MESOSCALE PRECIPITATION DISCUSSION 0387
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
820 AM EDT SUN JUL 26 2015
 
AREAS AFFECTED...FAR SOUTHERN IA...NORTHERN MO...WESTERN IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 261215Z - 261630Z
 
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WILL LIKELY PRODUCE
ADDITIONAL FLASH FLOODING AT LEAST LOCALLY THIS MORNING GIVEN
INTENSE RAINFALL RATES AND WET ANTECEDENT CONDITIONS.

DISCUSSION...THE SOUTHERN FLANK OF AN MCS MOVING THROUGH SOUTHERN
IA THIS MORNING IS BEGINNING TO DROP SOUTH INTO NORTHERN MO WHERE
LOCALLY SIGNIFICANT RAINS HAVE ALREADY OCCURRED OVER THE LAST
COUPLE OF DAYS. THE CONVECTION CONTINUES TO BE CHARACTERIZED BY
SOME VERY COLD TOPS APPROACHING OR EXCEEDING -70C AND THE GOES-OTD
ALGORITHM INDICATES A FEW EMBEDDED OVERSHOOTING TOPS WHICH
SUGGESTS A PERSISTENCE OF SOME VERY STRONG UPDRAFTS. 

GIVEN THE PROXIMITY OF A SHORTWAVE TROUGH JUST TO THE NORTH MOVING
ACROSS NORTHERN IA AND MN...LARGER SCALE ASCENT WILL CONTINUE TO
BE IN PLACE...AND WITH THE CONVECTION ADVANCING INTO AN
INCREASINGLY MOIST ENVIRONMENT OVER NORTHERN MO WHERE MULTIPLE
SURFACE BOUNDARIES ARE NOTED...THE CONVECTION SHOULD REMAIN
SUSTAINABLE AND LOCALLY INTENSE AT LEAST FOR A FEW MORE HOURS
BEFORE WEAKENING. GPS AND GOES-SOUNDER PWATS OVER NORTHERN MO ARE
RUNNING BETWEEN 2 TO 2.25 INCHES...AND THE CIRA LAYERED PW PRODUCT
AT 09Z SHOWS AN ENHANCED WSW/ENE AXIS OF MOISTURE IN THE
700MB/500MB AND 500MB/300MB LAYERS OVER MUCH OF EASTERN KS AND
NORTHERN MO. THIS WILL CONTRIBUTE TO EFFICIENT RAINFALL PRODUCTION
AND HEAVIER RAINFALL RATES AS A RESULT...WITH RAINFALL RATES
APPROACHING 2 TO 2.5 INCHES/HR.

THE HIRES MODELS HAVE BEEN HANDLING THE ONGOING CONVECTION RATHER
POORLY AND CONSECUTIVE RUNS OF THE HRRR ARE JUST SIMPLY NOT
DEPICTING THE INTENSITY AND PROPAGATION OF THE MCS VERY WELL.
ADJUSTING FOR LOCATION OF THE CONVECTION AND CURRENT
PROPAGATION...THE HIRES MODEL OUTPUT WOULD FAVOR ADDITIONAL
RAINFALL AMOUNTS OF LOCALLY 2 TO 4 INCHES THROUGH LATE MORNING.
UNFORTUNATELY THESE RAINS WILL BE FALLING OVER AREAS THAT HAVE
SEEN HEAVY AND LOCALLY EXCESSIVE RAINS THE LAST COUPLE OF DAYS
INCLUDING FROM OVERNIGHT. THUS FLASH FLOODING FROM ADDITIONAL
RAINS IS EXPECTED THIS MORNING.

ORRISON

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

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

LAT...LON   40939251 40839172 40629094 40128995 39438970 
            38859048 39279265 39879392 40239447 40629429 
            40829372 40929309