WWC Weather Station Notebook
Saffir-Simpson Hurricane Wind Scale updated for the 2012 Hurricane Season



148 PM EST Thu Mar 1 2012.

NOTICE: The Saffir-Simpson Hurricane Wind Scale (SSHWS) is undergoing a minor modification for 2012 in order to resolve awkwardness associated with conversions among the various units used for wind speed in advisory products. The change broadens the Category 4 wind speed range by one mile per hour (mph) at each end of the range, yielding a new range of 130-156 mph. This change does not alter the category assignments of any storms in the historical record, nor will it change the category assignments for future storms. The reasoning behind this change and a tabulation of the old and new scales is available here (PDF). The new summary table is shown below:

Category Winds Summary
74-95 mph
64-82 kt
119-153 km/h
Very dangerous winds will produce some damage
96-110 mph
83-95 kt
154-177 km/h
Extremely dangerous winds will cause extensive damage
111-129 mph
96-112 kt
178-208 km/h
Devastating damage will occur
130-156 mph
113-136 kt
209-251 km/h
Catastrophic damage will occur
157 mph or higher
137 kt or higher
252 km/h or higher
Catastrophic damage will occur
Effective May 15, 2012, to resolve these rounding issues,
Category 4 on the SSHWS will be broadened by one mph at each end
of the range, yielding a new range of 130-156 mph.  This will
also result in a minor modification of the Category 3 and 5 wind
speed thresholds. The SSHWS will change as follows:
 
From: 
 
Category 3: 111-130 mph (96-113 kt, 178-209 km/h)
Category 4: 131-155 mph (114-135 kt, 210-249 km/h)
Category 5: 156 mph or higher (136 kt or higher, 250 km/h or
            higher)
 
To:
 
Category 3: 111-129 mph (96-112 kt, 178-208 km/h)
Category 4: 130-156 mph (113-136 kt, 209-251 km/h)
Category 5: 157 mph or higher (137 kt or higher, 252 km/h or
            higher)
 
There will be no change to the wind speeds currently assigned to
Categories 1 and 2.

Additional information on this change can be found at:
 
      http://www.nhc.noaa.gov/aboutsshws.php
 
If you have any questions, please contact
 
   John Kuhn
   National Weather Service
   Silver Spring, Maryland 20910
   301 713 1677 ext. 121
   john.f.kuhn@noaa.gov
 
National Public Information Notices are online at:
 
   http://www.weather.gov/om/notif.htm