Hurricane track forecasts improve steadily over the last several decades.

However, intensity forecasts show very little improvement

over the last decade, partially, because small-scale inner-core circulation can not be properly resolved

by satellite observations.

To improve intensity forecasts, it is important to use high-resolution Doppler radar data

to properly initialize inner-core circulation for high-resolution numerical models.

A technique is developed for initialization of a hurricane vortex

using horizontal velocities through a deep layer of the atmosphere

obtained from Doppler radar.

The technique uses two new innovations.

The first is the use of the mesoscale vorticity equation

to diagnose the vertical velocity and divergent wind.

The second is the use of the Bounded Derivative Initialization

to obtain two dynamic constraints, one each for gravity and sound waves.

With the fast waves controlled, a nonhydrostatic model can be initialized

to allow a smooth and balanced start.

The technique is tested using the 1.5 km resolution MM5 model

with radar data from Hurricane Danny as it approached the Gulf Coast in 1997.

Numerical results show positive radar data impacts on track and intensity forecasts.

The initialization scheme correctly inserts the observed storm derived from radar data

in the right location. After initialization, the forecast storm track closely follows the

actual storm track observed from Doppler radar.

Comparisons of forecast winds and radar wind measurements show the use of radar data

substantially improves the intensity and horizontal structure of forecast wind fields.