MESOSCALE PRECIPITATION DISCUSSION 0542
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1014 PM EDT WED AUG 10 2016
 
AREAS AFFECTED...CENTRAL AND EASTERN ND 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 110214Z - 110631Z
 
SUMMARY...MERGING CONVECTIVE LINES AND LOW FLASH FLOOD
GUIDANCE/WET SOIL CONDITIONS POSE A FLASH FLOOD THREAT ACROSS MUCH
OF CENTRAL AND EASTERN NORTH DAKOTA OVERNIGHT

DISCUSSION...GOES-E VISIBLE AND RADAR MOSAIC INDICATE A LINE OF
ELEVATED CONVECTION DEVELOPING WITHIN SELY WARM ADVECTION AND
ISENTROPIC ASCENT THAT BECOMES CONVERGENT AROUND 750-800MB FROM
ACROSS S CENTRAL ND INTO NE ND.  THIS IS IN ADVANCE OF VERY STRONG
SUPERCELLULAR MODE CONVECTION FORMED ON STRONG HEIGHT FALLS FROM
DEEP CYCLONE ACROSS SW SASKATCHEWAN.  THE SUPERCELLS HAVE
MOISTENED THEIR NEAR STORM ENVIRONMENT MAKING THEM FAIRLY
EFFICIENT WITH RAIN RATES IN THE 1.25-1.5"/HR RANGE GIVEN SOME
LOSS TO HAIL GENERATION...BUT ALSO ARE QUITE PROGRESSIVE TO THE
EAST NOW POTENTIALLY ECLIPSING THE LOW FFG VALUES IN THE VICINITY
BUT ONLY IN AN ISOLATED MANNER. 

GREATER CONCERN IS DRIVEN BY THE STATIONARY NATURE OF THE
DEVELOPING CONVECTION WITHIN THE CONVERGENCE ZONE WHERE LOCALIZED
FLOW AND PROPAGATION VECTORS ARE NEAR ZERO DUE TO THE INFLUENCE OF
THE APPROACHING HEIGHT FALLS/UPSTREAM CONVECTIVE COMPLEX.  THOUGH
THIS LINE IS ORIENTED WITHIN A LOCAL INSTABILITY MINIMUM...WITH
MUCAPES ONLY AROUND 1000-1500 J/KG THE CONTINUOUS MST FLUX
CONVERGENCE SHOULD MAINTAIN UPDRAFT VIGOR EVEN WITH THIS LIMITED
AMOUNT OF INSTABILITY SUPPORTING INCREASING RAIN RATES TO 1.5"/HR
AND POSSIBLE 2-3" TOTALS PRIOR TO THE LINE OF SUPERCELLS MERGING. 
THE COMBINATION OF THE LINE OF STATIONARY CELLS AND THE SHORT TERM
INCREASE IN RAINFALL RATES DUE TO CELL MERGERS THAT WILL POSE
AREAS OF FLASH FLOODING CONDITIONS.   GIVEN FFG VALUES BELOW 1.5"
IN ONE HOUR...FLASH FLOODING IS POSSIBLE THROUGH THIS LINE IN THE
NEXT HOUR OR SO.  HOWEVER...THE LINE WILL CONTINUE TO ADVANCE INTO
E ND WHERE ANTECEDENT CONDITIONS FROM THE LAST FEW DAYS' RAINFALL
WILL CONTINUE THE FLASH FLOOD THREAT INTO THE EARLY MORNING HOURS. 

GALLINA

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

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

LAT...LON   48359755 47699691 46959690 46509737 46259863 
            46280038 46570076 47920032 48339889