FGUS73 KDVN 141659 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-MOC045-199-151800- Probabilistic Hydrologic Outlook National Weather Service Quad Cities IA IL 1159 AM CDT Thu Mar 14 2024 .2024 Spring Flood and Water Resources Outlook 3... ...Well Below Normal Flood Risk This Spring... This is the third and final update of the three planned Spring Flood and Water Resource Outlooks for 2024 for the Quad Cities Hydrologic Service Area (HSA), 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, English, Iowa, Skunk, North Skunk, and Des Moines Rivers in Iowa; the Fox River in Missouri; and the Pecatonica, Rock, and Green Rivers in Illinois, as well as the La Moine River in Illinois. This outlook is for the time period from mid March through mid June. .Flood Outlook Overview... The spring flood risk is well below normal for the Mississippi River, and below normal for local tributary rivers across the NWS Quad Cities Hydrologic Service Area. Some factors contributing to the current risk levels include: 1) Lack of a snowpack in the local area or in the headwater areas in Minnesota and Wisconsin. 2) Below normal soil moisture levels in the local area that will provide more potential storage for spring rains. 3) Lack of frozen soils in the local area or in the headwater areas to the north. 4) Local streams are currently flowing at, to below the normal level. .Key Takeaways… * Even though the overall risk of spring flooding is below average in the NWS Quad Cities HSA, this does not guarantee that high impact flooding will not occur. The severity of any flooding will be determined primarily by changes in the key factors mentioned above. In addition, we will be monitoring the outlooks for spring precipitation to see if that could become a contributing factor this year. * Current lack of snow cover and well below normal snowfall this winter has greatly reduced the overall flood threat. In addition, the snow water equivalent in the headwaters of the upper Mississippi River basin are well below normal, which will further decrease our likelihood of major impacts on the Mississippi River. * Widespread below normal soil moisture levels in the local area increases the capacity of the soils to soak in spring precipitation and which will significantly mitigate the near term flood risk as well as decrease the risk for prolonged flooding. Many factors are considered when determining the overall flood risk for the upcoming spring season. A combination of these are factored into the final threat categorization. These factors are discussed in detail below, and are categorized as an increased, neutral, or decreased contributor to potential spring flooding. .Seasonal Precipitation: Local Rivers - Neutral to Decreased Threat Mississippi River - Neutral to Decreased Threat Precipitation in eastern Iowa, northwest Illinois, and northeast Missouri has been near to slightly above average so far this winter. However, much of the Hydrologic Service Area (HSA), especially eastern Iowa, remains in some level of drought due to well below normal precipitation observed from the fall months in 2023. This is also reflected well in soil moisture levels (see below). North of the area, precipitation in the upper Mississippi River Basin so far this winter has averaged below normal, aside from parts of northern Minnesota. Latest outlooks from the Climate Prediction Center favor above normal precipitation through the second half of March for much, if not all, of the Mississippi River Basin. With dry soils and ongoing drought, much of the precipitation should be allowed to infiltrate into the ground. With all of this in mind, any contributions from seasonal precipitation to spring flood threat will be minimal. .Snow Cover and Liquid Water Content: Local Rivers - Decreased Threat Mississippi River - Decreased Threat The Mississippi River Basin and the area tributaries are completely free of snow cover per the latest analysis from the National Operational Hydrologic Remote Sensing Center (NOHRSC). Although additional snowfall is possible early in the spring, the likelihood of developing a deep snowpack is low. .Soil Conditions: Local Rivers - Decreased Threat Mississippi River - Decreased Threat Despite near to above normal precipitation values so far this winter, soil moisture levels remain below normal due to an extremely dry Fall. Latest analysis from the Climate Prediction Center shows soil moisture ranking profiles around 10-40% for the majority of the HSA, and also includes much of the upper Mississippi River Basin. This favors a decreased to neutral threat from this category for spring flooding, as drier soils will be better suited to soak in heavier rains. .Frost Depth: Local Rivers - Decreased Threat Mississippi River - Decreased Threat The ground remains thawed across the entire local area, and much of the Mississippi River basin. Some frost is in the ground in the headwaters of the Mississippi River in Minnesota, but it is less than normal and not deep. While colder air is still possible in early spring, it is unlikely that deeper frost depths will occur. .River Conditions: Local Rivers - Decreased Threat Mississippi River - Decreased Threat Streamflow analysis from the United States Geological Survey (USGS) indicates the majority of the Upper Mississippi River watershed and tributary streamflows are below to near normal. Streamflows that are below normal levels would have more capacity to hold runoff from heavy rains. .Ice Jam Flooding: Local Rivers - Decreased Threat for Breakup Jams Mississippi River - Decreased Threat for Breakup Jams The warmer weather this winter has largely limited the development of river ice. Bouts of colder air are possible through early spring, however, without a long period of extreme cold the development of river ice and ice jam flooding is unlikely. .Weather/Climate Outlooks: Local Rivers - Below normal Threat Mississippi River - Well below normal Threat While active weather patterns are typical of the spring months, this could lead to variations of warmer and colder temperatures, where the risk for flooding will be determined by the tracks of individual and multiple storm systems that could bring heavy rain or heavy snow to parts of the region. According to the latest climate outlooks from the Climate Prediction Center, probabilities are leaning toward near normal temperatures for much of the region for the remainder of March, with a signal for somewhat above normal precipitation during the same timeframe. The three month outlook for April through June is leaning toward a continuation of above normal temperatures for much of the region, with slightly above normal precipitation. .Summary: The spring flood risk is well below normal for the Mississippi River, and below normal for local tributary rivers across the NWS Quad Cities Hydrologic Service Area. With the lack of snow cover and persistent cold weather, current conditions are unfavorable for snowmelt or ice jam flooding on local tributaries. Some factors contributing to the current risk levels include: 1) Lack of deep and widespread snowpack in the local area and the headwater areas of the Mississippi River basin. 2) A general lack of deep, hard frozen ground across the upper Mississippi River Basin. 3) Near to below average stream flows and below average soil moisture levels. .Numerical Probabilistic River Outlooks... ...Advanced Hydrologic Prediction Service Probabilistic Outlook... 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: 03/18/2024 - 06/16/2024 : 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 : 6 48 <5 37 <5 12 Dubuque 17.0 18.0 21.5 : 7 54 5 45 <5 15 Bellevue LD12 17.0 18.0 20.0 : <5 36 <5 30 <5 12 Fulton LD13 16.0 18.0 20.0 : 5 53 <5 33 <5 14 Camanche 17.0 18.5 20.5 : 5 46 <5 33 <5 14 Le Claire LD14 11.0 12.0 13.5 : 6 52 <5 36 <5 17 Rock Island LD15 15.0 16.0 18.0 : 12 61 8 51 <5 25 Ill. City LD16 15.0 16.0 18.0 : 11 60 8 47 <5 24 Muscatine 16.0 18.0 20.0 : 18 62 8 47 <5 24 New Boston LD17 15.0 16.5 18.5 : 20 66 10 51 5 30 Keithsburg 14.0 15.5 17.0 : 20 64 10 50 <5 26 Gladstone LD18 10.0 12.0 14.0 : 22 65 10 47 <5 23 Burlington 15.0 16.5 18.0 : 18 64 11 48 <5 28 Keokuk LD19 16.0 17.5 19.0 : 8 33 <5 24 <5 12 Gregory Landing 15.0 18.0 25.0 : 25 65 9 42 <5 5 :Maquoketa River Manchester Hwy 20 14.0 17.0 20.0 : 17 25 11 18 <5 9 Maquoketa 24.0 26.0 28.5 : 5 12 <5 10 <5 6 :Wapsipinicon River Independence 12.0 13.0 15.0 : 7 10 6 7 <5 <5 Anamosa Shaw Rd 14.5 18.0 21.5 : 14 28 6 12 <5 <5 De Witt 4S 11.0 11.5 12.5 : 60 72 49 65 31 46 :North Skunk River Sigourney 16.0 18.0 21.0 : 45 56 26 41 7 11 :Skunk River Augusta 15.0 17.0 20.0 : 32 44 20 32 10 17 :Cedar River Vinton 15.0 18.0 19.0 : 5 17 <5 8 <5 5 Palo Blairs Ferry 12.5 15.5 17.0 : 6 27 <5 8 <5 <5 Cedar Rapids 12.0 14.0 16.0 : 7 33 5 16 <5 10 Cedar Bluff 16.0 20.0 26.0 : 6 32 <5 9 <5 <5 Conesville 13.0 15.0 16.5 : 15 55 <5 17 <5 8 :Iowa River Marengo 15.0 17.0 19.0 : 44 71 18 51 <5 6 Iowa City 23.5 24.5 26.0 : <5 <5 <5 <5 <5 <5 Lone Tree 16.0 18.5 22.0 : 18 28 6 8 <5 <5 Columbus Jct 23.0 25.0 26.5 : <5 18 <5 7 <5 <5 Wapello 21.0 25.0 27.5 : 15 46 <5 8 <5 <5 Oakville 11.0 15.0 20.0 : 9 36 <5 <5 <5 <5 :English River Kalona 14.0 16.0 18.0 : 40 49 22 32 8 13 :Des Moines River Keosauqua 22.0 25.0 27.0 : 8 13 <5 <5 <5 <5 St Francisville 18.0 22.0 25.0 : 23 40 9 10 <5 <5 :Fox River Wayland 15.0 18.0 20.0 : 26 27 13 14 <5 <5 :Pecatonica River Freeport 13.0 14.0 16.0 : 7 23 <5 9 <5 <5 :Rock River Como 12.5 15.5 18.0 : 17 23 7 8 <5 <5 Joslin 12.0 14.0 16.5 : 53 57 28 31 13 18 Moline 12.0 13.0 14.0 : 51 55 28 31 20 23 :Green River Geneseo 15.0 16.5 18.0 : 20 24 9 11 <5 <5 :La Moine River Colmar 20.0 22.0 24.0 : 68 65 43 43 23 22 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: 03/18/2024 - 06/16/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Mississippi River Dubuque LD11 6.3 6.7 7.9 10.0 12.6 14.8 16.7 Dubuque 8.7 9.0 10.2 11.8 14.4 16.7 18.5 Bellevue LD12 6.9 7.4 8.8 10.7 13.2 14.9 16.3 Fulton LD13 6.9 7.4 8.3 10.6 13.2 15.2 16.7 Camanche 9.8 10.1 10.8 12.3 14.1 15.8 17.2 Le Claire LD14 5.7 6.0 6.6 8.0 9.5 10.4 11.8 Rock Island LD15 7.4 8.4 9.5 11.2 13.4 15.7 17.6 Ill. City LD16 5.9 6.7 8.3 10.8 13.1 15.4 17.4 Muscatine 7.6 8.4 10.1 12.2 14.7 17.3 19.4 New Boston LD17 7.0 8.2 9.9 12.3 14.4 16.5 18.6 Keithsburg 8.4 8.8 10.4 11.7 13.8 15.6 16.6 Gladstone LD18 3.7 4.0 5.8 7.4 9.8 11.8 13.0 Burlington 9.8 10.0 11.4 12.7 14.6 16.9 17.6 Keokuk LD19 5.6 6.0 7.8 9.6 11.9 14.8 17.0 Gregory Landing 7.0 7.6 9.6 12.4 15.1 17.2 19.8 :Maquoketa River Manchester Hwy 20 5.8 6.2 7.2 8.5 10.6 17.1 19.1 Maquoketa 11.9 12.3 13.4 15.2 17.4 21.8 25.3 :Wapsipinicon River Independence 5.7 5.9 6.6 7.3 8.2 10.6 13.6 Anamosa Shaw Rd 6.6 7.7 8.5 10.3 12.4 16.3 18.6 De Witt 4S 8.9 9.3 10.2 11.4 12.7 13.3 13.8 :North Skunk River Sigourney 5.9 8.6 12.2 15.4 18.1 19.9 21.5 :Skunk River Augusta 4.9 6.2 8.5 12.8 15.9 20.1 23.8 :Cedar River Vinton 3.3 3.9 5.7 8.2 9.9 11.5 15.6 Palo Blairs Ferry 3.2 3.6 5.3 7.3 8.7 10.3 13.6 Cedar Rapids 3.6 3.9 4.7 6.0 7.3 9.5 14.4 Cedar Bluff 5.5 6.3 7.9 9.7 11.0 13.8 18.0 Conesville 6.6 6.9 8.7 10.1 11.9 13.3 14.9 :Iowa River Marengo 7.8 8.6 10.1 14.0 16.4 17.4 18.2 Iowa City 10.4 11.0 13.0 15.4 18.3 19.7 21.4 Lone Tree 6.0 7.4 9.9 12.4 14.4 17.3 18.7 Columbus Jct 10.7 11.2 14.2 15.3 17.5 20.7 22.8 Wapello 13.0 13.3 16.3 17.5 19.3 21.7 23.5 Oakville 2.3 2.7 5.1 6.4 8.5 10.6 12.5 :English River Kalona 6.1 7.6 11.2 13.5 15.6 17.5 19.3 :Des Moines River Keosauqua 11.7 13.3 16.0 17.0 19.3 21.6 23.5 St Francisville 9.0 10.5 13.8 15.2 17.7 21.0 23.7 :Fox River Wayland 4.5 6.1 8.0 11.5 15.2 18.6 19.7 :Pecatonica River Freeport 7.9 8.0 8.7 10.4 12.1 12.9 13.6 :Rock River Como 6.8 6.9 8.0 9.3 11.6 14.6 16.1 Joslin 9.3 9.6 10.6 12.6 14.4 17.5 20.5 Moline 10.1 10.2 10.7 12.2 13.4 15.4 18.4 :Green River Geneseo 6.0 6.4 9.3 12.0 14.7 16.0 17.5 :La Moine River Colmar 12.0 14.6 17.9 21.7 23.9 25.3 26.0 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: 03/18/2024 - 06/16/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Mississippi River Dubuque LD11 5.2 5.1 5.0 4.5 4.2 3.9 3.7 Dubuque 8.0 7.9 7.9 7.5 7.3 7.1 7.0 Bellevue LD12 4.9 4.8 4.8 4.1 3.7 3.3 3.1 Fulton LD13 4.9 4.9 4.8 4.5 4.3 4.1 4.1 Camanche 9.0 9.0 9.0 8.8 8.7 8.7 8.6 Le Claire LD14 4.8 4.8 4.8 4.6 4.4 4.3 4.3 Rock Island LD15 5.8 5.7 5.6 4.9 4.5 4.0 3.8 Ill. City LD16 4.8 4.7 4.5 4.0 3.6 3.3 3.2 Muscatine 6.8 6.7 6.6 6.3 6.1 5.8 5.7 New Boston LD17 5.3 5.2 4.8 4.0 3.6 3.2 3.0 Keithsburg 6.7 6.7 6.5 5.8 5.6 5.3 5.2 Gladstone LD18 2.4 2.3 2.2 1.5 1.2 0.9 0.7 Burlington 8.5 8.5 8.4 8.0 7.8 7.5 7.3 Keokuk LD19 4.7 4.6 4.5 3.4 2.5 2.3 2.1 Gregory Landing 6.7 6.7 6.6 6.4 6.3 6.2 6.1 :Maquoketa River Manchester Hwy 20 4.3 4.2 4.1 4.0 4.0 3.9 3.8 Maquoketa 11.0 10.8 10.6 10.4 10.2 10.0 10.0 :Wapsipinicon River Independence 5.2 5.1 5.0 5.0 4.9 4.8 4.7 Anamosa Shaw Rd 5.6 5.4 5.2 5.0 4.8 4.6 4.5 De Witt 4S 7.0 6.9 6.7 6.3 6.1 5.6 5.4 :North Skunk River Sigourney 5.1 4.3 3.9 3.5 3.4 3.0 2.8 :Skunk River Augusta 2.6 2.3 1.9 1.6 1.4 1.1 1.0 :Cedar River Vinton 2.0 1.8 1.7 1.6 1.4 1.2 1.1 Palo Blairs Ferry 2.1 1.9 1.8 1.6 1.5 1.3 1.2 Cedar Rapids 3.1 3.0 2.9 2.8 2.7 2.7 2.6 Cedar Bluff 4.6 4.4 4.1 4.0 3.8 3.6 3.5 Conesville 5.8 5.6 5.3 5.1 4.8 4.4 4.3 :Iowa River Marengo 6.6 6.5 6.3 6.0 5.8 5.6 5.4 Iowa City 10.0 9.8 9.4 9.2 9.2 9.1 9.1 Lone Tree 5.2 4.8 4.4 4.0 3.7 3.5 3.5 Columbus Jct 9.9 9.6 9.2 8.8 8.5 8.2 8.0 Wapello 12.2 11.9 11.3 10.8 10.3 9.7 9.5 :English River Kalona 4.9 4.7 4.5 4.1 4.0 3.6 3.5 :Des Moines River Keosauqua 10.7 10.5 10.2 9.9 9.7 9.6 9.5 St Francisville 6.9 6.6 6.1 5.7 5.4 5.2 5.1 :Fox River Wayland 2.1 2.0 1.9 1.7 1.5 1.4 1.3 :Pecatonica River Freeport 6.4 5.7 5.1 4.7 4.3 4.0 3.9 :Rock River Como 5.1 4.9 4.4 3.9 3.5 3.2 3.1 Joslin 7.2 6.9 6.2 5.5 5.0 4.5 4.4 Moline 9.1 9.0 8.7 8.3 8.1 7.9 7.9 :Green River Geneseo 3.5 3.2 3.1 2.7 2.5 2.1 2.0 :La Moine River Colmar 5.0 4.4 4.0 3.7 3.4 3.3 3.2 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 http://www.weather.gov/dvn for more weather and water information. The next outlook will be issued near the end of next month. $$