MESOSCALE PRECIPITATION DISCUSSION 0227
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
907 PM EDT SUN MAY 22 2016
 
AREAS AFFECTED...NORTHERN SOUTH DAKOTA...EASTERN NORTH DAKOTA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 230106Z - 230500Z
 
SUMMARY...CONVECTION FROM NORTHERN SOUTH DAKOTA INTO EASTERN NORTH
DAKOTAS HAS BECOME ALIGNED WITH THE MEAN LOW LEVEL FLOW...WHICH
INCREASES THE RISK OF FLASH FLOODING DUE TO TRAINING OF CELLS. 

DISCUSSION...SHORT TERM RADAR IMAGERY THROUGH 0045Z SHOWED CELLS
THAT WERE PRODUCING 1.00 TO 1.75 INCHES OF RAINFALL PER HOUR
RAINFALL RATES FROM NORTHERN SOUTH DAKOTA ALONG THE MISSOURI RIVER
NORTHEASTWARD INTO EASTERN NORTH DAKOTA.  THESE CELLS WERE
BECOMING ALIGNED WITH THE LOW LEVEL FLOW OF 30 TO 35 KTS.  THIS
SUGGESTS THAT TRAINING OF CELLS WILL LEAD TO SOME HEAVY RAINFALL
AMOUNTS AND THE POTENTIAL FOR FLASH FLOODING.  ALOFT...THE FLOW
WAS DIFLUENT WHICH WOULD AID VERTICAL MOTION THROUGH A DEEP LAYER.
 THE 00Z SOUNDING FROM KABR SHOWED A K INDEX VALUE OF 34...WHICH
THE MODELS SUGGEST IT...ALONG WITH THE PRECIPITABLE WATER
VALUES...WILL BE INCREASING DURING THE EVENING.

WITH RAINFALL RATES AT OR ABOVE 1.5 INCHES PER HOUR...AND THE
POSSIBILITY OF TRAINING...RAINFALL AMOUNTS COULD APPROACH FLASH
FLOOD GUIDANCE VALUES WHICH RANGE FROM 2.5 TO 3 INCHES OUT NEAR
KMBG DOWN TO VALUES OF 1 TO 1.5 INCHES IN FAR NORTHEAST ND.  

BANN

ATTN...WFO...ABR...BIS...FGF...

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

LAT...LON   49079874 48959720 48009737 46749791 46319804 
            45379863 45109968 45990014 47579952