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Ana, Bill, and Claudette--a rare early season triple threat

By: Dr. Jeff Masters, 8:58 PM GMT on August 16, 2009

After an unusually slow start to the Atlantic hurricane season, the tropics exploded into action this weekend. We have a rare triple threat this afternoon--simultaneous named storms beginning with the letters A, B, and C. The last time this occurred was in the slow-starting 1984 hurricane season, when Tropical Storms Arthur, Bertha, and Cesar were all active on September 1. This afternoon, the Hurricane Hunters confirmed than Tropical Storm Claudette had formed in the Gulf of Mexico. Radar animations out of the Florida Panhandle show a small but well-organized tropical storm with plenty of heavy thunderstorm activity, and improving low-level spiral banding. Claudette has built an eyewall that is 1/3 complete on the east side of the center. Some moderate wind shear from upper-level southwesterly winds is keeping Claudette from forming much heavy thunderstorm activity on its west side. Most of the rain is on the right side of the storm, and regions to the left of where Claudette comes ashore will get only a maximum of 1 - 2 inches of rain. Satellite loops show an area of intense thunderstorms with cold cloud tops continuing to expand near the storm's center.


Figure 1. Current short-range radar out of the Florida Panhandle.

Claudette developed literally overnight, and has enough time over water to be a 60 - 65 mph tropical storm by the time it makes landfall tonight along the Florida Panhandle. Claudette reminds me of 2007's Hurricane Humberto, which became a hurricane just 24 hours after first appearing as a tropical depression. By the time Claudette makes landfall, it will have been in existence just 18 hours since the first advisory. This is not enough time to strengthen into a hurricane. If Claudette had had another twelve hours over the 30°C waters of the Gulf of Mexico, it would likely have been a hurricane. Given that the storm is so small, storm surge flooding should not exceed 3 - 5 feet, and will not be the major hazard from Claudette. Inland flooding from heavy rains of 3 - 6 inches is likely to be the main threat from the storm.

Ana near death
The Hurricane Hunters are in Tropical Storm Ana, and have found that the storm is very disorganized, and may not survive another day. Dry air continues to plague the storm, thanks to the large area of Saharan air the storm is embedded in. Ana's very rapid forward motion of 20 - 25 mph has stretched out the storm's circulation from circular to elliptical. This non-circular flow around the center has made the heavy thunderstorm activity less organized, and it may be difficult for the storm to hold together much longer. The outer rain showers from Ana are now on radar out of Martinique.

Nearly all of the computer models forecast Ana will dissipate over the next two days. If there is anything left of the storm by the time it encounters the rugged terrain of Hispaniola, that should finish Ana off. At this time, it does not appear that Ana will be moist enough to cause a major flooding disaster on Hispaniola.

Tropical Storm Bill continues strengthening
Tropical Storm Bill continues to gather strength in the middle Atlantic Ocean, and appears poised to become a major Cape Verdes-type hurricane later this week. Water vapor satellite loops show that Bill has developed a core region of heavy thunderstorms that should be fairly impervious to the dry Saharan air to its northwest, and the storm should be able to start building an eyewall tonight.

Wind shear is low, 5 - 10 knots, and is forecast to be in the low range for the next three days. With Sea Surface Temperatures at 27.5°C, and ocean heat content sharply increasing 2 - 3 days from now, Bill should be able to intensify to a major Category 3 or 4 hurricane by Wednesday. At that time, some increasing shear may limit further intensification.

The big news is that our most reliable computer model from last year--the ECMWF model--appears to have made the right call yesterday, forecasting that a major trough of low pressure would develop along the U.S. East Coast, turning Bill more to the north. All of the other models have now jumped on the ECMWF bandwagon, forecasting that Bill will pass well north of the Lesser Antilles Islands. The UKMET model, which was resisting forecasting the northward turn, has now joined the other models in its latest 12Z run. The main drama with Bill this week will be to see how close it passes to Bermuda. Several models have Bill passing within 200 miles of Bermuda on Saturday. It is too early to be confident that Bill will miss the U.S. East Coast.

I'll have an update Monday.

Jeff Masters

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Quoting Drakoen:
Ana's circulation is just SE of Puerto Rico as confirmed by Surface Observations and Radar imagery. The cyclone is on the northern side of the forecast track and it will be interesting to see whether or not it goes over Hispaniola or into the Bahamas.


Glad you noticed that too, Drak. Good morning. I think this could put a large wrinkle in the forecast. It will move over PR, but it then may just graze Hispaniola. She may not be done, as I have said several times.
Quoting WxLogic:


I agree... I was looking at the steering flow and the Bermuda high has strengthen a bit... so still believe there won't be a northerly component getting established just yet with Bill.
i agree
3005. tbrett
Quoting HurricaneGeek:


They don't fly until a storm is West of 55W.

OK Thanks
Quoting listenerVT:
As a novice, I find that facts do help
but opinions at least make me have to think about the bare possibility being presented.
Lots of incentive there for inquiry and learning.
But I can understand that it could be frustrating to those of you more in the know.
Especially with a big storm looming.

Can someone clarify for me if there is a blog requirement (along the same lines of being reasonably good to one another) that during the heat of the season all opinions must be accompanied by facts?


All your posts seem so poetic. And very reasonable. Thank you.
strong convection firing east of p.r.
3008. Walshy
Quoting rxse7en:
Based on this map, what would keep Ana from developing like Claudette did on almost the same track? Are they predicting high shear?



There is a lot of uncertainty with Ana right now. Land interaction,COC relocating,path to GOM or Bahamas, current radar does not look impressive.
3009. WxLogic
Quoting Drakoen:
Ana's circulation is just SE of Puerto Rico as confirmed by Surface Observations and Radar imagery. The cyclone is on the northern side of the forecast track and it will be interesting to see whether or not it goes over Hispaniola or into the Bahamas.


If the convection stays deep enough in the Norther side of the track where the better SFC circulation resides... I won't be surprised that it will bypass Hispanola to its E and N. I truly hope that's the case and I prefer the southern end affects Hispanola than the North and Eastern side of TD Ana.
NEW BLOG!
3011. MrSea
Quoting Walshy:
NEW BLOG should be up within a few hours. Hope nobody jumped the gun there.


The swine flu must have hit the blog. Only about 3000comments. Last blog had a lot, and the one before that.


lol almost got me with the New Blog!
Listener,

As far as I know there aren't any special rules for posting comments during hurricane season. But I would imagine that someone intentionally posting incorrect information or things that simply have no place in the discussion may find themselves on a temporary ban. I'm not sure how they handle it or what discretion they use.
It appears that Ana has taken a definite turn to the northwest.

17/1145 UTC 17.4N 64.9W T2.0/2.0 ANA -- Atlantic
Quoting mikatnight:


You don't believe in models???

i believe them on a very rare occasion, because they have been wrong to many times before, and as you can see in this case i don't believe them
Quoting tbrett:

OK Thanks


No problem. It still has about 10° to go.
3016. jipmg
Eh idk.. if ANA moves north of Hispanola, I see it strengthening and almost rapidly, its looking real good and organizing on radar right now, but if it moves over DR, I dont care how much you guys want it, it will not survive. Ernesto which was a hurricane barely survived a similar scenerio..
Quoting LakeShadow:
lol...its getting funny in here...


You noticed that too...how are you, Lake?
What about swimsuit models?

Quoting HurricaneGeek:


They don't fly until a storm is West of 55W.


Is that due to capability of the aircraft or due to budget constraints?

By the time Bill gets to 55W he is expected to be a Cat 3.

Quoting Drakoen:
Ana's circulation is just SE of Puerto Rico as confirmed by Surface Observations and Radar imagery. The cyclone is on the northern side of the forecast track and it will be interesting to see whether or not it goes over Hispaniola or into the Bahamas.

as of now it looks like it may slide just north of Hispanoila.

shear is easing up somewhat just north of there and things could get a little interesting.
3023. jpsb
Quoting PensacolaBuoy:
Can the persistent convection over the GOM in the wake of TS Claudette possibly develop a new low level circulation over water? The old LLC is history and that's a big area of convection!
I've been watching that to, very interesting. I thought Claudette's center formed to far north and she was trying to relocate the center further south. I'm thinking that blob is where Claudette wanted her center to be. Haven't checked on it in a few hours, but maybe it will get pushed into the gulf and "Son Of Cluadette Revenge!" lol, ok, talk about wish casting. It would be nice if that blob came to Texas, we sure need the rain.
Quoting Category5hitsNewYork:
hey everyone come to the weather CHAT!

sorry we rather stay here
Quoting watchingnva:


theres no bandwagons here cane...go to school for that...taz gos back and forth with the mood of the blog....always has, thats what hes loved for...lol...i dont think badly of him for doing so...lol...i just laughed...

and why do you want a us landfall for so bad cane?...
Could you do us a favor and put cane on ignore so we don't have to continue to read your attacks on everything he says. It is becoming very redundant. He is entitled to his opinion just like you are, but if you are constantly and maliciously attacking everything he types then you are not contributing anything worth while to the blog. IMO you are being very counter-productive and would like to see you re-focus your energy on something a little more substantial than a personal vendetta. Thanks in advance.
Claudette was a bust here in Tally. Only one rain band and lots of clouds. I'd take that over the destruction that something Bill-esque could pose if it headed this way though.

Am curious if Ana has a snowball's chance though- as whatever is left of her is forecast to head my way.
Quoting Drakoen:
Ana's circulation is just SE of Puerto Rico as confirmed by Surface Observations and Radar imagery. The cyclone is on the northern side of the forecast track and it will be interesting to see whether or not it goes over Hispaniola or into the Bahamas.


It really depends on the speed of Ana. She is expected to move quickly around the islands, so she wont have to be over those mountains long. BUT, then she is expected to decrease in forward speed around the Bahamas region. So I see why the SHIPS is developing Ana.
3028. IKE
NEW BLOG!!!!
Living in the Caribbean, my attitude is that NO System is "done" until it is SAFELY PAST your location - sad thing then is that it may be "done" for u but it may still cause devestation and misery to someone else along the line. I will continue to watch ANA like a hawk until I am convinced it poses no threat to the Islands I am on - then it will be a case of examining BILL very closely.
As they say "Plans are the basis for change" and "An ounce of practicality is worth a ton of theory".
Yup Ana is moving fast through those mountains, so it may not weaken as much.:)
I wonder if Weather456 made it though out the night?Or maybe he is still making a new update.
3032. jpsb
Quoting canesrule1:
It is not that i want a US landfall, that is my opinion, for me it is not out of the question by no means that it will recurve, but my gut feeling and my opinion is that it will make landfall in Florida, and i will gladly eat my crow if im incorrect.
I've seen numberious hurricanes that were suppost to turn and didn't and ones that were not suppost to turn and did. Looks to me like Bill will turn, but I'll believe it when I see it. For the best example, off the top of my head, Hurricane Allen 1980.
Quoting SSideBrac:
Living in the Caribbean, my attitude is that NO System is "done" until it is SAFELY PAST your location - sad thing then is that it may be "done" for u but it may still cause devestation and misery to someone else along the line. I will continue to watch ANA like a hawk until I am convinced it poses no threat to the Islands I am on - then it will be a case of examining BILL very closely.
As they say "Plans are the basis for change" and "An ounce of practicality is worth a ton of theory".
I agree with you 200%. As I said before anything can and will happen and we seem to be in the perfect spot for that. Gustav last year. What a weird one.
Quoting floridastorm:
i have a friend whos flying to haiti, is there anything to be concerned about for him?
thanks


Kidnapping and murder would be at the top of my list.
Quoting stormwatcherCI:
I agree with you 200%. As I said before anything can and will happen and we seem to be in the perfect spot for that. Gustav last year. What a weird one.
Tore my hair out with that one (what little hair I have) - remember grabbing a catnap when Gustav was NE of Jamaica - woke up just a little while later and he has done a hand brake turn to the left!! Paloma - well - no comments!!
Quoting SSideBrac:
Tore my hair out with that one (what little hair I have) - remember grabbing a catnap when Gustav was NE of Jamaica - woke up just a little while later and he has done a hand brake turn to the left!! Paloma - well - no comments!!
Boy, the hurricanes last year all seemed to do the unpredictable which is why I ain't taking my eyes off any of them until they are long gone.
3037. yamil20
According to the 400-850hPa Steering Layer, which is the one steering bill, I think the Bermuda High has strengtened, can any one confirm this? Press the 3 and 3-, anyone see the difference
Link
Quoting CaneWarning:


They will be cured of that after they get hit by one. I remember being excited as Hurricane Andrew was heading straight for me. I was only 11 then. I was quickly cured of that as the house blew apart around my family.


Absolutely agreed here. I lurk in this blog because I live on the northeast coast of Florida, and it would be dumb for me to not stay up to date and be prepared. Seeing a storm heading our way brings a feeling of dread, because I have seen what storms like Andrew and Wilma have done to destroy lives and livelihood. Hurricanes may be an adrenaline high for some, but not for those who have witnessed their devastation.
"How come the ECMWF model Dr. Masters refers to does not show up in the computer model tracks? Am I missing something?"

ECMWF is currently calling for landfall (?) in the southern Nova Scotia area. Around Sunday the 23rd.

Current ECMWF
Light winds in San Juan. Another band of showers moving from east to west.