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 IKE:


Why can't he be IP banned?


Why don't you ban troublemakers by IP or somehow limit people by IP?


The only solution is to place him on ignore.
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Ok. My quote thing not working.
But doesn't this show the effects anyway of TD4 doing exactly what Mobilegirl suggested? Skimming the coast westward.


Link
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Well, I can't help but thinking TD4 might be somewhat of a blessing in disguise. It will help dissipate some of that excess heat in the gulf.
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Quoting dcoaster:
Bill is definitely moving WNW.



definitely wnw....staying north of the forecast points...
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Quoting ALCoastGambler:
I thought I saw that also. But I know nothing about weather so was waiting on you guys.

The GFS had it lingering along the coast, eventually moving into Mississippi.
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what will happen if Ana follows the south path and does not hit land at all.... every update they do on Ana it keep falling down and keep it less likely to have any problems except for dry air that she may keep off with any luck
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Maybe this will make WS happy, end of NAM 12z run...

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Well...now that Bill has turned to the WNW, I believe the forecasts that he will be a fish storm. Can we just get to winter already?
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Who remembers Ike last year? For a couple of days we thought Ike would recurve...slowly the models shifted west and they eventually shifted southwest.

What if Bill goes along the southern part of the cone? The northern Leeward Islands will get hit.

Bill is not to be discounted IMO.
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YEAH! Looks like Bill will miss FL and hopefully everyone else :) I live in a mobile home in S FL, so always hesistant when I see those tracks towards us.
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Quoting Giga2001:

Morning TS - you get any sleep?
That's his own take on things Mobilegirl
NAMMY

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I have to give props to stormno... I realize he embelishes a tad to say the least, but he definitely called it with soon-to-be Claudette. A little more time and I think she would have had plenty of opportunity to become a major player this season
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Quoting IKE:


Why can't he be IP banned?


he can, its that powers that be...aka..the wunderground IT fellas that have to make that call...
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The weatherstudent is probably not a homeowner or parent. Storms = money. When you have to pay for plywood, gas, food, when you have to pay for child care because school is closed, when you are ripping out sopping wet drywall and carpeting and crawling around in your attic looking for the hole in your roof, when you are trying to come up with $2,000 for a new fence, $3,000 deductible for a new roof, etc., etc., when you have 22 people from five families live with you for a week, you understand the power of a storm. Till then it's all fun and games for him.
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Quoting TampaSpin:
Here is my complete Tropical Update including TD4, ANA, and BILL

Morning TS - you get any sleep?
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Stormtop, was that a fake forecast?
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Quoting IKE:


I'm not 100% sure. It looks to almost be moving parallel to the NW FL. coast. I can't be 100% sure so far.
I thought I saw that also. But I know nothing about weather so was waiting on you guys.
Quoting IKE:


Why can't he be IP banned?


He should be. He ask the same questions repeatedly: "what does this mean for south FL ""Met"" ""Drakoen"" ""Adrian"" "Does this pose a threat to south FL" "Does this mean South FL will get hit"
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Interesting tidbit from the Ana discussion:

THE TRACK FORECAST IS QUITE SIMILAR TO THE PREVIOUS PACKAGE...
SHOWING A QUICK WESTWARD TO WEST-NORTHWESTWARD MOTION THROUGH THE
FIRST 3 OR 4 DAYS OF THE FORECAST PERIOD. BEYOND THAT TIME THERE
IS A SPLIT IN THE TRACK GUIDANCE...WITH THE ECMWF AND HWRF SHOWING
A TURN TOWARD THE NORTHWEST...WHILE THE UKMET AND NOGAPS SHOW A
CONTINUED WEST-NORTHWEST HEADING. THE OFFICIAL FORECAST IS NUDGED
TOWARD THE MULTI-MODEL CONSENSUS AT DAY 5 AND SHOWS A DECREASE IN
FORWARD SPEED.
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Quoting ALCoastGambler:
Stormno is another that gives bad info.
What the?
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Quoting IKE:


I'm not 100% sure. It looks to almost be moving parallel to the NW FL. coast. I can't be 100% sure so far.


Just keep us updated, you're good at what you're doing.
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Quoting Chicklit:
What are the coordinates of TD4s COC?




Apparently.
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Ana still racing westward with no signs of strengthening,

At 11 pm ast, 0300 utc, the government of the british virgin islands has issued a tropical storm watch for the british virgin islands which includes montserrat, antigua, barbuda, st.kitts, nevis and anguilla. At 11 pm ast, 0300 utc, a tropical storm watch has been issued for the u.s. Virgin Islands. A tropical storm watch remains in effect for st. Maarten, saba, and st. Eustatius. A tropical storm watch means that tropical storm conditions are possible within the watch area, generally within 36 hours.

Interests elsewhere in the leeward islands, and Puerto Rico should monitor the progress of ana. Additional watches and warnings may be required for portions of these areas tonight and Sunday.

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 1100 pm ast, 0300 utc, the center of tropical storm ana was located near latitude 14.4 north, longitude 51.5 west or about 710 miles, 1140 km, east-southeast of the leeward islands.

Ana is moving toward the west near 17 mph, 28 km/hr. A gradual turn to the west-northwest and an increase in forward speed is expected during the next two days. On this track, the center of ana will be moving over the leeward islands on Monday.

Maximum sustained winds are near 40 mph, 65 km/hr, with higher gusts. Little change in strength is forecast during the next 24 hours.

Tropical storm force winds extend outward up to 70 miles, 110 km from the center.

Estimated minimum central pressure is 1004 mb, 29.65 inches.

Summary of 1100 pm ast information, location, 14.4n 51.5w maximum sustained winds, 40 mph present movement, west or 270 degrees at 17 mph minimum central pressure, 1004 mb

An intermediate advisory will be issued by the national hurricane center at 200 am ast followed by the next complete advisory at 500 am ast.

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Front row view of 04L

http://www.beachview.com/Beach_Cams/St._George_Island.aspx
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According to the new advisory on Bill, Extreme may be right about Bill becoming a hurricane by tommorow.
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Quoting HurricaneKyle:
TD4 now forcasted to go up to 50 kts.
Thats the 5 am forecast, I would be highly surprised if the new forecast even took it to TS strength. Except for being a rain feature, not overly impressive and don;t see it improving. Pressures are still high so I don't see where all of the "----casting" is coming from.
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Wow...Bill to be a major hurricane in 3 days according to the NHC forecast.
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Coordinates of TD4s COC 28.7N 84.6W @ 11 a.m. per NHC.
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Quoting Joshfsu123:
Ana will be downgraded at 11am and should. I think she's on her last leg.




It's a meteorlogical fact that ANA can't strenghten until she's been wriiten off by everyone.
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Quoting Relix:
What I am seeing... correct me if I am wrong, which I am sure I will but..

1) Ana has relocated the COC? Maybe to the NW? Also she seems to be moving WNW... definitely following the forecast points but maybe a bit north of them.

2) Bill is moving WNW, and over the points, but in the latest imagery I see it going W... with a slight turn to N. Definitely not WNW


I had a feeling she may have done a few hours ago, as the positioning was moved to the east of where the visible previously indicated.

Right under the convection, but it's hard to tell. I don't even she knows what she's doing!
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Quoting MandyFSU:
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 :)


Thanks.......I checked in from Roanoke on Thursday night and nothing around Florida at that time....How quickly things can change in the tropics. Don't like Dr. Master's comparison to Humberto so our folks in the Panhandle (Ike) need to keep an eye on this one and prepare for some minor flooding and intermittent power outages.
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Bill is up to 60 mph.

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189. IKE
Quoting HurricaneJoe:


You mean it is going more to the West?


I'm not 100% sure. It looks to almost be moving parallel to the NW FL. coast. I can't be 100% sure so far.
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Quoting Joshfsu123:
Ana will be downgraded at 11am and should. I think she's on her last leg.


Watch..it will be the same!
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NAM 12Z reinvigorates Ana
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Quoting Joshfsu123:
Ana will be downgraded at 11am and should. I think she's on her last leg.


Their holding it as a TS on this advisory.
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Quoting WeatherStudent:
G'morning all! Thanks for the update, Dr. Masters. What a dissapointment, the dead season continues it would seem. None of these three crappy systems presently pose a significant threat to anyone, nor will they ever, probably. After these three pests are gone, it would appear as if the basin is going to re-commence another dead spell. But talk about not being surprised, right y'all? This being a typical and a classical El Nino Hurricane Season. Do not anticipate much in September, that's for damn sure, especially since we'll be having a major downward subsedence episode in the MJO. Have a terrific day, gang. Cheers, :).


is there something mentally wrong with you? i mean seriously, why is it such a disappointment to you that these storms don't cause a threat to peoples lives, homes and lively-hood...i personally think that the people who were going to be possibly directly affected are very happy at the course things seem to be taking...Claudette should give beneficial rain to some who need it....ana wont be bad for the islands, and hopefully will be dissipated enough that by the time it reaches the GOM, it will only re intensify to become a good rainmaker for someone else. and bill, bill still may affect Bermuda which is horrible...hopefully it gets pulled more out to sea...

look, i get excited and love tracking all things weather just as much as the next weather nut...but it has become so much more apparent this season that you have the school child mentality of getting outta school and have no mental capacity to think about others before yourself. people have dealt with your immaturity for awhile, but now i believe most are done with you. im sure you'll come back, again, with another name...but until then...flagged, reported and minimized...

on the topic at hand...Claudette is looking good for only have 24 hours or so to get going....bill isn't looking as hot as he was last night and is definitely going more nw already...and ana is just being her usual unimpressive self...

hope all are well, and ill check back in a lil' later.

chris.
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Extreme posted the reason the NHC did not upgrade to tropical storm status. A reconnaissance aircraft will investigate so we have a better idea of what is happening.
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TROPICAL DEPRESSION FOUR ADVISORY NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
1100 AM EDT SUN AUG 16 2009

...DEPRESSION APPROACHING TROPICAL STORM STRENGTH...AIRCRAFT
RECONNAISSANCE WILL INVESTIGATE SOON...


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 1100 AM EDT...1500 UTC...THE CENTER OF TROPICAL DEPRESSION FOUR
WAS LOCATED NEAR LATITUDE 28.7 NORTH...LONGITUDE 84.6 WEST OR ABOUT
75 MILES...120 KM...SOUTH-SOUTHEAST OF APALACHICOLA FLORIDA AND
ABOUT 200 MILES...320 KM...SOUTHEAST OF PENSACOLA FLORIDA.

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

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHER
GUSTS. SOME STRENGTHENING IS EXPECTED...AND THE DEPRESSION IS
FORECAST TO BECOME A TROPICAL STORM PRIOR TO REACHING THE
COASTLINE.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1011 MB...29.85 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 1100 AM EDT INFORMATION...
LOCATION...28.7N 84.6W
MAXIMUM SUSTAINED WINDS...35 MPH
PRESENT MOVEMENT...NORTHWEST OR 320 DEGREES AT 14 MPH
MINIMUM CENTRAL PRESSURE...1011 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 200 PM EDT
FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 500
PM EDT.

$$
FORECASTER BRENNAN/ROBERTS
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182. Relix
What I am seeing... correct me if I am wrong, which I am sure I will but..

1) Ana has relocated the COC? Maybe to the NW? Also she seems to be moving WNW... definitely following the forecast points but maybe a bit north of them.

2) Bill is moving WNW, and over the points, but in the latest imagery I see it going W... with a slight turn to N. Definitely not WNW
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TD4
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Ana will be downgraded at 11am and should. I think she's on her last leg.
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Stormno is another that gives bad info.
Update....Ana remains the same in the next advisory, Bill Intensifies to 55 mph. Tropical Depression 4 remains the same. Guillermo remains the same.
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...DEPRESSION APPROACHING TROPICAL STORM STRENGTH...AIRCRAFT RECONNAISSANCE WILL INVESTIGATE SOON...
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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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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.