Ana and TD 3 take aim at the Lesser Antilles

By: Dr. Jeff Masters , 4:17 PM GMT on August 15, 2009

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Tropical Storm Ana was born this morning, when the remnants of Tropical Depression Two made a comeback and organized into the first tropical storm of the 2009 Atlantic hurricane season. Ana is the latest first named storm of the season since Hurricane Andrew got its name on August 17, 1992. The two storms have some similarities, as Andrew formed in the same part of the ocean, and also struggled in its early days with high wind shear and dry air. Let's hope the similarities end there.

Ana is struggling this afternoon. After an modest burst of heavy thunderstorm activity prompted NHC to upgrade Ana to a tropical storm early this morning, Ana has run into strong upper-level winds from the west that are creating high wind shear. This shear was not forecast, and it is not clear how long it will last. The shear has acted to drive dry air into the core of Ana, destroying almost all of Ana's heavy thunderstorms. The low-level center of the storm is now exposed to view, something that often foreshadows the death of a storm. It is possible the shear will destroy Ana, and several models (the GFS and ECMWF) forecast this may be the case. However, the shear forecast calls for shear to drop into the low range, 5 - 10 knots, tonight through Tuesday. If the shear does drop as forecast, Ana should be able to moisten the atmosphere around it sufficiently to protest itself from the dry Saharan air that surrounds it (Figure 1). SSTs are 27°C today, and will increase to 28°C by Sunday. By the time Ana moves into the Bahamas, total ocean heat content rises steeply (Figure 2), and rapid intensification of Ana is possible, if the shear and dry air haven't disrupted the storm. The intensity forecast models, for the most part, predict a steady intensification of Ana to the threshold of hurricane strength five days from now. The HWRF model is on the strong side, predicting a Category 2 hurricane. The GFDL predicts a weak tropical storm five days from now, but that is because the model has Ana passing over the rugged terrain of Hispaniola, something the other models do not predict. In summary, the intensity forecast for Ana has higher than usual uncertainty, and I give equal chances that the storm will be a hurricane--or non-existent--four days from now.


Figure 1. Water vapor image from this morning showing the large area of dry, Saharan air surrounding Ana, and lying to the north of Tropical Depression Three. Image credit: NOAA/SSD

Tropical Depression Three forms, could be Bill later today
QuikSCAT data from this morning and satellite loops revealed that the tropical wave (90L) in the middle Atlantic has finally developed a well developed surface circulation and can be classified as Tropical Depression Three. Recent satellite imagery suggests that TD 3 may already be Tropical Storm Bill. Water vapor imagery (Figure 1) shows that TD 3's center consolidated a few hundred miles south of the dry air of the Saharan Air Layer (SAL). Thus, the storm should not be affected by dry air and dust as much as Ana has been. Ana may also act to moisten the atmosphere in front of TD 3, helping protect the storm from the SAL as it edges farther north over the the three days.



Figure 2. Heat content of the ocean, in kJ per square cm. Oceanic heat content steadily increases for Ana and TD 3 as they approach the Lesser Antilles Islands. Oceanic heat content levels of 90 kJ per square cm are frequently associated with rapid intensification of hurricanes. Image credit: University of Miami.

Wind shear is moderate, 15 knots, but is forecast to fall to 10 - 15 knots on days 2 - 5. Sea Surface Temperatures are about 27.5°C, and will remain in the 27.5 - 28°C range the next five days. The combination of low wind shear and sufficiently warm SSTs should allow TD 3 to intensify steadily, and I expect the storm will be at hurricane strength by Wednesday, when it will be near the northern Lesser Antilles Islands. Most of our reliable intensity models strengthen TD 3 into a hurricane by Wednesday. Oceanic heat content (Figure 2) increases sharply just before the islands, so TD 3 could be intensifying rapidly as it moves through or just north of the Lesser Antilles on Thursday. TD 3 consolidated farther south than expected, so the track models calling for a more northerly path were probably incorrect. In particular, the ECMWF model, which had TD 3 turning sharply northwestward and missing the Lesser Antilles Islands, was probably much too far to the north in this morning's 00Z run. TD 3 will probably pass very close to the northern Lesser Antilles islands on Wednesday and Thursday.

I'll have an update Sunday.

Jeff Masters

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has the power to steal attention away from Bill and Ana

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Ameister12:

It is an Invest.


Link?
Member Since: August 14, 2007 Posts: 0 Comments: 435
Quoting bajelayman2:
Hey Stormdude77.

Looks like we have a bit of a worry with Bill.

Each time I look at the loop and his size, it comes home that he is only two days away (Sunday, Monday) then Tuesday and Bill in our area.

I am most horrified at his size, impressive looking monster.

We need to be prepared to get anything we do not have Monday am, if necessary.

I did some supply shopping this morning, food, batteries.

It would be nice if the GFS, as Futuremet notes, is right, but I doubt it.

Even though I am an amateur, I have seen some of these things pass and my humble opinion is that some of the islands are going to get it.

My gut tells me to be prepared.

We shall see.

Keep safe.


Hi Baje and Stormdude. I guess our met people may mention something on Monday if we are lucky. Does our multi million dollar radar work yet?

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2111. sngalla
Link

The new invest
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Quoting A4Guy:


Excellent..and well said. I am sure someone will give you grief, however.
I second the motion. too many comparisons to past storms this storm looks like this past storm no to storms are alike they all have variables
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Long-range radar loop out of Tampa is pretty interesting. Zoom in to the area just west of Fort Myers. It appears that whatever "center" there is with this area is located here. Notice the increase in thunderstorms around this "center" as well. If that can persist, it will cause the pressures to lower and possibly form a surface reflection.

Long Range Tampa Bay Radar
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Quoting nishinigami:


I was thinking someone needs to Kill Bill


Sorry, I do not think that is in much good taste.
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Quoting sngalla:


Looks like the area around the Keys may be a invest soon.

It is an Invest.
Member Since: August 9, 2009 Posts: 10 Comments: 4498
Good evening everyone. Looks like this is going to be a very intense week for us here in Puerto Rico.
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Quoting canesrule1:
Latest Dvorak:

15/2345 UTC 11.4N 35.2W T2.5/2.5 BILL
15/2345 UTC 14.5N 50.8W T2.0/2.0 ANA


Ana TD once again? Some convective burst this evening closer to its llc d-max could be interesting.
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Quoting bajelayman2:
Stormdude,

The only thing I can see that is hopeful is the dry air to the immediate North of Barbados, that may impede A BIT.

But, that seems to be fast diminishing, unfortunately.

I know that the models have very often been right, but can we really say that they have previously initialised 'low latitude' storms well? I have a suspicion not.

We shall see.

Could this be another Ivan?


Well the 12Z UKMET had Bill cruising through the Caribbean and just north of us (at about 14N). The UKMET is a reliable models and it handles upper level features well

But I don't think this will go as far south as Ivan did, but in terms of intensity, very possible....
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another year StormW and yet you're still proving your worth......keep up the good work. Eyes wide open for the next several days......
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2101. Drakoen
Quoting WeatherStudent:


Evening Mr. W,

Sir, please, for the love of God, you do not have to justify your professional meteorological credentials to the dispeccable redundant needs of absolutely no one on here. You demonstrate those impeccable credentials of yours on here, every single day with your exceptional tropical outlooks. Unfortunately speaking, the predominant conundrum here appears to be that they're are certain bloggers that are very much jealous and envious of your skills, and that would basically have to be about it. That was my two cents worth right there. Talk about a sour dousage of inferiority and superiority complex, geeze. :)


Work on your syntax I see 2 errors.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
15/2345 UTC 25.7N 82.9W T1.0/1.0 INVEST -- Atlantic


looks like we have other INVEST
Member Since: May 21, 2006 Posts: 5089 Comments: 114024
Quoting sngalla:


Looks like the area around the Keys may be a invest soon.


It has been made an INVEST

http://www.nhc.noaa.gov/satellite.shtml
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Quoting weathersp:
Bill:
<
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Bill will probably track like Hurricane Hanna did last year
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Quoting WeatherStudent:


Evening Mr. W,

Sir, please, for the love of God, you do not have to justify your professional meteorological credentials to the dispecable redundant needs of absolutely no one on here. You demonstrate those impreccable credentials of yours on here, every single day with your exceptional tropical outlooks. Unfortunately speaking, the predominant conundrum here appears to be that they're are certain bloggers that are very much jealous and envious of your skills, and that would basically have to be about it. That was my two cents worth right there. Talk about a sour dousage of inferiority and superiority complex, geeze. :)
That's a mouthful for two cents but I totally agree with you.
Member Since: October 9, 2008 Posts: 0 Comments: 8242
Quoting Tazmanian:
the new T # is in


DATE/TIME LAT LON CLASSIFICATION STORM
15/2345 UTC 11.4N 35.2W T2.5/2.5 BILL -- Atlantic
15/2345 UTC 14.5N 50.8W T2.0/2.0 ANA -- Atlantic
15/2345 UTC 25.7N 82.9W T1.0/1.0 INVEST -- Atlantic


Looks like we have something in the gulf as well.
Member Since: August 10, 2009 Posts: 3 Comments: 672
2094. KEEPEROFTHEGATE (Mod)
i see things movin along nicly steady as she goes
Member Since: July 15, 2006 Posts: 163 Comments: 52096
2093. Dialady
Excited that hurricane season has finally begun. Was beginning to wonder if El Nino had walked off with all the hurricanes . . LOL

Looking forward to the excellent discussion on this blog!
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Quoting drg0dOwnCountry:
There is also a small trend from the south to ana.
Both ana and bill seem to feed from this scattered storm area.
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Quoting Weather456:


still a little difficult for me to say, but if bill is expected to go out sea, the storm would have to swerve nw and continue. The storm is approaching the critical 40-45W point.



ok
Member Since: May 21, 2006 Posts: 5089 Comments: 114024
2090. Dakster
Quoting WeatherStudent:


Evening Mr. W,

Sir, please, for the love of God, you do not have to justify your professional meteorological credentials to the dispecable redundant needs of absolutely no one on here. You demonstrate those impreccable credentials of yours on here, every single day with your exceptional tropical outlooks. Unfortunately speaking, the predominant conundrum here appears to be that they're are certain bloggers that are very much jealous and envious of your skills, and that would basically have to be about it. That was my two cents worth right there. Talk about a sour dousage of inferiority and superiority complex, geeze. :)


OMG!! Where's weatherstudent? What did you do with him? A very professional post. I almost had to pull out a dictionary too!
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Looks like Ana still going west. Convection seems to expanding northwest.
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Quoting Funkadelic:
Hey has anyone noticed the North West Jog in Ana in th last couple frames?? Sign of her getting stronger possibly...

Take a look:

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

Consider me the "Jog investigator" lol I will keep everyone up to date with the latest jogs/movements that may alter the track.


My eye is untrained, but on the loop, you can see a small "eye" right over the forecast point, then it disappears. I am not sure that it did a NW jog as much as there was a burst in convection while the defined "eye" retreated.
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the new T # is in


DATE/TIME LAT LON CLASSIFICATION STORM
15/2345 UTC 11.4N 35.2W T2.5/2.5 BILL -- Atlantic
15/2345 UTC 14.5N 50.8W T2.0/2.0 ANA -- Atlantic
15/2345 UTC 25.7N 82.9W T1.0/1.0 INVEST -- Atlantic
Member Since: May 21, 2006 Posts: 5089 Comments: 114024
Quoting Funkadelic:
Hey has anyone noticed the North West Jog in Ana in th last couple frames?? Sign of her getting stronger possibly...

Take a look:

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

Consider me the "Jog investigator" lol I will keep everyone up to date with the latest jogs/movements that may alter the track.


Looks to be a blowup of convection thats deceiving, not a real jog.
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hmmmmm!!!! seems the blog is filling up with a lot of nonsense talk are forgetting the real reason for this blog, lets get serious guys these storms/hurricane affect people lives, ok!! most come to the blog to get information that would assist them in knowing what to expect, so lets keep the nonsense talk to a minimum, thanks.
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2083. sngalla


Looks like the area around the Keys may be a invest soon.

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2082. 7544
every jog these two take will count at the end
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Quoting Funkadelic:
Hey has anyone noticed the North West Jog in Ana in th last couple frames?? Sign of her getting stronger possibly...

Take a look:

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

Consider me the "Jog investigator" lol I will keep everyone up to date with the latest jogs/movements that may alter the track.

Dvoraks show her strengthening over the last 4 hours.
Member Since: Posts: Comments:
2080. 996tt
Quoting Funkadelic:
Hey has anyone noticed the North West Jog in Ana in th last couple frames?? Sign of her getting stronger possibly...

Take a look:

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

Consider me the "Jog investigator" lol I will keep everyone up to date with the latest jogs/movements that may alter the track.


I thin eye is still exposed in the lower west quadrant. Eye seems to be going pretty steady and remaining exposed. Convection giving it an appearance of Northern jog.
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2079. A4Guy
I previously posted about how much can change in 5-10 days with the models...so I'll preface my comment with: "at this moment..." the models for Ana continue to trend south....while the ones for Bill start a curve well before the coast. Let's see how it plays out.
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Quoting CJ5:


Actually, you are right and I was wrong. I meant .2 N but after relooking at the latest coordinates it is .2S. I should have check coordinates than going by eye balling it..lol
I always check previous coordinates on the storms archive usually 12 hours before the previous. I checked 5am and 5 pm for that.
Member Since: October 9, 2008 Posts: 0 Comments: 8242
Quoting CatastrophicDL:

Hey Storm! You're one of the bestest mets on here :o) I appreciate all your updates. You are the only blogger I read regularly!


Agree 100%
Member Since: August 14, 2007 Posts: 0 Comments: 435
2076. Dakster
StormW - What is higher than a MET. I think that you have always been right on the money with the forecasts and the REASONS why you think so. You are always ahead of the NHC releases and last year you proved yourself even when you didn't have to.

Besides, I would think being a Master Chief makes you that much MORE.... Just my two cents.

And yes, Dr. Masters is very good as well as the NHC forecasters, this isn't meant to take anything away from them AT ALL. Just that StormW has been able to put together a good forecast without waiting for them to release theirs!

I do enjoy the bantering back and forth on this blog and the weather discussion that you just don't get on the NHC site. Plus you have to wait at least 3 hours to get anything additional!
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Quoting Tazmanian:



456 if it keeps doing that then there no way that bill will go out too sea then right???


still a little difficult for me to say, but if bill is expected to go out sea, the storm would have to swerve nw and continue. The storm is approaching the critical 40-45W point.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Latest Dvorak:

15/2345 UTC 11.4N 35.2W T2.5/2.5 BILL
15/2345 UTC 14.5N 50.8W T2.0/2.0 ANA
Quoting stormhank:
so is florida off the hook as far as bill is concerned?? i see models trending more north at end of runs??


Florida's still VERY much in the threat.
The models had the system in the Caribbean yesterday, but may I add only the ECMWF (which underestimates the speed of Bill and as jeff Masters stated the position is to far north) and the GFS take it out to sea, GFDL, HWRF, CMC, NOGAPS, arent on that boat.

Also its interesting to note for those who read Jeff's post how Bill consolidated farther south than expected made all those that indicated a more northen movement inaccurate.
Member Since: August 10, 2009 Posts: 3 Comments: 672
From the NHC.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SAT AUG 15 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM ANA...LOCATED ABOUT 735 MILES EAST-SOUTHEAST OF THE LEEWARD
ISLANDS...AND ON TROPICAL STORM BILL...LOCATED ABOUT 820 MILES
WEST-SOUTHWEST OF THE CAPE VERDE ISLANDS.

1. A LARGE AREA OF CLOUDINESS AND THUNDERSTORMS OVER THE SOUTHEASTERN
GULF OF MEXICO IS PRIMARILY ASSOCIATED WITH A TROPICAL WAVE
INTERACTING WITH A MID- TO UPPER-LEVEL TROUGH. THIS ACTIVITY HAS
BECOME A LITTLE MORE CONCENTRATED OVER THE SOUTHEASTERN GULF OF
MEXICO WHERE SURFACE PRESSURES ARE BEGINNING TO FALL. THERE ARE NO
SIGNS OF A SURFACE CIRCULATION AT THIS TIME AND ANY ADDITIONAL
DEVELOPMENT...IF ANY...SHOULD BE SLOW TO OCCUR. THIS SYSTEM SHOULD
MOVES TOWARD THE NORTHWEST OVER THE EASTERN GULF OF MEXICO ON
SUNDAY. THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS
SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

Member Since: August 9, 2009 Posts: 10 Comments: 4498
Quoting Funkadelic:
Hey has anyone noticed the North West Jog in Ana in th last couple frames?? Sign of her getting stronger possibly...

Take a look:

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

Consider me the "Jog investigator" lol I will keep everyone up to date with the latest jogs/movements that may alter the track.
very slight, ur eye is playing trick because of the burst of convection
AL 02 2009081600 BEST 0 144N 507W 35 1004 TS



AL 03 2009081600 BEST 0 112N 359W 35 1004 TS
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Reference Bill – would a stronger storm move west or would a stronger storm move more NW or curve more away from US, and would that also apply to Ana?
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Quoting StormW:


No problem...there's still quite a few that will give you that impression. But if you rad my 3:30 pm update, and notice what I say about the forecast track, the NHC basically followed suit on the 5:00 p.m. advisory

Hey Storm! You're one of the bestest mets on here :o) I appreciate all your updates. You are the only blogger I read regularly!
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Stormdude,

The only thing I can see that is hopeful is the dry air to the immediate North of Barbados, that may impede A BIT.

But, that seems to be fast diminishing, unfortunately.

I know that the models have very often been right, but can we really say that they have previously initialised 'low latitude' storms well? I have a suspicion not.

We shall see.

Could this be another Ivan?
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Quoting Weather456:
Bill moving slighty south of due west




456 if it keeps doing that then there no way that bill will go out too sea then right???
Member Since: May 21, 2006 Posts: 5089 Comments: 114024

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.