MESOSCALE PRECIPITATION DISCUSSION 0325
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
548 AM EDT WED AUG 27 2014
 
AREAS AFFECTED...NORTHERN MO...SOUTHERN IA...SOUTHEAST
NE...EXTREME NORTHEAST KS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 270945Z - 271345Z
 
SUMMARY...VERY SLOW-MOVING THUNDERSTORMS MAY TEND TO EXPAND IN
COVERAGE THROUGH MID MORNING. INTENSE RAINFALL RATES OF 2 TO 3
INCHES/HR WILL FOSTER A THREAT FOR FLASH FLOODING.

DISCUSSION...THE LATEST IR SAT IMAGERY SHOWS EXPANDING COLD-TOPPED
CONVECTION OVER EXTREME NWRN MO AND SWRN IA WHICH IS DEVELOPING
ALONG THE N SIDE OF AN INSTABILITY AXIS AND IS BEING AIDED BY SOME
LARGER SCALE FORCING ASSOC WITH AN APPROACHING SHORTWAVE IMPULSE
OVER S CNTRL NEB ATTM. THE CONVECTION WHILE IT IS NOT EXACTLY
SUPPORTED BY A WELL-DEFINED LOW LVL JET...IT IS FOCUSED NORTH OF A
STATIONARY FRONT WITHIN A BROAD WARM ADVECTION ZONE WHICH IS
FORECAST BY THE GLOBAL MODELS TO STRENGTHEN THROUGHOUT THE DAY.

CONSEQUENTLY...THE ONGOING CONVECTION SHOULD TEND TO MAINTAIN
ITSELF AND WILL LIKELY EXPAND GRADUALLY IN COVERAGE AS THE MORNING
PROGRESSES. THE AXIS OF CONVECTION SHOULD GENERALLY REMAIN FOCUSED
ALONG THE NRN SIDE OF THE INSTABILITY GRADIENT.

THE SLOW MOVEMENT OF THE CONVECTION AND VERY INTENSE RAINFALL
RATES WHICH ARE EXPECTED TO BE AS HIGH AS 2 TO 3 INCHES/HR WILL
FAVOR A POTENTIAL FOR FLASH FLOODING. THE 00Z ARW...00Z NMMB AND
00Z NSSL WRF ALL SUGGEST POTENTIAL FOR CONCENTRATED HVY TO
EXCESSIVE RAINS WITH LOCALLY SEVERAL INCHES OF RAIN POSSIBLE.

ORRISON

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

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

LAT...LON   40119159 39629212 39509281 39549342 39759427 39849526
            39889623 40299683 40979682 41489629 41669523 41389354
            40749192 40119159