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Regional and Mesoscale Meteorology Branch

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Flooding across the CONUS

Posted On: February 23, 2018 - By: Barbra Lashbrook

Within the last few days, extensive flooding has occurred due to heavy precipitation from Texas all the way to Michigan. Just look at the NOAA NWS River Forecast map, that encompasses river gauge data across the CONtinental United States (CONUS) on 23 February 2018. Each of the data points exhibit the magnitude of flooding. Notice the range of colors, depicting river gauges that are experiencing no flooding (green), near flood stage (yellow), minor flooding (orange), moderate flooding (red) and major flooding (purple).

If  one zooms in a little bit closer at the state of Michigan, one can see the range of flooding across the state.

In complement to river gauge data, one could also see the magnitude of flooding, utilizing the Visible Infrared Imaging Radiometer Suite (VIIRS) Flood Detection Map product via the RealEarth data portal. This product is at a spatial resolution of 375 – m spatial resolution and the product’s algorithm calculates the floodwater fraction percentage of a pixel (i.e. how much of a pixel is flooded, expressed in percent).

The example below shows southern Michigan and all the nearby cities (bottom-left) and the VIIRS Flood Detection product (bottom-right), highlighting the areas of floodwater (yellow, orange, and red colors) in the center of the image, and around the state. The images were taken at 2055 UTC, on 22 February 2018. The product also discriminates between different scene types, such as: ice, open water, land, clouds, cloud shadows, mixed ice and water, and snow. Notice the vast areas of cloud cover (grey), cloud shadows (dark grey) to the west and the mixed ice and water (purple) and open water (blue) over Lake Huron.

There is more rain and snow expected in the forecast this weekend for Michigan, potentially leading to more flooding.

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