MESOSCALE PRECIPITATION DISCUSSION 0301
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1000 AM EDT THU JUN 14 2018

AREAS AFFECTED...CENTRAL IOWA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 141359Z - 141759Z

SUMMARY...CELLS PRODUCING HEAVY RAINFALL CONTINUE TO TRAIN OVER
PORTIONS OF CENTRAL IOWA. THIS WILL CONTINUE THE THREAT OF FLASH
FLOODING INTO MID MORNING.

DISCUSSION...ELEVATED CONVECTION CONTINUES TO TRAIN ACROSS
PORTIONS OF CENTRAL IA. ACTIVITY IS FORMING ON THE NOSE OF A
STRONG CORRIDOR OF 850 MB MOISTURE TRANSPORT. THE PERSISTENT
MOISTURE TRANSPORT CONTINUES TO BE SUPPORTIVE OF BACKBUILDING INTO
THE BOUNDARY...WITH CORFIDI VECTORS PARALLEL TO THE MOISTURE
CONVERGENCE AXIS SUPPORTIVE OF NORTHWEST TO SOUTHEAST TRAINING OF
CELLS.

IN GENERAL WOULD ANTICIPATE THIS ACTIVITY TO BE ON A DOWNWARD
TREND AS WE LOSE THE NOCTURNAL LOW LEVEL JET RESULTING IN A
DECREASE IN THE FAVORABLE MOISTURE TRANSPORT/CONVERGENCE. HOWEVER
LATEST IR IMAGERY STILL SHOWS NO SIGNS OF WARMING CLOUD TOPS AS OF
1330Z...THUS WOULD APPEAR LIKE WE HAVE AT LEAST A FEW MORE HOURS
OF LOCALLY HEAVY RAINS AND A CONTINUED FLASH FLOOD THREAT. HAVE
NOTICED THE NORTHERN CONVECTIVE ELEMENTS HAVE BECOME A BIT MORE
PROGRESSIVE OFF TO THE SOUTHEAST RECENTLY...AND THUS THE WORST OF
THE FLASH FLOOD THREAT MAY HAVE PASSED.

NONETHELESS...THE MAINTENANCE OF THE MOISTURE TRANSPORT AND IR
SATELLITE TRENDS SUGGEST AT LEAST SOME THREAT WILL CONTINUE OVER
THE NEXT SEVERAL HOURS. THINK THAT BY 16-18Z WE SHOULD SEE THE
EXPECTED WEAKENING TAKE PLACE...WITH ANY REMAINING HEAVY CORES
PROBABLY BECOMING MORE PROGRESSIVE OFF TO THE SOUTHEAST BY THAT
TIME AS WELL BOTH OF THESE FACTORS WILL LIKELY RESUL IN A LOWER
FLASH FLOOD THREAT BY THAT TIME.

RECENT RUNS OF THE HRRR AND EXPERIMENTAL HRRR SEEM TO BE HANDLING
THE OVERALL EVOLUTION WELL. ALTHOUGH BOTH ARE TOO FAR NORTHEAST
WITH THE CONVECTIVE AXIS. THUS A SLIGHTLY SOUTHWESTWARD SHIFTED
HRRR/HRRRX SHOULD HANDLE THE SITUATION FINE.

CHENARD

ATTN...WFO...DMX...DVN...FSD...

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

LAT...LON   42869482 42519374 42079293 41719248 41309225
            40709248 40969335 41499414 41959484 42219509
            42329516 42779514