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 weathermanwannabe:
Good Morning Folks. Just got home to Tallahassee area last night after a Family road trip up the Eastern Seaboard (DC/Boston/Roanoke/Charleston), no rain for the entire last seven days on road (a little bit in Boston on Thursday), and, come back to a surprise TD/TS heading up my way. Was TD 4 forecasted at all by the models?


not really, I think the ECMWF had hints ogf a system at times but defintely not really in the long range. It came out of the tropical wave that came from Africa and merge with a upper trough and found a sweet spot off FL.
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Quoting IKE:


Looks like that may be happening.


You mean it is going more to the West?
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Quoting MandyFSU:
hurricanemaniac: IP ban is where the powers that be prohibit your IP address (your internet dial in) from being allowed on the site.


Thanks!
Member Since: Posts: Comments:
It's a legit question Funky.



What are the chances this thing could slow down and skim the coast line westward?"

Here's what NWS Mobile says this a,m,


NOTE: THE DEPRESSION IS BEING STEERED BY A LOW/MID LEVEL RIDGE THAT
IS NOSING WESTWARD INTO THE SOUTHEAST. IF THE RIDGE STRENGTHENS MORE
THAN CURRENTLY FORECAST...LANDFALL COULD OCCUR MORE TO THE WEST.
STAY TUNED TO THIS FAST EVOLVING SITUATION. /10
Member Since: Posts: Comments:
170. IKE
Quoting futuremet:
WS will never be gone, he'll just keep creating other accounts.

other accounts (that I know of)

JFV
Keywestman
presidentialelection
Weatherstudent


Why can't he be IP banned?
Member Since: Posts: Comments:
wannabe: I didn't see any models predict it lol. Lots of the good folks on here did though.

I'm in Tally too. Gonna do everything early today to avoid the rain :)
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168. IKE
Quoting PensacolaDoug:
Morning Discussion out of Mobile. ( Make sure you read the NOTE at the end.

SHORT TERM [TODAY AND TONIGHT]...A VERY INTERESTING AND BUSY SHIFT
TO SAY THE LEAST. WE NOW HAVE TROPICAL DEPRESSION 4 ON OUR HANDS
OVER THE EASTERN GULF...ABOUT 90 MILES WEST SOUTHWEST OF TAMPA FLORIDA.
THIS TROPICAL DEPRESSION HAS FORMED FROM A VIGOROUS MID LEVEL
VORTICITY MAXIMUM ALONG A TROPICAL WAVE THAT MOVED THROUGH THE
FLORIDA STRAITS 24 HOURS AGO. THE UPPER LOW THAT WAS IMPEDING ANY
DEVELOPMENT ALONG THE WAVE AXIS OVER THE PAST SEVERAL DAYS HAS MOVED
WESTWARD ACROSS THE YUCATAN PENINSULA. THE MID LEVEL ENERGY BECAME
DETACHED AND HAS MOVED INTO A MORE FAVORABLE UPPER AIR ENVIRONMENT AS
AN UPPER LEVEL ANTICYCLONE HAS FORMED OVER THE DEPRESSION.
CONSIDERING THIS...ALONG WITH WARM SST`S OVER THE GULF WATERS (MID
80S) AND THE CONVECTION PRESENTLY DEVELOPING/ORGANIZING AROUND THE
CENTER...THE NATIONAL HURRICANE CENTER IS CALLING FOR STRENGTHENING
TO STORM STATUS PRIOR TO LANDFALL TONIGHT OVER THE FL PANHANDLE.
THESE DEVELOPMENTS NECESSITATE AN UPWARD ADJUSTMENT TO THE WINDS IN
THE NEAR TERM. GIVEN THE PRESENT SMALL SIZE OF THE DEPRESSION AND THE
LIMITED AMOUNT OF RESIDENCE TIME FOR GROWTH AND EXPANSION OF THE WIND
RADII ENVELOPE OVER THE GULF WATERS...FORECAST WIND SPEEDS WILL BE A
CHALLENGE. WE EXPECT THE HEAVIER RAINS TO FALL EAST OF THE FORECAST
AREA...CLOSER TO AND EAST OF WHERE THE CENTER IS CURRENTLY FORECAST
TO MAKE LANDFALL. GIVEN THE OFFICIAL FORECAST BY THE NATIONAL
HURRICANE CENTER...A TROPICAL STORM WARNING IS IN PLACE FROM THE
AL/FL BORDER EASTWARD. RIP CURRENT RISK WILL BE ON THE INCREASE AS
WELL.

NOTE: THE DEPRESSION IS BEING STEERED BY A LOW/MID LEVEL RIDGE THAT
IS NOSING WESTWARD INTO THE SOUTHEAST. IF THE RIDGE STRENGTHENS MORE
THAN CURRENTLY FORECAST...LANDFALL COULD OCCUR MORE TO THE WEST.
STAY TUNED TO THIS FAST EVOLVING SITUATION. /10


Looks like that may be happening.
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Bill is definitely moving WNW.

Bill appears to be moving West, at this time...Link
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TD4 now forcasted to go up to 50 kts.
Member Since: August 10, 2009 Posts: 3 Comments: 672
Right, first set of advisories out.

No upgrade to TS, they're waiting for the Recon team. Be interesting to see what they find.
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hurricanemaniac: IP ban is where the powers that be prohibit your IP address (your internet dial in) from being allowed on the site.
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No TS at 11, likely at 2 PM though.
Member Since: August 10, 2009 Posts: 3 Comments: 672
WS will never be gone, he'll just keep creating other accounts.

other accounts (that I know of)

JFV
Keywestman
presidentialelection
Weatherstudent
Member Since: Posts: Comments:
Quoting CaptainTomato:


Anyone who has to tout their own self, is clearly not worth the ink they write with. I didn't even notice your writing so I can't speak for the veracity of what you said - however, if you really had any value, others would say it for you. If you were right, remember , even a blind squirrel finds a nut once in a while.

There are way too many egotistical dopes on here - completely diminishing the value of anything said on this site. personally, my advice is to listen to what you hear on here, look at the data yourself and make up your own mind. Don't bother trying to convince others how smart you are because that only PROVES your lack of intelligence.


Amen. You never hear Dr. Masters, Storm and most of the other heavyweights on here say "I was right."

Those who DO constantly pat themselves on the back, especially with little work apparent behind their original "forecast," end up on my ignore list. It's self-centered and childish to be giving yourself the kudos rather than graciously accepting them from others.
Member Since: Posts: Comments:
Good Morning Folks. Just got home to Tallahassee area last night after a Family road trip up the Eastern Seaboard (DC/Boston/Roanoke/Charleston), no rain for the entire last seven days on road (a little bit in Boston on Thursday), and, come back to a surprise TD/TS heading up my way. Was TD 4 forecasted at all by the models?
Member Since: Posts: Comments:
Quoting extreme236:


60MPH, thats 50 knots.


Well, this indicates that abundant inflow is feeding claudette from all channels. Ana upper level anticyclone is also helping diverging the air at the upper levels. Radar imagery shows the COC is well embedded within the convection mass.
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Next set of advisories should be coming out soon.
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Re:148


You're welcome!
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Quoting sporteguy03:



Ike, just want to check the Florida Panhandle did not get annexed to Alabama did it? :)
Alabama has insalled their forcefield. Nothing from FL gets in...LOL Well We will open the door for IKE
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Quoting extreme236:


Would be awesome if it were an IP ban.


I have a question, What's an IP ban?
Member Since: Posts: Comments:
Quoting hahaguy:


That's it you're gone.

he's been gone for a few day for me.... especially after his posts were it looked like he was either just woken up, been on the drink all night or both
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Quoting Cotillion:


Uhh, yes.

Thanks for the correction.


No problem...thats a common mistake people make so just wanting to make sure everyone knew/remembered :)
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Thanks, P'cola Doug! :)
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Thanks for the update Dr.M, will be watching TD4/Claudette whatever she may turn out to be. Have a great day all.
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"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."

Seems like only yesterday we were discounting the ECMWF because it was an outlier.
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in my personal opinion, i still dont see bill being a fish storm, despite the models. i mean, just yesterday, every model was forecasting a caribbean storm.

i think the high is going block most northward movement and the trough/cold front is not going to be strong enough or dip south enough to pull bill out to sea. i have to agree with kman's forecast with bill.
Member Since: Posts: Comments:
Morning Discussion out of Mobile. ( Make sure you read the NOTE at the end.

SHORT TERM [TODAY AND TONIGHT]...A VERY INTERESTING AND BUSY SHIFT
TO SAY THE LEAST. WE NOW HAVE TROPICAL DEPRESSION 4 ON OUR HANDS
OVER THE EASTERN GULF...ABOUT 90 MILES WEST SOUTHWEST OF TAMPA FLORIDA.
THIS TROPICAL DEPRESSION HAS FORMED FROM A VIGOROUS MID LEVEL
VORTICITY MAXIMUM ALONG A TROPICAL WAVE THAT MOVED THROUGH THE
FLORIDA STRAITS 24 HOURS AGO. THE UPPER LOW THAT WAS IMPEDING ANY
DEVELOPMENT ALONG THE WAVE AXIS OVER THE PAST SEVERAL DAYS HAS MOVED
WESTWARD ACROSS THE YUCATAN PENINSULA. THE MID LEVEL ENERGY BECAME
DETACHED AND HAS MOVED INTO A MORE FAVORABLE UPPER AIR ENVIRONMENT AS
AN UPPER LEVEL ANTICYCLONE HAS FORMED OVER THE DEPRESSION.
CONSIDERING THIS...ALONG WITH WARM SST`S OVER THE GULF WATERS (MID
80S) AND THE CONVECTION PRESENTLY DEVELOPING/ORGANIZING AROUND THE
CENTER...THE NATIONAL HURRICANE CENTER IS CALLING FOR STRENGTHENING
TO STORM STATUS PRIOR TO LANDFALL TONIGHT OVER THE FL PANHANDLE.
THESE DEVELOPMENTS NECESSITATE AN UPWARD ADJUSTMENT TO THE WINDS IN
THE NEAR TERM. GIVEN THE PRESENT SMALL SIZE OF THE DEPRESSION AND THE
LIMITED AMOUNT OF RESIDENCE TIME FOR GROWTH AND EXPANSION OF THE WIND
RADII ENVELOPE OVER THE GULF WATERS...FORECAST WIND SPEEDS WILL BE A
CHALLENGE. WE EXPECT THE HEAVIER RAINS TO FALL EAST OF THE FORECAST
AREA...CLOSER TO AND EAST OF WHERE THE CENTER IS CURRENTLY FORECAST
TO MAKE LANDFALL. GIVEN THE OFFICIAL FORECAST BY THE NATIONAL
HURRICANE CENTER...A TROPICAL STORM WARNING IS IN PLACE FROM THE
AL/FL BORDER EASTWARD. RIP CURRENT RISK WILL BE ON THE INCREASE AS
WELL.

NOTE: THE DEPRESSION IS BEING STEERED BY A LOW/MID LEVEL RIDGE THAT
IS NOSING WESTWARD INTO THE SOUTHEAST. IF THE RIDGE STRENGTHENS MORE
THAN CURRENTLY FORECAST...LANDFALL COULD OCCUR MORE TO THE WEST.
STAY TUNED TO THIS FAST EVOLVING SITUATION. /10
Member Since: Posts: Comments:
Quoting extreme236:


Thats 60 MPH.


Uhh, yes.

Thanks for the correction.
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Quoting HurricaneKyle:
JFV.. er PresidentalElection.. er.. WeatherStudent your getting banned, hopefully IP banned. Reporting to the Admins.


Would be awesome if it were an IP ban.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
I think it would make weather ratings more interesting if there was say a Fox News type of weather channel to watch. Fair and balanced weather! LOL! No Bastardi though, that would be too over the top to keep viewers coming back. TWC is becoming a joke anymore, I listen to Dr. Lyons and beyond that, I lurk this blog for info.

Quoting mobilegirl81:

The moring show is a huge joke.
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109 Captain Tomato,, Remember there are a lots of young forecasters here...WE SHOULD ALL TRY TO UNDERSTAND THAT, and not be harsh with there statements.
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JFV.. er PresidentalElection.. er.. WeatherStudent your getting banned, hopefully IP banned. Reporting to the Admins.
Member Since: August 10, 2009 Posts: 3 Comments: 672
Thanks, Dr. Masters..

Wow!!!! Things have exploded just in the last 48 hours.
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Quoting IKE:


I reported him. He needs to be banned.


yup...I reported him as well...he has passed his expiration date...
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Quoting Cotillion:
The 12z had Bill at 50kts, 997mb.

So, 55mph.. it'll be that unless they raise it further.



Thats 60 MPH.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
I'd say we have to wait and see what BOTH Bill and Ana will do. Sure, the models are sending Bill up into the Grand Banks but I remember just a few days ago both Dr. Masters and the NHC had written off Ana due to shear that was "not forcasted." Having been through Andrew I will also always remember them telling us a nothing Tropical Depression soon to become Andrew should not be even given a second look as it will most assuredly be slingshot up into the North Atlantic. With all of the models and satellites we have it really is all dependent on timing and in some cases "luck." I don't think anyone should forget about these systems until Bill is clearing moving on a northerly track.
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Quoting futuremet:


If it is 50MPH now, then expect it to start consolidating rapidly.


60MPH, thats 50 knots.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting futuremet:


Yes, it could, but should make landfall within 36hrs



What causes the difference between the ensemble members tracks and the model forecast tracks?
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Quoting IKE:


I reported him. He needs to be banned.


Same here.
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Link

Centre of TD 4 moves N of NOAA buoy 42036.

(TD 4 centre is 50 NMi east of this bouy)
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Quoting IKE:


Yup...looks like TD4 may be moving NW. Following it on radar.....



Ike, just want to check the Florida Panhandle did not get annexed to Alabama did it? :)
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The 12z had Bill at 50kts, 997mb.

So, 55mph.. it'll be that unless they raise it further.

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twh: just looked outside. Clouds have started moving in (it was sunshiny bright an hour ago) and the breeze is still steady.
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Quoting futuremet:


?

I would think the rain from TD4 is a threat to someone
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126. IKE
Quoting hahaguy:


That's it you're gone.


I reported him. He needs to be banned.
Member Since: Posts: Comments:
Quoting extreme236:
AL, 03, 2009081612, , BEST, 0, 119N, 377W, 50, 997, TS


If it is 50MPH now, then expect it to start consolidating rapidly.
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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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