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Scale of threat levels

for South Central and Southeast Wisconsin
Marine Thunderstorm Threat
Hazard Map Threat Levels Safety & Impact

The "Marine Thunderstorm Wind Hazard Map" depicts the local threat of strong to severe wind gusts associated with thunderstorms for specified marine areas.  It is based on the likelihood that strong to severe wind gusts will occur with marine thunderstorms combined with the anticipated speed of the greatest gusts.   

Marine Thunderstorm Wind Threat Level

Threat Level Descriptions

Extreme

"An Extreme Threat to Life and Property Aboard Small Marine Craft from Wind Gusts Associated with Thunderstorms."

Within 12 miles of a location, an extreme likelihood (36% or greater) of strong to violent thunderstorm wind gusts.

High

"A High Threat to Life and Property Aboard Small Marine Craft from Wind Gusts Associated with Thunderstorms." 

Within 12 miles of a location, a high likelihood (26% to 35% probability) of strong to violent thunderstorm wind gusts.

Moderate

"A Moderate Threat to Life and Property Aboard Small Marine Craft from Wind Gusts Associated with Thunderstorms."

Within 12 miles of a location, a moderate likelihood (16% to 25% probability) of strong to violent thunderstorm wind gusts.

Low

"A Low Threat to Life and Property Aboard Small Marine Craft from Wind Gusts Associated with Thunderstorms."

Within 12 miles of a location, a low likelihood (6% to 15% probability) of strong to violent thunderstorm wind gusts.

Very Low
" A Very Low Threat to Life and Property Aboard Small Marine Craft from Wind Gusts Associated with Thunderstorms."

Within 12 miles of a location, a very low likelihood (2% to 5% probability) of strong to violent thunderstorm wind gusts.

Non-Threatening
" No Discernable Threat to Life and Property Aboard Small Marine Craft from Wind Gusts Associated with Thunderstorms."

Within 12 miles of a location, environmental conditions do not support the occurrence of strong to violent wind gusts from thunderstorms.     

Note: Since small craft are vulnerable to rapid, gusty increases in wind speed, mariners should not allow strong to severe thunderstorms to get between them and safe harbor.    

Strong Wind Gusts - Thunderstorm wind gusts between 34 knots and 49 knots.

Severe Wind Gusts - Severe thunderstorm wind gusts between 50 knots and 63 knots. 

Very Severe/Violent Wind Gusts - Severe thunderstorm wind gusts between 64 knots and 79 knots, but in worse case situations may exceed 80 knots. 

Determining Likelihood

  • NOAA's National Weather Service
  • Milwaukee/Sullivan, WI Weather Forecast Office
  • N3533 Hardscrabble Road
  • Dousman, WI 53118
  • 414-744-8000
  • Page Author: MKX Webmaster
  • Web Master's E-mail: w-mkx.webmaster@noaa.gov
  • Page last modified: 2-Nov-2005 10:23 PM UTC
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