MOVEMENT OF
CONVECTION IN WESTERN IA AND LIFT THE ACTIVITY INTO SOUTHERN MN.
BOTH THE LATEST RAP AND GFS GUIDANCE INDICATE THAT PROPAGATION
VECTORS WILL BECOME NULL IN THIS REGION SHORTLY, WITH BOTH PIECES
OF GUIDANCE INDICATING THE HEAD OF A STALLING 40+ KT 850 HPA
INFLOW JET POINTING INTO WESTERN IOWA THROUGH 12Z/7 AM CDT.  FLASH
FLOOD GUIDANCE VALUES -- FFGS -- ARE AROUND TWO INCHES IN THREE
HOURS, WHICH SHOULD BE EXCEEDED BY JUST OVER ONE HOUR OF CELL
TRAINING, AS PRECIPITABLE WATER VALUES -- PWS -- LIE NEAR 1.50
INCHES.  DIVERGENCE ALOFT IS PLENTIFUL AHEAD OF AN INCREASINGLY
NEGATIVELY-TILTED UPPER LEVEL TROUGH.  LOCAL AMOUNTS OF 3-5 INCHES
ARE POSSIBLE IN THIS REGION, WHICH WOULD EXCEED FFGS.

ROTH


ATTN...WFO...ARX...MPX...DMX...EAX...FSD...OAX...

LAT...LON   44189262 41669284 39799441 41269618 43269660 44919598
            45459396 44189262 


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