Graphic for MPD #0486
MESOSCALE PRECIPITATION DISCUSSION 0486
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
555 PM EDT SAT JUL 23 2016
 
AREAS AFFECTED...NORTHERN IL...SOUTHEAST WI...EXT EASTERN IA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 232154Z - 240200Z
 
SUMMARY...STATIONARY EFFICIENT CELLS IN ADVANCE OF APPROACHING
CONVECTIVE COMPLEX IN E IA THAT WILL MERGE/COLLECT AND PRODUCING
FLASH FLOODING CONDITIONS ACROSS N IL THIS EVENING.

DISCUSSION...RADAR/OBSERVATIONS/GOES-E VIS DENOTE A WELL DEFINED
OUTFLOW BOUNDARY LAID OUT BY LEAD WAVE OF CONVECTION ACROSS SE WI.
 CURRENTLY FROM MXO SOUTH OF RFD TO N OF ORD.  VWP AND OBJECTIVE
RAP ANALYSIS INDICATES STRENGTHENING SWLY FLOW ABOVE 850MB WITH
BOUNDARY LAYER SLY FLOW BOTH SUPPORT DEEP MST CONVERGENCE AND
FLUX.   THE ENVIRONMENT ACROSS SE IA/N IL IS HIGHLY UNSTABLE WITH
MLCAPES OVER 5000 J/KG WITH TPWS AOA 2.25" SUPPORTING INCREASING
CONVECTIVE DEVELOPMENT AHEAD OF STRONGEST DPVA FORCING ASSOCIATED
WITH APPROACHING CONVECTIVE COMPLEX IN E IA ATTM.   WITH THE
STRONG SWLY FLOW SUPPORTS UPSTREAM REDEVELOPMENT/BACKBUILDING
ALONG THE OUTFLOW BOUNDARY WITH LIMITED DOWNSTREAM
EVACUATION...SHOULD LEAD TO APPARENT STATIONARY CONVECTION ACROSS
N CENT TO NE IL BEFORE MAIN FORCING APPROACHES FROM THE WEST.
GIVEN THE ENVIRONMENT THIS SHOULD SUPPORT RATES AT OR ABOVE
2"/HR...LIKELY COMPOUNDING TOTALS LIKELY TO EXCEED FFG VALUES
BELOW 2.0"/3HR  
AS FOR THE CONVECTION ALONG THE MAIN UL PVA FORCING...THOUGH IT
HAS BEGUN TO ADVANCE EASTWARD OBSERVED RATES UP TO 2-3"/HR HAVE
BEEN REPORTED...LEADING TO THE POTENTIAL FOR COMPOUNDED TOTALS
ACROSS N IL AFTER 00Z-02Z TIME PERIOD...WITH FF LIKELY...POSSIBLY
AFFECTING HIGH POPULATION CORRIDOR IN CHICAGOLAND AS WELL AS
KENOSHA/RACINE. 

GALLINA

ATTN...WFO...DVN...LOT...MKX...

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

LAT...LON   43078799 42488730 41858753 41708790 41678962 
            41849076 42159125 42429074 42488992 42698875 
            


Last Updated: 555 PM EDT SAT JUL 23 2016