5.2.1 Regional Climatology Description and History
A. The general climate of the region shall be described with respect to the types of topographic influences,
general airflow patterns, temperature and humidity, precipitation, and relationships between regional
atmospheric conditions and local meteorological conditions.
B. Regional extreme climatology history shall be reported with dates, event descriptions, and related
information on their effects.
5.2.2 Wind Data Collection
A. A distinction is made between three types of wind; straight winds, hurricane, and tornado winds. Site
specific characterization needs to be performed for each type of windstorm.
18.104.22.168 Straight Winds
A. Straight winds are non-rotating winds such as those found in thunderstorms. This type of wind data shall
be collected for locations near the site. On-site data shall be collected, if available, and if they meet the
There shall be at least 10 continuous years of annual extreme wind speed records with elevations at
which they were obtained.
The type of wind speed recorded over time shall be specified (e.g., fastest mile, peak, etc.,).
The recorded wind speeds shall be obtained from anemometers located in flat, open terrain.
The elevations at which wind speeds are recorded shall be 10m (33 feet) above ground.
B. If the last two conditions are not met, the recorded wind speeds shall be corrected using accepted wind
boundary layer conversion methods. It is possible to utilize data from on-site stations for which less than
10 years of records exist if there are a sufficient number of historical records from nearby stations, within
the same topographic environment.
C. In absence or lack of sufficient on-site wind record data, it is possible to utilize data collected by federal
agencies for stations close to the site (generally within 50 km) and located in a same wind environment
(stations close to but separated by mountainous ranges from the site do not qualify). Such data have been
collected at 129 weather stations (Simiu et. al., 1979) within the continental U.S. and at coastal locations
(Changery, 1985). In addition, wind speed records for more than 400 stations can be retrieved from the
National Climatic Center.
22.214.171.124 Hurricane Winds
A. Hurricane winds are rotating winds which can top 240 km/hr (150 mph). Hurricane-prone regions of the
continental U.S. are located along the coastal areas. There are very few wind speed records from hurricane
at coastal locations (Changery, 1985). Therefore, for sites in hurricane-prone areas and for which no
up-to-date site-specific probabilistic hurricane wind hazard analysis has been performed in accordance with
DOE-STD-1023-95, the meteorological data of past historical hurricanes within 400 km (250 miles) from
the site shall be collected, which include: