MESOSCALE PRECIPITATION DISCUSSION 0454
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
705 PM EDT MON JUL 11 2016
 
AREAS AFFECTED...CENTRAL/NORTHERN MN...NWRN WI 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 112304Z - 120500Z
 
SUMMARY...IMPRESSIVE MOIST AND UNSTABLE FLOW CROSSING A SURFACE
WARM FRONT WILL RESULT IN CONTINUED DEVELOPMENT OF CONVECTION OVER
THE NEXT SEVERAL HOURS. ADDITIONAL RAINFALL AMOUNTS OF 2 TO 4
INCHES, WITH LOCALLY HIGHER AMOUNTS, ARE POSSIBLE THROUGH 05Z.
FLASH FLOODING IS LIKELY.

DISCUSSION...A VERY MOIST (850 MB DEWPOINTS > 19 DEG C) AND
UNSTABLE (MLCAPE VALUES OF 2500-3500 J/KG) AIR MASS IN PLACE
ACROSS SRN MN AND IA IS BEING TRANSPORTED NORTH ACROSS A SURFACE
WARM FRONT ON 30-40 KT SOUTHERLY LOW-LEVEL FLOW. MOISTURE POOLING
IN THE VICINITY OF THE WARM FRONT HAS RESULTED IN PWAT VALUES
EXCEEDING 2 INCHES PER LATEST RAP ANALYSIS. THESE PWAT VALUES ARE
APPROXIMATELY 3 STANDARD DEVIATIONS ABOVE AVERAGE. ELEVATED
CONVECTION IS ONGOING AT THIS TIME NORTH OF THE SURFACE WARM FRONT
ACROSS MN, AND LATEST IR SATELLITE IMAGERY INDICATE CONVECTION IS
MAINTAINING ITSELF WELL WITH NO SIGNS OF CLOUD-TOP WARMING. 

THE AIR MASS IS CAPPED IN THE WARM SECTOR AT THE MOMENT BUT THIS
SHOULD CHANGE AS A VIGOROUS MID/UPPER-LVL SHORTWAVE APPROACHES
OVER THE NEXT FEW HOURS, RESULTING IN ADDITIONAL CONVECTION THAT
WILL BE TRANSPORTED NORTH ACROSS THE FRONTAL BOUNDARY. 

HI-RES CAM ARE IN GENERAL AGREEMENT ON CONVECTION CONTINUING AND
EVEN EXPANDING ALONG AND NORTH OF THE SURFACE WARM FRONT OVER THE
NEXT SEVERAL HOURS. THE HRRR-PARALLEL SEEMS TO HAVE THE BEST
HANDLE ON THE CURRENT CONVECTION, AND PRODUCES AN ADDITIONAL 2 TO
4 INCHES OF RAINFALL ACROSS THE OUTLINED AREA THROUGH 05Z. THE
HRRR-PARALLEL ALSO DEPICTS AN AREA OF 5-7 INCH AMOUNTS ACROSS
NORTHEASTERN MN. WHILE LIKELY TOO HIGH -- THIS DOES INDICATE THE
POTENTIAL FOR AMOUNTS EXCEEDING 5 INCHES IF VIGOROUS CONVECTION
CAN MANAGE TO TRAIN OVER AN AREA FOR AN EXTENDED PERIOD OF TIME.
GIVEN THAT FLASH FLOODING IS ALREADY ONGOING IN THIS AREA, AND
ADDITIONAL HEAVY RAINS ARE EXPECTED, CONTINUED FLASH FLOODING
APPEARS LIKELY.

RYAN

ATTN...WFO...ABR...DLH...FGF...MPX...

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

LAT...LON   48098980 47928956 47579013 47159045 46659042 
            46159124 45779224 45459344 45109421 44719486 
            44869596 45429670 46469688 47109649 47559514 
            47669393 47989211 48049103