Hot Weather DSS

Hot Weather Decision Support

Instructions: Select desired Time and Region, then choose a Forecast button to view image

The images below are the official NWS maximum temperatures, maximum heat index forecasts, and HeatRisk for the next 7 days. This data is determined by NWS forecasters to be the most likely outcome based on evaluation of data from computer models, satellite, radar, and other observations.

Time

Region

Forecast

These graphics are updated at least twice per day, around 4:15 AM/4:15 PM.
Temperature and Heat Index Graphic

Heat Related Warning/Watch/Advisory Criteria

The NWS Hazard Simplification (Haz Simp) project has led to changes to our hot weather related product suite beginning this season. These changes are designed to simplify the communication of information, improve understanding, and enhance the utility of forecasts and warnings. Detailed information about these changes can be found in the Service Change Notice and the Haz Simp Hot One-Pager.

Hot Weather related Warning, Watch, and Advisory statements will be issued by the National Weather Service in Tampa Bay when the following criteria is forecast:

Extreme Heat Warning - issued within 12 hours, or up to 24 hours out if confidence is high, when Heat Index values are expected to reach 113° Fahrenheit or higher.
Extreme Heat Watch - issued during the first 48 hours when Heat Index values could reach 113° Fahrenheit or higher.
Heat Advisory - issued within 12 hours, or up to 36 hours out if confidence is high, when Heat Index values are expected to reach 108° to 112° Fahrenheit.

What is the Heat Index?

The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature. In other words, the “feels-like” temperature. This has important considerations for the human body's comfort.

It surprises many people to learn that the heat index values forecasted and measured are for shady locations. If you are exposed to direct sunlight, the heat index value can be increased by up to 15°F. As shown in the table below, heat indices meeting or exceeding 103°F can lead to dangerous heat disorders with prolonged exposure and/or physical activity in the heat.

More detailed information, as well as records and average heat index values, can be found within our local Heat Tools and Statistics web page.

What is the NWS HeatRisk?

The NWS HeatRisk is an experimental color-numeric-based index that provides a forecast risk of heat-related impacts to occur over a 24-hour period. HeatRisk takes into consideration:

How unusual the heat is for the time of the year
The duration of the heat including both daytime and nighttime temperatures
If those temperatures pose an elevated risk of heat-related impacts based on data from the CDC

This index is supplementary to official NWS heat products and is meant to provide risk guidance for those decision makers and heat-sensitive populations who need to take actions at levels that may be below current NWS heat product levels.

NWS HeatRisk Categories and Risk of Heat-Related Impacts graphic

More details and graphics about the HeatRisk can be found at NWS HeatRisk web site.