Posted at 8:57 AM on August 18, 2009
by Paul Huttner
NHC forecast track brings Bill near Bermuda this weekend as a major hurricane.
We may have the season's first major hurricane in the next 24 hours.
Hurricane Bill has strengthened to a 100mph Category 2 storm as of Tuesday morning. All indications are Bill will become a category 3 storm on Wednesday. Bill has plenty of warm ocean and open water to work with.
The suite of forecast models has a tight cluster of forecast tracks taking Bill to somewhere west of Bermuda Saturday. If Bill does not make the turn to the northwest soon, there is an outlying chance it may continue on a more westward path, which could raise concerns along the eastern seaboard of the United States.
Bill's progress will have to be watched over the next 48 hours.
Ana is emerging from the north coast of Cuba today. There is a small chance that Ana could regenerate as it heads into the Gulf of Mexico. Stay tuned on that one.
Lightning and hurricanes:
It has often been believed that hurricanes do not generate much lightning. That may be true compares to supercell thunderstorms, but there is some evidence that lightning in hurricanes may be a key to understanding changes in hurricane intensity.
Vaisala, Inc. runs the National Lightening Detection Network (NLDN) in Tucson, Arizona. I have visited the facility many times and it is quite impressive. Sensors all over the U.S. collect cloud to ground lightning in real time and plot the strikes to within feet on a map.
Vaisala has deployed new sensors in the Caribbean and Gulf of Mexico recently. The hope is that by monitoring lightning activity in hurricanes they can correlate lightning flash rates to changes in hurricane intensity. Forecasting changes in hurricane intensity is one of the most difficult parts of hurricane forecasting. Perhaps the new lightning data gathered in 2009 will shed some light on how and when hurricanes intensify.