for a the final “Bill” discussion and cool photos and video of waves and other stuff from Hurricane Bill, CLICK HERE!
When I last posted on Bill, in my mind, it appeared that the beginnings of the end of Bill as a tropical system had begun. The National Hurricane Center reports this morning that indeed, the transformation of Bill from tropical system into an extra-tropical cyclone is far enough along that they feel as if the winds aloft are no longer able to be efficiently brought down to the surface. I think that’s an understatement based on the satellite image. It doesn’t look like a tropical cyclone but instead an extra-tropical system. Also, I had mentioned in the prior post abou that prospects of dry air getting into the middle. The Water Vapor imagery clearly indicates that has indeed happened. I had thought the storm would have picked up forward speed to about 40 mph by now but it is only up to 35 mph. I wouldn’t be surprised to see it moving at closer to 50 mph before it gets to Scotland. It would appear that the official forecast has discounted my complete speculation that there may be an opportunity for this to curve around the ridge back to Spain. Apparently, the ridge extends back into Europe so that ain’t gonna happen. Nevertheless, I see that a couple of models on the spaghetti model graphic do indicate a curve back to Spain, so there is hope that I will be vindicated!
At 9:50pm EDT there a buoy located 30 NM east of Nantucket reported winds of 21 kts gusting to 27 kts with 19 foot seas. Another 54nm SE of Nantucket had winds of 27 kts gusting to 38 kts with seas over 27 feet. An interesting observation came at 12pm ADT from a Canadian buoy at the mouth of Halfax Harbour. It indicated that the pressure was down .38″ in the past 3 hours and was falling rapidly. That tells you that the center of the storm was still approaching. The pressure was at 29.28″ Winds were 29 kts gusting to 35 kts and the wave height was 14.4 feet. A little farther out and to the Southeast, Buoy 44150 is located at 42.5 N and 64.02 W and had a steady pressure tendency at 29.12″. This tells me that the center of the storm is there. Winds at 12 ADT were 52 kts with gusts to nearly 70 kts. Seas were running at nearly 40 feet. So, it would appear from limited reports from a few buoys that Bill has minimal hurricane status winds but is kicking up some pretty big ocean swells. A morning news report brought an interesting story that the giant Hibernia offshore platform would be operating normally. Typically, when a storm passes through an oil field, the crews of production and drilling platforms are evacuated and operations are shut down. That can be expensive but it lessens the risk for life and also the risk of an oil spill. They evacuated Sable, which is a gas production platform…but the 98,200 barrel a day oil production Hibernia remains in operation. That is rather remarkable.
WTNT43 KNHC 231448
HURRICANE BILL DISCUSSION NUMBER 33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
1100 AM AST SUN AUG 23 2009
AFTER THE LAST AIR FORCE MISSION INTO BILL….JUST BEFORE 1200
UTC…THE CLOUD PATTERN OF THE HURRICANE HAS BEGUN TO LOOK A LITTLE
LESS TROPICAL. THE AIRCRAFT REPORTED A PEAK FLIGHT-LEVEL WIND OF
105 KT OVER THE EASTERN QUADRANT AROUND 1100 UTC. TYPICALLY THIS
WOULD SUPPORT A HIGHER INTENSITY OF GREATER THAN 75 KT.
HOWEVER…SINCE THE CYCLONE IS TRAVERSING COOLER WATERS…IT IS
BECOMING INCREASINGLY DIFFICULT FOR IT TO TRANSPORT STRONG WINDS
THE SURFACE. GIVEN THAT…ALONG WITH THE DETERIORATION OF THE
CLOUD PATTERN…THE CURRENT INTENSITY IS HELD AT 75 KT. BILL IS
EXPECTED TO BECOME AN EXTRATROPICAL STORM WITHIN A DAY OR SO AND
GRADUALLY WEAKEN AS IT MOVES RAPIDLY ACROSS THE NORTH ATLANTIC.
GLOBAL MODELS SUGGEST THAT THE SYSTEM WILL MERGE WITH A BROADER
CYCLONIC CIRCULATION NEAR THE BRITISH ISLES IN 3-4 DAYS.
CURRENT MOTION IS AROUND 045/29. BILL SHOULD CONTINUE ACCELERATING
OVER THE NEXT 24-36 HOURS AS IT BECOMES WELL EMBEDDED IN THE
MID-LATITUDE WESTERLIES. SOME SLOWING OF THE FORWARD SPEED IS
LIKELY LATER IN THE PERIOD AS THE EXTRATROPICAL REMNANT OF BILL
INTERACTS WITH THE LARGE CYCLONIC CIRCULATION OVER THE NORTHEAST
ATLANTIC. THE CURRENT OFFICIAL TRACK FORECAST IS SIMILAR TO THE
LARGE AND DANGEROUS SWELLS ASSOCIATED WITH BILL WILL BE IMPACTING
THE CANADIAN MARITIMES DURING THE NEXT 24 HOURS. SWELLS ALONG THE
EAST COAST OF THE UNITED STATES SHOULD BE DIMINISHING TODAY.
FORECAST POSITIONS AND MAX WINDS
INITIAL 23/1500Z 43.3N 64.0W 75 KT
12HR VT 24/0000Z 46.3N 59.1W 65 KT
24HR VT 24/1200Z 49.0N 49.7W 55 KT…EXTRATROPICAL
36HR VT 25/0000Z 50.8N 37.4W 45 KT…EXTRATROPICAL
48HR VT 25/1200Z 52.5N 26.5W 35 KT…EXTRATROPICAL
72HR VT 26/1200Z 57.0N 8.0W 30 KT…EXTRATROPICAL
96HR VT 27/1200Z…MERGED WITH ANOTHER LOW