MESOSCALE PRECIPITATION DISCUSSION 0480
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
748 PM EDT WED JUL 20 2016
 
AREAS AFFECTED...CNTRL AND ERN NORTH DAKOTA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 202347Z - 210530Z
 
SUMMARY...1-2 IN/HR RAINFALL RATES MAY EXCEED LOW FLASH FLOOD
GUIDANCE ACROSS NERN NORTH DAKOTA INTO NWRN MINNESOTA THROUGH 06Z.
COVERAGE OF ANY FLASH FLOODING IS ONLY EXPECTED TO BE SCATTERED
ACROSS THE REGION.

DISCUSSION...A COLD FRONT WAS ANALYZED FROM NE TO SW THROUGH SRN
MANITOBA INTO FAR NWRN NORTH DAKOTA AT 23Z...WITH THE PRE-FRONTAL
ENVIRONMENT ACROSS CNTRL AND ERN NORTH DAKOTA EXTREMELY MOIST AND
UNSTABLE. TEMPERATURES IN THE 90S AND DEWPOINTS FROM THE MID TO
UPPER 70S INTO THE LOWER 80S IN CNTRL/ERN NORTH DAKOTA HAVE
ALLOWED ESTIMATED MLCAPE VALUES OF OVER 4000 J/KG VIA RECENT SPC
MESOANALYSES. COOLER SURFACE TEMPERATURES FROM EARLIER CLOUD COVER
HAS LIMITED INSTABILITY AS WELL AS INCREASED CAPPING INTO MUCH OF
NRN MINNESOTA. 

RADAR/SATELLITE AND LIGHTNING DATA CONFIRMED THE PRESENCE OF
WIDESPREAD THUNDERSTORMS JUST NORTH OF THE U.S. BORDER ALONG THE
FRONTAL BOUNDARY WITH ACTIVITY MORE SCATTERED IN NATURE INTO NORTH
DAKOTA. HOWEVER...AS WEAK 700-500 MB HEIGHT FALLS OVERSPREAD NRN
NORTH DAKOTA OVER THE NEXT FEW HOURS...THE COLD FRONT IS EXPECTED
TO SINK SEWD ACROSS NORTH DAKOTA...WHICH MAY INCREASE THUNDERSTORM
COVERAGE IN THE HIGHLY UNSTABLE ENVIRONMENT. WHILE THESE STORMS
ARE EXPECTED TO BE GENERALLY PROGRESSIVE TOWARD THE EAST...CELL
MERGERS AND HIGH RAINFALL RATES OF 1-2 IN/HR MAY OVERSPREAD A
REGION OF LOW FFG VALUES...1-2 IN/HR...PRESENT FROM NERN NORTH
DAKOTA INTO NWRN MINNESOTA. SOME OF THESE SAME LOCATIONS RECEIVED
1-2 INCHES OF RAIN WITHIN THE PAST 24 HOURS WHICH MAY HAVE MADE
SOILS MORE SUSCEPTIBLE TO RUNOFF ISSUES.  WHILE CAPPING CURRENTLY
EXISTS ACROSS NWRN MINNESOTA...UNCERTAINTY IN CONVECTIVE COVERAGE
AND EVOLUTION KEEPS AT LEAST A CHANCE OF FLASH FLOOD PRODUCING
RAINFALL LATER TONIGHT FOR THIS AREA.

OTTO

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

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

LAT...LON   49290004 49229753 48779664 48519643 47929544 
            47649536 47299555 46989600 46869696 46999891 
            47309999 48050052 48860049