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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So how goes it, Drak?

I bet you couldn't wait for all this activity...haha
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Quoting sullivanweather:
Drak,

I agree. There is cyclonic turning evident on radar but no well-defined center of circulation.

I find it strange how some can argue that Ana is 'making a comeback' while in the same sentence talk about 'two centers of circulation'.

Typically, two centers of circulation for the same system would imply that it's not a tropical cyclone. They usually only have one center, if you know what I mean =)


I understand what you are saying.
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Quoting stevedish:
Thanks for the reply Nrtiwlnvragn. It's makes no sense to me that they would not share data if their model is more accurate than others. Anyone know if the GDFL tends to agree with the ECNWF?


The NHC and NWS get the data, just not the public at large. You can subscribe ($$) to some weather services to see the data, but again there are policies against sharing that data on open public forums.
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What a view.


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Dark,

I agree. There is cyclonic turning evident on radar but no well-defined center of circulation.

I find it strange how some can argue that Ana is 'making a comeback' while in the same sentence talk about 'two centers of circulation'.

Typically, two centers of circulation for the same system would imply that it's not a tropical cyclone. They usually only have one center, if you know what I mean =)
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Good afternoon from the UK.

Wow, after just a couple of days away from the blog the tropics go wild. Thanks to Dr Masters and StormW for their posts. After reading them I feel I'm up to date again.

One small question to StormW. Where do you get the steering forecasts from? I'm looking at the steering layers on the cimss website but as far as I have understood it, they only show the latest image but no forecasts. Is there a free website with steering forecasts or only one with subscription? Thank you very much in advance for you answer and thanks as well for the good job you do everyday.

Lastly, hello Floodman. Good to see you after a long time. Had a quiet season so far where you live, right? I hope it stays that way.
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Quoting Ameister12:

It kinda looks like Bill is starting a NW turn.
i agree
which is traveling faster the ULL to the west of Ana or Ana?
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ANA JSL Image

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Quoting Drakoen:


You could be right, in fact your conclusion has a higher chance of happening. Radar still shows me some cyclonic rotation though.


Wait, are you and drakoenG the same person?
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Quoting Relix:
Report from San Juan PR: Using College PC. It's cloudy, light rain... but I am seeing that the COC will be over us soon, probably over the metro area where I am right now thanks to the NW movement. It's been an hour without anything susbtantial but I expect in the next 15-20 mins to things get BAAAAD. It's looking organized enough that you could call Ana a minimal TS again. I can't watch vapor loops here so... is Bill still moving west?

It kinda looks like Bill is starting a NW turn.
Member Since: August 9, 2009 Posts: 10 Comments: 5085
Here's what Joe B. at ACCUWEATHER says this morning.

ANA CONSIDERATIONS.
The WCI last night was still at 6, which is one above my "neutral" zone and still well above my favorable which starts at 2.5. You are seeing an example of what happens when this is high, as Ana is racing west.

However consider this. After fighting off 1,500 miles of dry air, with more thunderstorms this morning than yesterday when TPC still had it as a tropical storm, with it racing through Hispaniola, with negative tilt to the wave axis, much like Claudette, if this is over eastern Cuba or just north tomorrow after all that... why would you think that with it slowing, more moisture and a favorable outflow pattern waiting for it, it should not be forecasted to come back?

I made no mention of it yesterday, but I found it very curious that after downgrading this, TPC snuck in an intensification back to a storm before Hispaniola. Storms moving faster than 18 mph in the Caribbean don't intensify. (Old Aggie rule from the 60s that I overheard in A&M weather station in the summer of '63 and again '64 with Flora and Cleo... my dad was out there talking with a bunch of met students and I was in the teletype room listening.. Like most weather addicts, the only talk was about the weather.. or Aggie football, which quickly went back to the weather. Hey parents.. ever notice that your kids pick up more when you aren't talking to them than when you are (lol).

Of course, I was the exception... when my mom told me to eat... I did, and still do, even if it is that 400-calorie "sliver" of cheesecake.

Okay where was I... that's right, hyping Ana. Look, I am not trying to be Mr Contrary Curmudgeon here with TPC. I am simply pointing out that it's odd that a system that has arguable been an open wave since yesterday may be given up on later today, even has the overall pattern is starting to improve as shown my more extensive clouds and the negative tilt. Watch the ones with negative tilts... that is why Claudette had my fancy for so long and she didn't even get all the wave energy as part never made it through the WCI easterlies.

Okay.. back to whatever it was you were doing before you decided to click the button.
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Quoting jipmg:


The northern on eis running into Puerto Rico right now


But PR is much smaller and less mountainous than the rugged Hispaniola, in which the southern COC will move over. That is why the northern one will likely become dominant, and if it does that could change the forecast dramatically.
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Quoting sullivanweather:
Drak,

I think Ana is a done deal for the next 3 days or so.

Current radar gives me the impression that the system is nearly an open wave with several regions of enhanced vorticity along the wave axis.

Trades are simply too strong and the system is too small and weak to withstand it.


You could be right, in fact your conclusion has a higher chance of happening. Radar still shows me some cyclonic rotation though.
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Quoting AllStar17:


That means models should now be taken with a grain of salt, as I am pretty certain a new COC has formed and is about to move over PR.
I agree. Even though there still seems to be a lot of dry air to the south of Ana, the NW seems to have abundant moisture and warm waters. I wouldn't call the the convection around Ana as "impressive", but there seems to be more to the systems than is being called for. I believe she shall move on a much more WNW course than the morning advisories. Just and opinion, not based on fact.
Member Since: July 17, 2009 Posts: 71 Comments: 27210
Yesterday several people were trying to compute the speed of bill's travel between two Lat Lon positions (dist/time = spd) and were comming up with different solutions - The biggest problem is getting the distance between the two positions. Here are two links - one is a calculator and the second explains the Math.

The Math

The distance between two points on the Earth Calculator
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Seeing Ana reform another LLC to the N of the NHC's current LLC is not out of the question, we've seen it happen before with weak systems.

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Quoting cchsweatherman:
Going to be very interesting to see how the NHC handles Ana since, as Drakoen has shown, there does appear to be dual circulations, even on satellite and radar imagery.
yup, so ANA has 2 circulations am i correct?
Fizzling....Ana was a zero.
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Quoting CJ5:


Based on local Nexrad, that doesn't seem apparent to me.


He is wrong, there are 2 COC's with the northern one probably becoming the dominant one.

Bill's NHC advisory came out very early, at 10:31
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Drak,

I think Ana is a done deal for the next 3 days or so.

Current radar gives me the impression that the system is nearly an open wave with several regions of enhanced vorticity along the wave axis.

Trades are simply too strong and the system is too small and weak to withstand it.
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Going to be very interesting to see how the NHC handles Ana since, as Drakoen has shown, there does appear to be dual circulations, even on satellite and radar imagery.
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147. jipmg
Quoting AllStar17:


I think the northern one is getting stronger and will become dominant, while the southern one will run into land and die a slow death.


The northern on eis running into Puerto Rico right now
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Bill may be slowing down to make that turn we"ll probably know by tonight if he makes that first curve or not.
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Bill has slowed down(it's going to make that wide right turn looking more & more likely). Are they not going to do an updated 11am chart/map for Anna?
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Bill is dropping in pressure... Hopefully he feels that first trof!

On satellite he appears to be following the NHC forecast line, so all is good so far.
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Quoting Drakoen:
These reports support dual low level circulations:



A small scale Fujiwhara type effect might be happening.
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142. Relix
Report from San Juan PR: Using College PC. It's cloudy, light rain... but I am seeing that the COC will be over us soon, probably over the metro area where I am right now thanks to the NW movement. It's been an hour without anything susbtantial but I expect in the next 15-20 mins to things get BAAAAD. It's looking organized enough that you could call Ana a minimal TS again. I can't watch vapor loops here so... is Bill still moving west?
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Quoting watchingnva:


have i not used or looked at this map much over the last couple of years...have they always put an m for major on the 5 day cone...or is that recently something new?
they put M for Major hurricane, because it is expected to become a Cat 3 or higher.
BILL RGB Image

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only about 1% of storms in the Atlantic become annular and Bill is nowhere close to being one.

annular hurricanes are major canes that keep their strength for days on end. this just became a hurricane and doesn't even have an eye that is visible on IR imagery.
Member Since: August 6, 2007 Posts: 0 Comments: 693
138. CJ5
Quoting sullivanweather:
Ana's 'center' may skirt the south coast of Puerto Rico but I think that it's apparent that the system is degenerating into an open wave.


Based on local Nexrad, that doesn't seem apparent to me.
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Quoting watchingnva:


wait and see...too early to tell...i find it funny that so many on here believe that the nhc doesnt know what their talking about..

people who use this blog for info should always go by the nhc 1st, then come in here for commentary...or at least a laugh, but most of the time thats what youll get from this blog...


She's a fighter though, she should of died yesterday. I'm surprised it has hung on. If she hangs on today, she could survive.
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Quoting Drakoen:
These reports support dual low level circulations:



I think the northern one is getting stronger and will become dominant, while the southern one will run into land and die a slow death.
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Quoting Patrap:



The SSS dosent relate well to Surge and well,Size.

Thats whay you Have to listen to the warnings. Not many Cat 3's push a 30 ft Storm Surge. A CAt number is MOOT when relating ImPACT.


AMEN!
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134. IKE
AT 1100 AM AST...1500 UTC...THE CENTER OF HURRICANE BILL WAS LOCATED
NEAR LATITUDE 14.1 NORTH...LONGITUDE 45.2 WEST OR ABOUT 1080 MILES
...1735 KM...EAST OF THE LESSER ANTILLES.


Wouldn't you know it...it's moving WNW.
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Quoting Drakoen:
I see two circulations with Ana. If the southern one winds this thing will die over Hispaniola if the northern one wins it has potential...

Agree with that. Southern square over Hispaniola and on to Cuba. North maybe some of both but be close.
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132. jipmg
Is it just me or is ANA's "Center" constantly re developing further North.. looks to me like it might stop its moving onto land
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I'm going to stop saying that it's going to Florida and just follow the NHC's path.
Morning everyone.
I fell horrible today due to laying awake in my bed 'til 3am.
Member Since: August 9, 2009 Posts: 10 Comments: 5085
49. Orcasystems

Thanks for the excellent images!

BTW, I'm at: 44° 28′ 53″ N, 72° 57′ 54″ W
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Quoting sailfish01:
It appears to me that the circulation around Ana is much further north than the tropical prediction path. Anna center may pass N of Hispaniola and if so, we may see a different senerio from her.


That is what is being discussed atm
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These reports support dual low level circulations:

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Quoting canesrule1:


have i not used or looked at this map much over the last couple of years...have they always put an m for major on the 5 day cone...or is that recently something new?
Member Since: September 7, 2005 Posts: 7 Comments: 1526
Claudette htis Florida; Ana approaches Puerto RIco; Bill becomes our first hurricane

low pressure is expected to develop along the U.S. East Coast late this week, turning Bill even more to the northwest.

...Monday morning before coffee?
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Always a consideration for a cyclone near Florida - SST (Swamp Surface Temperature)and near shore SSTs where our continental shelf profile slopes gradually & there is limited cooling from mixing or upwelling. I swear the humidity in the boundary layer just onshore pre-Fay was over 100% LOL with temp in the 90s F (calculate the Heat Index for that). In no way doomcasting so don't go there, just watching with interest.
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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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