Earl significantly weakening
Hurricane Earl has significantly weakened today. The Hurricane Hunters found a central pressure of 948 mb at 4:06pm EDT, a large 20 mb rise from the 928 mb pressure of the 5am EDT advisory this morning. The aircraft found flight level winds at 10,000 feet of 124 mph, which translates to surface winds at the boundary between Category 2 and Category 3 strength, 112 mph. However, the SFMR instrument on the aircraft saw top surface winds of just 98 mph. Satellite imagery shows that Earl is no longer as impressive--the eye is less distinct, and the hurricane has a lopsided appearance. Dry air and wind shear of 15 - 20 knots have chewed away at Earl's southwest side.
Earl has made its turn to the north, and is headed for a close brush with North Carolina's Outer Banks. Rain bands from the hurricane have reached the coast, as seen on long-range Cape Hatteras radar.

Figure 1. Afternoon satellite image of Earl.
Forecast for Earl
If you're wondering about your chances for receiving hurricane force or tropical storm force winds from Earl, I highly recommend the NHC wind probability product. The highest odds of hurricane force winds for any location on the U.S. coast are for Nantucket--25%. Yarmouth, Nova Scotia has the highest odds for Canada, 15%, and Cape Hatteras has the highest odds for North Carolina, 19%. The latest set of model runs from 8am EDT (12Z) this morning show little change to Earl's track, and the latest SHIPS model forecast also shows no surprises. Wind shear will remain moderately high, 15 - 20 knots, through Friday morning. This should allow Earl to maintain Category 2 hurricane status as it passes North Carolina early Friday morning. By Friday night, as Earl gets caught in the jet stream and accelerates to the northeast, wind shear will rise to 20 - 30 knots and ocean temperatures will plunge to 20°C, resulting in considerable weakening. Earl will still probably be a Category 1 hurricane early Saturday morning, when it will make its closest approach to New England. Earl is more likely to be a strong tropical storm early Saturday afternoon, when it is expected to make landfall in Nova Scotia or New Brunswick, Canada. The expected impacts on the coast should somewhat less than what I outlined in this morning's blog post, because of Earl's recent weakening.

Figure 2. Wind field analysis of Hurricane Earl from 3:30pm EDT Thursday, September 2, 2010. Note the asymmetry in Earl's wind field, caused by the storm's forward motion of 18 mph to the north at the time. The highest contour has top winds of 80 kt (92 mph) surrounding the "+" on the NNE side of Earl--the strong right front quadrant of the storm. However, winds in the left front quadrant (on the west side) were just 75 knots (87 mph.) The asymmetry is not nearly as great as what was observed at 9:30am this morning. Image credit: NOAA/AOML/Hurricane Research Division.
Fiona
There is little change in the forecast for Tropical Storm Fiona, which is struggling due to high wind shear, courtesy of strong upper-level northerly winds from Hurricane Earl's outflow. Satellite loops show the classic signature of a tropical storm experiencing high wind shear--an exposed center of circulation, and all the heavy thunderstorms pushed to one side (the south side in this case). Wind shear from Earl and dry air should keep Fiona from attaining hurricane status, and the shear may be strong enough to destroy Fiona.
Gaston dies
Tropical Depression Gaston lost its battle with dry air. Satellite imagery shows that Gaston no longer has a surface circulation, and NHC has declared the system dead. The latest SHIPS model forecast predicts shear will remain low to moderate, 5 - 15 knots, for the next five days, so it is possible Gaston could regenerate.

Figure 3. Afternoon satellite image of Gaston (left) and the latest tropical wave to move off of Africa (right).
New tropical wave
A large and well-organized tropical wave moved off the coast of Africa last night, and this wave has the potential to follow the pattern set by Danielle, Earl, Fiona, and Gaston. Several models do develop this system into a tropical depression early next week, and NHC is giving the wave a 10% chance of developing by Saturday afternoon. Wind shear is currently too high, 30 - 40 knots, for the wave to develop. However, once the wave reaches a point a few hundred miles southwest of the Cape Verdes Islands two days from now, wind shear will drop and development will be more likely.
There is also a tropical wave over Central Africa which will emerge from the coast in 4 - 5 days. Some of the models are predicting development of this wave, 7 or so days from now.
Links to follow today
Cape Hatteras weather
Cape Hatteras radar
Next post
I'll have an update in the morning, and Dr. Rob Carver will have a late-night update.
Jeff Masters
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 — Blog Index
Here I sit, reading all kinds of stuff and whatnot about Oz, Norcross and Sparks on Wires.
Whilst just a few thousand miles away there is Gaston the Undead, Looming, Lurking in the wings, ready to bring Sudden Palpitations and Spontaneous Merriment to the Blog (if he can only get his act together).
You guys are really weird.
Must be why I come here........
heheheh
Email me. I don't want to post it here.
I'm sure there's millions of us...
not just andrew, he was the best of CBS4 even with DAVID there, David imo is amazing and is becoming as good as bryan, but bryan is just astounding
I think the reports of Gaston's death were greatly exaggerated
no lack of those here sweetpea...
yeah, that would do it for most people.
He's with Luca Brasi.
Fuhgetaboutit!
The last models I saw took Gaston through the Caribbean Islands.
I believe that would constitute 'landfall', initially.
Yea you guys are great!
It's going to go. Oz is going out into the wind to measure the wind for us now!
Although he's never said so - I also suspect there was a *thorough* review of everything that took place on that flight. He has admitted some of the danger was compounded by the crew taking chances, and assuming things would work out. He may not have liked some of the assessments made of the whole situation by investigators.
Link please? Thanks.
Yea true...I mean the final destination...work with me here. I hope the islands dont get a repeat hit that Earl just hit before he headed NE
I think thats Gaston in the gulf???
Viewing: 1251 - 1301
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 — Blog Index