Ana and TD 3 take aim at the Lesser Antilles

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

Share this Blog
7
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1814 - 1764

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97Blog Index

8:00 PM AST Sat Aug 15
Location: 14.4°N 50.4°W
Max sustained: 40 mph
Moving: W at 17 mph
Min pressure: 1004 mb Per the NHC
Member Since: Posts: Comments:
1813. HadesGodWyvern (Mod)
Japan Meteorological Agency

Tropical Disturbance Summary (1800z 15AUG)
=========================================
SUBJECT: Tropical Depression Near Marshall Island

At 3:00 AM JST, Tropical Depression, Former Maka (1008 hPa) located at 14.6N 173.2E has 10 minute sustained winds of 30 knots with gusts of 50 knots. The depression is reported as moving north-northwest at 6 knots
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting palmbaywhoo:
so much for stormw's guess at ana being dead


You can say a lot of things about StormW... but to say he "guessed" is not one of them.
Poof
Member Since: October 1, 2007 Posts: 81 Comments: 26516
OBSERVATION #7
IF YOU DO NOT UNDERSTAND THIS PLEASE VISIT THIS LINK: Link


UZNT13 KWBC 152315
XXAA 65231 99165 70504 04260 99012 26824 ///// 00106 26021 09025
92790 21214 10030 85521 18229 10036 70163 09217 10538 50588 05356
07523 40760 16350 07523 30971 30950 09016 25097 41361 17513 20245
53561 16521 15425 643// 19502 88999 77999
31313 09608 82251
61616 NOAA9 WX02A ANA OB 07
62626 SPL 1655N05053W 2306 LST WND 017 MBL WND 09026 AEV 20801 DL
M WND 10520 010145 WL150 09024 091 REL 1653N05043W 225114 SPG 165
5N05053W 230614 =
XXBB 65238 99165 70504 04260 00012 26824 11914 20613 22850 18229
33803 15826 44761 14060 55731 11857 66717 11062 77695 08812 88678
08456 99660 07029 11652 06858 22646 06250 33622 04460 44611 03856
55581 01862 66554 00763 77541 02356 88532 03158 99527 03549 11478
07948 22471 08356 33462 09167 44450 10538 55445 11129 66415 13958
77405 15545 88395 16757 99383 18122 11351 22350 22329 25758 33303
30156 44267 37356 55242 43164 66224 47750 77194 55162 88170 619//
99145 65150
21212 00012 ///// 11010 09023 22975 09528 33850 10036 44651 10545
55599 08537 66514 08528 77433 06019 88414 08021 99381 08016 11359
06512 22314 10011 33290 09013 44265 13506 55255 17510 66231 19514
77206 16021 88182 16527 99170 15034 11160 18007
31313 09608 82251
61616 NOAA9 WX02A ANA OB 07
62626 SPL 1655N05053W 2306 LST WND 017 MBL WND 09026 AEV 20801 DL
M WND 10520 010145 WL150 09024 091 REL 1653N05043W 225114 SPG 165
5N05053W 230614 =


Member Since: Posts: Comments:
swfl low is starting to close off its center, question is does it have enough room to intensify before landfall.... Hope not...
Member Since: Posts: Comments:
Quoting caneluver:


Where do these people come from?


Basements. If I remember correctly coffee was on here last year and called out Gustav too.
Member Since: Posts: Comments:
Quoting coffeecrusader:
BILL WILL BE A FISH STORM. HERE FISHY FISHY!!!!

sure hope so
Member Since: Posts: Comments:

ANA

TD3

AOI
Member Since: October 1, 2007 Posts: 81 Comments: 26516
1804. HadesGodWyvern (Mod)
Japan Meteorological Agency

Tropical Disturbance Summary (1800z 15AUG)
=========================================

At 3:00 AM JST, Developing Low, Former Tropical Depression Etau (1000 hPa) located at 43.0N 179.0E is reported as moving east at 40 knots

FINAL FROM WWJP25

---
On its way to Alaska.
Member Since: Posts: Comments:
so much for stormw's guess at ana being dead
Member Since: Posts: Comments:
1802. BrandiQ
Quoting WeatherStudent:
True, Phil and his old meteorological antics. Got to love em'. Are you from here?


Yep Yep. I hope we will be spared this year...
Member Since: Posts: Comments:
1801. palmpt
Quoting Bailey1777:
I personally would not be suprised to see Ana's small size help her navigate through and into the GOM intact. I think she will be the story next week.


...and what happens when Ana gets inthe Gulf?!
Member Since: Posts: Comments:
Category5hitsNewYork has made a prediction in the Tropics Chat.

This is his warning, up to date info.

Ana is starting to cook up in the Atlantic. He predicts a landfall in the Miami area at Category 2 on around the 20th or 21st. It will then recurve and hit either Mobile or Tampa.

Bill, will become the monster of August, becoming a category 4 and hitting Charelston or Savannah on the 25th. It will be a Ghost of Hugo as he states.

One thing is certain, be prepared!!!

Join the tropics chat for one to track the storm and save lives!
Member Since: Posts: Comments:
1799. Patrap
NEXRAD Radar
Key West, Echo Tops Range 124 NMI


Member Since: July 3, 2005 Posts: 428 Comments: 129903
I'm no meteorologist, but if I had to say it based on current conditions and computer model trends, I am thinking Ana is feeling the pull of the dry air, thus keeping a more general west track.

I also noticed that upper level low feature to the northwest of both of these systems. So, this would suggest a weakness in the strong Bermuda high.

I think Bill will feel this weakness and follow the path where more moisture and less resistance exists. Resulting in and more northwest direction?
Member Since: Posts: Comments:
Quoting hurricane23:
new GFDL is south with ana it kills it near the caymans.
Before it reaches us I hope.
Member Since: Posts: Comments:
Quoting MeterologistDewon9:
Must say tjat WSVN has an impressive weather lab and weather broadcasting software
I agree
Member Since: Posts: Comments:
Quoting hurricane23:
new GFDL is south with ana it kills it near the caymans.
If the Nogaps kills it, the NHC will kill it, lets keep on waiting.
Member Since: Posts: Comments:
Must say tjat WSVN has an impressive weather lab and weather broadcasting software
Member Since: Posts: Comments:
Quoting CaneWarning:


I think when he said "we" I think he just meant our area.


Oh im sorry, I thought you meant Florida as a whole. But he's wrong about Ana.
WS, coffeecrusader, jrweatherman, I'll tell you this if you think Florida is in the clear a week in a half out with a storm this southern in latitude your mistaken. The point is you should have been prepared regardless. I'm not wishcasting it to hit Florida, people that assume I am are greatly, greatly either paranoid or in obsessive denial. Right now the Islands are in a great threat from Bill and they need to watch it in the short term.
Member Since: Posts: Comments:
Quoting flsky:

grosero adj (=descortés) rude
(=ordinario) coarse, vulgar
(=tosco) rough, loutish
(=indecente) indelicate

Again - please go away.



Been watching for a while now .... all you seem to do is cut on others ... heres a thought...why dont you go away ... that is unless your the blog police.
Member Since: Posts: Comments:
Quoting coffeecrusader:
BILL WILL BE A FISH STORM. HERE FISHY FISHY!!!!
Umm ok
Member Since: Posts: Comments:
new GFDL is south with ana it kills it near the caymans.
Member Since: Posts: Comments:
1787. Drakoen
Yesterday the GFS had this big ridge and now it has a big trough. I don't know how anyone can say with certainty that they are safe.
Member Since: October 28, 2006 Posts: 57 Comments: 30833
1785. CJ5
Quoting CJ5:
It appears the lower level clounds of Ana are starting to consolidate more...perhaps in a few more hours she can cover herself up.


Well back after my sons first football game and quoting myself...lol

It appears that the convection has covered the coc on Ana now. Lets see if she can hold it for a whole 24 hrs this time.
Member Since: Posts: Comments:
Quoting RyanFSU:
18Z HWRF takes Bill to Category 5, as it does with every storm over water that is at least 26C, and sometimes that doesn't even stop it.


Wow! That's some monster Category 5.
Member Since: Posts: Comments:
About 5 hours old, but I would think 60MPH at 11PM
Member Since: Posts: Comments:
1782. Patrap
NEXRAD Radar
Key West, Base Reflectivity 0.50 Degree Elevation Range 248 NMI

Member Since: July 3, 2005 Posts: 428 Comments: 129903
I personally would not be suprised to see Ana's small size help her navigate through and into the GOM intact. I think she will be the story next week.
Member Since: Posts: Comments:
Quoting WeatherStudent:


Wasn't that the same idiot that said the complete opposite yesterday? WOW!!! He should be stripped from his AMS entitlement. Geeze, it's people like that why the word ''complecency'' exists.


No, we have more than one met...
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting canesrule1:
LMAO


WSVN is the most sensationalist news station in south florida! oh how i miss south florida...
Member Since: Posts: Comments:
Quoting jrweatherman:
It is still too early to say what will happen with Bill.

I can tell you that Fl is safe with Bill. Everything is coming into place for that right turn to the north. The question is, will Bill curve back to the NE or drive into the Carolinas or up the NE coast.


If you think Florida's in the clear your mistaken. Everything shifts massively, heck Ike was at one point forcasted to hit SFL as a Category 4/5 and Dean was going to go north of the Islands for quite a few advisorys.
Member Since: Posts: Comments:
BILL WILL BE A FISH STORM. HERE FISHY FISHY!!!!
Member Since: Posts: Comments:
Quoting HurricaneKyle:


Your local met hasn't a clue then or he has a crystal ball to determine that. No one wants a storm to hit them, I don't especially after Charley Frances Jeanne and Wilma. Right now the NHC has Bill right or just north of the Islands and Ana as a strong TS in the gulf. This will all change over time of course.


I think when he said "we" I think he just meant our area.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
1774. fire635
Quoting CaneWarning:
Local met says we don't need to worry about either of these storms. Ana will probably be very weak, while Bill should curve out to sea.


Local met is an idiot then... WAAY to early to start telling people theres nothing to worry about
Member Since: Posts: Comments:
1773. RyanFSU
Just to see the progression of GFS forecasts during the past 21-forecast cycles -- I put together the wind swaths in a handy animation. GFS has been consistent -- which means absolutely nothing in itself.

Member Since: Posts: Comments:
Quoting TampaMishy:
So you think anything is possible with Bill?


sure...even though recent guidance are trending away from the southeast/eastcoast confidence in the long-term forecast is quite low.
Member Since: Posts: Comments:
Quoting CatastrophicDL:
Hey Cane! They may bring a little rain and perhaps some lightning to your area :o)


I doubt it!
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting KATRINABILOXIGIRL:
well let's pray neither of us have to worry about any of these entities...good luck and be safe
Same to you.
Member Since: Posts: Comments:
Thanks for adding the radar PaTrap, been watching it for a while.... Havent figured how to post like that yet...
Member Since: Posts: Comments:
1766. jdjnola
Quoting DestinJeff:


Ana looks to be fending off the dry air to her west fairly well...you can see moisture increase near center as well as on the western flank


Yikes the dry air is clearing out, save the dry air to Ana's west. This is why I don't trust the models. Most of them killed off Ana, yet she's a TS and after tonight's Dmax... our last hope is shear or land. Even still, I'm not sure those are enough. She's like a Phoenix rising from the ashes, and we've even named her. Like a human, what doesn't kill her only makes her stronger...?
Member Since: Posts: Comments:
Quoting CaneWarning:
Local met says we don't need to worry about either of these storms. Ana will probably be very weak, while Bill should curve out to sea.


Your local met hasn't a clue then or he has a crystal ball to determine that. No one wants a storm to hit them, I don't especially after Charley Frances Jeanne and Wilma. Right now the NHC has Bill right or just north of the Islands and Ana as a strong TS in the gulf. This will all change over time of course.
Member Since: Posts: Comments:
Quoting CaneWarning:
Local met says we don't need to worry about either of these storms. Ana will probably be very weak, while Bill should curve out to sea.
Hey Cane! They may bring a little rain and perhaps some lightning to your area :o)
Member Since: September 3, 2007 Posts: 3 Comments: 1519

Viewing: 1814 - 1764

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97Blog Index

Top of Page

About

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

Local Weather

Overcast
33 °F
Overcast

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron