754  
FGUS73 KLOT 281245  
ESFLOT  
ILC007-011-031-037-063-075-089-091-093-097-099-103-105-111-  
141-197-201-INC073-089-111-127-DDHHMM-  
 
PROBABILISTIC HYDROLOGIC OUTLOOK  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL  
744 AM CDT THU JUN 28 2018  
 
IN TABLE 1 BELOW...THE CURRENT (CS) AND HISTORICAL (HS) OR NORMAL  
PROBABILITIES OF EXCEEDING MINOR...MODERATE...AND MAJOR FLOOD STAGES  
ARE LISTED FOR THE VALID TIME PERIOD.  
 
CS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY  
BASED ON CURRENT CONDITIONS.  
 
HS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY  
BASED ON HISTORICAL OR NORMAL CONDITIONS.  
 
WHEN THE VALUE OF CS IS MORE THAN HS...THE PROBABILITY OF  
EXCEEDING THAT LEVEL IS HIGHER THAN NORMAL. WHEN THE VALUE OF CS IS  
LESS THAN HS...THE PROBABILITY OF EXCEEDING THAT LEVEL IS LOWER  
THAN NORMAL.  
 
   
..TABLE 1--PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING
 
 
VALID PERIOD: 07/08/2018 - 09/29/2018  
 
: CURRENT AND HISTORICAL  
: CHANCES OF EXCEEDING  
: FLOOD CATEGORIES  
: AS A PERCENTAGE (%)  
CATEGORICAL :  
FLOOD STAGES (FT) : MINOR MODERATE MAJOR  
LOCATION MINOR MOD MAJOR : CS HS CS HS CS HS  
-------- ----- ----- ----- : --- --- --- --- --- ---  
:HART DITCH  
DYER 12.0 13.0 14.0 : 5 5 5 <5 <5 <5  
:THORN CREEK  
THORNTON 10.0 15.0 16.0 : 6 5 <5 <5 <5 <5  
:LITTLE CALUMET RIVER  
MUNSTER 12.0 14.0 17.0 : 28 24 9 8 6 6  
SOUTH HOLLAND 16.5 18.0 20.0 : <5 <5 <5 <5 <5 <5  
:NORTH BRANCH CHICAGO RIVER  
CHICAGO ALBANY AV 7.0 7.5 8.0 : 9 6 6 5 5 <5  
:DES PLAINES RIVER  
RUSSELL 7.0 9.0 10.0 : 26 14 <5 <5 <5 <5  
GURNEE 7.0 9.0 11.0 : 18 8 9 6 <5 <5  
LINCOLNSHIRE 12.5 14.0 15.5 : 10 6 6 5 <5 <5  
DES PLAINES 15.0 18.0 19.0 : 23 16 13 9 11 8  
RIVER FOREST 16.0 17.5 18.5 : 13 12 11 10 11 6  
RIVERSIDE 7.5 8.0 9.0 : 19 16 18 14 11 10  
LEMONT 10.0 11.0 12.0 : 32 20 22 16 15 13  
:W BR DU PAGE RIVER  
WARRENVILLE 11.5 14.5 17.5 : 21 15 8 5 <5 <5  
:EAST BRANCH DU PAGE RIVER  
BOLINGBROOK 19.5 21.0 23.0 : 39 32 17 14 8 8  
:DU PAGE RIVER  
PLAINFIELD 12.0 14.0 15.0 : 10 9 <5 <5 <5 <5  
SHOREWOOD 6.5 8.0 10.0 : 13 12 9 8 <5 <5  
:FOX RIVER  
ALGONQUIN TAILWAT 9.5 10.5 12.0 : 43 23 28 12 23 11  
MONTGOMERY 13.0 14.0 15.0 : 42 19 15 11 8 7  
DAYTON 12.0 14.0 24.0 : 20 13 14 8 <5 <5  
:KANKAKEE RIVER  
DUNNS BRIDGE 10.0 12.0 13.0 : 21 6 7 <5 <5 <5  
KOUTS 11.0 13.0 14.0 : 21 6 8 <5 <5 <5  
SHELBY 9.0 11.0 12.5 : 50 17 18 7 8 6  
MOMENCE 5.0 6.5 9.0 : 9 7 5 6 <5 <5  
:IROQUOIS RIVER  
RENSSELAER 12.0 14.0 15.0 : 9 8 7 <5 6 <5  
FORESMAN 18.0 22.0 24.0 : 8 6 <5 <5 <5 <5  
IROQUOIS 18.0 24.0 25.0 : 25 13 7 <5 6 <5  
:SUGAR CREEK  
MILFORD 18.0 22.0 26.0 : 20 14 6 <5 <5 <5  
:IROQUOIS RIVER  
CHEBANSE 16.0 18.0 20.0 : 11 6 9 <5 5 <5  
:KANKAKEE RIVER  
WILMINGTON 6.5 8.0 10.0 : 16 5 7 <5 <5 <5  
:MAZON RIVER  
COAL CITY 12.0 14.0 17.0 : 8 <5 <5 <5 <5 <5  
:VERMILION RIVER  
PONTIAC 14.0 15.0 18.0 : 7 6 7 5 5 <5  
LEONORE 16.0 21.0 26.0 : 25 12 6 6 5 <5  
:PECATONICA RIVER  
SHIRLAND 12.0 14.0 15.5 : 27 20 15 13 7 <5  
:ROCK RIVER  
ROCKTON 10.0 11.0 14.0 : 16 8 10 6 <5 <5  
LATHAM PARK 10.0 11.0 14.0 : 19 8 11 6 <5 <5  
ROCKFORD 9.0 10.0 11.0 : <5 <5 <5 <5 <5 <5  
:KISHWAUKEE RIVER  
BELVIDERE 9.0 10.0 12.0 : 14 8 8 <5 <5 <5  
:SOUTH BRANCH KISHWAUKEE RIVER  
DE KALB 10.0 11.0 12.5 : 10 8 9 5 <5 <5  
:KISHWAUKEE RIVER  
PERRYVILLE 12.0 18.0 22.0 : 20 11 7 5 <5 <5  
:ROCK RIVER  
BYRON 13.0 14.0 16.0 : 20 8 14 7 11 5  
DIXON 16.0 18.0 20.0 : 14 8 11 6 <5 <5  
:ILLINOIS RIVER  
MORRIS 16.0 18.0 22.0 : 22 12 15 9 7 5  
OTTAWA 463.0 466.0 469.0 : 24 12 14 8 8 7  
LA SALLE 20.0 27.0 31.0 : 40 23 11 7 7 6  
 
LEGEND  
CS = CONDITIONAL SIMULATION (CURRENT OUTLOOK)  
HS = HISTORICAL SIMULATION  
FT = FEET  
 
IN TABLE 2 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE  
PROBABILITY OF EXCEEDING THE LISTED STAGE LEVELS (FT) FOR THE VALID  
TIME PERIOD.  
   
..TABLE 2--EXCEEDANCE PROBABILITIES
 
 
CHANCE OF EXCEEDING STAGES  
AT SPECIFIC LOCATIONS  
VALID PERIOD: 07/08/2018 - 09/29/2018  
LOCATION 95% 90% 75% 50% 25% 10% 5%  
-------- ------ ------ ------ ------ ------ ------ ------  
:HART DITCH  
DYER 2.4 2.5 3.0 4.3 5.4 7.2 13.0  
:THORN CREEK  
THORNTON 3.4 3.6 4.2 5.8 7.1 8.4 11.8  
:LITTLE CALUMET RIVER  
MUNSTER 8.2 8.5 9.1 10.0 12.2 13.7 20.2  
SOUTH HOLLAND 7.8 8.0 9.0 10.2 12.2 13.9 16.0  
:NORTH BRANCH CHICAGO RIVER  
CHICAGO ALBANY AV 3.7 3.7 4.2 4.7 5.8 6.9 8.2  
:DES PLAINES RIVER  
RUSSELL 3.7 3.7 4.8 6.1 7.0 7.8 8.9  
GURNEE 3.2 3.3 3.4 4.5 6.5 8.5 10.9  
LINCOLNSHIRE 8.0 8.0 8.4 9.4 10.6 12.3 14.9  
DES PLAINES 9.6 9.7 10.5 12.2 14.8 20.4 22.6  
RIVER FOREST 6.8 7.2 8.2 9.6 12.7 18.8 22.1  
RIVERSIDE 3.7 4.0 4.6 5.1 7.1 10.0 13.9  
LEMONT 7.1 7.4 8.2 8.7 10.7 14.0 16.9  
:W BR DU PAGE RIVER  
WARRENVILLE 8.5 8.7 9.1 10.1 11.2 12.8 15.7  
:EAST BRANCH DU PAGE RIVER  
BOLINGBROOK 16.8 17.0 18.0 19.0 20.3 22.4 24.2  
:DU PAGE RIVER  
PLAINFIELD 7.9 8.0 8.4 9.4 10.4 11.9 14.0  
SHOREWOOD 2.9 3.1 3.5 4.3 5.4 7.8 9.7  
:FOX RIVER  
ALGONQUIN TAILWAT 7.0 7.0 7.5 9.2 11.8 13.8 17.5  
MONTGOMERY 12.1 12.1 12.3 12.8 13.6 14.5 15.5  
DAYTON 7.7 7.8 8.3 9.7 11.8 16.0 22.2  
:KANKAKEE RIVER  
DUNNS BRIDGE 6.0 6.0 6.4 8.0 9.4 11.5 12.8  
KOUTS 6.5 6.5 6.8 8.9 10.6 12.7 13.9  
SHELBY 7.0 7.0 7.6 9.0 10.3 12.3 13.4  
MOMENCE 2.5 2.5 2.8 3.4 3.9 4.7 6.6  
:IROQUOIS RIVER  
RENSSELAER 4.7 5.2 6.3 7.9 10.6 11.9 15.7  
FORESMAN 7.7 8.3 10.2 12.7 15.8 17.8 20.2  
IROQUOIS 6.8 7.5 9.6 13.6 18.0 22.2 25.7  
:SUGAR CREEK  
MILFORD 6.2 6.6 7.4 11.4 17.3 19.7 22.4  
:IROQUOIS RIVER  
CHEBANSE 4.7 4.9 5.9 8.2 11.0 17.7 20.9  
:KANKAKEE RIVER  
WILMINGTON 2.0 2.1 2.3 3.3 4.7 7.3 8.1  
:MAZON RIVER  
COAL CITY 2.1 2.1 2.2 6.6 9.4 11.2 13.1  
:VERMILION RIVER  
PONTIAC 4.1 4.3 5.7 7.3 10.6 11.5 18.2  
LEONORE 5.3 5.7 7.3 10.8 16.0 18.3 26.2  
:PECATONICA RIVER  
SHIRLAND 8.1 8.1 8.8 10.3 12.1 15.1 15.7  
:ROCK RIVER  
ROCKTON 5.7 5.7 5.8 6.6 8.7 11.1 13.6  
LATHAM PARK 6.6 6.6 6.7 7.3 9.2 11.2 13.5  
ROCKFORD 3.3 3.3 3.3 3.5 4.0 5.3 6.9  
:KISHWAUKEE RIVER  
BELVIDERE 2.9 2.9 3.5 4.8 6.6 9.5 11.0  
:SOUTH BRANCH KISHWAUKEE RIVER  
DE KALB 3.9 4.0 4.9 5.7 7.5 9.7 11.8  
:KISHWAUKEE RIVER  
PERRYVILLE 7.2 7.3 7.9 9.2 11.3 15.2 20.6  
:ROCK RIVER  
BYRON 8.7 8.8 8.9 9.8 12.2 16.2 18.0  
DIXON 11.0 11.1 11.1 12.1 14.3 19.1 19.8  
:ILLINOIS RIVER  
MORRIS 5.9 6.0 7.5 10.4 13.4 20.4 24.4  
OTTAWA 459.8 459.8 460.0 460.3 462.6 467.9 474.2  
LA SALLE 12.7 12.8 14.2 18.8 23.7 28.4 34.2  
 
IN TABLE 3 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE  
PROBABILITY OF FALLING BELOW THE LISTED STAGE LEVELS (FT) FOR THE  
VALID TIME PERIOD.  
   
..TABLE 3--NONEXCEEDANCE PROBABILITIES
 
 
CHANCE OF FALLING BELOW STAGES  
AT SPECIFIC LOCATIONS  
VALID PERIOD: 07/08/2018 - 09/29/2018  
LOCATION 95% 90% 75% 50% 25% 10% 5%  
-------- ------ ------ ------ ------ ------ ------ ------  
:HART DITCH  
DYER 1.8 1.8 1.8 1.7 1.7 1.6 1.6  
:THORN CREEK  
THORNTON 2.8 2.8 2.7 2.7 2.7 2.7 2.6  
:LITTLE CALUMET RIVER  
MUNSTER 5.1 5.0 4.9 4.8 4.8 4.7 4.7  
SOUTH HOLLAND 5.3 5.3 5.2 5.2 5.1 5.1 5.0  
:NORTH BRANCH CHICAGO RIVER  
CHICAGO ALBANY AV 1.4 1.4 1.3 1.2 1.1 1.1 1.1  
:DES PLAINES RIVER  
RUSSELL 2.5 2.3 2.0 1.9 1.8 1.8 1.8  
GURNEE 2.0 1.9 1.5 1.4 1.4 1.3 1.3  
LINCOLNSHIRE 6.8 6.7 6.3 6.2 6.2 6.1 6.1  
DES PLAINES 8.2 8.2 7.8 7.7 7.7 7.6 7.6  
RIVER FOREST 4.0 3.8 3.3 3.0 2.9 2.7 2.6  
RIVERSIDE 2.2 2.1 1.9 1.8 1.7 1.7 1.6  
LEMONT 5.7 5.5 5.2 5.1 5.0 4.9 4.9  
:W BR DU PAGE RIVER  
WARRENVILLE 7.8 7.8 7.8 7.7 7.7 7.7 7.7  
:EAST BRANCH DU PAGE RIVER  
BOLINGBROOK 14.9 14.8 14.7 14.7 14.7 14.6 14.6  
:DU PAGE RIVER  
PLAINFIELD 7.2 7.2 7.1 7.1 7.1 7.0 7.0  
SHOREWOOD 2.2 2.1 2.1 2.1 2.1 2.1 2.0  
:FOX RIVER  
ALGONQUIN TAILWAT 5.5 5.2 4.9 4.8 4.7 4.6 4.6  
MONTGOMERY 11.5 11.3 11.2 11.1 11.1 11.1 11.0  
DAYTON 6.3 5.9 5.6 5.4 5.3 5.2 5.2  
:KANKAKEE RIVER  
DUNNS BRIDGE 4.2 4.1 3.9 3.7 3.6 3.5 3.4  
KOUTS 4.6 4.5 4.2 4.0 3.9 3.8 3.7  
SHELBY 5.4 5.3 5.0 4.8 4.7 4.5 4.4  
MOMENCE 1.9 1.8 1.7 1.6 1.6 1.5 1.5  
:IROQUOIS RIVER  
RENSSELAER 4.1 3.8 3.6 3.5 3.3 3.2 3.1  
FORESMAN 6.1 5.7 5.3 5.1 4.8 4.6 4.6  
IROQUOIS 5.5 5.0 4.7 4.6 4.1 3.9 3.9  
:SUGAR CREEK  
MILFORD 3.2 2.8 2.1 1.9 1.9 1.9 1.9  
:IROQUOIS RIVER  
CHEBANSE 3.3 3.2 2.9 2.7 2.4 2.3 2.3  
:KANKAKEE RIVER  
WILMINGTON 1.4 1.4 1.2 1.1 1.1 1.1 1.0  
:MAZON RIVER  
COAL CITY 1.5 1.2 0.3 0.3 0.3 0.3 0.3  
:VERMILION RIVER  
PONTIAC 3.2 3.2 3.1 3.0 2.9 2.9 2.8  
LEONORE 4.1 4.0 3.8 3.7 3.6 3.5 3.5  
:PECATONICA RIVER  
SHIRLAND 5.5 5.3 4.8 4.4 4.2 4.0 3.9  
:ROCK RIVER  
ROCKTON 3.2 3.0 2.7 2.4 2.3 2.2 2.2  
LATHAM PARK 4.5 4.4 4.2 3.9 3.8 3.7 3.7  
ROCKFORD 2.8 2.7 2.6 2.5 2.4 2.3 2.3  
:KISHWAUKEE RIVER  
BELVIDERE 1.8 1.6 1.5 1.4 1.3 1.2 1.1  
:SOUTH BRANCH KISHWAUKEE RIVER  
DE KALB 3.4 3.4 3.3 3.2 3.1 3.1 3.1  
:KISHWAUKEE RIVER  
PERRYVILLE 6.2 6.0 5.8 5.7 5.6 5.5 5.5  
:ROCK RIVER  
BYRON 6.4 6.0 5.7 5.5 5.3 5.2 5.2  
DIXON 9.0 8.6 8.4 8.2 8.0 7.9 7.9  
:ILLINOIS RIVER  
MORRIS 5.2 5.0 4.8 4.7 4.6 4.6 4.6  
OTTAWA 459.3 459.1 459.1 459.0 459.0 459.0 459.0  
LA SALLE 11.5 11.2 10.9 10.8 10.8 10.7 10.7  
 
THESE LONG-RANGE PROBABILISTIC OUTLOOKS CONTAIN FORECAST VALUES THAT  
ARE CALCULATED USING MULTIPLE SEASON SCENARIOS FROM 30 OR MORE YEARS  
OF CLIMATOLOGICAL DATA...INCLUDING CURRENT CONDITIONS OF THE  
RIVER...SOIL MOISTURE...SNOW COVER...AND 30 TO 90 DAY LONG-RANGE  
OUTLOOKS OF TEMPERATURE AND PRECIPITATION. BY PROVIDING A RANGE OF  
PROBABILITIES...THE LEVEL OF RISK ASSOCIATED WITH LONG-RANGE PLANNING  
DECISIONS CAN BE DETERMINED. THESE PROBABILISTIC FORECASTS ARE PART  
OF THE NATIONAL WEATHER SERVICE'S ADVANCED HYDROLOGIC PREDICTION  
SERVICE.  
 
VISIT OUR WEB SITE WEATHER.GOV/LOT FOR MORE WEATHER AND WATER  
INFORMATION.  
 
THE NEXT OUTLOOK WILL BE ISSUED TOWARD THE END OF NEXT MONTH.  
 

 
 
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