With the beginning of hurricane season nearing (June 1st), NOAA (National Oceanic and Atmospheric Administration) officials are revving up their tools to keep us all safe before, during and after a storm.
1) Storm Surge Watch/Warning becomes operational Beginning with the 2017 hurricane season, the National Weather Service (NWS) will issue storm surge watches and warnings to highlight areas along the Gulf and Atlantic coasts of the continental United States that have a significant risk of life-threatening inundation from a tropical cyclone, subtropical cyclone, post-tropical cyclone, or (pending final NWS approval) a potential tropical cyclone. Storm surge is often the greatest threat to life and property from a tropical cyclone, and it doesn’t always occur at the same times or locations as a storm’s hazardous winds. In addition, while in most cases coastal residents can remain in their homes (or in a secure structure nearby) and be safe from a tropical cyclone’s winds, evacuations are generally needed to keep people safe from storm surge. Having separate warnings for these two hazards will save lives by better identifying the specific tropical cyclone hazards communities face, and by enhancing public response to instructions from local officials.
The storm surge watch/warning areas are determined by a collaborative process between the NHC and local NWS Weather Forecast Offices (WFOs). The primary objective guidance will be P-Surge, an ensemble-based probabilistic system driven by the SLOSH model, the latest NHC official tropical cyclone forecast, and the typical historical errors associated with NHC forecasts. Forecaster confidence, continuity from advisory to advisory, and other subjective factors will also help determine the areas placed under a watch or warning. A graphic (e.g., Figure 1) depicting the watch and warning areas will be available on the NHC website (www.hurricanes.gov) whenever these watches/warnings are in effect.
In addition to the graphic, the watch and warning areas will be included in Hurricane Local Statements issued by NWS Forecast Offices, and in the NHC Public Advisory. The definitions for the new storm surge watch and warning are:
Storm Surge Watch: The possibility of life-threatening inundation from rising water moving inland from the shoreline somewhere within the specified area, generally within 48 hours, in association with an ongoing or potential tropical cyclone, a subtropical cyclone, or a post-tropical cyclone. The watch may be issued earlier when other conditions, such as the onset of tropical storm-force winds, are expected to limit the time available to take protective actions for surge (e.g., evacuations). The watch may also be issued for locations not expected to receive life-threatening inundation, but which could potentially be isolated by inundation in adjacent areas.
Storm Surge Warning: The danger of life-threatening inundation from rising water moving inland from the shoreline somewhere within the specified area, generally within 36 hours, in association with an ongoing or potential tropical cyclone, a subtropical cyclone, or a post-tropical cyclone. The warning may be issued earlier when other conditions, such as the onset of tropical stormforce winds, are expected to limit the time available to take protective actions for surge (e.g., evacuations). The warning may also be issued for locations not expected to receive lifethreatening inundation, but which could potentially be isolated by inundation in adjacent areas.
The Potential Storm Surge Flooding Map, which became operational in 2016, will continue to be issued in 2017.