MESOSCALE PRECIPITATION DISCUSSION 0085...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
518 PM EDT SAT MAY 31 2014
 
CORRECTED FOR TYPO IN FIRST LINE OF SECOND PARAGRAPH

AREAS AFFECTED...NORTHWEST WI...SOUTH-CENTRAL MN...EASTERN SD 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 312113Z - 010313Z
 
SUMMARY...THUNDERSTORMS WITH INCREASINGLY HEAVY RAIN ARE
DEVELOPING ACROSS AN AREA WHICH HAS RECENTLY BEEN SATURATED. 
REGIONAL FLASH FLOODING IS CONSIDERED POSSIBLE.

DISCUSSION...A SHORTWAVE MOVING ACROSS EASTERN SD IS HELPING TO
INSTIGATE INCREASINGLY ORGANIZED CONVECTION ACROSS EASTERN SD,
SOUTH-CENTRAL MN, AND NORTHWEST WI.  WIND SHEAR IN THE 0-3 KM
LAYER IS 25-35 KTS, AND CAPES ARE INITIALLY IN THE 1000-2000 J/KG
RANGE.  COMBINED WITH PRECIPITABLE WATER VALUES OF 1.50-1.75",
NEAR THE 95TH PERCENTILE FOR THE END OF MAY, THE CRITERIA FOR THE
WET MULTI-CELL ENVIRONMENT HAS BEEN REACHED.  CORFIDI VECTORS ARE
RELATIVELY LIGHT, IN THE 5-10 KT RANGE ORIENTED FROM
WEST-SOUTHWEST TO EAST-NORTHEAST.

THE GUIDANCE INDICATES THAT FLOW AT 850 HPA AND 700 HPA INCREASES
INTO THE EVENING HOURS -- WHICH INCREASES THE 0-3 KM WIND SHEAR IN
TANDEM -- AND REMAINS GREATER THAN THE 850-400 HPA LAYER WIND
AVERAGE, WHICH COULD LEAD TO PRECIPITATION LOADING OF CONVECTIVE
CELLS.  WHILE CAPES ACROSS EASTERN MN AND WESTERN WI WEAKEN AROUND
SUNSET, UPSTREAM CAPES OF 1000+ J/KG ARE ANTICIPATED TO FEED INTO
THE BOUNDARY FROM NE AND IA.  WITH NO VEERING SEEN IN THE 700 HPA
WIND FIELD OVER THE NEXT SEVERAL HOURS, IT IS POSSIBLE THAT THE
CONVECTION COULD DEVELOP INTO A FAIRLY LONG BAND STRETCHING
THROUGH THE DEFINED AREA.  THE NON-RAP MESOSCALE GUIDANCE
INDICATES THAT LOCAL AMOUNTS OF 3-6" ARE POSSIBLE IN THIS AREA. 
RAINFALL RATES NEAR 2" AN HOUR ARE EXPECTED NEAR STRONGER STORMS,
WITH LOCAL AMOUNTS TOWARDS 6" POSSIBLE, WHICH COULD LEAD TO FLASH
FLOODING IN AREAS OF CELL TRAINING.

ROTH

ATTN...WFO...DLH...MPX...FSD...

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

LAT...LON   46359189 45919389 45059611 43889678 44109453 44539291
            45289185 46189159 46359189