When looking at a hydrograph of your favorite river gauge you will notice a couple of things. On the x-axis is the date and time of the gauge reading. On the left side of the y-axis is the river stage (displayed in feet) and on the right side of the y-axis is flow (displayed in kilo cubic feet per second).
As you change from river gauge to river gauge, you will sometimes notice quite a difference in the stage height even though the gauges are relatively close together. This is because "0" stage for each location was selected somewhat randomly at some time in the past; the number has no direct relationship to the depth of the river or to the stage height at other gaging stations. Once you know which river level means what for your area it will be easier to correlate gauge height to river conditions.
When looking at hydrographs on the NWS Advanced Hydrologic Prediction Service website, you can often see information such as river height projections, historic crests, recent crests, and what flood impacts happen at specific river levels in your area. NOTE - NWS Missouri River forecasts usually include 24 hours of predicted precipitation (sometimes in winter and during floods, they may increase that to 48 hours - you will see the correct number above the forecast hydrograph). This means if the weather forecast says it's going to rain for the next four days, only the first day of rain will be included in the river forecast.
The US Geological Survey is the federal agency that installs, maintains and distributes data from the river gauges. The National Weather Service uses this and other data to create river forecasts.
Hydrograph provided by NWS - Advanced Hydrologic Prediction Service. This graph is not accurate and is for display purposes only.
USGS Real-Time Gauge Heights - An easy way to see the current gauge heights and discharge for most gauges from Rulo, NE to St. Charles, MO. This is also the best way to access historic data for specific gaging stations. The St. Joseph and Hermann gauges also have temperature and other water quality data such as turbidity, dissolved oxygen, nitrates and more.
NWS Advanced Hydrological Predictions (Make Your River Page) - This tool provided by the National Weather Service lets you design your own river monitoring page specific to your area that you can bookmark for easy reference. You can choose different options such as forecast graphs, flood impacts, record crest history and more for any location from Great Falls, MT to St. Louis, MO. Click the gauges you want to include on the left, the data you want to include on the right, then click "Make My River Page" at the bottom. Remember to look for the number of hours of predicted precipitation included in the forecast.
Army Corps of Engineers Missouri River Basin Web App - Not actually an app, but a collection of links to monitor reservoir levels, releases, Missouri River Basin news and a bunch of National Weather Service links.
NWS Missouri River Basin Forecast Center - Basin-wide river observations and forecasting for most gauges leading to and affecting the Missouri River. Colors indicate the current river level status. Click on a gauge station to link to the hydrological prediction graph for that specific gauge.
NWS Predictions for Major Missouri River Tributaries - Find out what rivers may be responsible for the rise in your neck of the woods. Clicking a river under the "Observed Stages/Forecast Hydrographs for Major Rivers in the Missouri River Basin" will take you to that river's specific gauges. There are also hydrologic text products here.
All Missouri River Gauges in Missouri - Here is a quick view of all Missouri River gauges located in Missouri on one page from Rulo, NE to St. Charles, MO. Each gauge's graph shows past, current and predicted river levels. Also, here's a link to all of the gauges on the MR340 Race Course (KC to St. Charles) - at the bottom are three maps that show past, current and predicted precip included in the forecast model.
US Army Corps of Engineers Missouri River Basin Current River & Dam Conditions - This page provides access to current water resource information for the entire Missouri River Basin. The Daily River & Reservoir Bulletins contain information on estimated dam discharges, 24-hour precipitation and river conditions for each gauge from Gavins Point Dam to St. Louis, MO. They also have an interactive map version of this data here.
Missouri Basin River Forecast Center Decision Support Page - Ever wonder how they predict rises and crests on the Missouri River? This page is a massive collection of tools, recent rainfalls and weather forecasts that the National Weather Service uses to issue river level projections. This page also hosts the U.S. Army Corps of Engineers Missouri River Reservoir Updates and Forecasts which give us a hint of what to expect for the upcoming season using current snowpack and reservoir levels.
Quantitative Precipitation Forecasts - This is a quick and easy way to see the predicted rainfall across the nation from the National Weather Service Weather Prediction Center.
Ventusky - Clearly displayed meteorological data from around the world and allows you to monitor weather development for any place on earth. Ventusky uses data from NOAA and DWD to beautifully display wind, temperature, air pressure, thunderstorms and even waves.