MESOSCALE PRECIPITATION DISCUSSION 0754
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
326 AM EDT WED OCT 26 2016
 
AREAS AFFECTED...NE IOWA...SE MINNESOTA...SW WISCONSIN...NW
ILLINOIS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 260725Z - 261200Z
 
SUMMARY...FLASH FLOODING WILL CONTINUE TO BE POSSIBLE ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY SOUTH OF MINNEAPOLIS.  THE HEAVIEST
RAINFALL IS LIKELY BETWEEN 7 AND 10Z. RAINFALL RATES OF 0.75 TO
1.50 IN/HR SHOULD CONTRIBUTE TO ADDITIONAL 1 TO 3 INCH TOTALS WITH
LOCALLY HIGHER AMOUNTS THROUGH 12Z.

DISCUSSION...THE LATEST INFRARED SATELLITE IMAGERY AT 7Z SHOWED A
LARGE MCS OVER SOUTHERN MINNESOTA AND NORTHERN IOWA WITH CLOUD TOP
TEMPERATURES NEAR -70C.  A MID-UPPER LEVEL SHORTWAVE WAS LOCATED
NEAR THE IOWA/NEBRASKA BORDER AND MOVING TOWARD THE EAST. 
REGIONAL RADAR IMAGERY SHOWED A NW-SE AXIS OF WIDESPREAD HEAVY
STRATIFORM RAIN AHEAD OF AN 850MB WARM FRONT.  A RICH INFLUX OF
DEEP MOISTURE AHEAD OF THE UPPER LEVEL VORTMAX IS FUELING REPEATED
ROUNDS OF THUNDERSTORM ACTIVITY ACROSS MUCH OF CENTRAL IOWA. 
WINDS AT 850MB PER LATEST RAP MODEL GUIDANCE ARE ON THE ORDER OF
45 TO 55KTS.  SPC MESOANALYSIS INDICATED MUCAPES OF 1000-1500
J/KG, WHICH IS MORE THAN ENOUGH TO SUPPORT ADDITIONAL CONVECTION
OVER THE NEXT SEVERAL HOURS.

PRECIPITABLE WATER VALUES OF 1.2 TO 1.4 ARE ALSO PRESENT OVER MUCH
OF IOWA, AND THIS IS WELL ABOVE NORMAL FOR THIS TIME OF YEAR. 
WITH THE APPROACH OF THE SHORTWAVE TROUGH, INCREASED LOW LEVEL
FLOW WILL CONTINUE TO TRANSPORT MOISTURE NORTHWARD IN THE PRESENCE
OF INCREASING UPPER DIFFLUENCE.  MOST HI-RES MODEL RUNS HAVE THE
AXIS OF HEAVIEST RAIN FROM NE IOWA TO SW WISCONSIN THROUGH 10Z,
AND GIVEN THE OVERALL SET-UP IN PLACE, IT IS POSSIBLE THOSE MODEL
PROJECTIONS MAY BE UNDERDONE IN AREAS WHERE TRAINING CONVECTION
OCCURS. 


HAMRICK

ATTN...WFO...ARX...DMX...DVN...GRB...LOT...MKX...MPX...

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LAT...LON   44789261 44439045 43428910 42498891 41928939 
            42129105 41569297 42159394 43259423 44259383