MESOSCALE PRECIPITATION DISCUSSION 0575
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
358 AM EDT THU AUG 18 2016
 
AREAS AFFECTED...ND 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 180757Z - 181357Z
 
SUMMARY...CONTINUED INCREASED CONVECTIVE COVERAGE...ALONG WITH
STORM MERGERS AND SOME WEST TO EAST TRAINING...WILL RESULT IN A
CONTINUED HEAVY RAINFALL THREAT OVER ND.

DISCUSSION...SYNOPTIC ASCENT CONTINUES TO INCREASE ACROSS NORTH
DAKOTA AHEAD OF A SHORTWAVE MOVING ACROSS SOUTHERN CANADA. A LOOK
AT THE ANALYZED 250 MB PATTERN ALSO SHOWS INCREASINGLY DIFFLUENT
FLOW ALOFT. AT THE LOW LEVELS INCREASED SOUTHERLY WINDS ARE
RESULTING IN A REGION OF STRONG MOISTURE FLUX INTO THE WEST TO
EAST DRAPED BOUNDARY CURRENTLY OVER NORTHERN ND. THIS COMBINATION
OF STRONG LOW LEVEL CONVERGENCE AND UPPER LEVEL DIVERGENCE HAS
ALLOWED FOR WIDESPREAD CONVECTIVE DEVELOPMENT. 

MEAN WIND FIELDS ARE GENERALLY FROM WEST TO EAST...HOWEVER GIVEN
THE STRONG LOW LEVEL INFLOW...STORMS WILL CONTINUE TO BACKBUILD
AND PROPAGATE OFF TO THE SOUTHEAST. THE LOW LEVEL FRONT SHOULD
CONTINUE TO PUSH SOUTH...WHICH SHOULD ALSO GENERALLY PUSH THE
HEAVY CONVECTIVE THREAT SOUTH WITH TIME. THERE SEEMS TO BE AN
INCREASING MODEL SIGNAL FOR THIS CONVECTION TO EVENTUALLY EVOLVE
INTO AN MCS...WHICH SHOULD THEN MOVE PRETTY PROGRESSIVELY OFF TO
THE SOUTHEAST INTO EASTERN ND AND WESTERN MN. HOWEVER OVER THE
NEXT SEVERAL HOURS...SOME EAST TO WEST TRAINING APPEARS LIKELY TO
CONTINUE...WITH SOME STORM MERGERS AS WELL. THE THREAT OF MERGERS
MAY ACTUALLY INCREASE OVER CENTRAL/EASTERN ND OVER THE NEXT FEW
HOURS AS THE CONVECTION BEGINS TO CONSOLIDATE INTO A COMPLEX.
RAINFALL TOTALS OF 1-2" IN AN HOUR...WITH LOCALLY HIGHER AMOUNTS
WILL CONTINUE TO BE POSSIBLE.

RECENT RUNS OF BOTH THE HRRR AND HRRRP ARE TOO FAR NORTH WITH THE
CURRENT ACTIVITY...BUT THE EVOLUTION SUGGESTED BY THE 06Z HRRRP
SEEMS PLAUSIBLE...WITH POCKETS 2-4" OF RAIN POSSIBLE. IT JUST MAY
HAPPEN A BIT EARLIER AND A BIT SOUTH OF WHERE THE MODEL SHOWS IT.
WOULD EXPECT AT LEAST AN ISOLATED FLASH FLOOD THREAT TO EXIST
THROUGH THE EARLY MORNING HOURS.

CHENARD

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

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

LAT...LON   48870196 48860032 48589926 48369825 47979700 
            47609657 47079679 46769888 47490070 48330199