Irma | 8 a.m. Wednesday | The Press and Standard
by The Press and Standard | September 6, 2017 8:17 am
Last Updated: September 6, 2017 at 8:18 am
Fixes from the latest satellite and radar imagery suggest that Irma is moving a little north of due west.
A strong ridge extending southwestward from the central Atlantic is expected to steer Irma west-northwestward during the next couple of days. A large mid-latitude trough over the eastern United States is forecast to lift northeastward, allowing the ridge to build westward and keep Irma on a westward to west-northwestward heading through Friday.
Over the weekend, a shortwave trough diving southward over the east-central U.S. is expected to weaken the western portion of the ridge, causing Irma to turn poleward.
The dynamical model guidance is in good agreement through 72 hours, but there is increasing spread thereafter. The HWRF, UKMET, and ECMWF show a more southerly track and a sharper turn around day 5, while the GFS is farther north and east late in the period. The NHC track is near a consensus of these models and close to the HFIP corrected consensus.
Users are reminded to not focus on the exact forecast track, especially at the longer ranges, since the average NHC track errors are about 175 and 225 statute miles at days 4 and 5, respectively.
At 800 AM AST (1200 UTC), the eye of Hurricane Irma was located near
latitude 18.1 North, longitude 63.3 West. Irma is moving toward the
west-northwest near 16 mph (26 km/h), and this general motion is
expected to continue for the next couple of days. On the forecast
track, the extremely dangerous core of Irma will move over portions
of the northern Virgin Islands today, pass near or just north of
Puerto Rico this afternoon or tonight, and pass near or just north
of the coast of the Dominican Republic Thursday.
Maximum sustained winds remain near 185 mph (295 km/h) with higher
gusts. Irma is a category 5 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Some fluctuations in intensity are likely
during the next day or two, but Irma is forecast to remain a
powerful category 4 or 5 hurricane during the next couple of days.
Hurricane-force winds extend outward up to 50 miles (85 km) from
the center and tropical-storm-force winds extend outward up to 175
miles (280 km). A wind gust to 90 mph (146 km/h) was recently on
the island of St. Eustatius located south of the eye of Irma. A
NOAA National Ocean Service station on Barbuda reported sustained
winds of 118 mph (190 km/h) with a gust to 155 mph (249 km/h)
before the instrument failed earlier this morning.
The estimated minimum central pressure based on data from an Air
Force Reserve aircraft and earlier surface observations is 918 mb
(27.11 inches). A NOAA National Ocean Service station on Barbuda
reported a minimum pressure of 916.1 mb (27.05 inches) earlier this