Flood Potential Outlook
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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032 FGUS73 KFSD 231301 ESFFSD IAC021-035-041-059-093-119-141-143-149-167-193-MNC033-063-081-083- 101-105-117-133-NEC043-051-SDC003-005-009-011-015-023-027-035-043- 053-061-067-073-077-079-083-087-097-099-101-111-125-127-135-251300- Probabilistic Hydrologic Outlook National Weather Service Sioux Falls SD 801 AM CDT Thu May 23 2024 In Table 1 below, the current (CS) and historical (HS) or normal probabilities of exceeding minor...moderate...and major flood stage 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: 05/27/2024 - 08/25/2024 : 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 -------- ----- ----- ----- : --- --- --- --- --- --- :Floyd River Sheldon 12.0 14.0 16.0 : 28 33 26 21 10 8 Alton 12.0 16.0 18.0 : 33 35 17 15 15 13 Le Mars 20.0 21.0 24.0 : 19 20 17 16 <5 <5 :West Branch Floyd River Struble 14.0 15.0 16.0 : 13 <5 5 <5 <5 <5 :Floyd River Merrill 12.0 14.0 16.0 : 17 11 10 7 8 <5 James 26.0 30.0 34.0 : 8 <5 <5 <5 <5 <5 :Little Sioux River Milford 12.0 14.0 16.0 : >98 82 >98 61 46 47 Spencer 10.0 14.0 16.0 : >98 64 20 17 6 7 :Ocheyedan River Spencer 8.0 9.5 10.5 : 44 41 26 24 16 12 :Little Sioux River Linn Grove 18.0 19.5 21.0 : 26 34 21 20 13 14 Cherokee 17.0 21.0 24.0 : 43 32 23 17 6 <5 Correctionville 19.0 21.0 23.0 : 19 15 14 13 10 <5 :West Fork Ditch Hornick 20.0 22.0 26.5 : 11 8 6 <5 <5 <5 :Perry Creek Sioux City 24.0 26.0 28.0 : <5 <5 <5 <5 <5 <5 :Big Sioux River Brookings 9.0 10.5 12.0 : 31 39 14 19 6 5 Dell Rapids 12.0 14.0 15.0 : 14 17 <5 8 <5 <5 Sioux Falls I-90 12.0 15.0 17.0 : 17 23 <5 5 <5 <5 :Skunk Creek Sioux Falls 12.0 15.0 17.0 : 17 23 <5 5 <5 <5 :Big Sioux River Sioux Falls N Cliff 16.0 18.0 31.0 : 8 13 5 10 <5 <5 :Split Rock Creek Corson 8.5 11.0 14.0 : 9 10 <5 6 <5 <5 :Rock River Luverne 10.0 12.0 14.0 : 9 10 6 8 <5 5 Rock Rapids 13.0 16.0 19.0 : 27 30 10 10 8 8 Rock Valley 16.0 17.0 19.0 : 11 13 9 11 7 8 :Big Sioux River Hawarden 20.5 24.0 27.0 : 45 43 22 18 14 14 Akron 16.0 18.0 20.0 : >98 48 30 29 15 15 Sioux City 32.0 38.0 41.0 : 7 9 5 6 5 <5 :James River Huron 11.5 15.0 19.0 : 35 47 <5 21 <5 <5 Forestburg 12.0 14.5 18.0 : 26 52 12 30 <5 <5 Mitchell 17.0 21.5 24.0 : 25 52 <5 12 <5 <5 :Firesteel Creek Mount Vernon 8.0 13.0 15.0 : 13 20 <5 <5 <5 <5 :James River Scotland 13.0 16.0 18.0 : 23 45 6 13 <5 8 Yankton 12.0 16.0 21.0 : 8 28 5 12 <5 6 :West Fork Vermillion River Parker 9.0 10.0 12.0 : 5 <5 <5 <5 <5 <5 :East Fork Vermillion River Parker 12.0 14.0 16.5 : 5 7 <5 5 <5 <5 :Vermillion River Davis 11.0 13.0 15.0 : 30 24 17 19 <5 <5 Wakonda 14.0 15.5 17.0 : 40 23 37 21 26 19 Vermillion 21.0 22.0 30.0 : 15 18 15 17 8 5 :Redwood River Marshall 14.0 15.0 16.5 : 16 5 9 <5 <5 <5 :West Fork Des Moines River Avoca 1425.0 1426.0 1428.0 : 14 10 8 9 <5 <5 Windom 19.0 21.0 25.0 : 9 8 <5 <5 <5 <5 Jackson 12.0 12.5 14.0 : 5 <5 <5 <5 <5 <5 :Missouri River South Sioux City 30.0 33.0 36.0 : 5 16 <5 11 <5 8 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: 05/27/2024 - 08/25/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Floyd River Sheldon 6.8 6.8 6.8 8.9 14.2 16.0 16.4 Alton 7.8 7.8 7.8 9.2 14.4 19.8 20.2 Le Mars 13.4 13.4 13.6 15.8 19.1 21.7 23.5 :West Branch Floyd River Struble 6.5 6.5 7.0 9.1 11.4 14.3 15.1 :Floyd River Merrill 4.3 4.3 4.8 5.6 8.4 13.9 17.2 James 12.5 12.5 12.8 13.6 16.5 22.9 28.4 :Little Sioux River Milford 14.7 14.7 14.7 15.2 16.9 21.5 24.7 Spencer 11.5 11.5 11.5 11.5 12.9 15.5 16.4 :Ocheyedan River Spencer 7.7 7.7 7.7 7.7 9.6 11.9 12.6 :Little Sioux River Linn Grove 16.4 16.4 16.4 16.5 18.2 21.2 22.1 Cherokee 15.6 15.6 15.6 16.5 19.6 23.5 24.5 Correctionville 12.8 12.8 13.0 14.3 18.2 23.1 25.1 :West Fork Ditch Hornick 9.4 10.0 10.7 12.1 15.8 20.6 22.5 :Perry Creek Sioux City 7.9 7.9 8.5 9.2 9.8 11.1 21.4 :Big Sioux River Brookings 5.4 5.4 5.6 7.5 9.9 11.2 12.0 Dell Rapids 6.3 6.3 6.6 8.4 10.7 13.2 13.4 Sioux Falls I-90 9.7 9.7 9.8 10.3 10.9 13.1 13.5 :Skunk Creek Sioux Falls 9.7 9.7 9.8 10.3 10.9 13.1 13.5 :Big Sioux River Sioux Falls N Cliff 8.3 8.3 8.4 10.3 12.5 15.4 17.9 :Split Rock Creek Corson 3.0 3.0 3.5 4.8 6.0 8.3 10.3 :Rock River Luverne 5.0 5.0 5.5 6.3 7.5 9.5 12.8 Rock Rapids 9.8 9.8 10.3 11.1 13.1 16.0 22.9 Rock Valley 10.7 10.7 10.7 11.9 14.5 16.4 20.9 :Big Sioux River Hawarden 18.9 18.9 18.9 20.0 23.5 28.9 36.8 Akron 16.6 16.6 16.6 16.6 19.0 22.0 24.2 Sioux City 21.1 21.1 21.1 21.1 23.4 29.1 39.1 :James River Huron 10.0 10.0 10.0 10.6 13.1 14.1 14.6 Forestburg 7.2 7.2 7.2 9.5 12.0 14.7 15.2 Mitchell 13.2 13.2 13.2 14.4 17.0 19.8 20.6 :Firesteel Creek Mount Vernon 2.8 2.8 2.8 4.5 6.2 8.2 10.3 :James River Scotland 6.1 6.1 6.1 9.1 11.9 14.5 16.8 Yankton 4.4 4.4 4.4 5.6 8.5 10.8 16.2 :West Fork Vermillion River Parker 2.1 2.1 2.1 2.6 4.1 5.5 9.1 :East Fork Vermillion River Parker 2.5 2.5 2.5 6.8 7.6 10.0 12.4 :Vermillion River Davis 5.8 5.8 5.8 7.2 11.3 14.5 14.7 Wakonda 9.2 9.2 9.2 10.1 17.0 17.8 18.4 Vermillion 9.8 9.8 9.8 10.2 17.9 27.7 31.6 :Redwood River Marshall 8.2 8.2 9.3 11.3 12.7 14.8 16.5 :West Fork Des Moines River Avoca 1420.7 1420.7 1420.7 1421.8 1423.5 1425.5 1427.7 Windom 14.1 14.1 14.3 15.3 17.2 18.8 20.0 Jackson 9.3 9.3 9.4 9.8 10.7 11.4 12.1 :Missouri River South Sioux City 14.4 14.4 14.9 16.0 17.9 23.7 29.4 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: 05/27/2024 - 08/25/2024 LOCATION 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Floyd River Sheldon 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Alton 6.2 6.0 5.9 5.8 5.7 5.7 5.7 Le Mars 10.0 9.6 8.6 7.7 7.2 6.9 6.8 :West Branch Floyd River Struble 4.6 4.3 4.1 4.0 3.9 3.8 3.8 :Floyd River Merrill 1.5 1.3 1.1 1.0 0.8 0.7 0.7 James 10.0 9.9 9.6 9.5 9.5 9.4 9.4 :Little Sioux River Milford 10.7 9.6 8.3 7.7 7.5 7.4 7.4 Spencer 7.4 6.8 3.7 3.0 3.0 3.0 3.0 :Ocheyedan River Spencer 4.3 3.9 3.1 2.9 2.8 2.8 2.7 :Little Sioux River Linn Grove 10.3 9.4 7.4 7.0 6.7 6.4 6.3 Cherokee 11.3 10.5 8.9 8.6 8.4 8.3 8.2 Correctionville 9.1 8.0 6.9 6.6 6.4 6.3 6.2 :West Fork Ditch Hornick 7.5 7.2 6.7 6.4 6.2 6.1 6.1 :Perry Creek Sioux City 7.2 7.2 7.1 7.1 7.0 7.0 6.9 :Big Sioux River Brookings 3.9 3.7 3.3 2.9 2.5 2.4 2.4 Dell Rapids 4.8 4.7 4.3 3.8 3.4 3.2 3.2 Sioux Falls I-90 6.7 6.5 6.0 5.4 4.8 4.3 4.3 :Skunk Creek Sioux Falls 6.7 6.5 6.0 5.4 4.8 4.3 4.3 :Big Sioux River Sioux Falls N Cliff 7.1 6.7 6.5 6.0 5.5 5.1 5.1 :Split Rock Creek Corson 2.6 2.4 2.2 2.0 1.7 1.6 1.5 :Rock River Luverne 4.7 4.6 4.5 4.4 4.3 4.3 4.3 Rock Rapids 8.6 8.2 7.7 7.3 7.1 7.1 7.0 Rock Valley 7.5 6.5 6.3 5.9 5.3 5.1 5.0 :Big Sioux River Hawarden 14.8 13.9 12.9 12.1 11.5 11.3 11.2 Akron 9.2 8.0 6.4 5.2 4.4 3.8 3.8 Sioux City 14.6 13.7 12.1 11.0 11.0 11.0 11.0 :James River Huron 9.7 9.7 9.6 9.4 9.4 9.3 9.3 Forestburg 6.3 6.2 5.7 5.2 4.9 4.8 4.8 Mitchell 12.4 12.3 11.7 11.1 10.9 10.7 10.7 :Firesteel Creek Mount Vernon 2.7 2.6 2.6 2.6 2.5 2.5 2.5 :James River Scotland 5.4 5.3 4.9 4.6 4.5 4.3 4.3 Yankton 4.0 3.7 3.0 3.0 3.0 3.0 3.0 :West Fork Vermillion River Parker 1.3 1.1 1.0 0.5 0.3 0.3 0.3 :East Fork Vermillion River Parker 2.5 2.5 2.5 2.5 2.5 2.5 2.5 :Vermillion River Davis 3.2 3.1 2.7 2.5 2.4 2.4 2.4 Wakonda 3.9 3.7 1.0 1.0 1.0 1.0 1.0 Vermillion 3.6 2.6 2.1 2.0 1.7 1.7 1.6 :Redwood River Marshall 7.3 7.2 7.1 6.8 6.7 6.7 6.7 :West Fork Des Moines River Avoca 1419.5 1419.3 1418.9 1418.6 1418.5 1418.3 1418.3 Windom 12.1 11.4 10.9 10.5 10.2 10.0 9.8 Jackson 8.5 8.2 7.9 7.6 7.4 7.3 7.2 :Missouri River South Sioux City 13.0 12.9 12.6 12.3 11.2 10.8 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/fsd for more weather and water information. The next outlook will be issued by the end of June. $$ Kalin