1500Z Tropical Update

Hurricane Bill

At 11:00 AM EDT...the Bermuda Weather Service have issued a Hurricane Watch for Bermuda. A hurricane watch means that hurricane conditions is possible generally within 36 hours.

At 11:00 AM EDT (1500Z)...the eye of Hurricane Bill is located near 22.4 N 61.2 W. Maximum sustained winds are near 130 mph...this makes Bill a strong category 3 hurricane on the Saffir-Simpson Scale...little change in strength is expected today. Movement is toward the northwest at 18 mph and this motion is expected to continue. Estimated minimum central pressure is 952 mb/28.11 in.

Bill is actually moving through some increasing shear but Bill is such a large hurricane that it is having little effects. While some of the T numbers have decreased slightly...MIMIC-IR still suggest winds of 113 kts...so I have decided to go with 115 kts for this update. Bill will also be going through an eyewall replacement cycle...so for the short term have kept Bill from strengthening much...but in about 24 to 36 hours...Bill will have one more opportunity to return to category 4 strength as Bill will move into the Gulf Stream. Following...Bill will begin to move into an even higher shear environment and much cooler water temps and Bill will begin to weaken rapidly...and will begin to show extratropical characteristics in 4 days and become extratropical in 5 days.

Initial motion 305/16 kts. Bill will continue on this northwest track for 24 to 36 hours...then will begin a track to the north as a longwave trough makes its way offshore. This trough will then push Bill to the northeast then east-northeast through the forecast period. I have been pushing Bill further and further west...so areas along the New England coast need to monitor Bill closely as he could get close enough that the area could experience some tropical storm force winds. Bermuda should also monitor Bill as any track to the right will increase your danger...and all areas from Florida to Maine should remain out of the water as dangerous waves will crash onshore during the next several days and again...the closer to the west Bill moves...the higher the waves/swells will become.

Forecast Positions and Intensity:

20/15Z 22.4 N 61.2 W 115 kts

21/04Z 24.1 N 63.8 W 115 kts

21/16Z 26.2 N 66.5 W 115 kts

22/04Z 28.4 N 68.6 W 120 kts

22/16Z 30.9 N 70.1 W 110 kts

23/16Z 38.0 N 68.5 W 100 kts

24/16Z 44.0 N 58.5 W 75 kts...becoming extratropical

25/16Z 45.0 N 40.0 W 35 kts...extratropical

Byron Jackson
Tropical Specialist