MESOSCALE PRECIPITATION DISCUSSION 0451
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
336 AM EDT MON JUL 11 2016
 
AREAS AFFECTED...EASTERN ND...FAR NORTHEAST SD...CENTRAL MN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 110735Z - 111200Z
 
SUMMARY...AN MCS ROLLING ACROSS SOUTHEAST ND AND CENTRAL MN COULD
PRODUCE HOURLY RAINFALL NEAR 1.50 INCHES...WHICH MAY PRODUCE FLASH
FLOODING IN AREAS OF RELATIVELY LOW FLASH FLOOD GUIDANCE VALUES. 

DISCUSSION...THE MCS APPEARS TO HAVE REACHED THE MATURE PHASE...AS
IR TOPS HAVE COOLED TO NEAR -72 C ACROSS SOUTHEAST ND AND NEAR BY
WEST CENTRAL MN. THE CONVECTION REMAINS OUTFLOW DOMINATED...AS THE
COLD POOL PUSHES ACROSS EASTERN ND. DESPITE THE FAIRLY RAPID
MOVEMENT OF THE CONVECTION...BOTH THE KMVX AND KABR RADARS SHOWED
AREAS OF HOURLY RAINFALL RATES OF 1.25 TO 1.50 INCHES ACROSS FAR
NORTHEAST SD INTO WEST CENTRAL MN (WITH MESONET STATIONS
CONFIRMING THIS ACROSS EAST CENTRAL ND). WHILE THERE COULD STILL
BE SOME HAIL CONTAMINATION IN THE HOURLY RAINFALL ESTIMATES...THE
KDP PRODUCT FROM THE KMVX RADAR SHOWED SEVERAL HEAVY RAIN CORES
MOVING THROUGH WEST CENTRAL MN. 

IN ADDITION...CONVECTION HAS MOVED INTO SOUTH CENTRAL ND...ON THE
NORTHERN EDGE OF A STRONG INSTABILITY GRADIENT OVER SOUTHERN
ND...WITH MLCAPE VALUES NEAR 3500 J/KG LOCATED OVER NORTH CENTRAL
SD. MOST OF THIS CONVECTION APPEARS TO BE OUTFLOW DOMINATED AS
WELL...WITH LARGE HAIL REPORTS TIED TO DISCRETE CELLS. THESE CELLS
LOOK AS THOUGH THEY WILL TRACK ACROSS AREAS THAT RECEIVED HEAVY
RAIN LATE LAST NIGHT AND EARLY THIS MORNING. IN ADDITION...CELL
MERGERS ARE POSSIBLE ACROSS PORTIONS OF SOUTHERN ND. IN FACT...
THE RAP SHOWS CORFIDI VECTORS BECOME OPPOSED TO THE MID LEVEL FLOW
OVER PORTIONS OF SOUTHEAST ND INTO WEST CENTRAL MN BEFORE 12Z. 

THERE IS DECENT AGREEMENT AMONG THE HIGH RESOLUTION GUIDANCE
SOLUTIONS TAKING THE MCS ACROSS CENTRAL MN BEFORE 12Z. AHEAD OF
THE MCS...THE LATEST RAP SHOWS A 35 TO 45 KNOT LOW LEVEL JET
TRANSPORTING 2.00 INCH PRECIPITABLE WATER AIR (WHICH IS BETWEEN
TWO AND THREE STANDARD DEVIATIONS ABOVE THE MEAN) INTO CENTRAL MN.
THE LOW LEVEL FORCING COULD SPARK ADDITION CONVECTION AHEAD OF THE
MCS (WHICH THE KMPX IS STARTING TO SHOW).

THE MCS WILL RUN INTO AN AIRMASS WITH LESS IN THE WAY OF
INSTABILITY...AND MAY START TO WEAKEN TOWARD 12Z. BEFORE THAT
TIME... THE LATEST HRRR/PARALLEL HRRR SHOWED THE POTENTIAL FOR
LOCAL 2-4 INCH RAINFALL AMOUNTS. THESE NUMBERS ARE PLAUSIBLE AS
LONG AS THE MCS CAN SUPPORT RAINFALL RATES NEAR 1.50 INCHES. THESE
RAINFALL AMOUNTS COULD BE SUFFICIENT FOR A FLASH FLOOD THREAT IN
AREAS WITH ONE HOUR FFG VALUES LESS THAN 1.50 INCHES ACROSS
CENTRAL MN...ESPECIALLY WHERE CELL MERGERS AND BACKBUILDING OCCUR. 

HAYES

ATTN...WFO...ABR...BIS...DLH...FGF...MPX...

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

LAT...LON   48059712 47329261 45419270 45139467 45449765 
            45449765 46159928 47019937 47779866