MESOSCALE PRECIPITATION DISCUSSION 0201
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
203 PM EDT WED MAY 10 2017

AREAS AFFECTED...SOUTHERN IA

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

VALID 101802Z - 102202Z

SUMMARY...CONVECTION IS STARTING TO EXPAND IN COVERAGE AND ALIGN
NEAR THE IA/MO BORDER.  WITH CONDITIONS BECOMING MORE RIPE FOR
CONVECTION WITH TIME, HOURLY RAIN RATES UP TO 1.75" WITH LOCAL
AMOUNTS OF 2-4" COULD LEAD TO FLASH FLOODING THIS AFTERNOON.

DISCUSSION...AN MCV MOVING INTO NORTHWEST IA ALONG WITH A LEADING
OUTFLOW BOUNDARY HAVE BEEN LEADING TO SCATTERED THUNDERSTORMS
ACROSS SOUTHERN IA WHICH ARE BEGINNING TO BROADEN IN COVERAGE. 
PRECIPITABLE WATER VALUES ARE 1.3-1.4" PER RECENT GPS VALUES. 
UPSTREAM, INFLOW OF 35 KTS OUT OF THE SOUTHWEST HAS BEEN NOTED IN
VAD WIND PROFILES ACROSS EASTERN KS.  MLCAPES OF 1000-2000 J/KG
EXIST ACROSS NORTHERN MO IN RECENT SPC MESOANALYSES.

DAYTIME HEATING IS EXPECTED TO INCREASE MLCAPES AN ADDITIONAL
500-1000 J/KG WITH TIME.  THE GALVEZ-DAVISON INSTABILITY INDEX
SHOWS INCREASINGLY UNSTABLE CONDITIONS WITH TIME TODAY AS
PRECIPITABLE WATER VALUES RISE ABOVE 1.5" WHICH SHOULD INCREASE
CONVECTIVE COVERAGE.  ORGANIZED STORMS ARE MOVING EAST AT 30 KTS,
WHICH COULD LEAD TO MERGERS WITH LESS ORGANIZED ACTIVITY FARTHER
EAST IN SOUTHERN IA.  THE MESOSCALE GUIDANCE APPEARS TOO LIGHT AND
TOO FAR NORTH WITH THEIR CONVECTIVE AREAS PER CURRENT TRENDS AND
EXPECTATIONS.  HOURLY RAIN RATES UP TO 1.75", WITH LOCAL AMOUNTS
OF 2-4", COULD LEAD TO ISSUES IN AND NEAR SOUTHERN IA.

ROTH

ATTN...WFO...DMX...DVN...EAX...LSX...OAX...

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

LAT...LON   41419337 41379205 41059116 40169154 40279363
            40309449 40309549 41129465