National Weather Service United States Department of Commerce

Cold Temperatures Continue in the Southeast; Snow in the Central Appalachians and Ohio Valley; Rain and Thunderstorms in the Southeast

Cold temperatures will persist across Florida and the Southeast through Tuesday, then milder conditions are expected beginning Wednesday. A frontal system is expected to bring wintry precipitation to the Central Appalachians and portions of the Mid-Atlantic Tuesday into Wednesday, meanwhile, showers and thunderstorms are expected along the Gulf Coast and Southeast. Read More >

Gridded Flash Flood Guidance (GFFG) provides a general indication of the amount of rainfall necessary to cause small streams to overflow their natural banks. During heavy rainfall, usage of this guidance must involve combination of rainfall that has already occurred plus any additional rainfall that is expected to fall over the same location, not to exceed the guidance duration (example: 1-hr or 3-hr). It should be noted that these GFFG values are based upon estimates of average soil moisture and stream flow conditions over 4km x 4km grids. GFFG values also assume that the rainfall event will be evenly distributed over the guidance duration. Flooding may occur with less rainfall than indicated in areas of very high rainfall intensities, impervious surfaces (urban areas), or steep slopes.

The 1, 3, and 6 Hourly Gridded Flash Flood Guidance is also viewable on NOAAs GIS Integrated Dissemination Program (IDP) web services. Metadata and additional information on the gridded flash flood guidance and other GIS Web Services can be found at the National Weather Service Data as OGC Web Services site .  Flash flood guidance on a national scale, can be found here.

 

National Precipitation Totals and Flash Flood Guidance