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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675. IKE
Quoting TStormSC:
OK Ike, go empty the rain gauge and keep us up to date. How 'bout grabbing that lady and sending some rain NE.


See what I can do for you.

Claudette is about to go west of Apalachicola latitude.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Are the models going off a NNW movement or NW movement on Claudettes landfall?
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Frist signs of Ana, mid-level altocumulus clouds overhead

stormwatch,

if she continues to sustain that convection, then I would say comback, not right now though
Member Since: July 24, 2005 Posts: 407 Comments: 19076
8o 3rd named storm!

...DEPRESSION BECOMES TROPICAL STORM CLAUDETTE...

DATA FROM THE NOAA DOPPLER RADAR IN TALLAHASSEE FLORIDA INDICATE
THAT SURFACE WINDS ASSOCIATED WITH THE DEPRESSION HAVE INCREASED TO
40 MPH...65 KM/HR...MAKING THE DEPRESSION TROPICAL STORM CLAUDETTE.
DETAILS WILL FOLLOW IN THE 2 PM EDT INTERMEDIATE ADVISORY.

Member Since: Posts: Comments:
Reloads every 5 minutes:
Quoting Weather456:


000
WTNT64 KNHC 161616
TCUAT4
TROPICAL STORM CLAUDETTE TROPICAL CYCLONE UPDATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
1215 PM EDT SUN AUG 16 2009

CORRECTED FOR ISSUANCE TIME

...DEPRESSION BECOMES TROPICAL STORM CLAUDETTE...

DATA FROM THE NOAA DOPPLER RADAR IN TALLAHASSEE FLORIDA INDICATE
THAT SURFACE WINDS ASSOCIATED WITH THE DEPRESSION HAVE INCREASED TO
40 MPH...65 KM/HR...MAKING THE DEPRESSION TROPICAL STORM CLAUDETTE.
DETAILS WILL FOLLOW IN THE 2 PM EDT INTERMEDIATE ADVISORY.

$$
FORECASTER ROBERTS/BRENNAN



Ike your Claudette has gone to 273 true last 35 minutes,around 10mph
Member Since: July 3, 2005 Posts: 426 Comments: 128874
Quoting leftovers:
taz 236 sky and others were on top of claudette from the beginning


I figured something could form here...didn't know it would happen so fast.
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Quoting IKE:


Those coordinates posted were in this area....I thought I heard an aircraft flying over.

Do they fly low enough to be heard?


I think so, I've seen them fly by in 2004.
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Quoting WatchingThisOne:


http://www.guiweather.com/kml.html



tyvm for this :D
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Quoting aquak9:


not a stupid question. I'd love to hear everyone's thoughts- many of us would.
G'morning, Aqua. Is that trough situated over Missouri now?
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Where has Floodman been?
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For Sale: Brand new set of Encyclopedia Britannica's. No Longer needed... Stormno, WS, sfla2 know everything!
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OK Ike, go empty the rain gauge and keep us up to date. How 'bout grabbing that lady and sending some rain NE.
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Quoting canesrule1:
Bill becoming more compact and intense, should develop an eye by tonight.
Have you not looked at water vapor loop? that is very dry air ahead and bill's circulation is drawing it in.
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Quoting nrtiwlnvragn:
Current forecast surge (above ground level)




That notch in FL is a really bad area for surge. Just be grateful it isnt stronger
Member Since: July 29, 2006 Posts: 28 Comments: 1799
Well,Size does matter,but the story on Claudette,other than Impact to come,was how it was a Classic case of a ULL that persisted over ripe SSt's and favorable upper Air Venting.

It Was the real,but albeit small threat close in 2 days ago,but the CV Vortex's got all the press.

That's why I LOVE to follow the real time,..it will surprise you,more often than not..in a El Nino year.
Member Since: July 3, 2005 Posts: 426 Comments: 128874
657. IKE
Quoting sporteguy03:


Did you wave???


Those coordinates posted were in this area....I thought I heard an aircraft flying over.

Do they fly low enough to be heard?
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting all4hurricanes:
So we officially have Claudette? It said so on the weather channel but i don't trust them


000
WTNT64 KNHC 161616
TCUAT4
TROPICAL STORM CLAUDETTE TROPICAL CYCLONE UPDATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
1215 PM EDT SUN AUG 16 2009

CORRECTED FOR ISSUANCE TIME

...DEPRESSION BECOMES TROPICAL STORM CLAUDETTE...

DATA FROM THE NOAA DOPPLER RADAR IN TALLAHASSEE FLORIDA INDICATE
THAT SURFACE WINDS ASSOCIATED WITH THE DEPRESSION HAVE INCREASED TO
40 MPH...65 KM/HR...MAKING THE DEPRESSION TROPICAL STORM CLAUDETTE.
DETAILS WILL FOLLOW IN THE 2 PM EDT INTERMEDIATE ADVISORY.

$$
FORECASTER ROBERTS/BRENNAN
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Looks to me like Ana is making a comeback once again. 456 am I right or just seeing things ?
Member Since: October 9, 2008 Posts: 0 Comments: 8399
Quoting clwstmchasr:
this storm came out of no where and none of the mode runs where forcasting it then boom you get Claudette out of no where

It is isteresting that none of the models developed this system. However, Dennis Phillips who is a very good TV met called it. On Thursday night, his model showed a storm forming in just about the exact location where TD4 formed. He said that he would not be surprised that a TD or weak TS formed off the west coast of Fl.


He's the met I trust most in Tampa.
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Anyone have a camera from Appilachicola area?
Member Since: July 29, 2006 Posts: 28 Comments: 1799
630. FLHurricaneChaser 4:29 PM GMT on August 16, 2009
I told you all Claudette would be nothing more than a 40kt weak TS.
--------

you "told us"? and btw, it still is over water and can strengthen even more. comments like that place ppl on ignore lists.
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Current forecast surge (above ground level)


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Quoting chevycanes:
trough isn't the main player for turning Bill to the north.

a break in the subtropical ridge is forecast to develop and that's what let's it gain a lot of latitude.

then the trough will sweep through and keep it away from the NE.

if the ridge doesn't break down as forecast, then the Leewards and Puerto Rico could be affected.
Much appreciated. Thanks
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Drak or someone,I have been reading what some folks is saying about TD4 and just wondering if folks in Mobile County should be worried? We have a boat repair shop on the creek and I just would like to know we have a lot to pick up in the shop to get things off the floor.

Sheri
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646. bcn
removed
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Quoting IKE:


LOL....they just flew over me here in DFS,FL.


Did you wave???
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Claudette will only help the trough move in. The remnant low will help the cold front move more quickly than it otherwise might in August.
Member Since: June 12, 2002 Posts: 0 Comments: 1589
Quoting FLHurricaneChaser:
I told you all Claudette would be nothing more than a 40kt weak TS.
Has Claudette made landfall yet. You don't know what she will end up being.
Quoting Funkadelic:


No weatherstudent, oh my bad I mean Canesrule1 you are not in danger in any way, shape, or form...
Never say never scenarios change I would still be vigilant It's still early in the game
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NHC says Claudette is moving NW not NNW.
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So we officially have Claudette? It said so on the weather channel but i don't trust them
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Interesting is that none of the global models forecasted for Claudette to develop before. Could possibly be because of how small a circulation it has.
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NEXRAD Radar
Tallahassee, Storm Total Surface Rainfall Accumulation Range 124 NMI


Member Since: July 3, 2005 Posts: 426 Comments: 128874
Quoting rmbjoe1954:


Thw Weather Channel seems to think the trough MAY not be strong enough or move south in time to pull Bill northward.


Well they need people to watch. If they go ahead and say its a fish storm people wouldn't bother turning to their station.
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634. IKE
Quoting pcbguy13:
looks like a rainy day is in store here in panama city beach


Satellite on Claudette...wow.....
Member Since: June 9, 2005 Posts: 23 Comments: 37858
trough isn't the main player for turning Bill to the north.

a break in the subtropical ridge is forecast to develop and that's what let's it gain a lot of latitude.

then the trough will sweep through and keep it away from the NE.

if the ridge doesn't break down as forecast, then the Leewards and Puerto Rico could be affected.
Member Since: Posts: Comments:
Quoting Weather456:


escape ITCZ?
that is what u told me earlier today
If anyone did not notice:

By August 20 we suppose to have 3 named storms

By August 14 - 1 hurricane (that will change soon)

This sudden burst easily justify a 10 named storm season.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
I told you all Claudette would be nothing more than a 40kt weak TS.
in other news, guillermo. thankfully no threat to HI this time.

Member Since: July 29, 2006 Posts: 28 Comments: 1799
this storm came out of no where and none of the mode runs where forcasting it then boom you get Claudette out of no where
Member Since: May 21, 2006 Posts: 5091 Comments: 115255
From the 11AM advisory to know Bill ha moved NW instead of WNW or West.
Quoting KEHCharleston:
Stupid Question Time:

As Claudette tracks inland will this have any effect on the trough that is supposed to come off the east coast and pull Bill eastward?

Thanking you in advance


not a stupid question. I'd love to hear everyone's thoughts- many of us would.
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looks like a rainy day is in store here in panama city beach
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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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