A probabilistic wind speed forecast product blending NHC TC-based fields with a dynamical model ensemble

It is often difficult to discriminate the wind circulation associated with a tropical cyclone from the large-scale synoptic environment which can include strong zones of high pressure, or large low pressure systems resulting from extratropical transition. Gale-force winds can often exist well beyond the actual TC circulation, which may not be depicted well by the traditional TC-only wind products issued by the National Hurricane Center. An augmented product is being explored at the Canadian Hurricane Centre that involves the merging of NHC's TC wind “swath” probability fields with fields cast in a similar manner from a dynamical model ensemble covering the large-scale environment. Such a product could be particularly useful for interests in the marine community making medium-range decisions that are dependent on wind and waves - regardless of the weather system generating them. Some examples will be shown highlighting the added value of fields generated during Hurricane Ida's extratropical transition in the Gulf of Mexico in November 2009.