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NWS_Forecasts_Guidance_Warnings/rfc_gridded_ffg (MapServer)

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Service Description:

The 12 National Weather Service (NWS) River Forecast Centers (RFC) across the continental United States (CONUS) produce Flash Flood Guidance (FFG) products for the purposes of helping NWS Weather Forecast Offices (WFOs) monitor and forecast flash flooding events. Flash Flood Guidance is an estimate of the amount of rainfall required over a given area during a given duration to cause small streams to flood. These estimates are based on the current soil moisture and stream flow conditions for the area. The RFCs issue FFG grids at 4-km resolution for 1-, 3-, and 6-hour rainfall durations, with the Ohio RFC additionally issuing FFG grids for 12- and 24-hour durations. The Northwest RFC does not provide FFG data for Washington and Oregon from the Pacific coast eastward across the Cascade Mountains. Once per hour, WPC checks for updated data from the RFCs and combines the latest grids from each RFC into a mosaicked CONUS-wide gridded product. The data are slightly upscaled to 5-km resolution, with a minor amount of smoothing applied at RFC boundaries to reduce discontinuities. However, note that the methodology used to calculate FFG varies from RFC to RFC, so users will notice stark boundary discontinuities in certain parts of the country; this is particularly true across the northern CONUS RFCs.

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Time Information:

This service is not time enabled

Map Name: Flash Flood Guidance


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Layers: Description:

Copyright Text:

Spatial Reference: 102100  (3857)

Single Fused Map Cache: false

Initial Extent: Full Extent: Units: esriMeters


Document Info: Supports Dynamic Layers: false

MaxRecordCount: 1000

MaxImageHeight: 4096

MaxImageWidth: 4096

Supported Query Formats: JSON, AMF, geoJSON

Min Scale: 0

Max Scale: 0

Supports Datum Transformation: true

Child Resources:   Info

Supported Operations:   Export Map   Identify   Find   Return Updates   Generate KML