MESOSCALE PRECIPITATION DISCUSSION 0139
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
250 AM EDT THU JUN 19 2014
 
AREAS AFFECTED...ERN SD...SRN MN...SW WI...NRN IA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 190649Z - 191049Z
 
SUMMARY...FOCUS OF LOW LEVEL WARM ADVECTION FROM A RESERVOIR OF
STRONGLY UNSTABLE AIR WILL LIKELY YIELD ADDITIONAL FLASH FLOODING.
A DOWNWARD TREND IN INTENSITY AND COVERAGE OF HEAVY RAIN IS
EXPECTED AFTER 10Z.

DISCUSSION...POCKETS OF CONVECTIVE INITIATION SPURRED BY LOW LEVEL
FRONTOGENESIS AND WARM ADVECTION HAD PRODUCED ORGANIZED FLASH
FLOOD EVENTS ON A LOCAL SCALE IN SRN MN AND NE IA. CONVECTION WITH
GREATER MID LEVEL SUPPORT HAD GROWN IN SCOPE FARTHER WEST IN MN
AND SD.

THERE ARE SOME COMPETING FACTORS DETERMINING THE LIKELIHOOD OF
CONTINUED ORGANIZED CONVECTION AND FLASH FLOODING...BUT THE
PRESENCE OF COLD POOLS AND ARRIVAL OF MID LEVEL HEIGHT FALLS FROM
THE WEST SHOULD TRUMP VEERING 850 MB WINDS AND SLACKENING LOW
LEVEL MOISTURE TRANSPORT IN THIS REGION AT LEAST THROUGH 10Z. THE
GREATEST RISK OF ADDITIONAL FLASH FLOODING WOULD BE IN THE WARM
ADVECTION WING AHEAD OF THE MORE ORGANIZED CONVECTION COMING OUT
OF SOUTH DAKOTA. PER THE NAM...SUPERCELL AND MULTICELL MOTIONS
REMAIN 0-5 KT THIS MORNING IN SRN MN AND ADJACENT WI/IA...WHILE
COLD POOLS WILL INTERCEPT SSW-ERLY INFLOW TO PROMOTE LOCAL
TRAINING. RADAR-INDICATED AND OBSERVED ACCUMULATION RATES HAVE
BEEN AS HIGH AS 2.5 INCHES/HR...SUGGESTING LIKELY FLASH FLOODING
IN THIS REGION OF PRIMED SOILS.

BEYOND 10Z...THE HRRR QPF AND GFS MASS FIELDS SUGGEST A DOWNWARD
TREND TO INTENSITY AND MORE FORWARD PROPAGATION. THIS SHOULD OCCUR
OWING TO DIURNAL COOLING/STABILIZATION ALONG WITH VEERING 850 MB
WINDS. BUT PRECIPITATION OF SOME LESSENED INTENSITY IS LIKELY TO
CONTINUE INTO THE DAYLIGHT HOURS.

BURKE

ATTN...WFO...ARX...MPX...DMX...FGF...FSD...ABR...

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

LAT...LON   44319631 43539463 43009351 42699249 42709140 43239093
            43809091 44269172 44859302 45459453 45869678 45699765
            45349780 44709729 44319631