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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Quoting ralphfurley:
I've been coming here for nearly 5 years and it always amazes me that the same people who said "ignore the models" yesterday are the same ones that say "believe the models" today. ugh. and dont get me started on the "ignore the center line/believe the center line" folks

What is it that bothers you about the ignore or believe center line folk?
Member Since: Posts: Comments:
1074. Michfan
The models always tend to underdo the A/B high and over do the troughs during this time of year. Red is right. Don't let your guard down regardless of what they say. Models are nothing but a tool in the arsenal. They are not the end all be all when it comes to the track of a cyclone. There is a reason we have cones on these.
Member Since: September 7, 2007 Posts: 0 Comments: 1747
1073. Dakster
Quoting Drakoen:


Sounded pedophile-ish


I didn't know Bill Kamal was blogging here today...
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1072. Drakoen
I see Claudette making landfall near Fort Walton Beach
Member Since: October 28, 2006 Posts: 57 Comments: 30830
1071. Lizpr
Quoting Relix:
Bill is pulling a Georges, the High is too strong.


Hope not =\
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1070. Grothar
Quoting reedzone:
Exactly! It is NOT official that Bill will curve out to sea just yet. We will know in a few more days. Everyone from the Carolinas to Maine need to really watch Bill.. I think models are also overdoing the trough that curves it, we'll see what happens.
Whom are you quoting? I am not an expert, but I do agree with you the models may be off on both systems.
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1069. Patrap
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Quoting Michfan:
Also for those of you in the path of Claudette. These are sustained winds. You can still see gusts higher than these in some of the storms that come ashore.



Yes, be careful, this could be like a strong afternoon t-storm, just longer!
Member Since: April 26, 2009 Posts: 3 Comments: 3667
1067. jipmg
Quoting Relix:
Ana is also moving sightly more due west now.


??? ANA is moving slightly more north of west bud
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1064. JLPR
Quoting 7544:


aqgree


no I dont agree xD no such thing as a Georges =\
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1063. Drakoen
Quoting Funkadelic:


That is a bit more concerning, due to the fact that the Bahamas area is VERY conductive for TC formation. Im afraid people have already written off Ana. I for one will stay on top of this little girl lol.. (I know that sounded wrong)


Sounded pedophile-ish
Member Since: October 28, 2006 Posts: 57 Comments: 30830
The models always do this.. They don't really focus on the high.. Ivan (2004) and Dean (2007) VERY good examples.. Ivan was supposed to hit South Florida, but the high kept going and it made it into the heart of the GOM and hit Alabama. Dean was supposed to go north of the Lesser Antilles, in fact Bill is in that very same spot where Dean was at the time it was foretasted to head north.. Instead the high remained strong and pushed Dean west. It's not official yet, lets wait and see what happen through the week.
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1061. sngalla
Quoting CycloneOz:
Computer Models...hmmmph!

I'll take experienced forecasters (like the late Dr. Lyons) over nerdy weather computer geeks and their worthless algorithms any day.


I think you meant John Hope.
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Quoting BenBIogger:



That is one powerful high, no wonder Ana is trucking at 23.
Member Since: August 10, 2009 Posts: 3 Comments: 672
1059. Patrap
Quoting CycloneOz:
Computer Models...hmmmph!

I'll take experienced forecasters (like the late Dr. Lyons) over nerdy weather computer geeks and their worthless algorithms any day.


..Last I saw Dr. Lyons was alive and well,on TWC..
I think you meant John Hope Oz man
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Amazing Claudette has caught the Panhandle by surprise... there are tourist playing on the beach while the condo management companies are trying to secure patio and pool furniture. Looking at the GOM, currently, there are folks playing in the water and its really pretty. I have a feeling that there are a lot of people who have not seen the weather forecast.........
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1057. 7544
Quoting Relix:
Bill is pulling a Georges, the High is too strong.


aqgree
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Quoting LightningCharmer:
This wasn't the first time a storm formed right over me so to speak. Back in 2007, I can't remember the name of it. It might just have been a TD. You are correct; it is awe inspiring.

By the way saw two waterspouts yesterday off the upper Keys from pre-Claudette.

Keep up the good work Oz.


Tropical Depression 10; was forecasted to become Jerry, but didn't.
Member Since: October 15, 2008 Posts: 11 Comments: 2312
Quoting serialteg:


yeah my bad dude was watching ana and didnt notice
oh ok no prob lol
Quoting CycloneOz:
Computer Models...hmmmph!

I'll take experienced forecasters (like the late Dr. Lyons) over nerdy weather computer geeks and their worthless algorithms any day.


ummmmmmmmm those "worthless algorithms" are used by NHC...

which is kind of scary considering :/
Member Since: August 22, 2006 Posts: 2 Comments: 1988
1052. Michfan
Also for those of you in the path of Claudette. These are sustained winds. You can still see gusts higher than these in some of the storms that come ashore.
Member Since: September 7, 2007 Posts: 0 Comments: 1747
1051. Relix
Ana is also moving sightly more due west now.
Member Since: August 3, 2006 Posts: 0 Comments: 2741
1049. Relix
Bill is pulling a Georges, the High is too strong.
Member Since: August 3, 2006 Posts: 0 Comments: 2741
A quick question: Due to the proximity to the islands of Ana and the quickly strengthening Bill, will the NHC put out intermediate advisories on Claudette; Claudette and Ana; or all three? Thanks!
Member Since: October 15, 2008 Posts: 11 Comments: 2312
1047. Michfan
http://tropicalatlantic.com/recon/ge/Recon_Data_for_the_Atlantic_Basin.kmz

For those that need the recon data for Google Earth again.
Member Since: September 7, 2007 Posts: 0 Comments: 1747
Quoting canesrule1:
yes with Claudette, update it and u will see.


yeah my bad dude was watching ana and didnt notice
Member Since: August 22, 2006 Posts: 2 Comments: 1988
thanks
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1043. Dakster
StormW - Is it true you are meeting Bartardi at your house next week... I am a little concerned.
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Quoting CycloneOz:


It's actually understandable. Many people are inclined to CV developers. Lots of lead time and there's plenty of crow to go around with those.

Backyard developers, like Claudette, aren't glamorous enough for most.

Still, if they had a chance to watch a depression form right above their standing position on the surface of the Earth, that would change, I truly believe that.

But if you have never seen one spin up from scratch, you don't know, so how can you expect people to appreciate it.
This wasn't the first time a storm formed right over me so to speak. Back in 2007, I can't remember the name of it. It might just have been a TD. You are correct; it is awe inspiring.

By the way saw two waterspouts yesterday off the upper Keys from pre-Claudette.

Keep up the good work Oz.
Member Since: September 1, 2007 Posts: 0 Comments: 1344
With Cs convection so lopsided I'm beginning to think it may wobble NE some as it strengthens and the convection becomes more symmetrical.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Quoting Michfan:


Im seeing over 5 of them.


sorry i was watching ana and thought it was claudette my bad :(
Member Since: August 22, 2006 Posts: 2 Comments: 1988
1039. IKE
Quoting Michfan:
Buoy updated.

Conditions at SGOF1 as of
(1:00 pm EDT)
1700 GMT on 08/16/2009:
Unit of Measure: Time Zone:

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.
5-day plot - Wind Direction Wind Direction (WDIR): SE ( 130 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 37 kts
5-day plot - Wind Gust Wind Gust (GST): 40 kts
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.98 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.04 in ( Falling )
5-day plot - Air Temperature Air Temperature (ATMP): 77.0 °F
5-day plot - Water Temperature Water Temperature (WTMP): 85.3 °F
5-day plot - Dew Point Dew Point (DEWP): 74.5 °F
5-day plot - Wind Speed, Wind Gust and Atmospheric Pressure Combined plot of Wind Speed, Gust, and Air Pressure


Close to the COC if not right at it.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
at the current position of BILL and the current track, I somehow will go with the UKMET i tracking the system thru the central antilles. one will have to wait until the ridge is broken, and that is not a certainity to see a more northerly track
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Exactly! It is NOT official that Bill will curve out to sea just yet. We will know in a few more days. Everyone from the Carolinas to Maine need to really watch Bill.. I think models are also overdoing the trough that curves it, we'll see what happens.
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ANNA is moveing way too fast its moveing at 23mph
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
Quoting IpswichWeatherCenter:
Guys - it looks like we may have Hurricane Bill - he is certainly starting to fight the dry air and is slowly developing an eye.


Not a hurricane yet. Close but I see nothing to suggest he is now.
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1033. Michfan
Quoting serialteg:


of claudette? dont see a single red barb on google earth


Im seeing over 5 of them.

Recon is heading back towards the center.
Member Since: September 7, 2007 Posts: 0 Comments: 1747
Alot of good news on here today it looks like a very weak Ana should get destroyed over the Mountains of the islands and not amount to much i don't even think it will be much if anything when it does Enter the gulf...Bill is mostly likely looking like a fish storm but not all good news is that i'm scared for our friends in Bermuda...Claudette is what is worrying me the most it looks to be heading due North right now hopefully it can go into land quickly so it can just be a rainmaker
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Quoting serialteg:


of claudette? dont see a single red barb on google earth
yes with Claudette, update it and u will see.
SFMR
43 knots
(~ 49.4 mph)

43 knots
(~ 49.4 mph)
Both For Claudette
Member Since: August 10, 2009 Posts: 3 Comments: 672
Quoting LightningCharmer:
Was in the Keys yesterday, and even though I think I was the first to report on this blog west shifting winds both, firsthand, and copy and pasting Sand Key Buoy's readings, you were the only one acknowledging me. Almost every other blogger (there were a few exceptions) were concentrating on Ana and soon to be Bill.
Afew of us were seeing some changes near key west that were of concern. What surprised me was the level of sarcasm exhibited by the comments,denying that things were developing.
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1028. Michfan
Time: 16:45:00Z
Coordinates: 29.1333N 84.85W
Acft. Static Air Press: 924.1 mb (~ 27.29 inHg)
Acft. Geopotential Hgt: 782 meters (~ 2,566 feet)
Extrap. Sfc. Press: 1011.9 mb (~ 29.88 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 139° at 54 knots (From the SE at ~ 62.1 mph)
Air Temp: 17.5°C (~ 63.5°F)
Dew Pt: 7.0°C (~ 44.6°F)
Peak (10s) Flt. Lvl. Wind: 55 knots (~ 63.2 mph)
SFMR Peak (10s) Sfc. Wind: 59 knots (~ 67.8 mph)
SFMR Rain Rate: 21 mm/hr (~ 0.83 in/hr)
Member Since: September 7, 2007 Posts: 0 Comments: 1747
Quoting Dakster:
Canesrule1 - I link the google earth link... I was following the recon mission as well.
cool
sorry bad post
Member Since: August 22, 2006 Posts: 2 Comments: 1988
Quoting szqrn1:
I am trying not to stay clued to the computer!
The local classic rock radio station weather girl just gave our forcast here for biloxi/gpt... 50% chance of rain ... 60% tomorrow "looking good right now" NO mention of Claudette in GOM whatsoever!! OMG really? LOL!

Radio stations are notorious for ignoring anything not in the immediate local area. Since the cone doesn't even quite reach Pensacola at this time I'm not surprised radio station doesn't mention it.
Member Since: August 22, 2008 Posts: 12 Comments: 6010

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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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