Over the last 20 years, we have averaged about 3 category one storms per year followed by about one each of categories 2, 3, and 4, with a category 5 storm occurring about every other year – on the average. This year, it doesn’t look like we will be much above average if even that.
In the reference frame of north being the direction the hurricane is heading, the NE quadrant would typically contain the strongest winds because it would contain the hurricane force winds and the speed of the forward motion of the hurricane. Conversely the winds on the west side are weaker because they are opposite of the direction the storm is moving.
Most know that a Tropical Storm must have wind speeds of at least 45 mph. And that hurricanes of Category 1 have msw (Maximum Sustained Winds) of 74 to 95 mph, and for Category 2 between 96 – 110 mph, Category 3 from 111 – 129 mph, Category 4 from 130 to 156 mph and anything above that is Category 5. Major hurricanes are those of Category 3 or higher. Since damage goes up somewhere between the square and the cube of the wind speed, the effect of higher Categories is significant.
The wind in a hurricane can be described this way. The maximum horizontal winds are typically 1500-3000 feet above the ground, not at the surface. The spiral (in the Northern hemisphere) is counter clockwise around a central low pressure core. The horizontal and vertical wind speeds are a maximum in the “eye wall” which surrounds the “eye” where the air is warm and calm, with descending air and cloudless skies.
The maximum wind speed is NOT the maximum wind speed. It is the maximum one-minute average wind speed at 10 meters (about 33 feet) above the ground. This is called the maximum sustained wind or msw. Typically the gusts are 25% to 30% higher and lower than the average. Often the maximum damage is due to the gusts and not the sustained wind. In fact the pulsing of the wind can act to pry loose some joints.
These gusts are important. Thus there are a plethora of other wind measurements, such as maximum gusts. The 10 second average wind speed would contain more of the highs and lows and the one minute average which is really the average of six 10 sec averages. Then there is the 3 sec gust (averaged over 3 sec) and the 1 sec gust. While all are useful, what is publically reported is the one minute average or msw.
Next is how the winds are measured.