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 Babsjohnson:


I have to agree. This is a freaky storm.


thank god you cant spell, i thought it was for real!
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Quoting canesrule1:
thanks.


yw bruddah / bruddette
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Quoting nrtiwlnvragn:
Recon for TD4 just transmitted, getting ready for takeoff. Monitor at Tropical Atlantic


storm name on that transmission says ana...
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372. JRRP
i am surprised that ana is a tropical storm yet
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Quoting rxse7en:
How's the drought been in the Panhandle this year? Is TD4 going to be beneficial for you guys?

US Drought Monitor
Link
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370. auburn (Mod)
Quoting floridafisherman:
cyclone oz...

how many times are you going to post the same thing?

you are now added to my ignore list.



No disrespect..but I just logged in and it was the 1st time I had seen that post
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Good morning everyone! Right now, with all this action in the tropics, I'm frantically trying to update the CCHS Weather Center site with new analysis and information. When I'm finished updating, I will let everyone know.
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...DEPRESSION APPROACHING TROPICAL STORM STRENGTH...AIRCRAFT RECONNAISSANCE WILL INVESTIGATE SOON...

...ANA CONTINUES WESTWARD...AIRCRAFT RECONNAISSANCE TO INVESTIGATE THIS AFTERNOON...

anyone know when?
Member Since: July 29, 2006 Posts: 28 Comments: 1799
TD 4

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 16 AUG 2009 Time : 141500 UTC
Lat : 28:34:30 N Lon : 84:30:00 W


CI# /Pressure/ Vmax
2.7 /1003.0mb/ 39.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.7 3.0 3.5

Member Since: August 2, 2007 Posts: 19 Comments: 19234
Claudette could get to 60 mph. surprise surprise Bill only 7 mbs from hurricane. Ana, da plane will decide her fate.
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Quoting Funkadelic:


Consider the NOGAPS the KNOWCRAP, this model never seem's to understand steering out there. I have never given that model much attention.
LOL,me either but the NHC's heart burns with love and compassion for the Nogaps, LMAO.
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Quoting stormno:
STORMTOP SPECIAL WEATHER STATEMENT ON TROPICAL STORM CLAUDETTE..CLAUDETTE HAS CONTINUED TO BECOME BETTER ORGANIZED AND IS NOW MOVING ON A MORE NW TO WNW COURSE AND HAS SLOWED DOWN..EXPECT THE NHC TO UPGRADE THIS SYSTEM TO CLAUDETTE AS SOON AS THEY PENETRATE THE SYSTEM. WITH CLAUDETTE SLOWING DOWN AND BEING AFFECTED BY THE RIDGE ABOVE HER ITS VERY POSSIBLE CLAUDETTE HAVING A LITTLE MORE TIME OVER THE WATER DOES REACH HURRICANE FORCE..IT SEEMS TO ME LOOKING AT THE LATEST SATELLITE PICS AND LAND BASED RADARS CLAUDETTE IS BEGINNING TO PARRALELL THE FLA PANHANDLE AS SHE CONTINUES TO HAVE STRONG FEEDER BANDS DEVELOPING AROUND HER..THIS IS NOT OVER BY A LONGSHOT PEOPLE EVERYONE NEEDS TO BE ON ALERT AS FAR WEST AS HOUSTON...THIS IS A STRONG HIGH BEGINNING TO AFFECT CLAUDETTES MOVEMENT AND SPEED..I WOULD NOT BE AT ALL SURPRISED IF CLAUDETTE BECOMES STATIONARY IN THE NEXT 2-4 HOURS..PRESSURES ARE FALLING IN THE AREA....Stormno


I have to agree. This is a freaky storm.
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Ana

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 16 AUG 2009 Time : 141500 UTC
Lat : 14:45:11 N Lon : 55:33:05 W


CI# /Pressure/ Vmax
2.4 /1005.8mb/ 34.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.4 2.5 2.5
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting listenerVT:
Here in the NE we are certainly hoping that Bill will turn away from the coast.

But we are also really overdue for a strike,
as the last was Bob in 1991.
Interesting that Bob was also a "B" storm.

Family on Cape Cod and Kennebunk, Maine.
I'm all ears (and eyes).

Thanks so much for this site!


wow, those last statements were in poetic form
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Quoting winter123:
If you ask me Ana is about to dissapate. Being squashed by Bills large circulation.

Loop

yup, anyways ana looks like its a T-Wave.
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Wobble watchers unite! I see a west wobble meaning it'll stay over water a few more hours.

Member Since: July 29, 2006 Posts: 28 Comments: 1799
Quoting eye:
CAN BLOGGERS REFRAME FROM POSTING HUGE HUGE GRAPICS (ANIMATED ONES ESPECIALLY). MY COMPUTER FROZE BECAUSE OF SOME GRAPHICS SOMEONE POSTED. NOT ALL OF US HAVE SUPER COMPUTERS THAT CAN HANDLE IT. PLEASE POST AS A LINK. I HAD TO HARD RESET MY COMPUTER BECAUSE OF THAT. I BELIEVE IT WAS DCOASTER
With due respect, I actually like the graphics and animations. Often when on the road, I read this blog on a cell phone that does not support flash or java. It also takes forever to link away from the site, and then return to the blog and try to find your place on a cell phone browser.

I don't always blog on a cell phone but when I do these images animated and static make it much easier at least for me.
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Is it strange that the NHC keeps Ana as a TD into the Gulf on the five-day forecast? After watching TD4 spin up, I would think that anything entering the Gulf has greater potential, no? Of course, they could be predicting some high shear that I just didn't see.
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.
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Funny thing is, even though the EURO is pretty dang good IMO, none of models predicted TD4 forming. Guess we still have awhile before we can accurately predict rapidly forming storms.
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is it possible ana formed a new center a little north and east of it old center. Looking ad the IR, it seems the energy transfers and it looks like a new center formed... anyone else see this?
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If you ask me Ana is about to dissapate. Being squashed by Bills large circulation.

Loop

Member Since: July 29, 2006 Posts: 28 Comments: 1799
Quoting troy1993:
Is it possible that Bill can hit the Northeast?


yes it is possible now here the key 1st i want too see where bill startes make his turn out too sea or if he dos snd that will be the key all so the forcast track has it off the coast of NJ SC and NC so if the high comes back in then watch out
Member Since: May 21, 2006 Posts: 5091 Comments: 115257
Link

TD 4 moving WNW just to the SE NOAA bouy 42036...winds came up fast....
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Quoting rxse7en:
How's the drought been in the Panhandle this year? Is TD4 going to be beneficial for you guys?


Tallahassee, in the Big Bend of Florida, has received plenty of rain this year. A little rain today will be welcomed although if she moves too far west today, we may not even get much rain.
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cyclone oz...

how many times are you going to post the same thing?

you are now added to my ignore list.

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Quoting serialteg:


the discussion clearly states its a trough (whatever the correct spelling is) coming down from conus i believe
thanks.
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looks like panama city is the target, too early to tell
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Ike, you still around? Check out the latest radar loop. Appears that the center is headed on a WNW course at the moment.

Link
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It's a shame that all the rain storms seem to be along the east coast when the west coast really needs it.
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Here in the NE we are certainly hoping that Bill will turn away from the coast.

But we are also really overdue for a strike,
as the last was Bob in 1991.
Interesting that Bob was also a "B" storm.

Family on Cape Cod and Kennebunk, Maine.
I'm all ears (and eyes).

Thanks so much for this site!
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Quoting canesrule1:
Can someone please tell me what will make Bill curve, and didn't stormW say the high was going to build more westward or something.


the discussion clearly states its a trough (whatever the correct spelling is) coming down from conus i believe
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Quoting taco2me61:


There is a strong front coming down towards the east coast and could pull Bill up the ecoast and of make him a fish storm....

Taco :0)
thanks a lot.
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335. IKE
Quoting rxse7en:
How's the drought been in the Panhandle this year? Is TD4 going to be beneficial for you guys?


Inland Florida panhandle...no drought here.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting hurricane23:
Thankfully its all bark no bite so far this season. A few weak td's which could be rain producers and mighty bill should stay out to sea.

Adrian


So far! The persistence of the dry air across the Eastern Atlantic may well up the ante for the Gulf as tropical energy struggles to bundle and travels further west with the low level flow.
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Recon for TD4 just transmitted, getting ready for takeoff. Monitor at Tropical Atlantic
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Quoting willdunc79:
I have to agree with the others who post and are thinking that Bill is going to curve and go out to sea. Bill will keep strengthening and will curve and go out to sea. Bill may have some type of effect(s) on Bermuda (maybe rain and wind or either one) but Bill is going to curve and miss the lower 48 states JMHO.


If Bill is huge, won't that keep it from turning?
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Quoting Funkadelic:


Im just messin with you, but if you look at the newer models you should be able to see that Miami is fine. And all the kiddies go back to school finally on te 24th! (Well my son goes back the 24th at least)
yup, and i go back to work, ughhhh, I will be posting after 3:30-ish (when i get out) but i did see a southward shift with the Nogaps, why did the NHC have it curving so early?
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Quoting canesrule1:
Can someone please tell me what will make Bill curve, and didn't stormW say the high was going to build more westward or something.


There is a strong front coming down towards the east coast and could pull Bill up the ecoast and of make him a fish storm....

Taco :0)
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If you look at the lates IR images Bill is moving to the west again. Looks like the center just relocated over night. Remember IR images can be decieving in terms of location of the llc. I think Bill will eventually recurve but not so soon as the models are predicting. Let's remember FRANCES was suppose to recurve!!
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327. Relix
Ana has a moisture band in front of her that's fighting the dry air it seems. She's moving WNW, IMO. I am still sticking to this. I'll just log off and come later. Too tired :p
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Is it possible that Bill can hit the Northeast?
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Quoting Babsjohnson:


I agree. If she does a loop, I would not be surprised.


im really confused...exactly what radar are you watching....cause panama city yes...pensacola...no way...fort walton beach is as far west as she is land falling and i still think it'll be closer to panama city...unless shes pushed on alot harder by the high..
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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.