Site Specific Hurricane Wind Forecast – Katia

I recently posted a large number of probabilistic wind forecasts for Hurricane Irene. Here are similar predictions for Hurricane Katia - Maximum Sustained Wind expected at 25% probability.

 A twist to these calculations are "Site Specific Wind Forecasts". Given a latitude and longitude of a forecast location (your house?), you can run out a large number of potential storm tracks and storm strengths, then plot wind versus future time for each storm at the forecast location. These wind curves then, form the basis for a statistical forecast specific to the site.  Below are my forecasts at Bermuda for Hurricane Katia at  9/5/2011 15 GMT. And 9/6/2011 15 GMT.  Note shift of the curves to the left as the storm gets closer.

The red, orange and yellow lines are the 95%, 75% and 50% exceedence levels. That is, the maximum sustained wind level at the given time and location that is expected to be exceeded at 5%, 25% and 50% probability.  Yellow boxes at right give probability of exceedence for any time during the 5 day window. Wind strength, onset time, duration, and probability are the elements needed for informed wind hazard decisions.

Steven N. Ward   Santa Cruz