Florence and Gordon and TD 8

Bermuda is cleaning up after a brush with Hurricane Florence that brought only minimal damage. The eye of Florence passed 52 miles to the west of the island at 10am Monday, bringing sustained winds of 80 mph gusting to 110 mph to the eastern end of the island. Higher winds likely occurred on the island's western end. The storm surge brought only minor flooding, and Florence's winds damaged just five buildings, one of them because of a rare tornado on Sunday afternoon. No deaths or injuries were reported, except to two pink flamingos at the zoo killed by falling branches. All but 6,000 of the 25,000 customers that lost power have had their power restored by this morning.

Florence continues north towards an encounter with Newfoundland. The storm is looking very much like an extratropical storm on satellite imagery this morning. Cooler waters and hostile upper level winds are gradually weakening the storm. Florence should still pack plenty of punch as a 60 mph tropical storm Wednesday afternoon as it passes over the southeast corner of Newfoundland. The remains of Florence will continue east and may bring heavy rain and 40 mph winds to Ireland on Saturday.


Figure 1. Today's lineup of storms. Invest 94L has now become Tropical Depression 8. Image credit: Navy Research Lab.

Gordon headed out to sea
Tropical Storm Gordon formed yesterday from the area of disturbed weather that tailed Florence all the way across the Atlantic. Gordon is over warm waters and under light wind shear of 10 knots, and is expected to intensify into the season's third hurricane by Wednesday. Gordon is being pulled north by the same trough of low pressure that grabbed Florence, and the storm is a threat only to shipping interests.


Figure 2. Preliminary model tracks for Invest 94L.

Tropical Depression Eight
A strong tropical wave with impressive rotation and plenty of intense thunderstorm activity that emerged from the coast of Africa yesterday is now Tropical Depression Eight. Wind shear as analyzed by the University of Wisconsin CIMSS group is a bit high, 15 knots, but the NHC's SHIPS model puts the shear much lower, at 6 knots. The shear is expected to stay low the next three days, and this should be Tropical Storm Helene by Wednesday night. There is an large area of dry air and African dust to the west and north of the system that may slow down the long-term development of the storm, and the storm may encounter higher shear due to stronger upper level winds on Friday.

The center of circulation was located about 200 miles southeast of the Cape Verde Islands, near 14N, 22W at 4:12am EDT today, according to the QuikSCAT satellite. Winds were about 20-25 mph near the center, with some stronger squalls several hundred miles to the south of the center. While it is too early to be confident of this storm's long range track, the historical map of similar September tropical depressions forming in this region show that only about 30% of these systems strike the Lesser Antilles or U.S. East Coast. Given this fact, plus the long range forecasts of an active jet stream pattern in the Atlantic the next two weeks, I'd give TD 8 a less than 20% change of striking land.

I'll be back with an update Wednesday morning.
Jeff Masters