MESOSCALE PRECIPITATION DISCUSSION 0673
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
642 AM EDT FRI SEP 16 2016
 
AREAS AFFECTED...CNTRL MO INTO CNTRL IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 161041Z - 161630Z
 
SUMMARY...RAINFALL RATES OF 1-2 IN/HR WITH PERIODS OF TRAINING MAY
DEVELOP ACROSS PORTIONS OF CNTRL MO AND SHIFT INTO IL BY 16Z. THIS
COULD CAUSE FLASH FLOODING IN A FEW PLACES...ESPECIALLY OVER WET
ANTECEDENT GROUNDS FROM PREVIOUS RAINFALL OVER THE PAST WEEK.

DISCUSSION...TRENDS IN RADAR IMAGERY HAVE SHOWN AN UPTICK IN
RAINFALL INTENSITY OVER CNTRL TO NRN MO DURING THE PAST HOUR. THIS
AREA IS OCCURRING DUE TO WEAK ISENTROPIC ASCENT ATOP THE LEADING
EDGE OF RETURNING HIGHER THETA-E AIR LOCATED SOUTH OF THE OZARKS.
WEAK INSTABILITY HAS BEEN A LIMITING FACTOR IN ALLOWING HIGHER
RAINFALL RATES OVER MISSOURI...BUT MUCAPE HAS BEEN INCREASING OVER
THE PAST 3 HOURS VIA 25-35 KTS OF 850 MB FLOW FROM THE
SOUTHWEST...OUT AHEAD OF AN 850 MB COLD FRONT...HELPING TO
TRANSPORT GREATER LOW LEVEL MOISTURE INTO THE REGION.

AS A LARGE UPPER TROUGH OVER THE NRN AND CNTRL PLAINS ADVANCES
EWD...UPPER LEVEL DIFFLUENCE BETWEEN THE SUBTROPICAL AND A BRANCH
OF THE POLAR JET IS EXPECTED TO INCREASE OVER THE NEXT FEW HOURS
ACROSS ERN MO. 850 MB WIND SPEEDS ARE EXPECTED TO WEAKEN SOMEWHAT
AFTER 12Z...BUT THE ONSET OF DAYTIME HEATING SHOULD INCREASE
INSTABILITY ENOUGH TO SUPPORT RAINFALL RATES OF 1-2 IN/HR IN A FEW
LOCATIONS WITH THE HELP OF INCREASING DYNAMICS ALOFT. 

FLASH FLOODING WILL BE MOST LIKELY ACROSS LOCATIONS THAT RECEIVED
HEAVY RAINFALL OVER THE PAST WEEK...INCLUDING LOCATIONS FROM NEAR
JEF TO SOUTH OF STL...AND EWD INTO IL...WHERE 7-DAY DEPARTURES
FROM NORMAL PRECIPITATION HAVE BEEN 300-600+ PERCENT.

OTTO

ATTN...WFO...DVN...EAX...ILX...LSX...SGF...

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

LAT...LON   41098955 40538902 39598906 38309025 37699133 
            37489255 37709324 38349360 39919234 40659105 
            41019041