Did you know the National Weather Service has numerous websites available to help you track flooding potential in Northwest Arkansas & the River Valley? Here are some of the links you may find helpful.
River observations: Live or work near a river or major stream? Find out what the current gauge observations are and if there is flooding upstream that may impact you. https://water.weather.gov/ahps/.
Inundation map: https://water.weather.gov/ahps/inundation.php
Weather Prediction Center National Forecast Overview: Interested in the national forecast? Here is an overview of the weather map across the United States. https://www.wpc.ncep.noaa.gov/#page=ovw
Weather Prediction Center Excessive Rainfall Outlook: Ever wonder where we get the excessive rainfall outlook from? It comes from the Weather Prediction Center. https://www.wpc.ncep.noaa.gov/#page=ero
River Forecast Centers
The duties of the River Forecast Centers are to 1) Provide river and flood forecasts and warnings for the protection of lives and property, and 2) Provide basic hydrologic forecast information for the nation’s environmental and economic well-being.
The process of forecasting rivers begins with the forecast of the rainfall expected over a period of time. Staff meteorologists prepare a full 5-day precipitation forecast to monitor developing systems.
Every hour staff meteorologists analyze Doppler radar products with measured rainfall from the local gage networks to determine the best estimate of actual rainfall over the region. This estimated rainfall is combined with the 12-hour forecasted rainfall to give the hydrologists an estimate on how much water can be expected to reach a river.
Headwater River Modeling
Heavy rainfall will impact any portion of the river, but the most sensitive areas during or immediately following rainfall are the small streams, tributaries, and headwaters that flow into the mainstem rivers. These watersheds react very quickly and cause hazardous flash flooding situations; however, these waterways can recede just as fast as they rise creating short-term flooding conditions.
Mainstem River Forecasting
Modeling river flow involves many pieces that must work together to create an accurate forecast. One such factor, soil moisture, is modeled to estimate how much of the rainfall will actually become runoff as opposed to remaining in the soil. A second factor is the time it takes for the runoff to reach gauge ‘A’.
Once that is known, the water is routed to the next gauge (guage ‘B’) downstream to learn how much runoff and the time it takes to arrive. This flow then combines with the local runoff between gauge ‘A’ and ‘B’ to create the forecast for gauge ‘B’. This process continues all the way downstream (e.g., ‘A’ to ‘B’, ‘B’ to ‘C’, ‘C’ to ‘D’, etc.).
For more river forecast information from the National Weather Service, check out these resources below.
River Forecast Center information: https://water.weather.gov/ahps/rfc/rfc.php
Arkansas-Red Basin River Forecast Center: https://www.weather.gov/abrfc/
Buffalo River Floating Conditions: https://ar.water.usgs.gov/buffaloriver/