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Florida Hazards Watch - Thunderstorms

What Makes a Severe Thunderstorm?

At any moment there are around 1,800 thunderstorms occurring around the world. That's 16 million thunderstorms a year! Of the estimated 100,000 thunderstorms that occur each year in the United States, about 10% are classified as severe. The National Weather Service considers a thunderstorm severe if it produces hail the size of a U.S. quarter or larger or winds of 58 mph or stronger. Severe thunderstorms are known to cause significant damage to well-built structures or cause bodily harm. These strong storms can also produce frequent and dangerous lightning, flooding and tornadoes.

Where Are Severe Thunderstorms Likely to Occur?

On average, the interior sections of central Florida receive the most thunderstorms with nearly 100 plus days per year. However, thunderstorms are also frequent along coastal areas which average 80 to 90 days per year.

Thunderstorms map image
Average number of thunderstorm days a year.


Where Can You Go For Up-To-Date Info?

  • Convective Outlooks - The Storm Prediction Center issues forecasts based on the potential for organized severe thunderstorms. The outlooks show the areas where severe thunderstorms may develop and qualifies the degree of risk. A SLGT (slight) risk implies that well-organized severe thunderstorms are expected but in relatively small numbers, or a small chance of a more significant severe event. A MDT (moderate) risk implies a greater concentration of severe thunderstorms, and in most situations, greater magnitude of severe weather and greater forecaster confidence compared to a SLGT risk. A MDT risk is usually reserved for days with an enhanced chance for a significant severe storm outbreak. The HIGH risk implies that a major severe weather outbreak is expected, with large coverage of severe weather and the likelihood of extreme severe (i.e., violent tornadoes or very damaging wind events). The HIGH risk category is only used a few times each year. In addition to the severe risk areas, general thunderstorms (non-severe) are outlined in brown on the map.

    Degree of rish for organized severe thunderstorms map image
    Degree of risk for organized severe thunderstorms for Day 1.

    • Day 1 Convective Outlook - Issued 5 times a day to display today's severe weather potential. This outlook highlights the probability for tornadoes, severe winds and hail over the locations that have the greatest potential for severe weather.

      probability of hail 1" or larger map
      Day 1 probability of hail 1" or larger. Hatched Area: 10% or greater probability of hail 2" or larger.

    • Day 2 Convective Outlook - Issued twice a day to show the potential for organized severe weather tomorrow.

    • Day 3 Convective Outlook - Issued once a day to display severe weather potential for the day after tomorrow.

    • Day 4-8 Outlook - Highlights the areas that have a 30% or higher probability for severe thunderstorms 4 to 8 days from today.

      probability for severe thunderstorms  map
      Day 4-8 map indicating a 30% or higher probability for severe thunderstorms and highlighting the area for Day 5.

  • Hazardous Weather Outlook - A statement produced by the local National Weather Service offices to provide information regarding the potential of significant weather expected during the next week.  This is issued to advise storm spotters and emergency managers of potentially hazardous weather and other threatening conditions.
  • Short Term Forecast - Issued by the National Weather Service as a 1-2 hour forecast of local weather conditions; emphasizing hazardous weather.
  • Severe Thunderstorm Watch - Issued by the Storm Prediction Center to alert the public that conditions are favorable for the development of severe thunderstorms in and close to the watch area.  These watches are issued with information concerning the watch area and the length of time they are in effect. During the watch, people should review severe thunderstorm safety rules and be prepared to move a place of safety if threatening weather approaches.
  • Severe Thunderstorm Warning - Issued by local National Weather Service offices to warn the public that a severe thunderstorm has been sighted by storm spotters or has been indicated by radar. People in the affected area should seek safe shelter immediately.


What Actions Should You Take To Be Prepared?

  • weather radioHave a NOAA All-Hazards Weather Radio and battery backup to receive important weather and other emergency-related warnings. With a NOAA All-Hazards Weather Radio, you can monitor current weather conditions and forecasts for your local area. These radios also have an alert feature which will sound an alarm - followed by important weather information - whenever a watch or warning is issued for your area
  • Discuss thunderstorm safety with all members of your household or business.
  • Locate or build a Safe Room in the interior of your home or business that can help provide protection for you and your family or your employees. This room should be located away from all windows.
  • Check the weather forecast before leaving for extended periods outdoors and watch for signs of approaching storms while outside. Postpone outdoor activities if storms are imminent.
  • Inquire if your Community is StormReady. StormReady helps community leaders and emergency managers strengthen local safety programs. StormReady communities are better prepared to save lives from the onslaught of severe weather through advanced planning, education and awareness.



February 12, 2016 14:55


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