Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
234 FGUS73 KBIS 261504 ESFBIS NDC009-013-023-049-069-075-079-101-281400- Probabilistic Hydrologic Outlook National Weather Service Bismarck ND 1004 AM CDT Thu Sep 26 2024 ...FLOOD AND WATER RESOURCES OUTLOOK... This Flood and Water Resources Outlook is for the Souris River Basin of North Dakota, covering the period of 30 September through 29 December, 2024. This is a monthly issuance of the 90-day flood risks for the Souris River Basin of North Dakota. These probabilities are updated 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 normal/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... Risk of widespread flooding is at normal levels for this time of year within the Souris River basin, which is actually quite low. This does not suggest flooding cannot take place in fall, but more that it would take something very unusual to initiate flooding along the Souris River and its forecast points. ...Snowpack Conditions... No snow exists within the Souris River basin of North Dakota. ...Soil Conditions... Soil moisture values across the Souris River Basin continuie to fall over the past month due to lower than normal amounts of rain, and a continuation of above normal temperatures. ...Current Drought Conditions... Drought, up to D2 (severe drought) has been creeping into the western portion of the Souris River Basin. Based on weather forecasts and outlooks, the most likely future is one of drought conditions becoming worse over the coming weeks and months. ...Reservoirs and Natural Wetlands... All major natural wetlands and lakes have been resilient and are near normal for this time of year. Man-made structures, such as Lake Darling and the upstream Canadian reservoirs of Grant Devine and Rafferty continue to fare well despite the intensifying drought in the western portion of the basin. ...Weather Outlook... The near term 6-10 and 8-14 day outlooks strongly favor above normal temperatures and below normal precipitation. However, in the one-month outlook for October, both temperature and precipitation outlooks reflect equal chances for an above normal, near normal, or below normal outcome. The same equal chances designations for temperature and precipitation are present in the three-month outlook covering October, November, and December. ...Ice Conditions... No ice exists along the Souris River and its tributaries in North Dakota. 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: 09/30/2024 - 12/29/2024 : 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 -------- ----- ----- ----- : --- --- --- --- --- --- :Des Lacs Foxholm 1651.0 1653.0 1654.0 : <5 <5 <5 <5 <5 <5 :Souris Sherwood 1623.0 1625.0 1630.0 : <5 <5 <5 <5 <5 <5 Foxholm 1573.0 1576.0 1578.0 : <5 <5 <5 <5 <5 <5 Minot 1562.0 1565.0 1570.0 : <5 <5 <5 <5 <5 <5 Minot 1551.0 1553.0 1557.0 : <5 <5 <5 <5 <5 <5 Logan 1536.0 1538.0 1540.0 : <5 <5 <5 <5 <5 <5 Sawyer 1524.0 1526.0 1528.0 : <5 <5 <5 <5 <5 <5 Velva 1507.0 1512.0 1517.0 : <5 <5 <5 <5 <5 <5 :Wintering Karlsruhe 1509.0 1511.0 1512.0 : <5 <5 <5 <5 <5 <5 :Souris Towner 1454.0 1456.0 1458.0 : <5 <5 <5 <5 <5 <5 Bantry 1440.0 1441.0 1443.0 : <5 <5 <5 <5 <5 <5 :Willow Creek Willow City 1442.0 1446.0 1448.0 : <5 <5 <5 <5 <5 <5 :Souris Westhope 1414.0 1418.0 1420.0 : <5 <5 <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: 09/30/2024 - 12/29/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Des Lacs Foxholm 1638.8 1638.8 1638.8 1638.8 1639.1 1640.4 1641.0 :Souris Sherwood 1605.8 1605.8 1605.8 1605.8 1606.9 1608.3 1610.5 Foxholm 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5 1568.4 Minot 1550.6 1550.6 1550.6 1550.6 1550.9 1551.4 1552.1 Minot 1541.2 1541.2 1541.2 1541.2 1541.4 1541.5 1541.8 Logan 1520.1 1520.1 1520.1 1520.1 1520.2 1522.0 1523.5 Sawyer 1507.3 1507.3 1507.3 1507.3 1507.5 1508.4 1509.8 Velva 1490.9 1490.9 1490.9 1490.9 1491.0 1492.1 1493.2 :Wintering Karlsruhe 1504.1 1504.1 1504.1 1504.1 1504.1 1505.7 1508.0 :Souris Towner 1446.2 1446.2 1446.2 1446.2 1446.2 1448.8 1452.2 Bantry 1432.1 1432.1 1432.1 1432.1 1432.1 1434.3 1437.7 :Willow Creek Willow City 1436.9 1436.9 1436.9 1436.9 1437.2 1437.5 1438.3 :Souris Westhope 1410.8 1410.8 1410.8 1410.8 1410.8 1411.7 1412.7 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: 09/30/2024 - 12/29/2024 LOCATION 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Des Lacs Foxholm 1638.7 1638.7 1638.7 1638.5 1638.5 1638.5 1638.5 :Souris Sherwood 1605.8 1605.8 1605.8 1605.8 1605.8 1605.8 1605.8 Foxholm 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5 Minot 1550.6 1550.6 1550.6 1550.4 1550.4 1550.4 1550.4 Minot 1541.2 1541.1 1541.1 1540.9 1540.9 1540.9 1540.9 Logan 1520.0 1519.9 1519.9 1519.7 1519.7 1519.7 1519.7 Sawyer 1506.9 1506.7 1506.6 1506.6 1506.6 1506.6 1506.6 Velva 1490.4 1490.2 1490.2 1490.2 1490.2 1490.2 1490.2 :Wintering Karlsruhe 1503.8 1503.6 1503.1 1503.0 1503.0 1503.0 1503.0 :Souris Towner 1445.6 1445.4 1444.7 1444.6 1444.6 1444.6 1444.6 Bantry 1431.4 1431.2 1430.7 1430.6 1430.6 1430.6 1430.6 :Willow Creek Willow City 1436.7 1436.7 1436.5 1436.1 1436.1 1436.1 1436.1 :Souris Westhope 1410.5 1410.1 1409.7 1409.7 1409.6 1409.6 1409.6 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 October. $$ Schlag