MESOSCALE PRECIPITATION DISCUSSION 0316
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
215 AM EDT MON AUG 25 2014
 
AREAS AFFECTED...NORTHEAST IA...EXTREME SOUTHEAST MN...CENTRAL AND
NORTHERN WI...U.P. OF MI 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 250610Z - 250930Z
 
SUMMARY...THE POTENTIAL TRAINING SHOWERS AND THUNDERSTORMS WILL
CONTINUE FOR THE NEXT SEVERAL HOURS. THIS COUPLED WITH INTENSE
RAINFALL RATES WILL FOSTER SHORT-TERM FLASH FLOOD POTENTIAL.

DISCUSSION...THE LATEST IR AND WV IMAGERY SHOWS INCREASINGLY
DIFFLUENT FLOW ALOFT OVER THE UPR MIDWEST AS JET ENERGY LIFTS NEWD
AROUND THE EAST SIDE OF AN UPPER TROUGH AND CLOSED LOW SITUATED
OVER THE NRN PLAINS. THE UPTICK IN LARGER SCALE ASCENT/FORCING IS
HELPING TO GENERATE VERY COLD-TOPPED CONVECTION OVER PORTIONS OF
NERN IA AND ESP NWRN WI AND MOVING INTO THE U.P. OF MI. THE
ACTIVITY IS FOCUSING ALONG AND JUST AHEAD OF A COLD FRONT AND
ALONG A VERY SHARP INSTABILITY GRADIENT. 

DESPITE THERE BEING SOME LOW LVL CINH...THERE WILL LIKELY BE
SUFFICIENT INSTABILITY OVER THE NEXT FEW HOURS ABOVE THE SFC AND
WITH LARGER SCALE FORCING FOR A RATHER ORGANIZED BAND OF
CONVECTION TO CONTINUE AND POTENTIALLY EXPAND SOMEWHAT IN
COVERAGE. THE 00Z NAM-CONEST AND 00Z ARW BOTH SHOW SIGNALS FOR
THIS. THE AXIS OF CONVECTION SHOULD TEND TO BE ORIENTED
SW/NE...WITH CELL PROPAGATION OFF TO THE NE AND CONTINUING TO
ALIGN ITSELF WITHIN THE SHARP INSTABILITY GRADIENT.

PWATS JUST AHEAD OF THE SLOW-MOVING COLD FRONT ARE UP NEAR 1.75
INCHES...AND ALREADY RAINFALL RATES OF 1.5 TO 2 INCHES/HR HAVE
BEEN REPORTED.

THIS COUPLED WITH THE REPEATING/TRAINING NATURE OF THE ACTIVITY
SHOULD FOSTER AN AXIS OF POTENTIAL FLASH FLOODING OVER THE NEXT
SEVERAL HOURS.

ORRISON

ATTN...WFO...MQT...GRB...MKX...DVN...DLH...ARX...MPX...DMX...

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

LAT...LON   46948696 45478778 44558867 43189040 42359248 42199386
            42389450 42839448 43959321 44719242 46339135 47329021
            47718809 46948696 
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