The National Hurricane Center issued storm surge watches and warnings Thursday for Hurricane Isaias, alerting coastal residents that life-threatening inundation from rising water moving inland from the shoreline is possible within 36 to 48 hours.
The NHC defines a storm surge warning as indicating “a danger of life-threatening inundation from rising water moving inland from the shoreline somewhere within the specified area, generally within 36 hours.” A storm surge watch carries a slightly longer window, signaling that life-threatening inundation is possible “generally within 48 hours.”
The agency released two products in quick succession Thursday morning — a Storm Surge Watch/Warning graphic at 9:02 a.m. and a Potential Storm Surge Flooding Map at 10:10 a.m. — both based on PSURGE modeling guidance developed by the National Weather Service.
The NHC cautioned that forecast uncertainty means the actual areas experiencing life-threatening inundation may differ from those shown on the maps. “All persons, regardless of whether or not they are in the highlighted areas shown in the graphic, should promptly follow evacuation orders and other instructions from local officials,” the agency stated.
Residents in affected zones are urged to monitor updates at hurricanes.gov and comply immediately with any evacuation orders issued by local emergency management officials. The NHC is expected to issue updated advisories and revised surge maps as Isaias tracks closer to the coast.