What alerts does the National Weather Service issue during heat waves?
• An EXCESSIVE HEAT WATCH is issued 24 to 48 hours in advance, when possible. The watch is issued when the Heat Index will equal or exceed 105 degrees for 3 hours or more during the day, and remain at or above 80 degrees at night. • A HEAT ADVISORY is issued about 24 hours in advance when the Heat Index will equal or exceed 105 degrees for at least 3 hours during the day, and remain at or above 80 degrees at night. • An EXCESSIVE HEAT WARNING is issued about 24 hours in advance when the Heat Index will equal or exceed 115 degrees for 3 hours or more during the day, and remain at or above 80 degrees at night. What special alerts does the National Weather Service issue for urban areas? A new system, Heat/Health Watch/Warning, is in place for certain urban areas. So far, Dallas/Fort Worth; Phoenix; Yuma, Ariz.; Philadelphia; Chicago; St. Louis; Cincinnati/Dayton; New Orleans; Little Rock, Ark.; Memphis, Tenn.; Shreveport, La., Lake Charles, La.; Jackson, Miss.; Seattle, and Portland all u
