449  
FGUS73 KLOT 132024  
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  
230 PM CST THU FEB 13 2020  
   
..2020 SPRING FLOOD AND WATER RESOURCES OUTLOOK NUMBER 1
 
 
   
..LOCATIONS COVERED BY THIS OUTLOOK
 
 
THIS OUTLOOK IS FOR RIVERS AND STREAMS WITHIN THE NATIONAL WEATHER  
SERVICE CHICAGO HYDROLOGIC SERVICE AREA (HSA). THE CHICAGO HSA COVERS  
MOST OF NORTHEAST ILLINOIS AND A PORTION OF FAR NORTHWEST INDIANA.  
THIS INCLUDES THE ILLINOIS RIVER DOWNSTREAM TO JUST BELOW LA SALLE,  
AND NUMEROUS ILLINOIS RIVER TRIBUTARIES INCLUDING THE FOX, DUPAGE,  
DES PLAINES, CALUMET, IROQUOIS, KANKAKEE, AND VERMILION RIVERS. THIS  
INCLUDES THE ROCK RIVER FROM NEAR ROCKTON DOWNSTREAM TO NEAR DIXON,  
AND ROCK RIVER TRIBUTARIES INCLUDING THE PECATONICA AND KISHWAUKEE  
RIVERS. THIS OUTLOOK COVERS THE TIME PERIOD FROM EARLY MARCH THROUGH  
LATE MAY.  
 
   
..OUTLOOK BRIEF SUMMARY
 
 
BASED UPON CURRENT CONDITIONS, THE RISK OF FLOODING IS NEAR AVERAGE  
TO ABOVE AVERAGE. THE GREATEST RISK OF FLOODING IS IN THE ROCK RIVER  
BASIN.  
 
ADDITIONAL RAINFALL OR SNOWFALL MAY CHANGE THE RISK OF FLOODING LATER  
THIS SPRING.  
 
   
..RISK FACTORS FOR SPRING FLOODING
 
 
TO DETERMINE THE RELATIVE RISK OF SPRING FLOODING, NUMEROUS FACTORS  
ARE CONSIDERED INCLUDING SNOW COVER, SOIL MOISTURE, AND CURRENT RIVER  
CONDITIONS. A SIGNIFICANT SNOW COVER WITH HIGH WATER CONTENT CAN  
INCREASE THE CHANCES OF FLOODING ONCE WARMER WEATHER MELTS THE SNOW.  
ELEVATED SOIL MOISTURE CONDITIONS REDUCE THE AMOUNT OF RAINFALL THAT  
IS SOAKED UP BY THE GROUND AND INCREASE THE AMOUNT OF WATER THAT THEN  
RUNS OFF INTO AREA STREAMS. ABOVE AVERAGE RIVER LEVELS REDUCE THE  
RIVER RISE REQUIRED TO REACH FLOOD STAGE, WHILE BELOW AVERAGE RIVER  
LEVELS WOULD REQUIRE AN INCREASED AMOUNT OF RIVER RISE TO REACH FLOOD  
STAGE.  
 
   
..SNOW COVER AND WATER EQUIVALENT
 
 
MODELED SNOW COVER ACROSS AREA RIVER BASINS RANGES FROM NEAR 1 INCH  
TO NEAR 8 INCHES, WHICH CONTAINS 0 INCHES TO 2 INCHES OF WATER  
EQUIVALENT. THE DEEPEST SNOW COVER WAS IN FAR NORTHERN ILLINOIS AND  
SOUTHERN WISCONSIN. THE MAJORITY OF THE AREA HAD SNOW WATER  
EQUIVALENT VALUES OF LESS THAN 1 INCH.  
 
   
..SOIL MOISTURE AND FROST DEPTH
 
 
MODELED SOIL MOISTURE VALUES ACROSS THE AREA RANGE FROM SLIGHTLY  
ABOVE AVERAGE TO MUCH ABOVE AVERAGE, WITH THE HIGHEST VALUES IN FAR  
NORTHERN ILLINOIS AND SOUTH CENTRAL WISCONSIN. IN FAR NORTHWESTERN  
INDIANA, SOIL MOISTURE VALUES RANGE FROM THE 90TH TO 95TH PERCENTILE  
FOR MID FEBRUARY WHILE WIDESPREAD AREAS OF VALUES ABOVE THE 99TH  
PERCENTILE EXIST IN ILLINOIS AND WISCONSIN.  
 
FROST DEPTH RANGED FROM 0 TO 8 INCHES ACROSS AREA RIVER BASINS, WITH  
AREAS SOUTH OF THE WISCONSIN BORDER 5 INCHES OR LESS.  
 
   
..CURRENT RIVER CONDITIONS
 
 
AS OF FEBRUARY 12, RIVER LEVELS ACROSS THE AREA RANGED FROM NEAR  
AVERAGE TO ABOVE AVERAGE. THE HIGHEST RIVER LEVELS WERE IN THE ROCK  
RIVER BASIN IN NORTHERN ILLINOIS.  
 
RIVER ICE SPOTTERS REPORT GENERALLY ICE-FREE CONDITIONS ACROSS AREA  
RIVERS. COLD TEMPERATURES IN THE NEAR TERM MAY CAUSE AN INCREASE IN  
RIVER ICE COVER. RIVER ICE MAY STILL CAUSE ICE JAMS THIS SPRING, BUT  
CONFIDENCE IS LOW AS OF THIS OUTLOOK.  
 
   
..FALL 2019 WEATHER SUMMARY
 
 
TEMPERATURES WERE GENERALLY BELOW THE CLIMATIC AVERAGE ACROSS  
NORTHEAST ILLINOIS AND NORTHWEST INDIANA DURING FALL 2019.  
TEMPERATURES TRENDED MORE TOWARD BELOW AVERAGE VALUES WHEN MOVING  
FROM SOUTHEAST TO NORTHWEST. ALMOST ALL AREAS EXPERIENCED  
TEMPERATURES 1-2F BELOW AVERAGE.  
 
PRECIPITATION WAS GENERALLY ABOVE THE CLIMATIC AVERAGE ACROSS  
NORTHEAST ILLINOIS AND NORTHWEST INDIANA DURING FALL 2019.  
PRECIPITATION WAS HEAVIEST TO THE NORTHWEST NEAR THE  
ILLINOIS/WISCONSIN/IOWA BORDER. PORTIONS OF NORTHWEST INDIANA  
EXPERIENCED PRECIPITATION ABOUT 125-150% OF AVERAGE WHILE NORTH  
CENTRAL AND NORTHWEST ILLINOIS EXPERIENCED PRECIPITATION GREATER THAN  
200% OF AVERAGE.  
 
   
..WINTER 2019-2020 WEATHER SUMMARY
 
 
TEMPERATURES FOR WINTER 2019-2020 THROUGH JANUARY AVERAGED ABOUT 6F  
ABOVE THE CLIMATIC AVERAGE IN NORTHEAST ILLINOIS.  
 
PRECIPITATION FOR WINTER 2019-2020 THROUGH JANUARY AVERAGED ABOUT 0.8  
INCHES ABOVE THE CLIMATIC AVERAGE IN NORTHEAST ILLINOIS.  
 
THE FIRST MEASURABLE SNOWFALL (>0.1 INCHES) ACROSS NORTHEAST ILLINOIS  
GENERALLY OCCURRED IN MID-OCTOBER. THE FIRST MEASURABLE SNOW IN  
NORTHWEST INDIANA GENERALLY OCCURRED IN EARLY NOVEMBER. AS OF  
FEBRUARY 12, 2020, THE SEASON-TO-DATE SNOWFALL RANGED FROM 10-30  
INCHES ACROSS THE AREA, WITH THE HIGHEST TOTALS (OVER 20 INCHES) TO  
THE NORTHWEST. OBSERVED SNOWFALL RANGES FROM MUCH BELOW THE CLIMATIC  
AVERAGE IN NORTHWEST INDIANA TO SLIGHTLY ABOVE AVERAGE IN SOME  
PORTIONS OF WESTERN AND NORTHWESTERN ILLINOIS.  
 
HEAVY RIVER ICE CONDITIONS IN JANUARY CAUSED ICE JAMS LEADING TO  
MINOR FLOOD IMPACTS IN A FEW AREAS.  
 
   
..SPRING WEATHER OUTLOOK
 
 
THE LONG TERM (NEXT COUPLE MONTHS) OUTLOOK FROM THE CLIMATE  
PREDICTION CENTER INDICATES NEAR EQUAL CHANCES OF BELOW AVERAGE, NEAR  
AVERAGE, OR ABOVE AVERAGE TEMPERATURES AND PRECIPITATION.  
 
ALTHOUGH SNOW COVER, SOIL MOISTURE, AND RECENT RIVER LEVELS CAN  
PROVIDE SOME INDICATION OF THE RELATIVE RISK OF SPRING FLOODING, ANY  
WEATHER SYSTEM THAT PRODUCES HEAVY RAINFALL COULD CAUSE FLOODING.  
SPRING FLOOD OUTLOOKS ARE NOT ABLE TO ASSESS THE RISK OF FLOODING DUE  
TO HEAVY RAINFALL MORE THAN A WEEK OR SO IN ADVANCE.  
 
   
..DETAILED FLOOD OUTLOOK
 
 
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: 02/17/2020 - 05/17/2020  
 
: 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 : <5 <5 <5 <5 <5 <5  
:LITTLE CALUMET RIVER  
MUNSTER (HOHMAN A 12.0 14.0 17.0 : 45 46 13 20 <5 6  
SOUTH HOLLAND 16.5 18.0 20.0 : <5 <5 <5 <5 <5 <5  
:NORTH BRANCH CHICAGO RIVER  
CHICAGO (PULASKI 18.0 20.0 21.0 : 26 21 6 5 <5 <5  
:DES PLAINES RIVER  
RUSSELL 7.0 9.0 10.0 : 44 47 <5 11 <5 6  
GURNEE 7.0 9.0 11.0 : 36 36 <5 9 <5 <5  
LINCOLNSHIRE 12.5 14.0 15.5 : 18 20 <5 9 <5 5  
DES PLAINES 15.0 18.0 19.0 : 15 16 <5 <5 <5 <5  
RIVER FOREST 16.0 17.5 18.5 : <5 <5 <5 <5 <5 <5  
RIVERSIDE 7.5 8.0 9.0 : 16 19 11 13 <5 <5  
LEMONT 10.0 13.0 15.0 : 48 45 <5 <5 <5 <5  
:WB DU PAGE RIVER  
WARRENVILLE 11.5 14.5 17.5 : 13 16 <5 <5 <5 <5  
:EAST BRANCH DU PAGE RIVER  
BOLINGBROOK 19.5 21.0 23.0 : 43 42 <5 5 <5 <5  
:DU PAGE RIVER  
PLAINFIELD 12.0 14.0 15.0 : <5 <5 <5 <5 <5 <5  
SHOREWOOD 6.5 8.0 10.0 : 10 13 <5 <5 <5 <5  
:FOX RIVER  
ALGONQUIN LOCK & 9.5 10.5 12.0 : 60 56 30 33 16 19  
MONTGOMERY 13.0 14.0 15.0 : 60 51 10 13 <5 <5  
DAYTON 12.0 14.0 24.0 : 46 48 17 18 <5 <5  
:KANKAKEE RIVER  
DUNNS BRIDGE 10.0 12.0 13.0 : 39 34 <5 7 <5 6  
KOUTS 11.0 13.0 14.0 : 37 27 <5 7 <5 5  
SHELBY 10.5 11.5 12.5 : 56 49 35 25 19 19  
MOMENCE 5.0 6.5 9.0 : 35 32 10 12 <5 <5  
:IROQUOIS RIVER  
RENSSELAER 12.0 14.0 15.0 : 31 34 8 7 6 6  
FORESMAN 18.0 22.0 24.0 : 35 36 <5 <5 <5 <5  
IROQUOIS 18.0 24.0 25.0 : 66 63 <5 6 <5 5  
:SUGAR CREEK  
MILFORD 18.0 22.0 26.0 : 52 49 10 15 <5 <5  
:IROQUOIS RIVER  
CHEBANSE 16.0 18.0 20.0 : 14 15 7 10 6 8  
:KANKAKEE RIVER  
WILMINGTON 6.5 8.0 10.0 : 15 18 6 8 <5 <5  
:MAZON RIVER  
COAL CITY 12.0 14.0 17.0 : 17 18 <5 5 <5 <5  
:VERMILION RIVER  
PONTIAC 14.0 15.0 18.0 : 12 12 8 8 <5 <5  
LEONORE 16.0 21.0 26.0 : 39 35 11 12 <5 <5  
:PECATONICA RIVER  
SHIRLAND 12.0 14.0 15.5 : 70 43 30 16 <5 <5  
:ROCK RIVER  
ROCKTON 10.0 11.0 14.0 : 43 25 25 14 <5 <5  
LATHAM PARK 9.0 11.0 13.5 : 57 34 25 13 7 7  
ROCKFORD (AUBURN 6.0 8.5 10.0 : 11 9 <5 <5 <5 <5  
:KISHWAUKEE RIVER  
BELVIDERE 9.0 10.0 12.0 : 13 12 <5 6 <5 <5  
:SB KISHWAUKEE RIVER  
DEKALB 10.0 11.0 12.5 : <5 <5 <5 <5 <5 <5  
:KISHWAUKEE RIVER  
PERRYVILLE 12.0 18.0 22.0 : 36 34 <5 <5 <5 <5  
:ROCK RIVER  
BYRON 13.0 14.0 16.0 : 31 15 16 12 7 8  
DIXON 16.0 18.0 20.0 : 14 14 <5 7 <5 <5  
:ILLINOIS RIVER  
MORRIS 16.0 18.0 22.0 : 42 42 24 26 7 6  
OTTAWA 463.0 467.0 471.0 : 37 39 16 16 <5 <5  
LA SALLE 20.0 27.0 31.0 : 76 73 18 19 <5 5  
 
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: 02/17/2020 - 05/17/2020  
LOCATION 95% 90% 75% 50% 25% 10% 5%  
-------- ------ ------ ------ ------ ------ ------ ------  
:HART DITCH  
DYER 3.8 4.0 4.7 5.6 6.7 7.5 8.2  
:THORN CREEK  
THORNTON 5.1 5.6 6.1 7.1 8.3 9.0 9.9  
:LITTLE CALUMET RIVER  
MUNSTER (HOHMAN A 9.0 9.2 10.3 11.6 12.9 15.0 16.3  
SOUTH HOLLAND 9.9 10.6 11.3 12.6 14.2 14.9 15.4  
:NORTH BRANCH CHICAGO RIVER  
CHICAGO (PULASKI 13.2 13.8 15.8 16.9 18.0 19.7 20.2  
:DES PLAINES RIVER  
RUSSELL 4.7 5.4 6.0 6.8 7.7 8.2 8.7  
GURNEE 4.0 4.7 5.3 6.2 7.4 8.5 8.8  
LINCOLNSHIRE 8.4 9.3 9.7 10.8 12.1 13.5 14.0  
DES PLAINES 9.9 11.1 12.1 13.0 14.1 16.4 17.9  
RIVER FOREST 7.1 8.3 10.3 11.5 12.8 15.2 15.8  
RIVERSIDE 3.8 4.4 5.6 6.1 6.9 8.1 8.7  
LEMONT 7.4 8.0 9.4 9.9 10.8 11.9 12.7  
:WB DU PAGE RIVER  
WARRENVILLE 9.1 9.3 9.8 10.6 11.2 11.6 12.0  
:EAST BRANCH DU PAGE RIVER  
BOLINGBROOK 16.6 16.9 17.8 18.9 20.1 20.5 20.8  
:DU PAGE RIVER  
PLAINFIELD 8.5 8.6 9.2 9.9 10.5 11.0 11.9  
SHOREWOOD 3.4 3.7 4.4 5.1 6.0 6.5 7.4  
:FOX RIVER  
ALGONQUIN LOCK & 7.8 8.3 8.9 9.9 11.0 13.0 14.4  
MONTGOMERY 12.3 12.5 12.7 13.1 13.4 14.0 14.2  
DAYTON 8.6 9.2 10.5 11.9 12.9 15.6 16.7  
:KANKAKEE RIVER  
DUNNS BRIDGE 7.5 7.9 8.8 9.7 10.7 11.4 11.8  
KOUTS 8.2 8.7 9.6 10.5 11.5 12.2 12.6  
SHELBY 8.8 9.0 9.8 11.1 12.0 13.3 13.3  
MOMENCE 3.4 3.5 3.9 4.7 5.3 6.5 8.2  
:IROQUOIS RIVER  
RENSSELAER 7.5 8.6 9.8 11.0 12.3 13.4 16.9  
FORESMAN 12.8 13.9 15.8 17.3 18.8 20.2 21.1  
IROQUOIS 13.7 14.5 17.2 19.1 21.3 22.4 23.9  
:SUGAR CREEK  
MILFORD 12.3 13.5 16.6 18.1 19.8 22.1 24.4  
:IROQUOIS RIVER  
CHEBANSE 8.1 9.1 10.7 12.8 15.1 16.6 20.1  
:KANKAKEE RIVER  
WILMINGTON 3.3 3.5 4.2 5.2 5.9 7.0 8.2  
:MAZON RIVER  
COAL CITY 5.1 5.6 7.6 9.7 11.0 13.2 13.5  
:VERMILION RIVER  
PONTIAC 6.1 6.6 7.6 10.1 11.6 14.2 17.4  
LEONORE 9.3 9.9 12.0 14.7 17.8 21.2 22.5  
:PECATONICA RIVER  
SHIRLAND 10.8 11.0 11.7 12.9 14.2 14.7 15.3  
:ROCK RIVER  
ROCKTON 6.7 6.9 7.7 9.3 11.0 12.5 13.8  
LATHAM PARK 7.2 7.4 8.1 9.4 11.0 12.7 14.1  
ROCKFORD (AUBURN 3.4 3.5 3.6 4.1 5.0 6.2 7.4  
:KISHWAUKEE RIVER  
BELVIDERE 4.3 5.0 5.7 6.7 7.9 9.1 9.5  
:SB KISHWAUKEE RIVER  
DEKALB 5.4 5.9 6.5 7.5 8.3 9.2 9.8  
:KISHWAUKEE RIVER  
PERRYVILLE 9.1 9.7 10.3 11.7 12.4 13.7 15.4  
:ROCK RIVER  
BYRON 9.7 9.9 10.7 12.5 13.4 15.0 16.4  
DIXON 11.9 12.0 12.7 14.2 15.2 16.7 17.8  
:ILLINOIS RIVER  
MORRIS 7.8 8.3 11.4 15.3 17.3 21.2 22.8  
OTTAWA 459.2 459.3 460.9 462.0 464.6 468.6 470.4  
LA SALLE 15.6 16.4 20.3 23.5 25.7 29.6 30.6  
 
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: 02/17/2020 - 05/17/2020  
LOCATION 95% 90% 75% 50% 25% 10% 5%  
-------- ------ ------ ------ ------ ------ ------ ------  
:HART DITCH  
DYER 2.2 2.2 2.1 2.1 2.0 2.0 1.9  
:THORN CREEK  
THORNTON 3.0 2.9 2.9 2.8 2.8 2.7 2.7  
:LITTLE CALUMET RIVER  
MUNSTER (HOHMAN A 5.5 5.4 5.3 5.1 5.0 4.9 4.9  
SOUTH HOLLAND 5.8 5.7 5.5 5.4 5.3 5.2 5.1  
:NORTH BRANCH CHICAGO RIVER  
CHICAGO (PULASKI 11.4 11.4 11.2 11.2 11.1 11.0 11.0  
:DES PLAINES RIVER  
RUSSELL 3.4 3.3 3.2 3.0 2.9 2.7 2.6  
GURNEE 2.6 2.4 2.2 2.0 1.8 1.5 1.5  
LINCOLNSHIRE 7.2 7.0 6.8 6.6 6.4 6.1 6.1  
DES PLAINES 9.0 8.8 8.5 8.3 8.0 7.8 7.7  
RIVER FOREST 5.3 5.1 4.6 4.0 3.6 3.1 3.0  
RIVERSIDE 2.6 2.4 2.3 2.0 1.9 1.6 1.6  
LEMONT 6.3 6.1 5.9 5.6 5.4 5.2 5.1  
:WB DU PAGE RIVER  
WARRENVILLE 7.8 7.8 7.8 7.7 7.6 7.6 7.5  
:EAST BRANCH DU PAGE RIVER  
BOLINGBROOK 14.9 14.8 14.8 14.6 14.5 14.5 14.4  
:DU PAGE RIVER  
PLAINFIELD 6.9 6.8 6.8 6.7 6.7 6.6 6.5  
SHOREWOOD 2.5 2.4 2.4 2.3 2.2 2.2 2.2  
:FOX RIVER  
ALGONQUIN LOCK & 6.6 6.2 5.8 5.4 5.2 4.9 4.8  
MONTGOMERY 11.9 11.8 11.6 11.4 11.3 11.2 11.2  
DAYTON 7.4 7.1 6.8 6.2 5.9 5.6 5.5  
:KANKAKEE RIVER  
DUNNS BRIDGE 5.3 5.1 4.9 4.5 4.2 4.0 3.7  
KOUTS 6.0 5.8 5.6 5.3 4.9 4.8 4.5  
SHELBY 6.7 6.5 6.2 5.9 5.4 5.2 5.0  
MOMENCE 2.5 2.4 2.3 2.2 2.0 1.9 1.8  
:IROQUOIS RIVER  
RENSSELAER 4.7 4.6 4.5 4.3 4.0 3.8 3.7  
FORESMAN 7.7 7.6 7.2 6.8 6.3 6.0 5.8  
IROQUOIS 7.7 7.3 6.9 6.4 5.7 5.3 5.2  
:SUGAR CREEK  
MILFORD 4.2 4.1 3.8 3.7 3.6 3.4 3.4  
:IROQUOIS RIVER  
CHEBANSE 4.8 4.5 4.2 3.9 3.6 3.4 3.2  
:KANKAKEE RIVER  
WILMINGTON 2.1 2.0 1.9 1.8 1.6 1.5 1.5  
:MAZON RIVER  
COAL CITY 2.1 2.0 1.9 1.8 1.6 1.4 1.4  
:VERMILION RIVER  
PONTIAC 3.7 3.6 3.5 3.4 3.3 3.2 3.0  
LEONORE 5.1 4.9 4.7 4.6 4.3 4.1 4.0  
:PECATONICA RIVER  
SHIRLAND 6.9 6.8 6.8 6.4 5.9 5.5 5.3  
:ROCK RIVER  
ROCKTON 4.6 4.6 4.6 4.5 3.6 3.2 2.8  
LATHAM PARK 5.5 5.5 5.4 5.4 4.7 4.4 4.2  
ROCKFORD (AUBURN 3.1 3.1 3.1 3.1 2.8 2.7 2.6  
:KISHWAUKEE RIVER  
BELVIDERE 2.3 2.2 2.1 1.8 1.7 1.5 1.4  
:SB KISHWAUKEE RIVER  
DEKALB 3.5 3.5 3.4 3.3 3.3 3.2 3.2  
:KISHWAUKEE RIVER  
PERRYVILLE 6.7 6.7 6.5 6.2 6.1 5.8 5.8  
:ROCK RIVER  
BYRON 7.4 7.4 7.4 7.2 6.4 6.0 5.8  
DIXON 9.8 9.8 9.8 9.5 9.0 8.6 8.4  
:ILLINOIS RIVER  
MORRIS 5.4 5.4 5.2 5.1 5.0 4.9 4.8  
OTTAWA 458.8 458.7 458.7 458.6 458.6 458.5 458.5  
LA SALLE 12.4 12.2 12.0 11.7 11.3 11.1 10.9  
 
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.  
 

 
 
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