####018012576#### FGUS73 KBIS 281808 ESFBIS NDC001-007-011-015-021-025-029-031-033-037-041-043-045-047-051-053- 055-057-059-061-065-083-085-087-089-093-103-105-301700- Probabilistic Hydrologic Outlook National Weather Service Bismarck ND 108 PM CDT Thu Mar 28 2024 ...FLOOD AND WATER RESOURCES OUTLOOK... This Flood and Water Resources Outlook is for the James and Missouri basins of North Dakota, covering the period of 30 March through 28 June, 2024. This is a routine monthly issuance of flood probabilities for NWS forecast locations. These probabilities are issued on, or around, the fourth Thursday of every month. The following message has four sections. The first provides some text on the highlights of this outlook and conditions affecting the local hydrology. The second section gives the current and historical risks of flooding as determined by the Ensemble Streamflow Forecast model of the National Weather Service. The third section gives the current probabilities for reaching flood stage at the listed forecast locations. And finally, the fourth section covers the risk of the river sites falling below the listed stages. ...Flood Outlook Highlights... A lack of appreciable snow accumulation and an overall very warm winter season has the area entering April with nominal snow on the countryside. At this point in time the risk of widespread flooding is considered below normal to well below normal going forward into early summer. The risk of flooding depicted in the below tables is proportional to the risk of heavy spring rains, in particular the advent of the summer thunderstorm season. Perhaps the greater risk going into the growing season continues to be the long-term trend of below normal precipitation. Given the lack of substantial water in the existing snowpack, increased and expanded drought designations are a real concern going forward without timely spring rains. ...Missouri and Yellowstone Rivers... In western North Dakota the Missouri and Yellowstone rivers above Lake Sakakawea are below normal for this time of year. A lack of significant snowpack in the mountainous headwaters area of Montana suggests overall runoff will be well below normal along the Missouri and Yellowstone rivers. However, a planned "Test Flow" release out of Fort Peck on the Missouri River to help endangered species should cause a rise to near flood stage for the Missouri River near Williston. ...Snowpack Conditions... The snowpack across the Missouri and James River basins of North Dakota never attained a near-normal state over the past winter. Both a lack of received snow and unseasonably warm periods this winter kept the overall snowpack well below normal. There are wide areas of both the Missouri and James River basins of North Dakota that currently contain snow. However, that snowpack generally ranges from less than one-quarter of an inch of water to no more than seven tenths of an inch of water. In no way is this amount of water on the ground a significant contributor to the existing flood risks. ...Current Drought Conditions... Small improvements to the drought extent and designations have recently been made across the state. These improvements though were intended to better reflect current conditions and should not be interpreted as the beginning of a trend for more improvements. It will take at least normal amounts of timely rains going forward to prevent expansion and degradation of the current drought afflicting North Dakota. ...Reservoirs and Natural Wetlands... Despite an overall snow deficit across most of the state this winter, enhanced runoff due to a wet and frozen ground surface has been remarkable at times. Most small livestock dams and natural wetlands are near normal for early spring water levels. Larger water impoundments though are at greater risk of below normal water levels going through late spring and into summer. ...Soil Conditions... Soil moisture values across the Missouri and James basins are a mixture of somewhat above normal in parts of western and central North Dakota, to well below normal in parts of the James River basin and eastern North Dakota. ...Weather Outlook... The Climate Prediction Center 6-10 day outlook favors near normal temperature and precipitation. This evolves into a near normal temperature with above normal precipitation for the 8-14 day outlooks. Looking out even farther, the weeks 3-4, one-month, and three month outlooks for April, May and June generally favor above normal temperatures with equal chances for above normal, near normal, or below normal precipitation. ...Ice Conditions... Ice is quickly waning across most of North Dakota with most rivers now being at least mostly ice free after those streams experienced runoff in late winter. Wetlands, ponds, lakes, and larger reservoirs are still largely covered in ice of varying thickness and quality. 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: 03/30/2024 - 06/28/2024 : 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 -------- ----- ----- ----- : --- --- --- --- --- --- :Pipestem Pingree 11.0 13.0 15.0 : 5 12 <5 <5 <5 <5 :James River Grace City 12.0 14.0 15.0 : <5 15 <5 9 <5 8 LaMoure 14.0 16.0 18.0 : <5 17 <5 8 <5 <5 :Missouri River Williston 22.0 24.0 26.0 : 9 42 5 31 <5 9 :Cannonball River Regent 22.0 24.0 26.0 : <5 <5 <5 <5 <5 <5 :Cedar Creek Raleigh 12.0 14.0 16.0 : <5 9 <5 5 <5 <5 :Cannonball River Breien 10.0 20.0 23.0 : 7 52 <5 <5 <5 <5 :Beaver Creek Linton 12.0 14.0 16.0 : <5 45 <5 30 <5 13 :Little Muddy River Williston 10.0 12.0 14.0 : 8 63 <5 23 <5 7 :Little Missouri River Marmarth 18.0 23.0 30.0 : <5 6 <5 <5 <5 <5 Medora 15.0 18.0 20.0 : <5 21 <5 8 <5 6 Watford City 20.0 24.0 30.0 : <5 11 <5 5 <5 <5 :Knife River Manning 15.0 17.0 20.0 : <5 20 <5 <5 <5 <5 :Spring Creek Zap 14.0 18.0 20.0 : 8 21 6 11 <5 8 :Knife River Hazen 21.0 24.0 25.0 : 13 34 8 25 5 20 :Heart River Mandan 27.0 33.0 38.0 : <5 19 <5 <5 <5 <5 :Apple Creek Menoken 15.0 16.0 17.0 : 26 61 17 55 <5 34 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: 03/30/2024 - 06/28/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Pipestem Pingree 5.4 5.4 5.4 5.7 7.4 9.1 11.1 :James River Grace City 4.3 4.3 4.3 5.0 6.1 6.5 8.5 LaMoure 7.9 7.9 8.0 8.3 9.0 11.3 13.3 :Missouri River Williston 18.0 18.4 18.7 19.4 20.2 21.8 23.9 :Cannonball River Regent 5.2 5.2 5.7 6.7 7.7 8.8 9.6 :Cedar Creek Raleigh 1.3 1.3 2.2 3.4 4.3 5.3 5.7 :Cannonball River Breien 2.6 2.8 4.7 5.8 7.9 9.7 10.1 :Beaver Creek Linton 4.3 4.4 4.9 5.6 6.6 10.5 11.8 :Little Muddy River Williston 4.3 4.3 5.0 7.0 8.5 9.3 11.1 :Little Missouri River Marmarth 1.1 1.1 1.1 1.9 5.1 7.9 11.0 Medora 1.5 1.5 1.5 2.7 5.5 8.4 11.5 Watford City 7.1 7.1 7.2 8.4 10.8 12.9 15.0 :Knife River Manning 6.4 6.4 6.6 8.3 9.5 12.6 13.3 :Spring Creek Zap 5.1 5.2 6.1 7.4 9.2 11.1 19.1 :Knife River Hazen 2.7 3.0 6.4 9.8 15.6 23.4 25.2 :Heart River Mandan 11.6 12.1 14.3 16.2 20.2 23.5 26.1 :Apple Creek Menoken 6.3 6.5 7.3 12.0 15.1 16.7 16.9 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--Nonexceedance Probabilities... Chance of Falling Below Stages at Specific Locations Valid Period: 03/30/2024 - 06/28/2024 LOCATION 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Pipestem Pingree 5.1 5.1 5.1 5.1 5.1 5.1 5.1 :James River Grace City 4.2 4.2 4.2 4.1 4.1 4.1 4.1 LaMoure 7.8 7.3 7.1 7.0 6.9 6.9 6.8 :Missouri River :Cannonball River Regent 5.1 5.1 5.1 5.1 5.1 5.1 5.1 :Cedar Creek Raleigh 1.2 1.2 1.1 1.1 1.1 1.0 1.0 :Cannonball River Breien 2.3 2.3 2.2 2.2 2.2 2.1 2.1 :Beaver Creek Linton 4.2 4.2 4.2 4.2 4.2 4.2 4.2 :Little Muddy River Williston 4.3 4.3 4.3 4.3 4.3 4.2 4.2 :Little Missouri River Marmarth 1.1 1.1 1.1 1.0 0.9 0.9 0.9 Medora 1.5 1.5 1.4 1.3 1.2 1.2 1.2 Watford City 7.1 7.0 7.0 6.9 6.8 6.8 6.7 :Knife River Manning 6.4 6.3 6.3 6.3 6.1 6.0 6.0 :Spring Creek Zap 4.8 4.8 4.8 4.8 4.8 4.8 4.8 :Knife River Hazen 0.6 0.6 0.6 0.5 0.3 0.3 0.2 :Heart River Mandan 9.6 9.4 9.3 9.1 8.8 8.6 8.5 :Apple Creek Menoken 4.5 4.4 4.4 4.1 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 weather.gov/bis for more weather and water information. The next outlook will be issued by the end of April. $$ Schlag