MESOSCALE PRECIPITATION DISCUSSION 0207
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
207 PM EDT SAT JUN 13 2015
 
AREAS AFFECTED...PORTIONS OF MO, IA, AND IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 131806Z - 140006Z
 
SUMMARY...A PAIR OF SHORTWAVES INTERACTING WITH A STALLED FRONTAL
BOUNDARY ARE EXPECTED TO FOCUS THUNDERSTORMS WITH HEAVY RAINFALL
THIS AFTERNOON.  FLASH FLOODING IS POSSIBLE.

DISCUSSION...WIDELY SCATTERED THUNDERSTORMS HAVE BEGUN TO DEVELOP
ACROSS PORTIONS OF MO AND IL AS SURFACE HEATING HAS REDUCED CIN
FROM OVERNIGHT.  PRECIPITABLE WATER VALUES IN THE REGION ARE JUST
OVER 1.75", 2-2.5 SIGMAS ABOVE THE MEAN FOR MID-JUNE.  MIXED LAYER
CAPES ARE 1000-3000 J/KG ACROSS SOUTHERN MO AND CENTRAL IL. 
INFLOW AT 850 HPA IS 20 KTS OUT OF THE SOUTH-SOUTHWEST, NEAR THE
MAGNITUDE OF THE 850-400 HPA MEAN LAYER WIND.

THE RAP GUIDANCE INDICATES THAT CONVERGENCE AT 850 HPA OCCURS
ACROSS NEAR THE THERMAL BOUNDARY ACROSS CENTRAL MO DUE TO A PAIR
OF UPSTREAM SHORTWAVES ACROSS EASTERN KS AND EASTERN OK, WHICH
HELPS SET OFF NUMEROUS THUNDERSTORMS.  INFLOW AT 850 HPA INCREASES
TOWARDS 30 KTS BY 00Z, WHICH SHOULD HELP ORGANIZE CONVECTION WITH
TIME.  LAKE BREEZE BOUNDARIES FROM SOUTHERN LAKE MICHIGAN COULD
COME INTO PLAY.  THE FORWARD PROPAGATING CORFIDI VECTORS ARE
ALIGNED AND OF THE SAME MAGNITUDE AS THE MEAN FLOW (WHICH IS
NEARLY UNIDIRECTIONAL WITH HEIGHT), IMPLYING THAT CELL TRAINING IS
THE MAIN THREAT.  THE MESOSCALE GUIDANCE SHOWS A MODERATE SIGNAL
FOR LOCAL 2-3" MAXIMA ACROSS NORTHERN MO AND NORTHWEST IL.  HOURLY
RAIN RATES OF 2" ARE POSSIBLE WITH THE AVAILABLE MOISTURE, WHICH
COULD BE HIGHER IN AREAS OF EXTENSIVE CELL TRAINING OR CELL
MERGERS.  FLASH FLOODING IS POSSIBLE OVER SATURATED SOILS.  

ROTH

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

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

LAT...LON   42438774 42198767 41888753 41708739 41688724 
            41798675 41578674 41238695 40648755 39918851 
            38699097 37599339 38869362 40729201 41389077 
            41928948 42208851