MESOSCALE PRECIPITATION DISCUSSION 0310
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
122 AM EDT MON JUL 06 2015
 
AREAS AFFECTED...NORTHEAST NEB...SOUTHEAST SD...NORTHWEST
IA...SOUTHWEST MN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 060515Z - 061000Z
 
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
ORGANIZE OVERNIGHT AS A WAVE OF LOW PRESSURE LIFTS NORTHEAST.

DISCUSSION...SATELLITE IMAGERY SHOWS VERY COLD-TOPPED CONVECTION
WITH NUMEROUS OVERSHOOTING TOPS AND MERGING CLUSTERS OF CELLS
IMPACTING NORTHERN NEB AND SOUTHEAST SD WHICH IS IN ASSOCIATION
WITH A DEVELOPING FRONTAL WAVE. THE WAVE OF LOW PRESSURE IS BEING
FOSTERED BY THE SOUTHERN EXTENSION OF A SHORTWAVE TROUGH THAT IS
PIVOTING EAST ACROSS THE NORTHERN HIGH PLAINS.

THIS ENERGY WILL CONTINUE TO ADVANCE EAST OVERNIGHT AND WILL DRIVE
LOW PRESSURE TOWARD NORTHWEST IA BY SUNRISE...WITH A FRONT
EXTENDING NORTHEAST UP ACROSS CENTRAL MN. DEEP MOISTURE AND
MODERATE INSTABILITY POOLED ALONG THE BOUNDARY AHEAD OF THE
FRONTAL WAVE WILL REMAIN FOCUSED OVERNIGHT BY A GRADUALLY VEERING
40 TO 50 KT LOW LEVEL JET. THIS COUPLED WITH WITH INCREASINGLY
DIVERGENT FLOW ALOFT AHEAD OF THE SHORTWAVE TROUGH WILL ALLOW FOR
A PERSISTENT AND RATHER SLOW-MOVING AXIS OF ORGANIZED CONVECTION
THROUGH THE EARLY MORNING HOURS. THE STRONGEST ACTIVITY IS
EXPECTED TO FOCUS PRIMARILY OVER SOUTHEAST SD...SOUTHWEST MN AND
EXTREME NORTHWEST IA OVER THE NEXT FEW HOURS.

GOES-SOUNDER AND GPS-DERIVED PWATS OF 1.7 TO 1.8 INCHES WILL
SUPPORT INTENSE RATES OF UP TO OVER 2 INCHES/HR...AND THIS COUPLED
WITH THE POTENTIAL FOR TRAINING CONVECTIVE CELLS WILL FAVOR A
POTENTIAL FOR FLASH FLOODING. IN FACT...THE 12Z ARW/12Z NMMB AND
04Z HRRR OUTPUT SUGGEST RAINFALL AMOUNTS THROUGH 10Z OF 3 TO 5
INCHES WITH LOCALLY HEAVIER AMOUNTS. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...ABR...DMX...FSD...LBF...MPX...OAX...

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

LAT...LON   45309503 44879414 44159415 43059513 42179628 
            41859756 42159847 43549812 44379720 44929639