The heat wave is expected to peak in the eastern Great Lakes and New England today, and the Ohio Valley and Mid-Atlantic Friday into the weekend. Widespread daily record high temperatures are likely. Heavy to excessive rainfall will be associated with thunderstorms forecast to move across parts of the northern Plains and Upper Midwest today into Friday. Read More >
Beginning June 1st, the National Weather Service Weather Forecast Office in Miami (WFO Miami) will test a change to the Heat Advisory and Excessive Heat Warning criteria for public forecast zones in Miami-Dade County. This change is part of a pilot project in partnership with Miami-Dade County, and the new criteria is better aligned with local climatology, as well as recent health data which indicate that significant health impacts from heat occur at heat index values lower than the current advisory/warning criteria.
The current heat advisory/warning criteria is as follows for all public zones in the WFO Miami service area:
Heat Advisory: Heat Index of 108F or higher for at least 2 hours
Excessive Heat Warning: Heat Index of 113F or higher for at least 2 hours
The new, experimental heat advisory/warning criteria for public forecast zones in Miami-Dade County (Table 1) will be the following:
Heat Advisory: Heat Index of 105F or higher for at least 2 hours
Excessive Heat Warning: Heat Index of 110F or higher for at least 2 hours
| UGC Forecast Zone Number | Weather Forecast Zone Name |
|---|---|
| FLZ073 | Inland Miami-Dade |
| FLZ074 | Metro Miami-Dade |
| FLZ173 | Coastal Miami-Dade |
| FLZ174 | Far South Miami-Dade |
Table 1: Universal Geographic Codes (UGC): Weather Zones included in the new Heat Advisory/Excessive Heat Warning Criteria
The new experimental criteria for Miami-Dade County for this heat season is based on local temperature climatology and frequency of heat index values at or above the newly defined criteria. The new criteria better aligns with the historical frequency of heat index values above the newly defined criteria, and is closer to heat index values at which significant health impacts from heat can occur.
The following public forecast zones will continue with the existing heat advisory/excessive heat warning criteria (advisory: 108F or higher for at least 2 hours, warning: 113F or higher for at least 2 hours):
| UGC Forecast Zone Number | Weather Forecast Zone Name |
|---|---|
| FLZ063 | Glades |
| FLZ066 | Hendry |
| FLZ067 | Inland Palm Beach |
| FLZ068 | Metro Palm Beach |
| FLZ069 | Coastal Collier |
| FLZ070 | Inland Collier |
| FLZ071 | Inland Broward |
| FLZ072 | Metro Broward |
| FLZ075 | Mainland Monroe |
| FLZ168 | Coastal Palm Beach |
| FLZ172 | Coastal Broward |
Table 2: Universal Geographic Codes (UGC): Weather Zones included in the current Heat Advisory/Excessive Heat Warning Criteria
Evaluation of this experiment will take place during and after the 2023 heat season to determine if these changes will become official policy for 2024 for parts or all of the WFO Miami service area.
For any questions, please contact:
Robert Molleda, Warning Coordination Meteorologist
Robert.Molleda@noaa.gov, 305-229-4522 ext. 223
Image 1: New Heat Advisory/Excessive Heat Warning Area in Red, and entire WFO Miami County Warning Area in white with red outlines. UGC public zone numbers inside the zone boundaries
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