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 HurricaneRoman:
haha, poor little ana, she just cant get it together! if she goes over the islands she for sure done for


After seeing how fast Claudette fired up overnight, I won't write off Ana if her remnants get to the GOM.
Quoting FLHurricaneChaser:


Give it up. Bill is out to sea. We gotta wait for the next wave train, not sure when it will be. Perhaps the end of this month.


There are 2-3 waves crossing Africa right now.
Quoting KEHCharleston:
St George Island



that looks like a very rippable point break!
Member Since: August 22, 2006 Posts: 2 Comments: 1983
Based on Dr. Lyon's comments (which I'm not sure I trust after last night), a stronger Bill will favor a more northerly turn and keep him off the East Coast.
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Bill is strengthening but Claudette is really rapidly strengthening due to very hot waters and no shear.
1371. Patrap
Member Since: July 3, 2005 Posts: 424 Comments: 128273
Quoting IpswichWeatherCenter:
Big Shock, Bastardi is talking slight sense


I know, I believe him when he says the models might be off too much to the east. Bill needs to be watched and not discounted.
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Quoting reedzone:
WOW!! Bastardi proves my very point! Carolinas to New England needs to watch Bill, PLEASE don't let your guard down just because models show a recurvature and people who are boldly saying it won't hit.. We don't know yet, give it time.


Give it up. Bill is out to sea. We gotta wait for the next wave train, not sure when it will be. Perhaps the end of this month.
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1368. jpsb
Cluadette is becomming very impressive, a center relocation a significant distance south/west would be a real game changer. This is something to pay serious attention too.
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1367. Patrap
Member Since: July 3, 2005 Posts: 424 Comments: 128273
1366. fire635
Quoting HurricaneRoman:
haha, poor little ana, she just cant get it together! if she goes over the islands she for sure done for


I still think even if she falls apart now.. her energy may regenerate when she hits the gulf
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1365. jdjnola
Quoting HurricaneRoman:
haha, poor little ana, she just cant get it together! if she goes over the islands she for sure done for


Poor little Ana? She's a fighter. I said it before and I'll say it again, I'm amazed she's survived even this long! You never know, she might pull a Fay on us. Both female three letter names--coincidence?
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1364. Drakoen
Both Bill and Claudette are strengthening.
Member Since: October 28, 2006 Posts: 57 Comments: 30490
Quoting HurricaneRoman:
haha, poor little ana, she just cant get it together! if she goes over the islands she for sure done for


After seeing how fast Claudette fired up overnight, I won't write off Ana if her remnants get to the GOM.
Quoting icepilot:


Just my luck. and now steady rain but not much wind ......I'm 30 mile N of coast in Wewahitchka




Wind is increasing a little in Tallahassee and the first rain band is about to move through- going to be rainy and windy for most of the afternoon it seems.
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Quoting willdunc79:
Canesrule you're on! I'm going on record as saying Bill will be a fish storm and either strike or brush Bermuda and Nova S. only but won't effect the lower 48 states. I'm leaning more towards striking/brushing Bermuda. If I'm wrong then I'll eat crow.


And how is that a fish storm if it strikes Bermuda, not everything is about the US you know. To me a fish storm is a storm that doesnt affect any land areas. Bermuda and Nova Scotia have people living there you know.
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Quoting Weather456:
Both Bill and Claudette is stregthening

Bill is forming an eyewall





yup, an eye at 5 is very possible, imo
Big Shock, Bastardi is talking slight sense
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St George Island

Member Since: August 19, 2008 Posts: 6 Comments: 2490
Both Bill and Claudette is stregthening

Bill is forming an eyewall





Member Since: July 24, 2005 Posts: 407 Comments: 19076
StormW
could you please post a link to your most recent synopsis? I can't find it! Thanks!!
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Quoting willdunc79:
Canesrule you're on! I'm going on record as saying Bill will be a fish storm and either strike or brush Bermuda and Nova S. only but won't effect the lower 48 states. I'm leaning more towards striking/brushing Bermuda. If I'm wrong then I'll eat crow.
alright, $50 it is not a fish.
1353. jdjnola
Quoting Tazmanian:
ANNA is RIP


How many times is she RIP now? Wednesday, Thursday, Friday, Sunday...
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WOW!! Bastardi proves my very point! Carolinas to New England needs to watch Bill, PLEASE don't let your guard down just because models show a recurvature and people who are boldly saying it won't hit.. We don't know yet, give it time.
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haha, poor little ana, she just cant get it together! if she goes over the islands she for sure done for
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Quoting Skyepony:
Recon has the pressure off Tampa at 1021mb. Not only is Claudette strengthin the high is quickly strengthening which in turn is increasing the pressure gradient & winds fast...This may be why we are seeing winds higher at the surface, then what wind average wind reduction would dictate, since the surface gradent is increasing fast..



yes sky and with the high is quickly strengthening that is why bill wont be a fish
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Quoting tennisgirl08:
Link for Claudette - showing where she has relocated further South.

http://www.ssd.noaa.gov/goes/flt/t3/loop-wv.html


Any thoughts on this?? Anyone??
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1348. TX2FL
Quoting Tazmanian:
bill wont be a fish


if bill be comes a fish i eat crow


Explain? I keep seeing different scenarios..I don't think the high is as weak as some forecasts say. When is the cold front that affects possibly the trof supposed to move through?
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This is the first time I have seen Maka mentioned on this blog, but whatever. Anyway, I think there were some problems with it crossing over from the Central Pacific LOL.

Member Since: October 15, 2008 Posts: 11 Comments: 2312
Latest RECCO observation on Ana:

Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 16th day of the month at 18:17Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 300)
Storm Number: 02
Storm Name: Ana (flight originating in the North Atlantic basin)
Mission Number: 1
Observation Number: 05

Mandatory Data...

Observation Time: Sunday, 18:16Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 14.4N 57.4W
Location: 174 miles (280 km) to the ENE (59°) from Bridgetown, Barbados.
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 440 meters
Flight Level Wind: From 100° at 14 knots (From the E at ~ 16.1 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 23°C
Flight Level Dew Point: 13°C
Weather (within 30 nautical miles): Scattered clouds (trace to 4/8 cloud coverage)
Mean Sea Level Pressure (MSLP): 1010 mb (extrapolated)

Optional Data...

Estimated Surface Wind Direction: Bearing was unavailable.
Estimated Surface Wind Speed: 5 knots (~ 5.8 mph)

Remarks Section...

Surface Wind Speed (likely by SFMR): 11 knots (~ 12.7mph)
Quoting tennisgirl08:
Link for Claudette - showing where she has relocated further South.

http://www.ssd.noaa.gov/goes/flt/t3/loop-wv.html


I'm no expert...but it looks that way to me too.
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Quoting Skyepony:
Recon has the pressure off Tampa at 1021mb. Not only is Claudette strengthin the high is quickly strengthening which in turn is increasing the pressure gradient & winds fast...This may be why we are seeing winds higher at the surface, then what wind average wind reduction would dictate, since the surface gradent is increasing fast..

Bending her further west?
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SAB confirms the TAFB number. The organization of the cloud pattern is lagging the actual data.

16/1745 UTC 29.1N 84.9W T2.5/2.5 CLAUDETTE -- Atlantic
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting WPBHurricane05:
Time for our Bastardi fix. LOL


omg

lol

ty... i believe besides having the funniest last name in a while (Kilkenny being the other one ive heard of this month) this man is a rock star
Member Since: August 22, 2006 Posts: 2 Comments: 1983
Canesrule you're on! I'm going on record as saying Bill will be a fish storm and either strike or brush Bermuda and Nova S. only but won't effect the lower 48 states. I'm leaning more towards striking/brushing Bermuda. If I'm wrong then I'll eat crow.
Member Since: June 27, 2009 Posts: 0 Comments: 152
1340. jdjnola
Man Claudette is just exploding with convection. I'm not happy it's hitting Florida by a longshot, but at the same time, I'm glad this thing didn't head out WNW towards us... Claudette Rainbow IR
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Quoting Tazmanian:



nop i dont have you on ignore but i have been puting the fishcasters on ignore i wont take then off ignore in tell the storm gets too 50W then will se oh ends up being right the fishcaster or us
oh, that means a lot to me, lol
Quoting stormwatcherCI:
Can someone please tell me what year was Georges. I would like to look it up but I don't remember it. TIA
1998
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Quoting stormwatcherCI:
Can someone please tell me what year was Georges. I would like to look it up but I don't remember it. TIA


Link
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Quoting canesrule1:
i agree, i know u have me on ignore, but i agree, lol



nop i dont have you on ignore
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1335. Skyepony (Mod)
Recon has the pressure off Tampa at 1021mb. Not only is Claudette strengthin the high is quickly strengthening which in turn is increasing the pressure gradient & winds fast...This may be why we are seeing winds higher at the surface, then what wind average wind reduction would dictate, since the surface gradent is increasing fast..
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Pat - that radar shows the northern edge of the storm. I think Claudette has relocated her COC further south. Can you look at satellite images and let me know what you think??
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1333. bcn
Sorry for the duplicated post, but I'm interested on opinions about loop at 25N-70W. Any one?
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1332. CJ5
Quoting Tazmanian:
ANNA is RIP


LOL...it is obvious I don't agree.
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1331. Relix
Quoting BrandiQ:


Georges path...


I meant it more in the way of it being a strong system and quite big... not the exact path. Thoooouuuughh... who knows if Bill follows the path from that midpoint on and forward? =P
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Quoting HurricaneRoman:


what makes you think that Taz?



the high is too strong and the mode runs is overe doing it with the cold front
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Quoting hahaguy:

1998


darn haha, you barely beat me.
Member Since: October 15, 2008 Posts: 11 Comments: 2312
from Dr. Master's Blog: title - "Ana, Bill,--and Claudette?"

I guess the title he chose for today's blog is his way of eating crow as he did not even mention the Key West disturbance in yesterday's blog.
Member Since: August 26, 2006 Posts: 10 Comments: 3684
Quoting canesrule1:
i agree, i know u have me on ignore, but i agree, lol



nop i dont have you on ignore but i have been puting the fishcasters on ignore i wont take then off ignore in tell the storm gets too 50W then will se oh ends up being right the fishcaster or us
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Satellite estimates are lagging the actual wind data on Claudette...TAFB just came with only a T2.5.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting stormwatcherCI:
Can someone please tell me what year was Georges. I would like to look it up but I don't remember it. TIA


1998
Member Since: October 15, 2008 Posts: 11 Comments: 2312

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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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