Claudette hits Florida; Ana approaches Puerto RIco; Bill becomes our first hurricane

By: Dr. Jeff Masters , 2:10 PM GMT on August 17, 2009

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Tropical Storm Claudette made landfall at about 1:15 am EDT near the eastern end of Santa Rosa Island, just southeast of Fort Walton Beach in Florida. Claudette's top winds were around 50 mph. A Personal Weather Station in Eastpoint, FL recorded sustained winds of 49 mph, gusting to 66 mph last night. So far, the rain from Claudette has had a tough time penetrating inland (Figure 2). Heavy rains of 3 - 4 inches have been confined to a narrow strip of coast, and Claudette is unlikely to cause any major flooding. Apalachicola received just over 4 inches of rain so far from Claudette. Radar animations out of the Florida Panhandle show that heavy rains continue along the coast in association with a main spiral band of Claudette, and these rains will gradually subside today.


Figure 1. Radar reflectivity image of Tropical Storm Claudette as it approached landfall just southeast of Fort Walton Beach shortly after midnight on 8/17/09.

The tropics featured a rare triple threat the past two days--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 year's A, B, and C storms all got their names in just a 33 hour span. This is not a record, since in 1995, three tropical storms--Humberto, Iris, and Jerry--got their names in a 27-hour span (thanks to NOAA's Ryan Sharp for looking up this stat).


Figure 2. Total precipitation estimated by radar for Claudette, as of 3:28pm EDT 8/17/09.

Ana not dead yet
Tropical Depression Ana continues to cling to life, and is now approaching landfall in Puerto Rico. Radar animations from the San Juan, Puerto Rico radar show a surface circulation just southeast of the island, with some low-level spiral banding trying to develop to the south. Recent satellite images also show a rejuvenation of the heavy thunderstorm activity near Ana's center, as the storm regroups from being nearly torn apart yesterday. Ana has already dumped up to 4 inches of rain along the north coast of Puerto Rico, according to radar-estimates.

It is unlikely that Ana will survive past today, however, since the storm will move over both Puerto Rico and the rugged terrain of Hispaniola. The high mountains of these islands should act to disrupt the relatively small and fragile circulation of Ana. None of the computer models foresee that Ana will survive passage over Hispaniola. The Dominican Republic can expect 3 - 6 inches of rain from Ana, and Haiti can expect 1 - 3 inches.


Figure 3. Total precipitation estimated by radar from Ana for Puerto Rico.

Bill becomes the first Atlantic hurricane of 2009
Hurricane Bill continues to gather strength, and is now the first hurricane of the 2009 Atlantic hurricane season. An eye has appeared on visible and infrared satellite imagery, and Bill is displaying an impressive symmetry, with plenty of low-level spiral banding.

Wind shear is low, 5 - 10 knots, and is forecast to be in the low range through Wednesday. With Sea Surface Temperatures only 27°C today, substantial intensification may not occur until Tuesday and Wednesday, when SSTs warm to 28 - 29°C and ocean heat content sharply increases. By Thursday, Bill is expected to leave the favorable upper-level wind environment it currently finds itself in, and moderate shear of 15 - 20 knots may limit further intensification.

Water vapor satellite imagery shows that there is a modest trough of low pressure in the upper atmosphere near 50°W longitude, that Bill is currently approaching. All of the computer models except the UKMET predict that this trough will be strong enough to turn Bill more to the northwest so that the hurricane misses the Lesser Antilles Islands. The UKMET predicts the trough will not affect Bill much, and that the hurricane will pass through or just north of the islands on Thursday. For now, the UKMET solution is being discounted, since the trough at 50W appears substantial enough on satellite imagery to be able to turn Bill more to the northwest.

A much larger trough of low pressure is expected to develop along the U.S. East Coast late this week, turning Bill even more to the northwest. Most of the models predict Bill will pass very close to Bermuda on Saturday as a result. The HWRF model predicts Bermuda will receive a direct hit at Category 4 strength. Until Bill interacts with the small trough at 50°W, it is too early to be confident of the potential threat to Bermuda. By Tuesday, we should have a much better idea of the threat. Likewise, I would like to see the UKMET model come around in line with the other models before dismissing the possible threat to the U.S. East Coast. It currently appears that Bill will miss the U.S. East Coast, but that a strike on the Canadian provinces of Newfoundland or Nova Scotia is possible.

I'll have an update Tuesday morning, or possibly this afternoon.

Jeff Masters

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Quoting CaneWarning:
Does everyone think the next wave off of Africa will become Danny?

I'm not sure. Some models yesterday and earlier today had been showing development of the next wave, but the latest runs are showing nothing.
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Quoting JLPR:


I wouldn't expect hurricane watches but tropical storm watches seem reasonable considering the size of the system
possible
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Quoting MiamiHurricane80:
On 8/17/2009 at 145 PM EST, Bill was located at 12.5W & 39.3N. 24 hours later, Bill wa slocated at 14.5W & 46.1N. That translates into a movement of 2W & 6.8N in 24 hours. Not the movement models have predicted.


What? Try again.
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Quoting Jebekarue:
lurker from Pensacola here, was wondering if anyone had a clue what the remnants of Caudette were doing, looking at the radar it seems like the storm is backtracking and the moisture doesn't want to get onto land....any ideas? or are my eyes playing tricks on me. TIA

I believe the circulation has moved well to the North.
http://www.wunderground.com/tropical/tracking/at200904_sat.html#a_topad
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Quoting kmanislander:


Sorry, stepped away for a bit. The steering layer is determined by the strength of the system. The 850 mb level would be for a storm no stronger than 1000 mb pressure.

At Bill's strength the steering is up around the 400 mb level as shown in the graphics posted by others.

While there is still some W to WSW steering shown there are other factors that affect steering such as the strength of the ridge to the N. The stronger a system the more it is inclined to move poleward and will " seek out " any weakness to its North in order to do so.

In 2004 and similar years we had very strong ridges far S that forced hurricanes like Ivan all the way W across the Atl. This year the ridge is further N and not continuous. A " bridged " ridge will have a weakness in it, such as the weakness now located near 50W and any weakness will attract a strong storm unless it is far South of it.

Also, the WNW to NW track is a forecasted track assuming the future evolution of features that affect steering, such as the trough that is forecasted to move off the East coast and erode the western flank of the ridge.

Hope this helps.


MAN YOUR SMART!!
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Quoting pottery:
Hey, WeatherSP.
It's OK for Bill to pull the moisture up from the ITCZ. We are having our first dry day here, in over a week. So leave it alone LOL
At 11n 61w.


LOL ok, Have fun in the sun.. It won't last long once bill moves North.
Member Since: January 14, 2007 Posts: 17 Comments: 4140
1566. JLPR
Quoting btwntx08:

yes i wouldn't be surpised if the issue hurricane watches up later tonight or in the am


I wouldn't expect hurricane watches but tropical storm watches seem reasonable considering the size of the system
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting Golladan:

It'll go back to being an outlier again I'm sure. Didn't that model join the rest of the models for some time yesterday too?


True. I probably shouldn't have said that...but it appears to be reality for today.
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NHC can drop Ana,but my guess is she'll be back, I've seen storms in this area before where no west winds could be found and came back as strong TS or Hurricane. Fay & Dolly comes to mind, the HH looked for west winds til I'm sure they were sick.
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Quoting pottery:
KMAN, please see post 1502.


Sorry, stepped away for a bit. The steering layer is determined by the strength of the system. The 850 mb level would be for a storm no stronger than 1000 mb pressure.

At Bill's strength the steering is up around the 400 mb level as shown in the graphics posted by others.

While there is still some W to WSW steering shown there are other factors that affect steering such as the strength of the ridge to the N. The stronger a system the more it is inclined to move poleward and will " seek out " any weakness to its North in order to do so.

In 2004 and similar years we had very strong ridges far S that forced hurricanes like Ivan all the way W across the Atl. This year the ridge is further N and not continuous. A " bridged " ridge will have a weakness in it, such as the weakness now located near 50W and any weakness will attract a strong storm unless it is far South of it.

Also, the WNW to NW track is a forecasted track assuming the future evolution of features that affect steering, such as the trough that is forecasted to move off the East coast and erode the western flank of the ridge.

Hope this helps.
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Quoting TampaHelpDesk:


I took a look at those surge maps... I'm far enough north of the worst-case scenario that I still remain unworried about flooding. The building I'm in would probably be demolished by the cat 5 winds, but flash flooding would be the only flooding concern.

I understand people's desire to live on a beautiful beach... I also think that to do so is a bad thing.


Ehh, the likelihood of a cat 5 landfall is pretty slim - only 3 since 1851 in the CONUS.

Cover your windows, brace your doors (esp the garage door) and take in all your outside stuff, and the odds your home will survive even up to a cat 4 rise significantly...
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Something does not add up about Bill'S forecast track. I wont believe it until I see it.
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Does everyone think the next wave off of Africa will become Danny?
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Quoting stormpetrol:
I hate to say this but I don't Bill is going miss the Leewards, I hope everyone there is prepared and have a plan, not trying to alarm anyone, jmo.

I agree I think bill will be a caribbean hurricane
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Quoting WPBHurricane05:


AKA...reality.

It'll go back to being an outlier again I'm sure. Didn't that model join the rest of the models for some time yesterday too?
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Quoting pottery:
Kman, Question.
The 700-850 mb winds are showing WSW in front of Bill. Why the WNW to NW forecast?


400-850mb steering is in order currently for Bill until he gets to 90kts then the 300mb takes over. Bill is feeling the effect of the trough directly to its North for the short term.....
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Looks to me like the models aren't really shifting so much as converging...the two outliers (GFS and UKMET) coming together in the center.
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1552. Thaale
Quoting rwdobson:
Looks like UKMET has finally joined the rest of the models on Bill...
Shhh...it's not good breeding to mention any models shifting their tracks away from land. The polite thing to do is ignore them and focus only on models which have shifted landward.
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DPH? Glad I'm not in that way of that. Hope nobody else is either.
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1550. pottery
Hey, WeatherSP.
It's OK for Bill to pull the moisture up from the ITCZ. We are having our first dry day here, in over a week. So leave it alone LOL
At 11n 61w.
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1549. Grothar
Does anyone know why Tazmanian and StormW are not on more often. I hope they don't have jobs or anything HORRIBLE like that. I find their obsverations interesting.
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I hate to say this but I don't Bill is going miss the Leewards, I hope everyone there is prepared and have a plan, not trying to alarm anyone, jmo.
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Quoting JeffMasters:


Large waves from Bill will probably reach the Florida coast by Saturday night, but the the only places in the U.S. that likely need be concerned about Bill's winds are Cape Cod and Maine.

Jeff Masters
But I have noticed models have shifted westward could this become a trend or is it nothing to worry about? And those are all my questions thanks for answering.
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Quoting rwdobson:
Looks like UKMET has finally joined the rest of the models on Bill...


AKA...reality.
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Quoting AwakeInMaryland:
Quoting atmoaggie:
I was just about to say that it has been nice how the blog today has pretty well focused on the tropics, rather than any individuals present or not present, as a primary topic of conversation.

If you don't feed a feral cat anything, it moves.


Greetings, everyone,

After lurking for a year or more, thought it was time to introduce myself. I'm a grandma in Silver Spring, MD, and work as a disaster reservist and I'm a member of our County CERT team (though not as active as late, which I need to change). I really like this blog as it greatly informs my disaster assistance activities... plus if his path changes...well, hello, Big Bad Bill...

I may be a bit slower than some of you youngsters, but I'm not stupid. I haven't learned how to properly use the "quote" device yet...but I want you to know that I have definitely studied up on the IGNORE button and as my second act on this blog (the first being posting), I may use it...though I am afraid I would miss ROTFLMAO.

Take care and stay safe!

Hey Gramma. I love Silver Spring. Spent at least 15 days there over the last 2 years for visits to the NOAA/NOS offices.
If you haven't done so, you have to try out the little Demarco Italian restaurant on Colesville. Best Northern Italian I've ever had.
Hope you weren't looking to ignore me! But, if you must...

If Bill were subject to primarily mid-level steering, he wouldn't be moving N at all...south a little, actually. (Yeah, I know he is just off of this plot)

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Ya'll see accuweather's worst case? Looks like it goes right over OBX.
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I think what i am seeing now is the first trough starting to nudge at Bill and slow him down a little...i think it will start a more NWestern motion but the models are thinking that the first trough won't be strong enough to fully lift him out and that is why the left shift but the second trough will be stronger and is still forecasted to send him off to sea...
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1541. Walshy
The dry slot on the north-west side is starting to erode away. Also, notice the pink convection on the southern side of the eye.


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Looks like UKMET has finally joined the rest of the models on Bill...
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Hey Bill... Stop sucking up the ITCZ will ya?!?!

Member Since: January 14, 2007 Posts: 17 Comments: 4140
1538. Thaale
Not sure if the east coast of Florida storm surge link was posted:

http://www.wunderground.com/hurricane/FlAtlCoastSurge.asp
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1537. JeffMasters (Admin)
Quoting canesrule1:
Hello, Jeff do you think there is any chance of Bill being a threat here in Florida in the long run?


Large waves from Bill will probably reach the Florida coast by Saturday night, but the the only places in the U.S. that likely need be concerned about Bill's winds are Cape Cod and Maine.

Jeff Masters
1536. PSL2007
Quoting Twinkster:


weakness that was supposed to pull bill towards the nw at 50W is not as evident anymore it seems ridge is stronger than though and has built back in. Expect a westward trend with models over the next 12-24 hours


The models did indicate a westward track for the next 48 hours before a more northerly track is established by the coming weakness.
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1533. unf97
Although the HH are not finding west winds at the moment investigating the Ana's remnants, don't count her out just yet. I still think there is a possibility that a centrer can reform in 24 - 48 hours as the system moves along farther W-NW to NW. Convective bursts are still occuring, and it will be intersting if this continues on for the next day or so.
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1532. pottery
TWINKSTER, thanks, appreciated.
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Quoting CaneWarning:


This is a que for Patrap to post his hot towers video.
LMAO, i agree
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Quoting kmanislander:


I can certainly understand why they would not declassify Ana just East of the Islands in the absence of definitive data and risk lulling people into a false sense of security only to have it possibly blow up overnight. I wasn't being critical, just commenting that overall Ana appeared to lack the essential characteristics of a tropical cyclone long before this afternoon.
Agreed. I didn't get a critical tone from what u said. I guess Ana is a more interesting watch for me right now first because it is "closer to home" so to speak and second because Bill's near term fate seems pretty set (i.e. WNW @ abt 15, possible NW turn in the next 24). But Ana also has that aura of the underdog in the suspense-ridden story, to the point where one is almost rooting for a storm that could potentially devastate one's home / country. . . . . lol
Member Since: October 25, 2005 Posts: 19 Comments: 22728
Quoting yamil20:
i think the models are trending west because they are seeing a stronger Bermuda ridge. this is the steering layer for Layer : 400-850 hPa
TC MSLP : 970-989 hPa, just click the 3+/3- and see the difference. What do everyone think about this.


high looks to have strengthened
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1527. fmbill
18z NAM is taking whatever is left of Ana into the Bahamas toward Florida.
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1525. pottery
KMAN, please see post 1502.
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Well I was right, and the models are beginning to see my point of view form yesterday. This can still be a Northeast threat.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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