MESOSCALE PRECIPITATION DISCUSSION 0478
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
528 PM EDT TUE JUL 19 2016
 
AREAS AFFECTED...SERN IA..NERN MO...WRN IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 192127Z - 200215Z
 
SUMMARY...A FLASH FLOOD THREAT WILL LINGER IN ADVANCE OF AN
FORWARD PROPAGATING MCS MOVING THROUGH SRN IOWA INTO NERN MISSOURI
AND WRN ILLINOIS. ADDITIONAL RAINFALL TOTALS OF 3-4 INCHES WILL BE
POSSIBLE IN A FEW LOCATIONS THROUGH 02Z.

DISCUSSION...RADAR IMAGERY AS OF 21Z SHOWED A SMALL BOWING SEGMENT
ALONG THE IOWA/MISSOURI BORDER EMBEDDED IN WHAT REMAINS OF A
FORWARD PROPAGATING MCS OVER THE REGION. MOVEMENT OF THIS SYSTEM
WAS TOWARD THE SE AT ROUGHLY 20-30 KTS INTO A POOL OF INSTABILITY
SOUTH OF A STATIONARY FRONT DRAPED FROM ESE TO WNW ACROSS THE
REGION. ADDITIONAL THUNDERSTORMS WERE OBSERVED TO BE DEVELOPING
AHEAD OF THE MCS WITHIN AN UNSTABLE AND MOIST
AIRMASS...CHARACTERIZED BY PRECIPITABLE WATER VALUES NEAR 1.9
INCHES AS OBSERVED AT A RECENT GPS MEASUREMENT OUTSIDE OF HANNIBAL
MISSOURI. 

WHILE THE MCS IS EXPECTED TO REMAIN FORWARD PROPAGATING TOWARD THE
SOUTHEAST ALONG AN EXISTING GRADIENT IN ML CAPE...A THREAT FOR
FLASH FLOODING WILL PERSIST OVER THE NEXT FEW HOURS. SLOW MOVEMENT
OF CELLS AHEAD OF THE MCS AT 5 TO 15 KTS...COUPLED WITH CELL
MERGERS AND THE APPROACH OF THE REMAINING CLUSTER OF CONVECTION
ALONG THE IOWA/MISSOURI BORDER WILL CONTINUE TO ALLOW FOR 2-3 HOUR
RAINFALL RATES OF 3-4 INCHES. FLASH FLOOD GUIDANCE IS LOWEST ALONG
THE NRN HALF OF THE MPD THREAT AREA DUE TO RECENT HEAVY RAINFALL
WHICH IS WHERE THE FLASH FLOOD THREAT IS GREATEST. ANY FLASH
FLOODING ACROSS THE SRN HALF OF THE MPD THREAT AREA MAY BE MORE
ISOLATED GIVEN SOIL CONDITIONS DO NOT APPEAR TO BE AS WET. SWD
ADJUSTED RECENT RUNS OF THE HRRR/HRRR_PARALLEL APPEAR TO HAVE THE
BEST HANDLE ON THE ONGOING SITUATION.

OTTO

ATTN...WFO...DMX...DVN...EAX...ILX...LSX...

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

LAT...LON   41429229 41289131 41039016 40888983 40568919 
            40018849 39688828 39368831 39058861 38738920 
            38449017 38889180 39839340 40309373 41099356