Hurricane Bill Spaghetti Models Indicate It Will Be Reluctant to Die


Notice Sea Surface Temps Off NE US Coast Are Colder 12Z Aug 21

Notice Sea Surface Temps Off NE US Coast Are Colder 12Z Aug 21

Bill Visible Satellite 2215Z Aug 21...Small Eye

Bill Visible Satellite 2215Z Aug 21...Small Eye

For a more recent update on Hurricane Bill, CLICK HERE

 Hurricane Bill is providing a pretty good lesson on how hurricanes work and forecasting.  If you look at the National Hurricane Center Hurricane Bill Discussion, they note that the winds have decreased and that the pressure was up a bit to 954 mb.  Also, the satellite imagery makes it hard to find the eye.  The Hurricane Hunter Aircraft reports an eye of 14 miles.  If you recall, earlier it had been running about 35 miles and was clearly visible on the satellite images.  One thing that the discussion does not say is that the vortex message indicates that the eye is open in the Southwest quadrant.  On the surface, this all appears to mean that Bill is dying.  In a sense, it is because it is headed toward colder water and a more hostile environment….but not just yet.  Again, in the discussion it talks about a second wind maxima.  What appears to be going on is that Bill is going through another eyewall replacement cycle.  Most likely, the open part of the eye

2215z Aug 21 Bill Infared rainbow Satellite

2215z Aug 21 Bill Infared rainbow Satellite

is indicative of a deteriorating inner eye all and the second maxima is indicating that a new eye is forming.  The smaller eye is probably a result of the old eye collapsing in.  The pressure rise was not all that dramatic and fairly typical of a storm going through a replacement cycle.  The idea here is that as the storm bends on Saturday from its Friday evening 340 degree vector to a 360 degree heading, it will still be in a relatively weak shearing environment and be over warm water.  It will have completed the eyewall replacement cycle and so it should ramp up a bit in intensity.  This eyewall replacement process is why it is really tough for a mature hurricane to maintain a maximum intensity for a long period. For that reason, it is rare for a category 5 hurricane to make landfall in the United States.  I think its only happened 3 times..Camille in 1969, Andrew in 1992 and a Florida hurricane in the 1920s or 1930s…maybe the Keys Hurricane.  The timing just has to be right..or wrong as the case may be. 

2215z aug 21 Bill Water Vapor Shows some trouble

2215z aug 21 Bill Water Vapor Shows some trouble

Anyway, Bill’s uptick will probably not be back up to category 4 status and whatever increase in intensity will not last long.  The big long wave trof has made its way across the Ohio Valley and weekend temperatures will be in the 70’s over much of the region.  It’s a fall like pattern and Bill is behaving like a fall-like storm.  As Bill moves north….probably about the time its even with Washington DC, it will start to encounter strong southwesterly winds ahead of the trof and that will start to rip it up.  It will also be running into cold water and as it approaches Nova Scotia, Bill will start to take on a northeastward component and its forward speed  will increase rapidly and markedly. It will lose its tropical characteristics and probably be in Scotland by the middle of next week.  But, even though it may parallel the coast of Nova Scotia and be losing its tropical characteristics, the pressure gradient between it and the big ridge in the Atlantic will still be large and therefore strong winds, perhaps still running about 100 mph will be pushing water on the right hand side of the storm up in the form of a storm surge.  Harbors, bays and inlets in Nova Scotia and other land masses will have a pretty rapid and significant sea rise.  What’s interesting is that with the storm moving so fast, if it does parallel the coast, then they may see a rapid retreat of extreme tidal surges as the wind shifts around from the north on the back side.    If I’m in Halifax or anywhere in Nova Scotia, I’m still heeding the local warnings and advisories.

Hurricne  Bill Spaghetti Model 08.21.09

Hurricane Bill Spaghetti Model 08.21.09

Hurricane Bill Spaghetti Intensity Model 18Z Aug 21

Hurricane Bill Spaghetti Intensity Model 18Z Aug 21

NHC Official Bill Forecast Track Aug 21 5pm

NHC Official Bill Forecast Track Aug 21 5pm

WTNT43 KNHC 212040
TCDAT3
HURRICANE BILL DISCUSSION NUMBER  26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
500 PM AST FRI AUG 21 2009

AN AIR FORCE HURRICANE HUNTER AIRCRAFT REACHED BILL THIS
AFTERNOON AND FOUND THAT THE CENTRAL PRESSURE HAS REMAINED AROUND
954 MB…BUT THE WINDS HAVE DECREASED AND INITIAL INTENSITY IS NOW
90 KT. THE PLANE REPORTED A SMALL EYE OF 14 N MI DIAMETER.
GIVEN THE CONCENTRIC RING STRUCTURE OBSERVED ON MICROWAVE AND THE
DOUBLE WIND MAXIMA PROVIDED BY THE PLANE…IT IS LIKELY THAT THE
HURRICANE IS GOING THROUGH AN EYEWALL REPLACEMENT AND THE REASON
FOR THE CURRENT WEAKENING. THERE IS AN OPPORTUNITY FOR BILL TO
REGAIN SOME STRENGTH DURING THE NEXT 12 TO 24 HOURS WHILE THE SHEAR
IS LOW AND BEFORE THE HURRICANE REACHES COOLER WATERS.
THEREAFTER…A STEADY WEAKENING IS INDICATED AND BY 72 HOURS…BILL
SHOULD ALREADY BE AN EXTRATROPICAL CYCLONE INTERACTING WITH THE
HIGH LATITUDE WESTERLIES.

BILL IS NOW MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 17
KNOTS. THE HURRICANE SHOULD GRADUALLY TURN MORE TO THE NORTH AROUND
THE BERMUDA-AZORES HIGH TONIGHT AND SATURDAY AND SHOULD BE FORCED TO
RECURVE AS A LARGE MID-LATITUDE TROUGH MOVES EASTWARD ACROSS THE
EASTERN UNITED STATES.  THERE HAS NOT BEEN ANY CHANGE IN TRACK
GUIDANCE WHICH IN FACT CONTINUES TO BE TIGHTLY PACKED…MAINTAINING
HIGH CONFIDENCE IN THE TRACK FORECAST.

LARGE SWELLS GENERATED BY THIS HURRICANE WILL AFFECT A LARGE PORTION
OF THE WESTERN NORTH ATLANTIC COASTAL AREA DURING THE NEXT FEW
DAYS.  THESE SWELLS WILL LIKELY CAUSE EXTREMELY DANGEROUS SURF AND
LIFE-THREATENING RIP CURRENTS.  PLEASE CONSULT STATEMENTS ISSUED BY
YOUR LOCAL WEATHER OFFICE AND METEOROLOGICAL SERVICES FOR MORE
DETAILS.

AT THIS TIME…TROPICAL-STORM-FORCE WINDS ARE NOT FORECAST TO REACH
NEW ENGLAND.  HOWEVER…A SLIGHT SHIFT OF THE FORECAST TRACK TO THE
LEFT WOULD REQUIRE A TROPICAL STORM WATCH OR WARNING TONIGHT.  THE
WIND SPEED PROBABILITY PRODUCT INDICATES THAT THERE IS ROUGHLY A 25
PERCENT CHANCE OF THESE WINDS REACHING EXTREME SOUTHEASTERN NEW
ENGLAND.

FORECAST POSITIONS AND MAX WINDS

INITIAL      21/2100Z 29.4N  66.9W    90 KT
12HR VT     22/0600Z 31.7N  68.0W   100 KT
24HR VT     22/1800Z 35.1N  68.4W   100 KT
36HR VT     23/0600Z 39.0N  67.2W    85 KT
48HR VT     23/1800Z 43.0N  64.0W    75 KT
72HR VT     24/1800Z 49.5N  47.0W    50 KT…EXTRATROPICAL
96HR VT     25/1800Z 54.5N  20.0W    45 KT…EXTRATROPICAL
120HR VT     26/1800Z 60.0N   6.0W    35 KT…EXTRATROPICAL

$$
FORECASTER AVILA

8 Responses

  1. All Altlantic naval ships pulling out of harbour and are going to ride out cabled in the sea away from the path.

    From what I see on numerous local projections/ models right now here in Halifax, I am told to expect the potential of being on the right side of the storm, how much worse will it be if is does pass me on the right? Swells to 3m expected by Saturday night with the highest tides of the season making the chance I may be flooded by then. 1 foot or so above sea level and only a flat 50 foot parking lot between me and open seas. Weather network stating wind gust potentially exceeding 160km but sustained at 90.

    Does this mean I may have to be ready to get out of here tomorrow due to the swells? Don’t want to get stuck here if it strenthens as expected tomorrow we could be hit with cat 2 landfall…is this right by your charts? Appreciate your insights and want to ensure I make the right choices for my son and pets. I live in an odd location, low lying & sea level my home is also a real windtunnel with open spaces around me. Even in blizzards, when I can see my neighbours grass still…I tend to lose siding shingles and get 10 foot drifts. Afraid if it is an unusual location, they may not consider my single house in particular, may be affected worse as with all other storms, so think I’ll have to make the call first. Be nice to know what you think based on you projections. Eastern Passage NS is pretty much where I am.

  2. I would plan to leave now. Getting stuck in traffic sucks. You need to find some place to go too. Hotels are probably already full. My aunt in New Orleans didnt leave until Saturday before Katrina…about 36 hrs prior…her friends all said that you should go to Mississippi and I told her that was the wrong way..to go west. It took her 18 hours to get to Houston…usually takes 5 hours. You should go northwest…inland and west. I would go now. It may not make landfall…may be moving ENE paralleling the coast. If it does, it would throw up a bunch of water ahead of it and then shove it out as it passes. Any increase in intensity now would be irrelevant for you as it will run into much colder water and wind shear. It will be falling apart by the time it gets to you. But, you would still probably be getting sustained winds of say 50-80 mph with gusts to 100…that’s a guess. But, I’d go now. Its going to pick up forward speed soon…wouldn’t be surprised if its moving at 35 to 40 mph at least as it either passes or goes ashore near you. I’m trying to be as specific as possible but I really can’t because I don’t know the topography so I still say to do what the local authorities are saying.

  3. Thanks, just getting final stuff together. Have made 2 emergency kits – 1 for car 1 for the house, so that I don’t even need to pack, just grab pets n’ go. Hotel booked yesterday, thanks. Now local warning is of a 4 metre (12ft)swell at 11 am tomorrow for Halifax – going to leave first thing in the early morning. Hotel only 20 min drive away, but at least above sea level and off the ocean unlike my poor house.

    It’s so beautiful here tonight, a deep sunset with a forward layer of low lying fog pushing by. Very quiet, warm. Suprised how many sailboats are still anchored in the water just outside. Will check in and tell you how I fared and if my basement made it. Thanks for your advice.

  4. Worst of storm blew off the coast, we were fortunate. Left in the morning before high tide, no damage to my place, 5 minutes down the road was so bad, waves threw rocks from the sea and crushed the guardrails and area was closed off. Was glad to have had you to help me think about making the right plans to keep my family safe, never been close to a hurricane like this before, and if it had jumped land like they said it could have, I’d have been safe with my pets and little one thanks to your not making me feel silly to ensure I had a plan. Many thanks.

  5. So good to hear from you! I thought that it would stay offshore but, it technically could do that and you still catch part of the eyewall which was still falling apart but..you know…75 mph winds are 75 mph winds…that is unless its 120 kmh!

    Anyway, on the good side, everything was fine. On the bad side it was a pain to leave and come back. But, keep in mind, you did not really get a hurricane. You the edge of a strong tropical storm. So you got a weenie. The power of these storms go up exponentially as the wind speed increases. So, you can’t imagine what a big bopper would be like. There is another storm potentially brewing…could become Danny and it may very well be threatening your area in 5-7 days. Hasn’t even formed yet so its certainly not immiment…but…much data suggests it.

  6. LOL, Danny hunh? Well, for Bill my husband was serving in the arctic and poor little me had 6 pets and a little boy to keep safe, with no hurricane experience & that’s why your advice was invaluable😉 was nervous. I know we got lucky with Bill, we’ve had much worse winds than that. I learned a lot though and the good news is I now have a great emergency kit & plan, routes programmed into my GPS and if Danny comes to visit, I’ll have my hubby to help pack the car full of animals! Also, it occurred to me that I have no personal insurance on the house, getting that this week. It would have been one thing to replace a washer/dryer in the event of a flood, but it occurred to me the day of the storm what other kinds of costs I would’ve incurred with mold, clean up, etc. Know I will be better prepared from now on & can teach the hubby a few things from this experience. Hope Danny more interesting than Bill, but not too interesting. Love a good storm!

    You know I miss the lightening storms since I’ve moved here, they’d go on for hours where I used to live and I always imagined they’d be even more spectacular on the coast, but have only seen a few flashes over the last couple of years. Wondering why that is?

  7. You need to check on that insurance. if you got flooded then it wouldnt just be appliances and stuff. You’re talking about replacing dry wall, floors all sorts of stuff. Really a pain. Not sure if in your environment mold would be an issue but I’m betting it is. Flood insurance often is not the same as hurricane insurance. I know a homeowners policy generally does not cover “acts of God” and I think many flood insurance policies do not cover hurricanes and storm surge. Make sure it specifically has that. Have some ideas about the lightning issue but not substantial enough to hazard a guess publically.

  8. Ah, thank you, of course, acts of God, will make sure to see if we can slip into a hurricane policy…makes me feel better in a way as no way we’ll be set up by Sunday.

    My best guess on the lightening is that the cooler oceanside air stops the sweltering daytime heating and dramatically cooler evenings and pushes away my chances of lightening.

    LOL! I told one of my friends from my old town about your comments on hurricanes, and the potential of Danny visiting. To which he replied…”Wow, your friend is full of good news…thank goodness he’s not your doctor!” HaHaHa, sorry but I was very amused.
    “Grasshopper” from Halifax😉

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