MESOSCALE PRECIPITATION DISCUSSION 0355
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1145 PM EDT WED JUL 15 2015
 
AREAS AFFECTED...PORTIONS OF THE CNTRL MISSOURI RIVER VALLEY INTO
CNTRL IOWA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 160344Z - 160900Z
 
SUMMARY...AN INCREASING FLASH FLOOD THREAT WILL EXIST ACROSS PARTS
OF SERN NEBRASKA...NWRN MISSOURI INTO IOWA THROUGH 09Z. RAINFALL
RATES OF 1-2 IN/HR WITH LOCALLY 3-5 INCHES ARE EXPECTED THROUGH
09Z.

DISCUSSION...RADAR IMAGERY FROM 03Z SHOWED AN EXPANDING NUMBER OF
THUNDERSTORMS IN THE VICINITY OF SERN NEBRASKA WITH KOAX DUAL POL
ESTIMATES OF 1-2 IN/HR WITHIN THE STRONGER CORES. 00Z RAOB DATA
SUPPORTED A 700-500 MB SHORTWAVE OVER N-CNTRL NEBRASKA...FORECAST
TO MOVE ENE OVER THE NEXT SEVERAL HOURS. 00Z TOP SOUNDING SHOWED
3700 J/KG CAPE WHILE ONLY 600 J/KG REPORTED AT OAX...BUT WITH BOTH
LOCATIONS HAVING VEERING WIND PROFILES IN THE SFC - 600 MB LAYER
AS THEY ARE LOCATED JUST NORTH OF A STATIONARY FRONT WHICH
EXTENDED SEWD ACROSS KANSAS AT 03Z. CONVECTION WAS OCCURRING DUE
TO OVERRUNNING FLOW ACROSS THE FRONT WITH PLENTY OF MOISTURE
PRESENT...AS BLENDED TPW PRODUCT AND GPS SITES AVERAGED ABOUT 1.75
INCHES FOR THE THREAT AREA AT 03Z.

AS THE AFOREMENTIONED SHORTWAVE MOVES ENEWD ACROSS THE PLAINS
THROUGH 09Z...RAP FORECAST WINDS IN THE 850-700 MB LAYER BECOME
MORE ALIGNED FROM THE SOUTHWEST...WHILE STRENGTHENING AN
ADDITIONAL 10-15 KTS FROM THEIR PRESENT MAGNITUDE OF 25-30 KTS.
THIS DIRECTION BECOMES MORE PARALLEL WITH OBSERVED INDIVIDUAL
STORM MOTIONS TOWARD THE NORTHEAST...ALLOWING FOR A SETUP
CONDUCIVE TO TRAINING. WHILE A CONSENSUS OF THE LATEST CAM
GUIDANCE SUPPORTS A FLASH FLOOD THREAT INTO IOWA THROUGH
09Z...RECENT RUNS OF THE OPERATIONAL HRRR SEEM TO BE HANDING THE
EVOLVING SITUATION THE BEST...ALTHOUGH DELAYED. THESE MODELS
SUPPORT AN AVERAGE OF 3-5 INCHES ACROSS PORTIONS OF CNTRL/SRN IOWA
INTO NWRN MISSOURI...WHICH MAY ALLOW FOR FLASH FLOOD CONCERNS
GIVEN FFG VALUES ARE ONLY 2-3 INCHES IN 3 HOURS.

OTTO

ATTN...WFO...DMX...DVN...EAX...FSD...GID...OAX...TOP...

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

LAT...LON   42659520 42579280 42429169 42059088 41099118 
            40549213 40269263 39719418 39529653 39909820 
            40799849 42029759