Md. Powell et Sd. Aberson, Accuracy of United States tropical cyclone landfall forecasts in the Atlantic basin (1976-2000), B AM METEOR, 82(12), 2001, pp. 2749-2767
About 13% of all Atlantic basin tropical cyclone forecasts issued from 1976
to 2000 are for landfalls along the United States coastline, and 2% more a
re for storms forecast to make landfall in the United States but that remai
n at sea. Landfall position and time forecasts are skillful at all forecast
time periods and are more skillful than Atlantic basin track forecasts as
a whole, but within 30 h of predicted landfall, timing errors demonstrate a
n early bias of 1.5-2.5 h. Landfall forecasts are most accurate for storms
moving at oblique or normal angles to the coastline and slow-moving storms.
During the last quarter century. after adjustment for forecast difficulty,
no statistically significant improvement or degradation is noted for landf
all position forecasts. Time of landfall forecasts indicate no degradation
at any period and significant improvement for the 19-30-h period. The early
bias and lack of improvement are consistent with a conservative or "least
regret" forecast and warning strategy to account for possible storm acceler
ations. Landfall timing uncertainty is similar to 11 h at 24 and 36 h, whic
h suggests that hurricane warnings could be disseminated about 12 h earlier
(at 36 h. rather than 24 h, before predicted landfall) without substantial
loss of lead time accuracy (although warning areas necessarily would be la
rger). Reconsideration of National Weather Service Strategic Plan and Unite
d States Weather Research Program track forecast goals is recommended in li
ght of these results.