446  
FGUS73 KDVN 131747  
ESFDVN  
IAC011-019-031-045-055-057-061-087-095-097-101-103-105-107-111-113-  
115-139-163-177-183-ILC011-015-067-071-073-085-109-131-155-161-177-  
187-195-MOC045-199-271800-  
 
PROBABILISTIC HYDROLOGIC OUTLOOK  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
1147 AM CST THU FEB 13 2020  
   
..ELEVATED RISK FOR FLOOODING THIS SPRING
 
 
   
2020 SPRING FLOOD OUTLOOK
 
 
THIS IS THE FIRST OF THREE PLANNED SPRING FLOOD OUTLOOKS FOR 2020  
FOR THE NWS QUAD CITIES HYDROLOGIC SERVICE AREA, WHICH COVERS  
PORTIONS OF EASTERN IOWA, NORTHWEST AND WEST CENTRAL ILLINOIS, AND  
EXTREME NORTHEAST MISSOURI. RIVERS INCLUDED IN THIS OUTLOOK ARE THE  
MISSISSIPPI RIVER AND ITS TRIBUTARIES FROM ABOVE DUBUQUE, IOWA TO  
BELOW GREGORY LANDING, MISSOURI. THE PRIMARY TRIBUTARY SYSTEMS  
INCLUDE THE MAQUOKETA, WAPSIPINICON, CEDAR, IOWA, SKUNK, NORTH  
SKUNK, AND DES MOINES RIVERS IN IOWA; THE FOX RIVER IN MISSOURI; AND  
THE PECATONICA, ROCK, GREEN, AND LA MOINE RIVERS IN ILLINOIS. THIS  
OUTLOOK IS FOR THE TIME PERIOD FROM MID FEBRUARY THROUGH MID MAY.  
   
FLOOD OUTLOOK OVERVIEW
 
 
A WET FALL OF 2019 SET THE STAGE FOR ELEVATED FLOODING POTENTIAL FOR  
SPRING 2020. VERY WET SOIL CONDITIONS REMAIN ACROSS A LARGE PORTION  
OF THE UPPER MIDWEST, WITH RIVER LEVELS RUNNING WELL ABOVE NORMAL  
FOR LATE WINTER, AND WELL ABOVE NORMAL SNOW WATER EQUIVALENT ACROSS  
THE NORTHERN HALF OF THE UPPER MISSISSIPPI RIVER WATERSHED.  
 
CURRENT CONDITIONS SUGGEST THAT THE POTENTIAL FOR REACHING FLOOD  
STAGE IS ABOVE NORMAL FOR NEARLY ALL RIVERS ACROSS EASTERN IOWA,  
NORTHWEST AND WEST CENTRAL ILLINOIS, AND NORTHEAST MISSOURI. THE  
HIGHEST CONCERN FOR FLOODING THIS SEASON IS ON THE MISSISSIPPI  
RIVER, AS CURRENT FACTORS SUGGEST THAT REACHING FLOOD STAGE IS  
EXPECTED, WITH HIGH PROBABILITIES OF REACHING MAJOR FLOOD STAGE FROM  
DUBUQUE, IA THROUGH KEOKUK, IA.  
 
THE EVENTUAL SEVERITY OF ANY FLOODING WILL DEPEND ON ADDITIONAL  
PRECIPITATION, THE RATE OF SNOWMELT, AND SPRING-TIME RAINS. THERE  
WILL ALSO BE A RISK FOR LONG DURATION FLOODING THIS SEASON IF SOIL  
MOISTURE ACROSS THE REGION STAYS VERY WET.  
 
KEY POINTS:  
 
* THE HIGHEST CONCERN FOR FLOODING THIS SPRING IS ON THE MISSISSIPPI  
RIVER, WHERE THE RISK OF MAJOR FLOODING IS MUCH ABOVE NORMAL.  
HOWEVER, CONFIDENCE IS LOW AT THIS TIME IN EXACTLY HOW SEVERE  
FLOODING WOULD BE AT SPECIFIC LOCATIONS.  
* POTENTIAL FOR WIDESPREAD MINOR FLOODING IS ABOVE NORMAL FOR ALL  
RIVERS IN THE AREA.  
* ADDITIONAL HEAVY SNOWFALL, A RAPID SNOW MELT, AND HEAVY SPRING  
RAINS WOULD INCREASE THE THREAT FOR MORE SEVERE FLOODING.  
CONVERSELY, LITTLE OR NO ADDITIONAL SNOWFALL, A PROLONGED MELT,  
AND LIGHTER SPRING RAINS WOULD DECREASE THE FLOOD THREAT.  
* IF HIGH SOIL MOISTURE LEVELS PERSIST, THE THREAT FOR LONG-DURATION  
MISSISSIPPI RIVER FLOODING WILL INCREASE.  
 
MANY FACTORS HAVE BEEN CONSIDERED WHEN EVALUATING THE OVERALL FLOOD  
RISK FOR THE UPCOMING SPRING SEASON. THE COMBINATION OF THESE  
INFLUENCES FACTOR INTO THE FINAL DETERMINATION. THE PRIMARY FACTORS  
LEADING TO THIS YEARS ABOVE NORMAL FLOOD RISK ARE:  
 
* AN EXPANSIVE PORTION OF THE UPPER MISSISSIPPI RIVER WATERSHED IS  
OBSERVING EXTREMELY WET SOIL CONDITIONS. THE FLOOD RISK WILL  
REMAIN ELEVATED UNTIL SOILS DRY OUT.  
* SNOWPACK VARIES ACROSS THE REGION. A SUBSTANTIAL SNOWPACK IS IN  
PLACE ACROSS THE NORTHERN HALF OF THE UPPER MISSISSIPPI RIVER  
WATERSHED, WHILE WATERSHEDS FOR LOCAL IOWA, ILLINOIS, AND MISSOURI  
RIVERS HAVE LIMITED SNOW COVER.  
 
FOR FURTHER DETAILS ON ALL FACTORS CONSIDERED, SEE BELOW.  
 
.SEASONAL PRECIPITATION SUMMARY:  
 
FOR THE WINTER SEASON, DECEMBER THROUGH MID-FEBRUARY, MUCH OF THE  
LOCAL AREA HAS OBSERVED NEAR TO BELOW NORMAL PRECIPITATION. THIS HAS  
LED TO LOWER THAN NORMAL SNOW COVER ACROSS EASTERN IOWA, WESTERN  
ILLINOIS AND NORTHEAST MISSOURI. ON THE OTHER HAND, FURTHER NORTH IN  
NORTHERN IOWA, MINNESOTA, AND WISCONSIN INTO THE HEADWATERS OF SOME  
OF THE LOCAL RIVERS, PRECIPITATION HAS BEEN ABOVE NORMAL FOR THE  
WINTER MONTHS. THE PRECIPITATION THIS WINTER HAS EITHER CONTRIBUTED  
TO BUILDING THE SNOWPACK, OR HAS KEPT RIVER LEVELS HIGH AS THE  
PRECIPITATION EITHER FELL AS RAIN OR WAS SNOW THAT HAS ALREADY  
MELTED, WITH THE RUNOFF ALREADY MAKING INTO THE RIVERS.  
 
THE OBSERVED WINTER PRECIPITATION RAISES THE RISK FOR FLOODING ON  
THE MISSISSIPPI RIVER, AS WELL AS RIVERS THAT HAVE HEADWATERS UP  
INTO MINNESOTA, NORTHERN IOWA, AND WISCONSIN. THESE RIVERS INCLUDE  
THE ROCK RIVER IN ILLINOIS, AND THE IOWA, CEDAR, AND WAPSIPINICON  
RIVERS IN IOWA.  
 
.SNOW COVER AND LIQUID WATER CONTENT:  
 
MISSISSIPPI RIVER - INCREASED RISK  
LOCAL RIVERS - DECREASED RISK  
 
THE SNOWPACK ACROSS THE NORTHERN PARTS OF THE REGION DEEPENED DURING  
THE SECOND PORTION OF THE WINTER MONTHS, WITH THESE AREAS OBSERVING  
ABOVE NORMAL LIQUID WATER CONTENT. THE WATERSHEDS FOR THE LOCAL  
RIVERS ARE OBSERVING BELOW NORMAL SNOW COVER, LESSENING THE RISK FOR  
FLOODING DUE TO SNOWMELT RUNOFF. UNLESS LOCAL SNOWPACK BUILDS  
SIGNIFICANTLY, ANY LOCAL RIVER FLOODING WILL BE THE RESULT OF SPRING  
RAINS.  
 
THE HIGHEST RISK FOR FLOODING DUE TO THE CURRENT SNOWPACK WILL BE  
ALONG THE MAINSTEM MISSISSIPPI RIVER, WHERE EVEN A FAVORABLE  
SNOWMELT IS STILL EXPECTED TO LEAD TO SOME DEGREE OF FLOODING. THE  
RATE OF THE SNOWMELT WILL BE A KEY CONTRIBUTOR TO THE SEVERITY OF  
FLOODING THAT OCCURS.  
 
.FROST DEPTH: DECREASED RISK  
 
ON AVERAGE, TEMPERATURES HAVE BEEN ABOVE NORMAL ACROSS THE REGION  
THIS WINTER, WITH ONLY LIMITED PERIODS OF EXTREME COLD. THE LACK OF  
LONG PERIODS OF EXTREME COLD RESULTED IN A BELOW NORMAL FROST DEPTHS  
FOR PORTIONS OF THE UPPER MIDWEST. FROST DEPTHS ACROSS MINNESOTA AND  
WISCONSIN ARE GENERALLY 6 INCHES TO 2 FEET, WHICH WILL REMAIN A  
CONCERN FOR ANY FLOODING ON THE MISSISSIPPI RIVER. ACROSS IOWA,  
ILLINOIS, AND NORTHEAST MISSOURI, FROST DEPTHS ARE SHALLOWER THAN  
NORMAL, WITH OBSERVATIONS SHOWING FROZEN GROUND LESS THAN 6 INCHES  
FOR MUCH OF THE AREA.  
 
THE DEPTH OF FROZEN GROUND NOT ONLY CONTRIBUTES TO THE FLOOD RISK BY  
SIMPLY IMPLYING ANY FROZEN GROUND WILL CAUSE EFFICIENT RUNOFF FROM  
SNOWMELT OR RAINFALL, BUT THE DEPTH OF FROZEN GROUND IS ALSO A  
FACTOR TO HOW LONG IT MIGHT TAKE FOR THE GROUND TO THAW. THE LONGER  
THE GROUND STAYS FROZEN, THE LONGER TIME IT WILL TAKE BEFORE THE  
GROUND CAN BEGIN TO DRY OUT, THUS LENGTHENING THE PERIOD OF TIME  
CONDITIONS REMAIN AT A HIGHER THREAT FOR EXTREME RUNOFF DUE TO  
FROZEN GROUND OR HIGH SOIL MOISTURE.  
 
.RIVER CONDITIONS: INCREASED RISK  
 
RIVER LEVELS ARE HIGH FOR THIS TIME OF YEAR ACROSS MUCH OF THE UPPER  
MIDWEST AS PERIODS OF RAIN OR MELTING SNOW HAVE KEPT THE RIVERS FROM  
REACHING BASELINE LEVELS THIS WINTER. ACCORDING TO THE US GEOLOGICAL  
SURVEY, THE ENTIRE REGION IS EXPERIENCING ABOVE NORMAL STREAMFLOWS  
(HIGH RIVER LEVELS) FOR LATE WINTER, WITH MANY RIVERS OBSERVING  
FLOWS MUCH ABOVE NORMAL READINGS (>90 PERCENT OF NORMAL).  
 
THE SIGNIFICANCE OF HIGH STREAMFLOWS TO FLOOD RISK IS THAT A RIVER  
WITH HIGHER WATER LEVELS WILL HAVE LESS SPACE FOR ADDITIONAL WATER.  
AS A RESULT, FLOOD LEVELS CAN BE REACHED WITH LESSER RUNOFF THAN IT  
WOULD TAKE GIVEN NORMAL RIVER LEVELS FOR LATE WINTER/EARLY SPRING.  
 
.SOIL MOISTURE: INCREASED RISK  
 
WET SOILS HAVE PERSISTED THROUGH THE WINTER MONTHS AS MOISTURE FROM  
LAST FALL WAS LOCKED INTO THE SOILS DURING THE COLD SEASON. THERE  
ARE AREAS WHERE THE SOILS REMAINED THAWED THROUGH PORTIONS OF THE  
WINTER, BUT STAYED WET DUE TO RAIN OR SNOWMELT WITH LITTLE OR NO  
EVAPORATION OCCURRING TO ALLOW DRYING OF THE SOILS.  
 
THE WETTEST SOILS ARE CURRENTLY OBSERVED ACROSS MINNESOTA,  
WISCONSIN, NORTHERN IOWA AND NORTHERN ILLINOIS AS OF MID-FEBRUARY.  
SOILS ARE SLIGHTLY LESS WET FROM SOUTHERN AND EAST CENTRAL IOWA AND  
NORTHERN MISSOURI INTO WEST CENTRAL ILLINOIS.  
 
THE THREAT FOR RIVER RISES FROM SNOWMELT OR SPRING RAINFALL RUNOFF  
DUE TO VERY WET SOILS IS HIGH FOR THE MISSISSIPPI RIVER AS THE  
ENTIRE WATERSHED IS EXPERIENCING VERY WET TO SATURATED SOILS. THIS  
MEANS VERY LITTLE RUNOFF WILL BE ABLE TO BE ABSORBED BY THE SOILS SO  
RUNOFF FROM BOTH SNOWMELT AND RAINFALL WILL EFFICIENTLY MOVE INTO  
THE RIVER SYSTEMS. LOCAL WATERSHEDS WILL ALSO HAVE AN ELEVATED RISK  
FOR HIGH RUNOFF FROM SNOWMELT OR RAINFALL THIS SPRING. THESE  
WATERSHEDS ARE OBSERVING VERY WET SOILS ACROSS THE UPPER PARTS OF  
THE WATERSHEDS. HOWEVER THE LOWER PARTS OF THE WATERSHEDS HAVE  
SLIGHTLY LESS MOISTURE.  
 
.ICE JAM FLOODING: LOWER RISK  
 
THE WARMER WEATHER THIS WINTER HAS LIMITED DEVELOPMENT OF THICK  
RIVER ICE. ALTHOUGH COLDER TEMPERATURES IN MID-JANUARY DID CAUSE  
SOME ICE JAM IMPACTS ON THE MISSISSIPPI AND ROCK RIVERS, ALL RIVERS  
OBSERVED DIMINISHED ICE COVER BY MID-FEBRUARY. MANY AREA RIVERS ARE  
PRESENTLY OBSERVING LITTLE OR NO ICE COVER. COLDER AIR WILL LIKELY  
RETURN YET THIS WINTER, SO ICE DEVELOPMENT AND BUILD-UP IS STILL  
POSSIBLE. HOWEVER, WITHOUT A LONG PERIOD OF EXTREME COLD, THE RISK  
FOR DEVELOPMENT OF THICK RIVER ICE WILL BE LOW. THIS KEEPS THE RISK  
FOR SPRING BREAK-UP ICE JAMS LOW.  
 
.WEATHER OUTLOOKS:  
 
ON AVERAGE, WARMER TEMPERATURES ARE EXPECTED THROUGH THE REMAINDER  
OF FEBRUARY AND INTO MARCH, WITH HIGH PROBABILITIES FOR ABOVE NORMAL  
TEMPERATURES THROUGH THE ENTIRE UPPER MIDWEST DURING THE LAST WEEK  
OF FEBRUARY. WITH HIGH TEMPERATURES AVERAGING AROUND THE FREEZING  
MARK OVER THE FOLLOWING WEEKS, THE IMPACT TO THE SNOWPACK, AND IF IT  
WILL CAUSE RIVER RISES WILL DEPEND ON HOW WARM DAILY HIGHS GET, AND  
IF LOWS DROP BELOW FREEZING DURING THE OVERNIGHT HOURS.  
 
RISES ABOVE FREEZING DURING THE DAY, WITH BELOW FREEZING  
TEMPERATURES AT NIGHT, WOULD PROMOTE A SLOW SNOWMELT AND BE  
FAVORABLE TOWARD LIMITING THE FLOOD RISK.  
 
PRECIPITATION OUTLOOKS FOR THE NEXT 2 WEEKS TO THREE MONTHS KEEP THE  
HIGHEST RISK FOR ABOVE NORMAL PRECIPITATION GENERALLY TO THE SOUTH  
AND EAST OF THE REGION, BUT AVERAGING ABOVE NORMAL FOR MUCH OF THE  
UPPER MISSISSIPPI RIVER WATERSHED.  
 
ABOVE NORMAL TEMPERATURES WITH BELOW NORMAL PRECIPITATION WOULD BE  
FAVORABLE FOR A LESSER RISK FOR FLOODING.  
 
.SUMMARY:  
 
* MISSISSIPPI RIVER - HIGH CONFIDENCE ON MINOR FLOODING. THE RISK  
FOR REACHING EACH CATEGORY OF FLOODING IS MUCH ABOVE NORMAL,  
HOWEVER THERE IS LOW CONFIDENCE ON PEAK SEVERITY OF ANY FLOODING  
THAT WILL OCCUR.  
* LOCAL RIVERS - ABOVE NORMAL RISK FOR WIDESPREAD MINOR FLOODING,  
WITH NEAR NORMAL RISK FOR REACHING HIGHER SEVERITY FLOOD LEVELS.  
SOILS ARE WET, BUT SNOW COVER IS LIMITED SO THE FLOODING RISK WILL  
DEPEND ON ADDITIONAL SNOWS THIS SEASON OR HEAVY SPRING RAINS.  
 
* A SCENARIO TO REDUCE THE FLOOD RISK THIS SPRING WOULD BE LITTLE  
ADDITIONAL WINTER PRECIPITATION AND A GRADUAL SNOWMELT, FOLLOWED  
BY ABOVE NORMAL TEMPERATURES AND BELOW NORMAL PRECIPITATION.  
* ANY OF THE FOLLOWING SCENARIOS WOULD INCREASE THE FLOOD RISK: THE  
SNOWPACK CONTINUING TO BUILD, A COOL AND WET SPRING, A LATE AND  
QUICK SNOWMELT, AND WET CONDITIONS CONTINUING THROUGH SPRING.  
 
   
NUMERICAL RIVER OUTLOOKS
 
 
THIS OUTLOOK PROVIDES LONG-RANGE PROBABILISTIC RIVER OUTLOOKS FOR  
RIVER BASINS IN THE NWS QUAD CITIES SERVICE AREA. THIS OUTLOOK IS  
DIVIDED INTO THREE PARTS, THE FIRST PART FOR THE PROBABILITIES OF  
MINOR, MODERATE AND MAJOR FLOODING, THE SECOND PART FOR HIGH WATER  
AND THE FINAL PART FOR LOW WATER.  
 
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 GREATER 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  
-------- ----- ----- ----- : --- --- --- --- --- ---  
:MISSISSIPPI RIVER  
DUBUQUE LD11 16.0 17.0 20.5 : >95 46 >95 35 87 11  
DUBUQUE 17.0 18.0 21.5 : >95 51 >95 44 91 13  
BELLEVUE LD12 17.0 18.0 20.0 : >95 34 >95 26 86 11  
FULTON LD13 16.0 18.0 20.0 : >95 49 >95 31 90 13  
CAMANCHE 17.0 18.5 20.5 : >95 46 >95 32 90 13  
LE CLAIRE LD14 11.0 12.0 13.5 : >95 48 >95 33 92 17  
ROCK ISLAND LD15 15.0 16.0 18.0 : >95 54 >95 48 >95 22  
ILL. CITY LD16 15.0 16.0 18.0 : >95 53 >95 43 95 21  
MUSCATINE 16.0 18.0 20.0 : >95 56 >95 43 95 20  
NEW BOSTON LD17 15.0 16.5 18.5 : >95 57 >95 51 >95 28  
KEITHSBURG 14.0 15.5 17.0 : >95 56 >95 44 >95 23  
GLADSTONE LD18 10.0 12.0 14.0 : >95 57 >95 43 91 21  
BURLINGTON 15.0 16.5 18.0 : >95 56 >95 44 92 24  
KEOKUK LD19 16.0 17.5 19.0 : >95 43 94 31 80 21  
GREGORY LANDING 15.0 18.0 25.0 : >95 60 >95 39 30 <5  
 
:MAQUOKETA RIVER  
MANCHESTER HWY 20 14.0 17.0 20.0 : 15 17 12 13 6 <5  
MAQUOKETA 24.0 26.0 28.5 : 10 17 <5 14 <5 5  
 
:WAPSIPINICON RIVER  
INDEPENDENCE 12.0 13.0 15.0 : 11 6 6 6 <5 <5  
ANAMOSA SHAW RD 14.5 18.0 21.5 : 27 21 8 9 <5 <5  
DE WITT 4S 11.0 11.5 12.5 : 86 68 81 64 54 45  
 
:NORTH SKUNK RIVER  
SIGOURNEY 16.0 18.0 21.0 : 60 57 38 42 7 10  
 
:SKUNK RIVER  
AUGUSTA 15.0 17.0 20.0 : 45 43 28 32 12 14  
 
:CEDAR RIVER  
VINTON 15.0 18.0 19.0 : 21 15 8 6 7 <5  
PALO BLAIRS FERRY 12.5 15.5 17.0 : 24 20 8 6 <5 <5  
CEDAR RAPIDS 12.0 14.0 16.0 : 31 26 16 13 9 7  
CEDAR BLUFF 16.0 20.0 26.0 : 28 28 9 7 <5 <5  
CONESVILLE 13.0 15.0 16.5 : 81 52 27 25 9 7  
 
:IOWA RIVER  
MARENGO 15.0 17.0 19.0 : 84 69 53 45 6 5  
IOWA CITY 23.5 24.5 26.0 : <5 6 <5 <5 <5 <5  
LONE TREE 16.0 18.5 22.0 : 10 16 <5 7 <5 <5  
COLUMBUS JCT 23.0 25.0 26.5 : 17 13 9 5 <5 <5  
WAPELLO 21.0 25.0 27.5 : 51 44 9 6 <5 <5  
OAKVILLE 11.0 15.0 20.0 : 49 44 8 5 <5 <5  
 
:ENGLISH RIVER  
KALONA 14.0 16.0 18.0 : 56 55 31 33 10 15  
 
:DES MOINES RIVER  
KEOSAUQUA 22.0 25.0 27.0 : 15 9 <5 <5 <5 <5  
ST FRANCISVILLE 18.0 22.0 25.0 : 60 37 9 6 <5 <5  
 
:FOX RIVER  
WAYLAND 15.0 18.0 20.0 : 24 25 8 9 <5 <5  
 
:PECATONICA RIVER  
FREEPORT 13.0 14.0 16.0 : 59 34 32 17 <5 <5  
 
:ROCK RIVER  
COMO 12.5 15.5 18.0 : 34 21 5 8 <5 <5  
JOSLIN 12.0 14.0 16.5 : 80 51 56 30 19 16  
MOLINE 12.0 13.0 14.0 : 77 51 62 32 35 23  
 
:GREEN RIVER  
GENESEO 15.0 16.5 18.0 : 21 19 11 9 7 6  
 
:LA MOINE RIVER  
COLMAR 20.0 22.0 24.0 : 71 66 56 47 30 21  
 
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%  
-------- ------ ------ ------ ------ ------ ------ ------  
:MISSISSIPPI RIVER  
DUBUQUE LD11 18.8 20.0 21.7 23.2 26.4 29.0 30.4  
DUBUQUE 20.6 21.8 23.7 25.2 27.7 30.2 31.5  
BELLEVUE LD12 18.4 19.5 21.1 22.3 24.3 26.3 27.5  
FULTON LD13 19.0 20.0 21.7 23.1 26.1 28.6 30.3  
CAMANCHE 19.5 20.5 22.3 23.7 26.6 29.1 30.9  
LE CLAIRE LD14 13.2 14.0 15.3 16.8 19.7 22.4 24.4  
ROCK ISLAND LD15 18.1 18.8 20.3 21.6 24.2 26.6 28.0  
ILL. CITY LD16 18.0 18.8 20.6 22.9 25.7 27.8 29.1  
MUSCATINE 20.0 20.7 22.3 24.3 26.7 28.6 29.8  
NEW BOSTON LD17 19.2 20.0 21.4 23.0 25.5 27.3 28.4  
KEITHSBURG 17.0 17.6 18.6 20.2 23.0 25.1 25.6  
GLADSTONE LD18 13.6 14.1 15.3 17.3 20.6 22.7 23.2  
BURLINGTON 17.8 18.5 19.5 21.4 24.6 25.9 26.2  
KEOKUK LD19 17.2 18.3 19.6 21.5 24.9 26.6 27.3  
GREGORY LANDING 18.3 19.2 20.8 22.9 25.8 27.1 27.8  
 
:MAQUOKETA RIVER  
MANCHESTER HWY 20 8.1 8.3 9.1 10.3 12.8 17.7 20.5  
MAQUOKETA 15.1 15.6 17.0 18.4 20.2 24.2 25.7  
 
:WAPSIPINICON RIVER  
INDEPENDENCE 6.6 7.1 7.6 8.4 9.5 12.1 14.4  
ANAMOSA SHAW RD 9.4 10.2 11.3 12.6 14.6 17.5 19.6  
DE WITT 4S 9.8 10.8 11.9 12.6 12.9 13.6 13.8  
 
:NORTH SKUNK RIVER  
SIGOURNEY 12.8 13.4 15.0 17.3 18.8 20.1 21.4  
 
:SKUNK RIVER  
AUGUSTA 7.0 9.2 11.2 14.5 17.3 20.4 22.3  
 
:CEDAR RIVER  
VINTON 10.4 10.5 11.5 13.1 14.8 16.7 19.6  
PALO BLAIRS FERRY 9.2 9.3 10.2 11.3 12.4 14.3 16.7  
CEDAR RAPIDS 8.0 8.1 9.2 10.6 12.3 15.4 20.0  
CEDAR BLUFF 10.9 11.4 12.7 14.3 16.9 19.8 23.5  
CONESVILLE 12.0 12.6 13.4 14.2 15.2 16.4 17.6  
 
:IOWA RIVER  
MARENGO 13.0 14.1 16.0 17.1 17.9 18.8 19.0  
IOWA CITY 15.3 15.9 18.2 19.4 19.6 19.7 22.0  
LONE TREE 10.8 11.6 13.1 14.2 14.7 16.1 18.4  
COLUMBUS JCT 15.9 17.1 18.7 19.9 21.3 24.2 26.4  
WAPELLO 17.5 18.6 20.0 21.0 22.0 24.7 26.9  
OAKVILLE 7.8 8.8 10.1 11.0 11.9 14.4 16.4  
 
:ENGLISH RIVER  
KALONA 10.0 11.1 13.1 14.7 16.4 18.0 18.7  
 
:DES MOINES RIVER  
KEOSAUQUA 16.2 17.8 18.6 19.8 20.8 22.3 24.2  
ST FRANCISVILLE 14.0 16.0 16.9 18.2 19.9 21.4 24.0  
 
:FOX RIVER  
WAYLAND 5.4 6.2 8.9 12.0 14.7 17.5 18.9  
 
:PECATONICA RIVER  
FREEPORT 11.7 11.9 12.4 13.3 14.2 15.2 15.7  
 
:ROCK RIVER  
COMO 8.6 8.8 9.9 12.1 13.1 14.4 15.6  
JOSLIN 11.1 11.4 12.6 14.5 15.8 17.7 18.3  
MOLINE 11.0 11.3 12.1 13.4 14.5 15.8 16.4  
 
:GREEN RIVER  
GENESEO 7.0 8.3 11.2 13.0 14.7 17.1 18.5  
 
:LA MOINE RIVER  
COLMAR 12.3 16.2 19.0 22.5 24.4 25.4 26.9  
 
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--NON-EXCEEDANCE 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%  
-------- ------ ------ ------ ------ ------ ------ ------  
:MISSISSIPPI RIVER  
DUBUQUE LD11 5.9 5.8 5.7 5.6 5.2 5.0 5.0  
DUBUQUE 8.4 8.3 8.3 8.2 8.0 7.9 7.9  
BELLEVUE LD12 6.2 6.1 5.9 5.6 5.2 4.9 4.9  
FULTON LD13 6.4 6.3 6.0 5.7 5.2 5.0 4.9  
CAMANCHE 9.7 9.7 9.6 9.4 9.3 9.2 9.1  
LE CLAIRE LD14 5.6 5.5 5.4 5.3 5.0 4.9 4.9  
ROCK ISLAND LD15 7.2 7.1 7.1 6.8 6.3 5.9 5.7  
ILL. CITY LD16 5.7 5.7 5.7 5.5 5.1 4.8 4.7  
MUSCATINE 7.6 7.5 7.5 7.4 7.1 6.8 6.7  
NEW BOSTON LD17 6.9 6.8 6.8 6.4 5.9 5.4 5.1  
KEITHSBURG 8.2 8.1 8.1 8.0 7.4 7.1 6.8  
GLADSTONE LD18 3.6 3.5 3.5 3.4 3.0 2.7 2.5  
BURLINGTON 9.8 9.7 9.7 9.5 9.1 8.8 8.6  
KEOKUK LD19 6.5 6.5 6.3 6.2 5.9 5.4 5.2  
GREGORY LANDING 7.8 7.8 7.6 7.4 7.0 6.9 6.8  
 
:MAQUOKETA RIVER  
MANCHESTER HWY 20 4.3 4.3 4.3 4.3 4.3 4.3 4.3  
MAQUOKETA 10.8 10.8 10.8 10.8 10.7 10.6 10.5  
 
:WAPSIPINICON RIVER  
INDEPENDENCE 5.0 5.0 5.0 5.0 5.0 5.0 5.0  
ANAMOSA SHAW RD 5.6 5.6 5.6 5.6 5.6 5.5 5.5  
DE WITT 4S 6.3 6.2 6.1 6.1 6.0 6.0 5.9  
 
:NORTH SKUNK RIVER  
SIGOURNEY 4.9 4.8 4.6 4.6 4.5 4.4 4.2  
 
:SKUNK RIVER  
AUGUSTA 3.8 3.7 3.5 3.4 3.2 2.5 2.4  
 
:CEDAR RIVER  
VINTON 3.3 3.3 3.3 3.3 3.2 2.9 2.8  
PALO BLAIRS FERRY 3.8 3.8 3.8 3.7 3.6 3.3 3.3  
CEDAR RAPIDS 4.4 4.4 4.4 4.3 4.3 4.1 4.1  
CEDAR BLUFF 5.0 5.0 5.0 4.9 4.8 4.5 4.4  
CONESVILLE 7.1 7.1 7.1 7.0 6.8 6.3 6.2  
 
:IOWA RIVER  
MARENGO 6.9 6.9 6.9 6.8 6.8 6.5 6.3  
IOWA CITY 11.1 10.9 10.7 10.5 9.4 8.8 8.8  
LONE TREE 7.1 7.0 6.7 6.1 4.8 4.1 4.0  
COLUMBUS JCT 11.3 11.3 11.3 11.1 10.3 9.6 9.4  
WAPELLO 13.2 13.2 13.1 13.1 12.1 11.4 11.1  
OAKVILLE 4.0 4.0 4.0 3.9 3.1 2.5 2.4  
 
:ENGLISH RIVER  
KALONA 5.0 4.9 4.7 4.4 4.2 3.8 3.7  
 
:DES MOINES RIVER  
KEOSAUQUA 13.2 13.2 13.0 12.6 11.8 11.5 11.2  
ST FRANCISVILLE 10.4 10.4 10.1 9.6 8.5 8.0 7.6  
 
:FOX RIVER  
WAYLAND 2.4 2.3 2.1 2.0 1.9 1.8 1.6  
 
:PECATONICA RIVER  
FREEPORT 6.2 6.2 6.2 6.1 5.7 5.3 5.1  
 
:ROCK RIVER  
COMO 5.5 5.5 5.5 5.2 4.5 4.0 3.8  
JOSLIN 7.9 7.9 7.9 7.4 6.7 5.9 5.6  
MOLINE 9.4 9.4 9.4 9.2 8.8 8.4 8.3  
 
:GREEN RIVER  
GENESEO 4.7 4.4 4.1 3.9 3.6 3.3 3.2  
 
:LA MOINE RIVER  
COLMAR 5.9 5.5 5.0 4.4 4.0 3.5 3.4  
 
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 AT WEATHER.GOV/DVN FOR MORE WEATHER AND WATER  
INFORMATION AND HTTP://WWW.WEATHER.GOV/DVN/2020_SPRINGFLOODOUTLOOK  
FOR MORE SPECIFIC SPRING FLOOD OUTLOOK INFORMATION.  
 
TWO UPDATES TO THE SPRING FLOOD OUTLOOK HAVE BEEN SCHEDULED. THESE  
OUTLOOKS WILL BE ISSUED BY 5 PM ON THE FOLLOWING DATES:  
 
FEBRUARY 27, 2020  
MARCH 12, 2020  
 

 
 
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