Figure 1: Snow Water Equivalent Image. (Courtesy of NOHRSC)
Figure 2: USGS Current Streamflow Analysis
Figure 3: 180 Day Percentage of Mean Precipitation Analysis (Courtesy of Midwest Climate Center)
Figure 4: Palmer Drought Severity Index
Figure 5: Soil Moisture (mm)
Figure 6: Three Month Temperature Outlook
Figure 7: Three Month Precipitation Outlook

NWS
St. Louis, Missouri

Spring Flood Outlook
Issued: March 5, 2015

Snow Water EquivalentCurrent Snow Water Equivalent

Streamflow AnalysisUSGS Stream Analysis

  180 Day Rainfall DeparturePrecipitation 180 Day Percentage of Mean

 Palmer Drought IndexPalmer Drought Index

Soil Moisture PercentileCurrent Soil Moisture

1-Month Precip Outlook3 Month Precipitation Outlook

1-Month Temp Outlook3 Month Temperature Outlook

3-Month Precip Outlook3 Month Precipitation Outlook

3-Month Temp Outlook3 Month Temperature Outlook


PROBABILISTIC HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE ST. LOUIS MO 135 PM CST THU MAR 05 2015 ...Spring Flood and Water Resources Outlook Number 2... ...Flooding less likely along the Mississippi and Missouri Rivers... ...Local tributaries have mixed flood chances this spring... This updated outlook uses the term St. Louis Service Area to refer to the Mississippi River from above Canton Missouri to above Cape Girardeau Missouri, the Missouri River above Jefferson City Missouri to its confluence with the Mississippi River, the Illinois River downstream from Beardstown Illinois to its confluence with the Mississippi River, and for tributary rivers in eastern Missouri, and west central and southwest Illinois. There is no flooding anywhere within the St. Louis Service Area, so the probabilities within this outlook are not skewed by any ongoing flooding. This outlook is based on current streamflows and soil moisture over the area, upstream snowpack in the Mississippi, Missouri, and Illinois river basins, and forecast rainfall over the next two weeks to three months. More than expected rainfall could cause additional flooding over the area, while less than expected rainfall could rivers from reaching expected crests. The chances of flooding along local tributaries in the St. Louis Service Area over the next 90 days are mixed. Across Central Missouri, flood chances are between 6 and 8 percent below the seasonal average on the Maries River, the Gasconade River, and the Moreau River. However, after several recent snow events, flood chances along tributaries in northeastern Missouri and western Illinois are mostly 4 to 8 percent above the seasonal average. Thanks to several inches of snow water equivalent across much of north central Illinois, flood chances along the Illinois River and the Kaskaskia River are also above average. Snowpack in the upper Illinois River basin contains 1 to 3 inches of water equivalent, leading to flood probabilities more than 10 percent above the historical average. Similar water equivalent in the snowpack across the Kaskaskia River basin is generating flood chances at least 23 percent higher than the historical average. In the Meramec River basin, the flood chances are within 6 percent of seasonal norms. This reflects the typical lack of significant snowpack and near normal soil moisture. Meanwhile, this outlook update along the Mississippi and Missouri rivers indicates the spring flood chances are below the seasonal average. In fact, flooding this spring is not likely from Canton, Missouri to Saverton, Missouri, except at Hannibal, where flood chances sit at 52 percent. Minor flooding appears to be a bit more likely downstream of Louisiana, but those chances of flooding remain well below an average spring. In addition, moderate flood chances are running 10 to 23 percent below historical averages. While snowpack in the upper Mississippi River basin is widespread, it is also quite shallow. Simply put, this has been a lean year for snowfall across the upper Midwest, and most of the upper Mississippi River basin has much less snow on the ground than we typically see. In the Missouri River basin, snow depths are also below the seasonal average, with many areas south of the Missouri River having lost all snowcover. This combined with a soil moisture conditions ranging from near to above normal over the lower Missouri River basin leads to slightly below normal chances of flooding along lower Missouri River this spring. In the near term, the Climate Prediction Center calls for a strong likelihood of above average temperatures in the 6 to 10 day and 8 to 14 day outlooks. Precipitation in the 6 to 10 day outlook should be below average, and near average during the 8 to 14 day period. For the month of March, temperatures will most likely be below average, and there will be equal chances of precipitation being above average, near average, or below average. For the period March through May, there are equal chances that temperatures and precipitation will be above average, near average, or below average. 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 more 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: 3/9/2015 - 6/7/2015 : 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 -------- ----- ----- ----- : --- --- --- --- --- --- :Dardenne Creek St. Peters 18.0 20.0 23.0 : 38 38 24 24 13 13 :Mississippi River Canton LD20 14.0 20.0 25.0 : 47 64 <5 15 <5 <5 Quincy 17.0 18.0 22.5 : 47 64 33 60 7 24 Hannibal 16.0 22.0 24.0 : 52 67 6 16 <5 7 Saverton LD22 16.0 20.0 22.0 : 46 63 13 35 6 21 Louisiana 15.0 20.0 25.0 : 64 69 10 33 <5 <5 Clarksville LD24 25.0 31.0 33.0 : 64 69 7 27 <5 12 Winfield LD25 26.0 30.0 34.0 : 53 67 18 40 <5 7 :North Fabius River Ewing 11.0 14.0 18.0 : 47 43 23 24 9 10 :Middle Fabius River Ewing 12.0 17.0 19.5 : 52 44 13 13 9 9 :South Fabius River Taylor 9.5 14.0 19.0 : 60 53 16 15 <5 <5 :North River Palmyra 13.0 16.0 22.0 : 50 44 23 20 <5 <5 :Mid Fork Salt River Holliday 17.0 22.0 26.0 : 50 49 6 <5 <5 <5 :Salt River New London 19.0 25.0 27.0 : <5 <5 <5 <5 <5 <5 :Cuivre River Troy 21.0 25.0 29.0 : 58 52 30 30 7 7 Old Monroe 24.0 27.0 30.0 : 36 58 13 24 <5 10 :Meramec River Steelville 12.0 20.0 25.0 : 44 40 <5 <5 <5 <5 Sullivan 11.0 20.0 29.0 : 69 70 15 13 <5 <5 :Bourbeuse River Union 15.0 22.0 26.0 : 47 46 7 7 <5 <5 :Meramec River Pacific 15.0 23.0 27.0 : 52 53 9 9 <5 <5 :Big River Byrnesville 16.0 20.0 28.0 : 70 64 29 26 <5 <5 :Meramec River Eureka 18.0 25.0 30.0 : 46 47 20 16 10 10 :Kaskaskia River Carlyle TW 423.5 431.0 435.0 : 70 47 <5 <5 <5 <5 Vandalia 18.0 24.0 26.0 : >95 72 32 23 15 9 :La Moine River Ripley 22.0 23.0 27.0 : 47 40 43 38 10 9 :Moreau River Jefferson City 17.0 25.0 29.0 : 68 76 25 29 11 11 :Maries River Westphalia 10.0 15.0 20.0 : 29 35 10 9 <5 <5 :Gasconade River Rich Fountain 20.0 25.0 30.0 : 14 21 <5 7 <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: 3/9/2015 - 6/7/2015 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Dardenne Creek St. Peters 9.5 10.1 11.7 15.4 20.8 24.2 24.8 :Mississippi River Canton LD20 8.9 9.6 11.6 14.0 15.9 18.6 20.2 Quincy 12.9 13.2 14.8 17.0 19.2 22.1 24.2 Hannibal 12.5 13.1 14.3 16.3 18.2 20.4 22.6 Saverton LD22 9.8 10.8 12.7 15.9 18.2 20.9 23.2 Louisiana 12.1 12.2 13.3 16.3 18.2 20.1 22.5 Clarksville LD24 20.0 20.9 23.0 26.5 28.7 30.7 33.1 Winfield LD25 20.2 21.2 23.2 26.6 28.8 30.7 33.0 :North Fabius River Ewing 6.9 7.3 8.8 10.9 13.9 18.3 20.7 :Middle Fabius River Ewing 6.2 6.9 9.3 12.3 15.3 19.1 21.4 :South Fabius River Taylor 6.7 7.1 7.9 10.2 12.4 15.1 17.5 :North River Palmyra 8.2 8.5 10.6 13.3 15.9 20.2 21.2 :Mid Fork Salt River Holliday 11.7 12.1 15.5 17.2 18.5 20.8 22.3 :Salt River New London 9.5 9.6 9.9 10.6 12.2 14.7 16.1 :Cuivre River Troy 13.1 14.6 18.4 23.4 25.7 28.2 30.1 Old Monroe 16.9 17.6 20.1 22.7 25.5 28.5 30.0 :Meramec River Steelville 4.3 5.6 8.1 11.5 13.7 15.8 18.8 Sullivan 6.8 7.5 10.0 14.5 17.6 21.7 25.5 :Bourbeuse River Union 9.1 10.2 12.3 14.9 18.2 21.1 23.9 :Meramec River Pacific 4.9 7.1 10.7 15.3 18.9 23.0 24.6 :Big River Byrnesville 8.8 12.0 15.2 18.0 20.8 23.6 25.8 :Meramec River Eureka 8.5 9.7 13.3 17.1 24.3 30.5 33.1 :Kaskaskia River Carlyle TW 422.8 423.2 423.5 424.3 425.7 426.4 426.5 Vandalia 21.1 21.2 21.8 22.6 25.3 26.9 27.5 :La Moine River Ripley 14.6 16.4 19.8 21.7 25.0 27.3 28.2 :Moreau River Jefferson City 5.3 9.5 15.8 19.4 25.0 30.1 34.7 :Maries River Westphalia 2.9 3.1 4.3 7.1 10.8 14.8 17.2 :Gasconade River Rich Fountain 5.2 6.5 8.4 11.4 17.3 21.9 23.4 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: 3/9/2015 - 6/7/2015 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Dardenne Creek St. Peters 3.4 3.4 3.2 3.2 3.1 3.0 3.0 :Mississippi River Canton LD20 4.0 3.6 3.3 3.2 3.2 3.1 2.5 Quincy 11.6 11.3 11.1 11.0 10.9 10.9 10.9 Hannibal 10.4 10.1 10.0 10.0 9.9 9.8 9.6 Saverton LD22 5.6 5.3 5.1 5.0 4.9 4.6 4.1 Louisiana 11.9 11.9 11.9 11.9 11.9 11.8 11.8 Clarksville LD24 16.0 15.8 15.5 15.3 14.9 14.2 13.7 Winfield LD25 15.8 15.6 15.4 15.2 14.8 14.1 13.5 :North Fabius River Ewing 3.3 3.2 3.1 3.0 2.9 2.8 2.8 :Middle Fabius River Ewing 3.2 3.1 3.0 2.9 2.9 2.8 2.8 :South Fabius River Taylor 2.4 2.2 2.1 2.0 1.8 1.7 1.7 :North River Palmyra 4.4 4.4 4.3 4.2 4.1 4.1 4.0 :Mid Fork Salt River Holliday 4.7 4.6 4.5 4.5 4.4 4.3 4.3 :Salt River New London 6.1 5.3 5.0 3.5 2.2 2.2 2.2 :Cuivre River Troy 6.0 5.8 5.5 5.3 5.1 5.0 5.0 Old Monroe 12.8 12.6 12.2 11.9 10.6 9.7 9.4 :Meramec River Steelville 2.4 2.2 2.0 1.9 1.8 1.7 1.6 Sullivan 3.3 3.1 2.8 2.6 2.4 2.2 2.1 :Bourbeuse River Union 2.1 1.9 1.8 1.6 1.5 1.3 1.2 :Big River Byrnesville 3.7 3.4 3.1 2.7 2.4 2.2 2.1 :Meramec River Eureka 3.1 2.9 2.7 2.5 2.3 2.2 2.1 :Kaskaskia River Carlyle TW 417.5 417.4 417.3 417.3 417.2 417.1 417.0 Vandalia 9.7 9.6 9.4 9.4 9.3 6.2 4.0 :La Moine River Ripley 6.3 6.1 5.9 5.6 5.0 4.6 4.5 :Moreau River Jefferson City 2.1 2.0 1.9 1.8 1.7 1.6 1.6 :Maries River Westphalia 1.8 1.8 1.5 1.4 1.3 1.2 1.1 :Gasconade River Rich Fountain 3.4 3.3 3.3 3.1 2.9 2.7 2.5 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/lsx for more weather and water information. The next outlook is scheduled to be issued the last week of this month. Fuchs $

 

 

 


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.