Heavy Rain Developing Prompts NWS ‘Hazardous Weather Outlook’

Radar indicates steady, heavy rain developing in the Chicagoland area.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
505 AM CST WED DEC 14 2011

WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE-
DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-
IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON-
505 AM CST WED DEC 14 2011

HAZARDOUS WEATHER OUTLOOK FOR NORTH CENTRAL ILLINOIS…
NORTHEAST ILLINOIS AND NORTHWEST INDIANA.

.DAY ONE…TODAY AND TONIGHT.

ISOLATED THUNDERSTORMS ARE POSSIBLE TODAY AND TONIGHT ACROSS ALL
OF NORTHERN ILLINOIS AND NORTHWEST INDIANA.

PERIODS OF MODERATE TO AT TIMES HEAVY RAINFALL WILL BE POSSIBLE
TODAY THROUGH TONIGHT. ADDITIONAL RAINFALL WILL BE AROUND 1 INCH.
SOILS WILL REMAIN RELATIVELY MOIST…RESULTING IN INCREASED RUNOFF
FROM ADDITIONAL PRECIPITATION INTO AREA STREAMS.

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HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
428 AM CST WED DEC 14 2011 /528 AM EST WED DEC 14 2011/

…RISES ON AREA STREAMS POSSIBLE TODAY AND TONIGHT…

A POTENT STORM SYSTEM WILL CONTINUE TO IMPACT NORTHERN ILLINOIS
AND NORTHWEST INDIANA THROUGH TONIGHT. NUMEROUS ROUNDS OF MODERATE
TO AT TIMES HEAVY RAINFALL CAN BE EXPECTED TODAY AND TONIGHT.
SOILS ACROSS THE AREA ARE NOT COMPLETELY SATURATED…WHICH SHOULD
ALLOW SOME OF THE PRECIPITATION TO FILTER INTO THE GROUND.
HOWEVER…WITH THE EXPECTED PERIODS OF HEAVY RAINFALL AND ISOLATED
CONVECTION THIS WILL ADD TO THE RUNOFF AND FLOW INTO AREA STREAMS.

ADDITIONAL PRECIPITATION TOTALS EXPECTED THROUGH TONIGHT SHOULD BE
BETWEEN 0.7 AND 1.1 INCHES. THE HIGHEST PRECIPITATION TOTALS ARE
EXPECTED TO FALL ALONG AND WEST OF A WAUKEGAN TO PONTIAC LINE.

THIS MAY BE SUFFICIENT TO CAUSE SOME LOCATIONS TO RISE ABOVE
BANKFULL AND POSSIBLY TO FLOOD STAGE. THE HIGHEST RISK FOR
STREAMFLOW RISES WILL BE ACROSS THE KANKAKEE WATERSHED. FLOWS HERE
HAVE REMAINED ELEVATED FROM RECENT RAINFALL.

PERSONS LIVING IN LOW LYING FLOOD PRONE AREAS SHOULD CONTINUE TO
CLOSELY MONITOR THIS DEVELOPING WEATHER SITUATION.