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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Hopefully Claudette doesn't stick around too long giving Tallahassee a repeat of Fay...
Member Since: Posts: Comments:
48 knots
(~ 55.2 mph)

Claudette.
Member Since: August 10, 2009 Posts: 3 Comments: 672
still no advisory on ANA at 2 yet.
1172. Nimitz
Quoting CaneWarning:
So Claudette, even with winds at 50 mph would not even be considered a severe t-storm at this point.


Keep in mind that the worst affects of a tropical storm after storm surge are tornado's and flooding. The lower tier of southern states have had a lot of rainfall already (In Jax, we've averaged 5 inches a week for a month now).
Member Since: August 17, 2008 Posts: 0 Comments: 98
nhc found 50knot barbs in quite a few places, guess they're going with those as gusts.
Member Since: August 22, 2006 Posts: 2 Comments: 1975
1170. IKE
12HR VT 17/0000Z 30.2N 85.8W 55 KT

That's 30 miles SSE of me.
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Quoting catastropheadjuster:
I was just wondering am I like on ignore where no one can see me? I asked a little further back on the blog if Mobile might get anything out of Claudette cause we have a boat repair shop on Chickasabogue Creek and we might need to get stuff off the floors so it won't get wet. I'm not wishcasting or anything just trying not to loose valuable materials.

Sheri


Right now neither Pensacola nor Mobile are in the warning areas nor the forecast cone. This is subject to change obviously, but it appears you should, I repeat should, be okay. Again, always subject to change, but Claudette getting very close to land now.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Looks like the NHC answered my question on what storms would get a 2pm intermediate advisory. :)
Member Since: October 15, 2008 Posts: 11 Comments: 2305
Recon has found 55.2MPH at the surface.
Quoting snow2fire:
It looks like the counterclockwise circulation near 70W and 25 N (East of Miami and North of Haiti) is persisting. What's up with that? See Satellite Images like Eastern US IR AVN.


Looks like an upper level low.
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Quoting Drakoen:


lots of dry air on that bill :/
Member Since: August 22, 2006 Posts: 2 Comments: 1975
Quoting Funkadelic:


WoW!! Bill would have to go almost due north to follow that track lmao. NW at least, I suggest you do that track over. Other then that its preety good.

Oh and Drakoen, Im married and have a 5 year old lol... put I agree it did sound pedofilish :)


Yeh - I got the compass bearing wrong on my software - I was trying to follow the loop, as #3 was moving over Florida, and therefore Bill could slot in that new Tropical Cyclone size gap.
Member Since: April 27, 2008 Posts: 29 Comments: 2097
000
WTNT44 KNHC 161749
TCDAT4
TROPICAL STORM CLAUDETTE SPECIAL DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
200 PM EDT SUN AUG 16 2009

DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT CLAUDETTE HAS CONTINUED TO INTENSIFY. BASED ON A MAXIMUM
FLIGHT LEVEL WIND 54 KT MEASURED AT AN ELEVATION OF ABOUT 2500
FEET...THE INITIAL INTENSITY IS RAISED TO 45 KT. THE 12-HOUR
FORECAST INTENSITY IS ALSO ADJUSTED UPWARD TO ACCOUNT FOR THE
POSSIBILITY FOR ADDITONAL STRENGTHENING PRIOR TO LANDFALL. THE WIND
RADII HAVE ALSO BEEN EXPANDED BASED ON THE AIRCRAFT DATA AND THE
CHANGE IN THE INTENSITY FORECAST.

FORECAST POSITIONS AND MAX WINDS

INITIAL 16/1800Z 29.1N 85.1W 45 KT
12HR VT 17/0000Z 30.2N 85.8W 55 KT
24HR VT 17/1200Z 32.1N 87.1W 35 KT...INLAND
36HR VT 18/0000Z 34.0N 88.2W 20 KT...DISSIPATING INLAND
48HR VT 18/1200Z...DISSIPATED

$$
FORECASTER BRENNAN/ROBERTS
Member Since: Posts: Comments:
It looks like the counterclockwise circulation near 70W and 25 N (East of Miami and North of Haiti) is persisting. What's up with that? See Satellite Images like Eastern US IR AVN.
Member Since: Posts: Comments:
Quoting canesrule1:
WOW:



behind Bill. next invest
Member Since: August 22, 2006 Posts: 2 Comments: 1975
1160. KEEPEROFTHEGATE (Mod)
Quoting StormW:
I see Claudette making landfall etween Apalachicola and Panama City.
i see the same thing stormw

good afternoon to you friend
Member Since: Posts: Comments:
Claudette looking to come ashore near Miramar Beach, FL, I'd say a little east of there. It's rather moot, though, the effects will be felt over a wide spread area. It's not the point of impact, after all. Also, Bill looking like it could reach hurricane status soon, he's really insulating himself from the drier air now.
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1158. Drakoen
Member Since: October 28, 2006 Posts: 57 Comments: 29864
Quoting alpha992000:
Relix, JLPR: Sorry to bother you guys but right now I'm not home so don't have all my links and info available. I've got a friend stuck with his family in Culebra and wants to know what's the deal with Ana just in case they can't make it back in time. Any info you could provide would be really appreciated. Can't wait to get back home and see the latest. I'm having Weather Underground withdrawals! :-s


looks like its gonna be a stormy monday/tuesday, nothing major
Member Since: August 22, 2006 Posts: 2 Comments: 1975
WOW:

Quoting KEEPEROFTHEGATE:
CLAUDETTE will make landfall at or slightly to the left of APALACHCOLA FLA with TROPICAL STORM FORCE WINDS with poss HURRICANE FORCE GUSTS IN NE QUAD


I completely agree! Appalachicola and Tallahassee FL will bear the brunt of Claudette. She will mostly be a rainmaker.
Member Since: July 17, 2008 Posts: 0 Comments: 1242
1154. SaoFeng
Claudette at 45kts, 50mph as per the NHC advisory
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Quoting winter123:
I still think the tiny center of claudette may relocate to the west-center part of this huge convection:



Loop

Probably wont relocate it has great low level circulation. But, as I said, I think it may *move* in that direction.. NNE-NE very slowy before tracking WNW is my guess.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Quoting serialteg:


she is gonna knock some lawn chairs out better believe that


A few garbage cans too! She'll probably even bring down a few trees.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
winds up to 50mph
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55 knots at landfall predicted.
Member Since: August 10, 2009 Posts: 3 Comments: 672
1149. Michfan
Time: 17:47:00Z
Coordinates: 28.8167N 84.6W
Acft. Static Air Press: 925.1 mb (~ 27.32 inHg)
Acft. Geopotential Hgt: 810 meters (~ 2,657 feet)
Extrap. Sfc. Press: 1016.0 mb (~ 30.00 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 179° at 38 knots (From the S at ~ 43.7 mph)
Air Temp: 17.4°C (~ 63.3°F)
Dew Pt: 7.9°C (~ 46.2°F)
Peak (10s) Flt. Lvl. Wind: 40 knots (~ 46.0 mph)
SFMR Peak (10s) Sfc. Wind: 48 knots (~ 55.2 mph)
SFMR Rain Rate: 20 mm/hr (~ 0.79 in/hr)

Well away from the center too. Looks like recon may be heading back to base or making a pass around the SE quadrant.
Member Since: September 7, 2007 Posts: 0 Comments: 1665
1148. Patrap
Member Since: July 3, 2005 Posts: 419 Comments: 127374
1147. IKE
TROPICAL STORM CLAUDETTE SPECIAL DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
200 PM EDT SUN AUG 16 2009

DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT CLAUDETTE HAS CONTINUED TO INTENSIFY. BASED ON A MAXIMUM
FLIGHT LEVEL WIND 54 KT MEASURED AT AN ELEVATION OF ABOUT 2500
FEET...THE INITIAL INTENSITY IS RAISED TO 45 KT. THE 12-HOUR
FORECAST INTENSITY IS ALSO ADJUSTED UPWARD TO ACCOUNT FOR THE
POSSIBILITY FOR ADDITONAL STRENGTHENING PRIOR TO LANDFALL. THE WIND
RADII HAVE ALSO BEEN EXPANDED BASED ON THE AIRCRAFT DATA AND THE
CHANGE IN THE INTENSITY FORECAST.

FORECAST POSITIONS AND MAX WINDS

INITIAL 16/1800Z 29.1N 85.1W 45 KT
12HR VT 17/0000Z 30.2N 85.8W 55 KT
24HR VT 17/1200Z 32.1N 87.1W 35 KT...INLAND
36HR VT 18/0000Z 34.0N 88.2W 20 KT...DISSIPATING INLAND
48HR VT 18/1200Z...DISSIPATED

$$
FORECASTER BRENNAN/ROBERTS

Member Since: Posts: Comments:
Quoting CaneWarning:
So Claudette, even with winds at 50 mph would not even be considered a severe t-storm at this point.


she is gonna knock some lawn chairs out better believe that
Member Since: August 22, 2006 Posts: 2 Comments: 1975
Quoting catastropheadjuster:
I was just wondering am I like on ignore where no one can see me? I asked a little further back on the blog if Mobile might get anything out of Claudette cause we have a boat repair shop on Chickasabogue Creek and we might need to get stuff off the floors so it won't get wet. I'm not wishcasting or anything just trying not to loose valuable materials.

Sheri


Based on the NHC cone, if the storm goes to the west side, there'll be some rain and wind. Fortunately you won't be in the NE quadrant. I'd pick up loose objects so they won't be blown around.
Member Since: Posts: Comments:
Relix, JLPR: Sorry to bother you guys but right now I'm not home so don't have all my links and info available. I've got a friend stuck with his family in Culebra and wants to know what's the deal with Ana just in case they can't make it back in time. Any info you could provide would be really appreciated. Can't wait to get back home and see the latest. I'm having Weather Underground withdrawals! :-s
Member Since: Posts: Comments:
1142. Grothar
Dakster,
Sorry I asked, but just too much information for me.
Member Since: July 17, 2009 Posts: 68 Comments: 25087
Claudette up to 50mph.

Straight from the NHC.
Max sustained: 50 mph
Moving: NW at 14 mph
Min pressure: 1008 mb
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000
WTNT34 KNHC 161748
TCPAT4
BULLETIN
TROPICAL STORM CLAUDETTE SPECIAL ADVISORY NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
200 PM EDT SUN AUG 16 2009

...AIRCRAFT RECONNAISSANCE FINDS CLAUDETTE STRONGER...

A TROPICAL STORM WARNING REMAINS IN EFFECT FROM THE ALABAMA/FLORIDA
BORDER EASTWARD TO THE SUWANNEE RIVER FLORIDA. A TROPICAL STORM
WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE
WITHIN THE WARNING AREA WITHIN 24 HOURS.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA
OUTSIDE OF THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR NATIONAL METEOROLOGICAL SERVICE.

AT 200 PM EDT...1800 UTC...THE CENTER OF TROPICAL STORM CLAUDETTE
WAS LOCATED NEAR LATITUDE 29.1 NORTH...LONGITUDE 85.1 WEST OR ABOUT
40 MILES... 65 KM...SOUTH OF APALACHICOLA FLORIDA AND ABOUT 160
MILES...255 KM...SOUTHEAST OF PENSACOLA FLORIDA.

CLAUDETTE IS MOVING TOWARD THE NORTHWEST NEAR 14 MPH...22 KM/HR.
THIS MOTION IS EXPECTED TO CONTINUE TODAY...AND ON THIS FORECAST
TRACK...THE CENTER WILL BE NEAR THE NORTHERN GULF COAST OF FLORIDA
THIS EVENING.

DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 50 MPH...85
KM/HR...WITH HIGHER GUSTS. SOME ADDITIONAL STRENGTHENING IS
POSSIBLE PRIOR TO LANDFALL.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON AIRCRAFT DATA IS
1008 MB...29.77 INCHES.

RAINFALL ACCUMULATIONS OF 3 TO 5 INCHES...WITH ISOLATED MAXIMUM
AMOUNTS OF 10 INCHES ARE EXPECTED ACROSS THE FLORIDA PANHANDLE...THE
BIG BEND REGION OF FLORIDA...SOUTHERN ALABAMA...AND SOUTHWESTERN
GEORGIA NEAR THE PATH OF THE CENTER.

STORM TIDE IS EXPECTED TO PRODUCE MAXIMUM WATER LEVELS OF 3 TO 5
FEET ABOVE GROUND LEVEL ALONG PORTIONS OF THE FLORIDA PANHANDLE...
INCLUDING THE BIG BEND.

...SUMMARY OF 200 PM EDT INFORMATION...
LOCATION...29.1N 85.1W
MAXIMUM SUSTAINED WINDS...50 MPH
PRESENT MOVEMENT...NORTHWEST OR 325 DEGREES AT 14 MPH
MINIMUM CENTRAL PRESSURE...1008 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 500 PM EDT.

$$
FORECASTER BRENNAN/ROBERTS



It appears to me that Claudette is both moving very slowly and growing. It also looks to be moving to the east of the forecast track maybe coming onshore around Appalachicola with heaviest rain bands into Tallahassee & big bend area. Does anyone else agree with this?
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bill is consolidating and strengthening nicely
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So Claudette, even with winds at 50 mph would not even be considered a severe t-storm at this point.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting weatherfan92:
Is it just me or is Bill trying to form an eye?


He is forming an eye. Hurricane likely tomorrow, at the latest.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
Quoting catastropheadjuster:
I was just wondering am I like on ignore where no one can see me? I asked a little further back on the blog if Mobile might get anything out of Claudette cause we have a boat repair shop on Chickasabogue Creek and we might need to get stuff off the floors so it won't get wet. I'm not wishcasting or anything just trying not to loose valuable materials.

Sheri

As of now if it heads your (our) way it will be very slow moving so you should have time. Outside of that our winds should remain offshore.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Winds up to 50 mph according TWC.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
Hurricane, imo:

1132. jipmg
Claudette up to 50mph
I still think the tiny center of claudette may relocate to the west-center part of this huge convection:



Loop
Member Since: July 29, 2006 Posts: 28 Comments: 1776
I'm betting on between PCB and FWB... currently its really pretty in PCB, folks frolicking in the GOM....
Quoting Drakoen:


Maybe near Panama City Beach
Member Since: July 10, 2005 Posts: 157 Comments: 29383
Is it just me or is Bill trying to form an eye?
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1128. Michfan
Bill is huge.
Member Since: September 7, 2007 Posts: 0 Comments: 1665
Quoting weatherfan92:


Looks like Bill has closed off the dry air.


that's what I had meant to say... LOL
Member Since: October 15, 2008 Posts: 11 Comments: 2305
once again downcaster and claudette is wnw or nw not due north imo

Maybe NNW (345) but definatley not WNW the one bad thing is that it is moving slowly not good news as i feel this could pull a Humberto and strengthen rapidly all the ingredients are there...I feel this could be a strong tropical storm once it hits maybe even a Low end Hurricane at this rate
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1125. KEEPEROFTHEGATE (Mod)
CLAUDETTE will make landfall at or slightly to the left of APALACHCOLA FLA with TROPICAL STORM FORCE WINDS with poss HURRICANE FORCE GUSTS IN NE QUAD
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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.