Each
National Weather Service (NWS) Weather Forecast Office (WFO) can issue the following heat-related bulletins as conditions warrant:
Excessive Heat
Warning
Take Action! An Excessive Heat Warning is issued within 12 hours
of the onset of extremely dangerous heat conditions. The general rule of thumb
for this Warning is when the maximum heat index temperature is expected to be
105° or higher for at least two days and night-time air temperatures will not
drop below 75°; however, these criteria vary across the country, especially for
areas not used to extreme heat conditions. If you don't take precautions
immediately when conditions are extreme, you become seriously illness or even
die.
Excessive Heat
Watches
Be Prepared! Heat watches are issued when conditions are favorable
for an excessive heat event in the next 24 to 72 hours. A Watch is used when
the risk of a heat wave has increased but its occurrence and timing are still
uncertain.
Heat Advisory
Take
Action! A Heat Advisory is issued within 12 hours of the onset of extremely
dangerous heat conditions. The general rule of thumb for this Advisory is when
the maximum heat index temperature is expected to be 100° or higher for at
least two days, and night-time air temperatures will not drop below 75°; however,
these criteria vary across the country, especially for areas that are not used
to dangerous heat conditions. Take precautions to avoid heat illness. If you
don't take precautions, you could become seriously illness or even die.
Excessive Heat Outlooks
Issued when the potential exists
for an excessive heat event in the next 3-7 days. An Outlook provides
information to those who need considerable lead-time to prepare for the event.