MESOSCALE PRECIPITATION DISCUSSION 0070
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1008 PM EDT SUN MAY 26 2013
 
AREAS AFFECTED...NORTHERN MO...WESTERN AND CENTRAL IL...FAR
SOUTHERN IA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 270207Z - 270607Z
 
SUMMARY...MOISTURE FLUX THAT IS FOCUSED BY A SOUTHEASTWARD MOVING
TROUGH WILL SUPPORT CONTINUATION OF ORGANIZED HEAVY RAIN AND THE
POSSIBILITY OF NEW FLASH FLOODING.

DISCUSSION...REPEATED WAVES OF THUNDERSTORMS HAD OCCURRED IN THE
ELEVATED FRONTAL ZONE ACROSS IA/IL...SUPPORTED ON A LARGER SCALE
BY A SOUTHEASTWARD MOVING LOW/MID LEVEL TROUGH AND A NORTHEASTWARD
MOVING HIGHER-LEVEL VORT MAX NOTED BY NESDIS/SAB. THE SMALL SCALE
MESOSCALE CONVECTIVE SYSTEMS NORTH OF THE TROUGH AXIS HAD BEGUN TO
BOW OUT WITH THE LOSS OF VEERED LOW LEVEL WIND PROFILES. THIS
PROGRESSION...HOWEVER...MAY NOT PREVENT FLASH FLOODING OVER
WESTERN AND CENTRAL ILLINOIS WHERE FLASH FLOOD GUIDANCE WAS ONLY
1-1.5 INCHES IN AN HOUR. 00Z ILX SOUNDING WAS MODERATELY UNSTABLE
FOR ELEVATED PARCELS...WITH PW VALUE OF 1.45 INCHES AND RAP
FORECASTS BRINGING PW UP TO 1.5-1.75 INCHES INTO WESTERN/CENTRAL
IL OVERNIGHT.

ANOTHER AREA OF GREATER RAINFALL POTENTIAL WILL BE NORTHWEST AND
CENTRAL MISSOURI...WHERE THE TAIL END MCS THAT WAS ON THE IA/MO
BORDER AT 02Z WILL SEE UNINHIBITED SOUTHWESTERLY INFLOW. THIS
WOULD PROMOTE CELL REDEVELOPMENT AND TRAINING ON THE STORM
SCALE...WHILE FORWARD MOVING CORFIDI VECTORS BRING A MATURE MCS
SSE AT ONLY 10 KNOTS. MEANWHILE THE MCS THAT EARLIER PRODUCED
FLOODING IN CENTRAL MISSOURI HAD BECOME PROGRESSIVE...BUT TRAINING
ALONG THE WESTERN FLANK MAY OCCUR...ESPECIALLY IF THE COLD POOL
ESTABLISHED HERE IS OVERTAKEN BY THE CONVECTION FARTHER NORTH.
GENERALLY PREDICTING THAT POCKETS OF 3-4 INCH RAINFALL ARE
POSSIBLE...WHICH WILL APPROACH GUIDANCE VALUES IN NORTHWEST MO AND
EXCEED THEM IF HEAVY RAIN REDEVELOPS TOWARD CENTRAL MO.

BURKE


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

LAT...LON   40968772 41348956 41449129 41139330 40819445 40249516
            39789524 39219448 38309236 38479087 39048950 39738850
            40248793 40968772