MESOSCALE PRECIPITATION DISCUSSION 0129
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1158 PM EDT MON JUN 16 2014
 
AREAS AFFECTED......NORTHEAST NE/NORTHWEST IA... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 170400Z - 170630Z
 
SUMMARY...NEW CONVECTION TRAINING OVER AREAS WHICH RECEIVED HEAVY
RAIN EARLIER MAY RESULT IN ADDITIONAL FLASH FLOODING THROUGH 07Z.

DISCUSSION...NEW CONVECTION IS FIRING OVER NORTHEAST NE INTO
NORTHWEST IA ON THE NOSE OF A 45 TO 65 KNOT LOW LEVEL JET (AS
CONFIRMED BY REGIONAL VWP). THERE IS A COPIOUS SUPPLY OF UPSTREAM
INSTABILITY...AS EVIDENCED BY MUCAPE VALUES BETWEEN 3000-4000 J/KG
OVER EASTERN NE. THE CONVECTION IS FORMING IN A 1.80 INCH
PRECIPITABLE WATER MAXIMUM...WHICH COULD LEAD TO HIGH RAINFALL
RATES WITH THE DEVELOPING CONVECTION.

INCREASING MID LEVEL SHEAR...COMBINING WITH THE STRONG
INSTABILITY...SHOULD RESULT IN CONVECTION TAKING ON MORE OF A
LINEAR MODE THROUGH 07Z...ESPECIALLY OVER NORTHWEST IA. WHILE NOT
NECESSARILY CONDUCIVE TO FLASH FLOODING...ONE HOUR FLASH FLOOD
GUIDANCE VALUES ARE AS LOW AS 0.50 INCHES IN PORTIONS OF NORTHEAST
NE AND NORTHWEST IA. THE ADDITIONAL CONVECTION COULD RESULT IN
POSSIBLE FLASH FLOODING.

THE LATEST HIGH RESOLUTION GUIDANCE SHOWS THE INSTABILITY
WEAKENING AND BECOMING MORE ELEVATED WITH TIME. BEFORE 07Z...THE
LATEST HRRR SHOWS A SWATH OF 2 TO 4 INCHES OF RAIN WITH THE NEWLY
DEVELOPED CONVECTION...BUT GIVEN THE EXPECTED LINEAR CONVECTIVE
MODE...ADDITIONAL RAINFALL MAY BE CLOSER TO THE LOWER END OF THAT
RANGE.

HAYES

ATTN...WFO...ARX...DMX...FSD...OAX...

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

LAT...LON   43369637 43359325 43249271 42859243 41849276 41469453
            41419556 41529604 42199677 43049683 43379633 43369637