 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 <unk> ( <unk> ) pattern ( <unk> @-@ <unk> ) , banding eye pattern ( <unk> @-@ <unk> ) , eye pattern ( <unk> - <unk> ) , and central cold cover ( <unk> ) pattern . Both the central dense <unk> and embedded eye pattern utilize the size of the <unk> . The <unk> pattern <unk> start at <unk> , equivalent to minimal tropical storm intensity ( 40 miles per hour ( 64 km / h ) ) . The shape of the central dense <unk> is also considered . The farther the center is <unk> into the <unk> , 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 <unk> obscured by cloudiness within visible and infrared satellite imagery , which makes diagnosis of their intensity a challenge . 
