Ana, Bill,--and Claudette?

By: Dr. Jeff Masters , 1:52 PM GMT on August 16, 2009

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After one of the slowest starts to hurricane season in the past twenty years, the hurricane season of 2009 has exploded with activity over the past 48 hours. This morning, Tropical Depression Four joined Ana and Bill in the Atlantic, and appears poised to become Tropical Storm Claudette later today. Indeed, this may already be Claudette, as morning's QuickSCAT pass showed top winds of 45 mph. NEXRAD radar animations out of Tallahassee, FL, show a small but well-organized tropical cyclone with plenty of heavy thunderstorm activity, and improving low-level spiral banding. Satellite loops show an area of intense thunderstorms with cold cloud tops expanding near the storm's center.


Figure 1. Current long-range radar out of Tallahassee, FL.

It's pretty amazing (and a little unnerving) how quickly this storm sprang up. TD 4 developed literally overnight, and has the potential to be a strong tropical storm by the time it makes landfall tonight along the Florida Peninsula. TD 4 reminds me of 2007's Hurricane Humberto, which became a hurricane just 24 hours after first appearing as a tropical depression. I don't think TD 4 has time to reach hurricane strength, since wind shear as diagnosed by the SHIPS model was moderate, 10 - 15 knots, but it does have time to strengthen into a 50 - 60 mph tropical storm before landfall. Given that the storm is so small, storm surge flooding should not exceed 3 -5 feet, and will not be the major hazard from TD 4; inland flooding from heavy rain of 3 - 6 inches is likely to be the main threat from the storm.

Tropical Storm Ana continues to struggle
Tropical Storm Ana continues to struggle. Dry air continues to plague the storm, thanks to the large area of Saharan air the storm is embedded in. Ana's heavy thunderstorms are limited to just one small spot near the center. Wind shear appears to have lessened some, though, since yesterday. Thunderstorms were not able to form at all near the center yesterday, since strong wind shear tends to blow a storm's heavy thunderstorms to one side of the storm, exposing the low-level center to view. With heavy thunderstorms building near the center this morning, shear appears to be less of a problem for the storm. Top winds seen by this morning's QuikSCAT pass were about 35 mph. The outer rain showers from Ana should appear on radar out of Martinique today.

Shear is low (5 - 10 knots), and is forecast to remain low for the next two days. SSTs are warm, 28°C, and will warm further over the next two days. However, there is so much dry air around Ana that significant strengthening appears unlikely. Nearly all of the models predict Ana will dissipate sometime in the next three days, though the HWRF and GFDL predict that this will happen because Ana will move over the rugged terrain of Hispaniola. Ana is likely not strong enough to survive an encounter with the big island that the Dominican Republic and Haiti share. At this time, it does not appear that Ana will be moist enough to cause a major flooding disaster on Hispaniola.


Figure 2. Water vapor image from this morning showing the large area of dry, Saharan air surrounding Ana, and lying to the northwest of Tropical Storm Bill. Image credit: NOAA/SSD

Tropical Storm Bill gathers strength
Tropical Storm Bill is gathering strength in the middle Atlantic Ocean, and appears poised to become a powerful Cape Verdes-type hurricane later this week. QuikSCAT data from this morning shows a large circulation with top winds of 35 - 40 mph. Water vapor imagery (Figure 2) shows that there is some dry air to the northwest of Bill, and this dry air is being drawn into Bill's center, slowing intensification. It will likely take another day before Bill can moisten the atmosphere enough to ward off the dry air, and allow more significant intensification.

Wind shear is low, 5 - 10 knots, and is forecast to be in the low to moderate range, 5 - 15 knots, for the next five days. Sea Surface Temperatures are about 27.5°C, and will remain in the 27.5 - 28°C range the next four days, then warm substantially as the storm nears the Lesser Antilles Islands. The combination of low wind shear and sufficiently warm SSTs should allow Bill to intensify steadily to hurricane strength by Wednesday.

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--with the notable exception of the UKMET model--have now jumped on the ECMWF bandwagon, forecasting that Bill will pass well north of the Lesser Antilles Islands. The UKMET has Bill hitting the islands, but is being discounted since it is an outlier. It currently appears that the trough approaching the U.S. East Coast will be strong enough to recurve Bill before it reaches the U.S., though it is too early to be confident of this. Several of the longer range models show Bill passing near Bermuda or Nova Scotia, Canada.

I'll have an update later today.

Jeff Masters

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Hey Pat, ya still around?

What's Claudette doing?? Is she trying to stall or possibly relocate her center a bit? I'm not so sure about a relocation of the center as I've yet to see anything to prove that, but it's definitely in the realm of possibilities.
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French forecast put ANA between Guadeloupe and DOminique. But it seems to take a more northern track.
can you make it clear for me.
Thanks
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Quoting swlagirl:
Is invest 91 the same thing as Claudette? I don't see anything else it could be. Just wondering if they were watching something else in the gulf.


invest 91L became Td 4 which beacame Claudette.

basically the same system
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting canesrule1:
at 11 he was at 38.4W and now he is 39.8 in about 4 hours that (1 point of latitude is 70 miles) it is moving around 21+ MPH


The nunbers look a little high to me. but I can't remember the formula for figureing distances between Long. lines

Each Degree of Latitude equals 60 nautical miles - 1 nautical mile equals 1.150779 statute miles - 600 nm = (1.150779 mi / 1 nm) = 690.5 miles so each tenth of a deg LAT = 6.9 Stat Miles...
BUT the distance between Degrees of Longitude vary depending on the Lat where the measurment is taken. within 30 deg of the equator the distances are roughly the same as they are for distances between Lat lines but they are not exactly the same so ....
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Quoting Drakoen:
The early models do take it out to sea...

And everyone knows that those simple early cycle models are the ones that carry the most consensus weight and have very high verification rates, right?
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1719. Drakoen
According to the models Bill is one for the fishes or Bermuda... Not much of a difference to me.
Member Since: October 28, 2006 Posts: 57 Comments: 30727
Quoting CatastrophicDL:

Taz where are you getting this info. I've got 997 still. Link


i dont no why evere one like uesing that site for it not all way right and it mass up a lot and it donts keep you update too date the olny time this site works well is when you have a strong hurricane or then that i find that site ues less

Link


i got that mb from here wish this update not too long a go


Link


000
WHXX01 KWBC 161903
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1903 UTC SUN AUG 16 2009

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE BILL (AL032009) 20090816 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090816 1800 090817 0600 090817 1800 090818 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 12.5N 39.2W 13.3N 42.5W 14.1N 45.5W 14.5N 48.3W
BAMD 12.5N 39.2W 13.3N 42.3W 14.2N 45.3W 15.0N 48.0W
BAMM 12.5N 39.2W 13.2N 42.6W 13.9N 45.8W 14.3N 48.5W
LBAR 12.5N 39.2W 13.2N 42.2W 14.1N 45.5W 14.6N 48.9W
SHIP 55KTS 67KTS 79KTS 89KTS
DSHP 55KTS 67KTS 79KTS 89KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090818 1800 090819 1800 090820 1800 090821 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 15.0N 50.8W 17.7N 55.0W 22.1N 60.3W 25.9N 65.1W
BAMD 15.8N 50.5W 18.3N 54.8W 22.1N 58.9W 27.8N 62.7W
BAMM 14.9N 50.9W 17.6N 54.9W 21.8N 59.4W 26.5N 63.7W
LBAR 15.1N 52.3W 16.4N 58.3W 21.3N 61.3W 26.9N 64.4W
SHIP 96KTS 107KTS 106KTS 103KTS
DSHP 96KTS 107KTS 106KTS 103KTS

...INITIAL CONDITIONS...
LATCUR = 12.5N LONCUR = 39.2W DIRCUR = 290DEG SPDCUR = 14KT
LATM12 = 11.5N LONM12 = 36.5W DIRM12 = 290DEG SPDM12 = 12KT
LATM24 = 11.2N LONM24 = 34.5W
WNDCUR = 55KT RMAXWD = 45NM WNDM12 = 40KT
CENPRS = 994MB OUTPRS = 1011MB OUTRAD = 200NM SDEPTH = D
RD34NE = 120NM RD34SE = 120NM RD34SW = 60NM RD34NW = 90NM

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1717. CJ5
Quoting stormwatcherCI:
ANA.35kts-1005mb-149N-578W.100pc.jpg | From the Navy Site


Maybe, but to my untrained eye, I have it at 15.7/59
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1716. 996tt
Quoting AFCriskDOTCOM:


WHY are many individuals SO NASTY on this forum when a newbie posts something?!? Everyone is contributing to the activity we face TOGETHER. Blogger 996tt ought to refresh "Rules Of The Road" at this Website.


Dude, not directed at you. Was more or less making fun of myself because I had not heard of the fancy words.
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Is invest 91 the same thing as Claudette? I don't see anything else it could be. Just wondering if they were watching something else in the gulf.
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Quoting CapeFish:


I am not sure where you are getting this from, especially on Ana.

She has certainly never wandered outside the forecasted 5 day cone for her at any point:

http://www.nhc.noaa.gov/archive/2009/graphics/al02/loop_5NLW.shtml

Again, remember, the "forecast" is the cone, not the actual point put in the middle of it.


what?


look at Ana's 5 day point when she tropical depression 2.


Look at where is now.

You gonna watch that loop and tell me Ana track did not shift?

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting IKE:


Defuniak Springs,FL.


Ike getting a squall here now...no lightning though.
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Dry air does not appear to be much of a factor anymore with Bill. He has explosive convection right now around his center.
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can somebody post the most recent models. Thank you
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Quoting jake436:
I thought the coriolis effect is when two storms are spinning right next to each other...?

Nope, that's the Fujiwara effect. Coriolis is the force the spinning of the earth creates.
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afternoon kman! do you think bill will go north or are you of the impression it gets much bigger much faster and goes west through that trough like me thru a cheesecake!
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Quoting Weather456:
The models did shift

12Z Consensus

50W-18N

18Z Consensus

50W-16N
southward? or am i seeing things?
1707. GatorWX
Quoting Tazmanian:


???


lol
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Link
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Quoting 996tt:


Haha, one thing I have learned is this is a bunch of conjecture regardless how many big words you try and use to support the conjecture and Steve Lyons and those with a bunch of fancy equipment don't do much better than mua whose degrees have nothing to do with weather.


WHY are many individuals SO NASTY on this forum when a newbie posts something?!? Everyone is contributing to the activity we face TOGETHER. Blogger 996tt ought to refresh "Rules Of The Road" at this Website.
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Originally I am from New Hampshire. The cute doggy in my avatar is from Florida though.
I wanted ask one more thing was the storms yesterday going over St Lucie county from the now named Claudette?
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1703. 996tt
Quoting IKE:


Defuniak Springs,FL.


Cool. We have an office in Ft. Walton right by the bridge. Stay safe. About to head back out and find some surf before the water gets too choppy.
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Quoting Drakoen:
The early models do take it out to sea...



Except, if they continue that NW track or even NNW, they would have Bill hitting Bermuda, Carolina Coast (sorry press), or New England.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
1701. Drakoen
FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):290/ 14 CX,CY: -12/ 5
T-12 MAX WIND: 40 PRESSURE OF STEERING LEVEL (MB): 579 (MEAN=624)
Member Since: October 28, 2006 Posts: 57 Comments: 30727
Quoting canesrule1:
i think it should be a little more southerly.


Pray tell, why?

Bill is not forecast to pass 15N until at least Tuesday morning, if not even Wednesday morning. So of course he is going to head much more west the next two days than north.

In the next two days he is going to move a whole 2 degrees north. This western movement is fully expected by the NHC's forecast and does not show or warrant any sort of change.
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1699. GatorWX
Quoting Weather456:
Those of you on the right side is going to get some pretty gusty winds. 50 knots + forward speed



Meanwhile, Bill's eastern eyewall



Thanks 456 for providing the microwave loop. I guess my pseudo-eyewall theory was incorrect as it appears it was another vorticy or perhaps the center relocated, though not as likely, I think it was already too well developed for that and virtually no shear at that time. I think it wsas just a vorticy, but still most likely contained the strongest winds. You can see what I'm referring to in the first few frames of the loop.
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The models did shift

12Z Consensus

50W-18N

18Z Consensus

50W-16N
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting champagnedrmz:


Originally? Or where am I know?


Originally.
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Quoting jake436:
I thought the coriolis effect is when two storms are spinning right next to each other...?
-
Does anyone have a link to the floaters? Had it saved on my home PC...but just got this laptop...and have NOTHING saved. Thanks in advance.
-
By the way...after a long time off from the blog...it's amazing how ridiculous it has gotten. There should be a mandatory waiting period for posters...and a background check. IMO, the waiting period should end in November.


1) The coriolis effect is the effect that the spinning of the earth has on a whole bunch of stuff, like why tornadoes and hurricanes spin in opposite directions in the Northern and Southern hemispheres. What you're thinking of is the Fujiwhara effect.
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Quoting hurristat:


I don't mean to sound rude and/or stepping over any lines, but where are you from?


Originally? Or where am I know?
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1693. Michfan
Quoting jake436:
I thought the coriolis effect is when two storms are spinning right next to each other...?
-
Does anyone have a link to the floaters? Had it saved on my home PC...but just got this laptop...and have NOTHING saved. Thanks in advance.
-
By the way...after a long time off from the blog...it's amazing how ridiculous it has gotten. There should be a mandatory waiting period for posters...and a background check. IMO, the waiting period should end in November.


Your thinking of the Fujiwara effect. Strong storms tend to move poleward due to the earths rotation and weak storms tend to move west in conjunction with the westerly trade winds.
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1692. Drakoen
The early models do take it out to sea...

Member Since: October 28, 2006 Posts: 57 Comments: 30727
Quoting champagnedrmz:


Yes I know. I was just trying to figure why some are so intent on the turning. Some are dead set on it is turning. If they can't be predicted how can that be? I am not a wishcaster either. I want it to go out to sea because during Fay we found out we had leaking from the foundation and our landlord still hasn't fixed it.


I don't mean to sound rude and/or stepping over any lines, but where are you from?
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Quoting Weather456:



Ana and many other never ended up at their 5-day points.


I am not sure where you are getting this from, especially on Ana.

She has certainly never wandered outside the forecasted 5 day cone for her at any point:

http://www.nhc.noaa.gov/archive/2009/graphics/al02/loop_5NLW.shtml

Again, remember, the "forecast" is the cone, not the actual point put in the middle of it.
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Quoting jake436:
I thought the coriolis effect is when two storms are spinning right next to each other...?
-
Does anyone have a link to the floaters? Had it saved on my home PC...but just got this laptop...and have NOTHING saved. Thanks in advance.
-
By the way...after a long time off from the blog...it's amazing how ridiculous it has gotten. There should be a mandatory waiting period for posters...and a background check. IMO, the waiting period should end in November.


http://www.ssd.noaa.gov/PS/TROP/floaters.html#atlantic
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Quoting Tazmanian:
the mb in bill has drop from 997mb too 994mb and wind are up too 65mph

Taz where are you getting this info. I've got 997 still. Link
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Quoting canesrule1:
it is in English, it is a different story if he doesn't know how to read it.


it's just a bunch of coordinates, why not just write what it means instead of "???"
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Quoting Skylink:
I have just updated the web cams, click below for cams in the path of Claudette. If you have any extra links I will add them, so let me know thanks!


Link

Thanks, there are a lot people still on the water, lol
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1685. IKE
Quoting 996tt:
Hey Ike. Where are you located? I was thinking about heading to a spot near Grayton and seem if swell was any better, but decided to stay put. A friend told me it was poor form chop an hour ago.


Defuniak Springs,FL.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting dcoaster:


Not expected AT ALL...


Wow...east coast could be seeing a cat 3 or higher storm. Let's all hope they shift back North.
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Tomorrow the northern Antilles should be under a hurricane watch.
At Bill's current intensity the steering is at the 500 mb level and those winds suggest a due West motion for quite a while. If Bill is pulling up to the N already then he may be strengthening quicker than expected.
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Quoting hurristat:


Last time I checked, hurricanes never predicted. LOL.


Yes I know. I was just trying to figure why some are so intent on the turning. Some are dead set on it is turning. If they can't be predicted how can that be? I am not a wishcaster either. I want it to go out to sea because during Fay we found out we had leaking from the foundation and our landlord still hasn't fixed it.
Member Since: Posts: Comments:
1680. jake436
Quoting CatastrophicDL:

The stronger a hurricane gets, the more it will move north. I think it is the coriolis effect.
I thought the coriolis effect is when two storms are spinning right next to each other...?
-
Does anyone have a link to the floaters? Had it saved on my home PC...but just got this laptop...and have NOTHING saved. Thanks in advance.
-
By the way...after a long time off from the blog...it's amazing how ridiculous it has gotten. There should be a mandatory waiting period for posters...and a background check. IMO, the waiting period should end in November.
Member Since: Posts: Comments:
1679. Drakoen
Quoting FLHurricaneChaser:


Are those further west than 12Z?


Yes. The 12z took it out to sea.
Member Since: October 28, 2006 Posts: 57 Comments: 30727
Quoting dcoaster:
Haha, TWC calls this the "Atlantic Explosion". Quite funny actually.


i saw that a couple hours ago. i lol'd. they call dr. greg forbes "funkmaster G" or something now, and he poses like a rapper in front of a storm background. That channel is so cheesy now it's entertaining.
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Quoting Tazmanian:
the mb in bill has drop from 997mb too 994mb and wind are up too 65mph
im surprised, it should be at 70 or higher
Quoting WPBHurricane05:
Quoting WPBHurricane05:
18Z early for Bill.

What do you know...west they go!


Not expected AT ALL...
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Quoting Funkadelic:
As of 3:00pm EST, Anna is north of forcast points, and so is bill.

http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html

If you look at Bill his initialized point was just after a westerly wobble .. or just before a northerly one. Regardless the prevailing currents are west. He will continue West to WNW in the nearterm. After that? Who knows anyone from Mexico to nova scotia needs to be prepared. Me personally I prefer a southerly track. Until I more northerly components in steering I'll remain of that opinion.
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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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