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Middle Atlantic River Forecast Center

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Flash Flood Guidance and Drought Information

[Spring Flood Potential] [Flash Flood Guidance] [Headwater Flood Guidance] [Drought Info]

Spring Flood Potential Statement

Throughout the winter, the MARFC issues Spring Flood Potential Statements, which describe the possibility of Spring flooding, based on current hydrologic conditions.

Flash Flood Guidance

NEW! Gridded Flash Flood Guidance. The values are computed on a 4km by 4km grid. Finer scale variations due to terrain, urbanized areas, and uneven rainfall patterns are taken into account.

  • 1 hour guidance
  • 3 hour guidance
  • 6 hour guidance
  • Here are the county average FFG values in text format:

  • Delaware
  • Maryland
  • New Jersey
  • New York
  • Pennsylvania
  • Virginia
  • (please note that the Ohio RFC also issues Flash Flood Guidance using this product ID. Please use the "Previous Version" link if needed)
  • West Virginia
  • FYI: Flash Flood Guidance (FFG) provides a general indication of the amount of rainfall evenly distributed over various durations (in hours), necessary to cause small streams to overflow their natural banks. During heavy rainfall, accurate interpretation of the guidance consists of the combination of rainfall that has already occurred plus any additional rainfall that can be confidently expected to fall over the same location in the immediate future.

    It should be noted that FFG values represent an estimate of average soil moisture and stream flow conditions in a given county. Flooding may occur with less rainfall than indicated in areas where recent rain has been locally heavier. In addition, during prolonged dry spells, soils may temporarily have impervious characteristics at the onset of heavy rain, resulting in extra runoff and possible flooding from lower rainfall amounts than those indicated by the FFG.

    Headwater Flood Guidance

    Headwater Flood Guidance depicts the approximate rainfall evenly distributed over various durations to cause selected streams to reach official NWS flood stage (may not necessarily coincide with the natural bank) at U. S. Geological Survey gauging stations. As with Flash Flood Guidance, these values are intended as general guidance.

    Drought Information:

    [Spring Flood Potential] [Flash Flood Guidance] [Headwater Flood Guidance] [Drought Info]



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