RFC Layers

These are the same exact layers that are found on the NOAA RFC Page.  These layers show the amount of rain/snow/hail that's fallen over a given time period.  The 'About This Page' tab on the NOAA has a lot of details.


This section discusses the "Gauges" map layer. Be sure to read the information about the "secondary gauges" below.

Rain Gauges:  As of now, all of the rain gauges come from NOAA's Hydrometeorological Automated Data System (HADS)
The HADS site is a jackpot of very useful data, but it's an absolute bitch to navigate.  Most of these rain gauges are updated every hour.  Click on a rain gauge icon for more information about gauge update timing.  The numbers (labels) under the raindrop icons represent the 6hr/12hr/24hr rainfall totals.  Click the icon for detailed info.
Stream Gauges:
  Most of these are USGS Streamflow Gauges, but some come through HADS. 
The most recent stage and CFS reading (if that gauge records CFS) is labeled underneath these icons.  For now, the icons show trends that are based on the last hour's worth of data.
HoldingThis icon means that the stream is rising or falling at less than 0.24"/Hour -- or holding steady

HoldingThis icon means that the stream is rising more than 0.24"/Hour but less than 2"/Hour

HoldingThis icon means that the stream is rising more than 2"/Hour

HoldingThis icon means that the stream is falling more than 0.24"/Hour but less than 2"/Hour

HoldingThis icon means that the stream is falling more than 2"/Hour

Rain and Stream Gauges:  Some gauges record both rain and stream flow data.  See above for more details

Secondary Gauges

The data for these gauges is pulled from the Mesonet website, but the data originates from other sources. These sources include

Automated Flood Warning System
Advanced Hydrologic Projection Service
– Possibly other sources

The data from these gauges is problematic in that most of them record and transmit readings at irregular time intervals. In contrast, the data in 'Gauges' map layer originates from USGS and HADS and is reported in 15 minute intervals. That makes it easy to calculate hourly summaries of the data that are shown under the rain drop icons and determine which arrow icon (rising/falling) to display for the stream gauges. But this is not so easy with the irregular nature of the secondary gauges. It appears that many of the secondary gauges do not transmit data when there has been no or little change in rainfall or a stream's stage. Many hours can elapse between readings in these cases. Then some gauges only report data at 12 hour intervals. Both of these scenarios can make it impossible to accurately report the amount of rain in the past 6 hours. Because of these difficulties, please be aware that the 6/12/24 hr labels under the rain drop icons may be misleading – sometimes very misleading. Also be aware that a river may have started to rise but the direction of the arrow may not reflect that change or any other change. It's best to click on the gauge icons and then review the graph and data table that are shown. Pay close attention to the timestamp of the last several readings.

Because of the potential misinterpretation with the secondary gauges, I decided to put them in a separate map layer that you can turn off using the “Layer Switcher” on the desktop map or by clicking the “Layers” button on the mobile version of the map. I've also used different colors for the icons: the rain gauge icons are light blue and the stream gauges icons (arrows) are gray.

Please note that the secondary gauges are a work in progress. People in the IT industry might say that they are “in beta.” I already have a short term to do list includes:

– Identify gauges that haven't reported data in more than 24 hours and display a warning symbol on the gauge, such as a red exclamation mark
– Identify gauges that haven't reported data in weeks and remove them from the map.
– Remove duplicate gauges. Some of these secondary gauges appear to be in the USGS or HADS systems as well. The gauge in the secondary gauges layer will be deleted in these instances.
– Visually review the rain gauge labels (6hr/12hr/24hr) and the stream stage arrows to determine if they're communicating good information

I'm open to comments and suggestions. Please feel free to post them on the Rain Pursuit Facebook Page or send me and email at alexzendel at hotmail dot com.

National Water Model Streams

Recently released by NOAA's Office of Water Prediction, the National Water Model is a massive hydrologic modeling project that estimates and forecasts streamflow on nearly every stream reach in the entire Continental US. Yep, that includes some of the smallest streams that we paddle like Courthouse Creek, Yellow Creek (Daddys Creek trib) and Thunderhead Prong. These reaches are shown in the "NWM Streams" layer in Rain Pursuit. The numeric labels on the stream segments are the most recent estimated flow (in CFS) from the NWM. NOAA has a map that shows you the forecast for a reach when you click on it. I'm working on integrating those forecasts into Rain Pursuit. As of November 2016, the introduction window on that NOAA map raises the caution flag about the need for further NWM refinement and calibration:
As this output is from the first version of the NWM, it does not yet contain information on the anthropogenic effects on streamflow and output should be viewed with caution. The output is undergoing extensive validation and verification to identify where updates to the science model parametrization and configurations can make the most improvements to the model output. The next version of the NWM will be released in the spring 2017 time frame. For official NWS river forecasts please see http://water.weather.gov.

HUC 12 Watershed Boundaries

Hydrologic Unit Codes were established by the USGS.  The 12-digit HUCs are the smallest watersheds that they derive.  I've found an error or two in the watershed names -- the Dunlap and Soak Creek watershed was named Upper Whites Creek (or something like that).  Please feel free to post any other errors on the Rain Pursuit Facebook Page or send me and email at alexzendel at hotmail dot com.



This layer is served up by NOAA.  It's the live/current radar.  More about NEXRAD here.