 Within the Dvorak satellite strength estimate for tropical cyclones , there are several visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity . The primary patterns used are curved band pattern ( <unk> @-@ <unk> ) , shear pattern ( <unk> @-@ <unk> ) , central dense overcast ( CDO ) pattern ( T2.5 @-@ <unk> ) , banding eye pattern ( <unk> @-@ <unk> ) , eye pattern ( <unk> - T8.0 ) , and central cold cover ( CCC ) pattern . Both the central dense overcast and embedded eye pattern utilize the size of the CDO . The CDO pattern intensities start at T2.5 , equivalent to minimal tropical storm intensity ( 40 miles per hour ( 64 km / h ) ) . The shape of the central dense overcast is also considered . The farther the center is tucked into the CDO , the stronger it is deemed . Tropical cyclones with maximum sustained winds between 65 miles per hour ( 105 km / h ) and 100 miles per hour ( 160 km / h ) can have their center of circulations obscured by cloudiness within visible and infrared satellite imagery , which makes diagnosis of their intensity a challenge . 
