550  
FGUS73 KILX 281357  
ESFILX  
ILC009-017-025-033-057-079-095-101-113-123-125-129-137-143-147-  
155-159-167-169-179-183-203-291400-  
 
PROBABILISTIC HYDROLOGIC OUTLOOK  
NATIONAL WEATHER SERVICE LINCOLN IL  
856 AM CDT FRI SEP 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: 09/30/2018 - 12/29/2018  
 
: 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  
-------- ----- ----- ----- : --- --- --- --- --- ---  
:ILLINOIS RIVER  
HENRY 23.0 24.0 31.0 : 11 13 8 13 <5 <5  
PEORIA 18.0 22.0 28.0 : 17 22 7 6 <5 <5  
PEORIA L/D 447.0 449.0 455.0 : 11 13 7 9 <5 <5  
HAVANA 14.0 17.0 23.0 : 27 28 9 9 <5 <5  
BEARDSTOWN 14.0 18.0 28.0 : 36 37 18 15 <5 <5  
:MACKINAW RIVER  
CONGERVILLE 13.0 14.0 20.0 : <5 8 <5 7 <5 <5  
:SPOON RIVER  
LONDON MILLS 15.0 21.0 24.0 : 28 17 7 6 <5 <5  
SEVILLE 22.0 25.0 30.0 : 21 16 9 7 <5 <5  
:SANGAMON RIVER  
MONTICELLO 13.0 17.0 20.0 : 33 31 6 <5 <5 <5  
RIVERTON 23.0 26.0 29.0 : 7 <5 <5 <5 <5 <5  
PETERSBURG 23.0 24.0 33.0 : 8 <5 7 <5 <5 <5  
:SALT CREEK  
GREENVIEW 16.0 17.0 20.0 : <5 6 <5 5 <5 <5  
:SANGAMON RIVER  
OAKFORD 471.0 472.9 478.5 : 11 10 <5 <5 <5 <5  
CHANDLERVILLE 456.6 459.0 462.0 : 18 14 6 <5 <5 <5  
:EMBARRAS RIVER  
LAWRENCEVILLE 30.0 37.0 41.0 : 58 33 17 8 <5 <5  
STE. MARIE 19.0 20.0 27.0 : 30 19 26 15 <5 <5  
:LITTLE WABASH RIVER  
CLAY CITY 18.0 22.0 25.0 : 81 52 36 10 <5 <5  
:VERMILION RIVER  
DANVILLE 18.0 22.0 28.0 : 8 9 <5 <5 <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: 09/30/2018 - 12/29/2018  
LOCATION 95% 90% 75% 50% 25% 10% 5%  
-------- ------ ------ ------ ------ ------ ------ ------  
:ILLINOIS RIVER  
HENRY 15.0 15.1 15.6 16.7 19.9 23.2 27.4  
PEORIA 12.1 12.2 12.6 13.2 15.1 19.7 23.6  
PEORIA L/D 432.5 433.0 435.0 436.5 442.8 447.1 450.9  
HAVANA 5.6 6.0 8.5 11.5 14.1 16.7 19.0  
BEARDSTOWN 9.9 10.0 10.7 12.1 16.5 20.4 23.3  
:MACKINAW RIVER  
CONGERVILLE 0.9 1.1 1.7 3.1 5.8 8.1 12.6  
:SPOON RIVER  
LONDON MILLS 3.5 4.5 6.3 9.3 15.6 19.7 21.8  
SEVILLE 6.6 7.4 9.6 13.1 19.8 24.7 28.7  
:SANGAMON RIVER  
MONTICELLO 6.1 6.8 7.6 11.2 13.8 15.6 17.1  
RIVERTON 6.2 6.3 8.9 13.6 18.3 22.3 24.3  
PETERSBURG 5.8 6.1 8.0 11.2 15.8 22.5 24.8  
:SALT CREEK  
GREENVIEW 1.4 1.7 2.7 4.3 8.1 11.7 14.6  
:SANGAMON RIVER  
OAKFORD 457.3 457.6 459.3 461.7 466.6 471.2 472.8  
CHANDLERVILLE 444.6 445.0 446.5 449.2 454.3 458.2 459.6  
:EMBARRAS RIVER  
LAWRENCEVILLE 22.4 23.6 27.4 31.1 34.9 38.9 40.0  
STE. MARIE 4.3 6.3 9.3 14.7 20.2 22.9 23.4  
:LITTLE WABASH RIVER  
CLAY CITY 12.7 15.4 19.5 21.3 22.5 23.2 24.1  
:VERMILION RIVER  
DANVILLE 4.2 4.7 7.3 10.0 13.2 17.1 20.2  
 
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: 09/30/2018 - 12/29/2018  
LOCATION 95% 90% 75% 50% 25% 10% 5%  
-------- ------ ------ ------ ------ ------ ------ ------  
:ILLINOIS RIVER  
HENRY 14.6 14.6 14.5 14.4 14.3 14.2 14.2  
PEORIA 10.6 10.6 10.6 10.6 10.6 10.5 10.5  
PEORIA L/D 430.9 430.7 430.4 430.2 429.9 429.7 429.6  
HAVANA 5.0 4.9 4.9 4.8 4.8 4.8 4.8  
BEARDSTOWN 9.4 9.3 9.2 9.1 9.1 9.0 9.0  
:MACKINAW RIVER  
CONGERVILLE 0.8 0.8 0.8 0.8 0.8 0.7 0.7  
:SPOON RIVER  
LONDON MILLS 3.2 3.0 2.8 2.5 2.2 2.2 2.2  
SEVILLE 6.2 6.0 5.7 5.3 5.1 5.0 5.0  
:SANGAMON RIVER  
MONTICELLO 5.3 5.2 5.1 4.9 4.7 4.6 4.6  
RIVERTON 3.9 3.6 3.3 3.0 2.8 2.6 2.6  
PETERSBURG 5.2 5.1 4.9 4.8 4.7 4.5 4.5  
:SALT CREEK  
GREENVIEW 0.8 0.8 0.7 0.7 0.7 0.6 0.6  
:SANGAMON RIVER  
OAKFORD 456.5 456.4 456.2 456.0 455.9 455.7 455.7  
CHANDLERVILLE 443.8 443.8 443.5 443.3 443.1 443.0 443.0  
:EMBARRAS RIVER  
LAWRENCEVILLE 18.5 18.4 18.0 17.8 17.7 17.6 17.5  
STE. MARIE 2.9 2.7 2.3 2.1 2.0 2.0 1.9  
:LITTLE WABASH RIVER  
CLAY CITY 5.3 5.1 5.1 5.0 4.9 4.9 4.8  
:VERMILION RIVER  
DANVILLE 2.8 2.6 2.5 2.4 2.3 2.3 2.3  
 
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/ILX FOR MORE WEATHER AND WATER  
INFORMATION.  
 
THESE OUTLOOKS ARE TYPICALLY ISSUED DURING THE THIRD OR FOURTH WEEK  
OF THE MONTH.  
 

 
 
DRH  
 
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