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 Babsjohnson:


I agree. If she does a loop, I would not be surprised.


im really confused...exactly what radar are you watching....cause panama city yes...pensacola...no way...fort walton beach is as far west as she is land falling and i still think it'll be closer to panama city...unless shes pushed on alot harder by the high..
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alot of potential tropical storm forced winds

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Good Morning. WOW TD4 has really been on the move since last night. Did her COC relocate or did she just "bust a move" northward in the PM?
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Quoting canesrule1:
ROFLMAO! For real or are you just messing with me? LOL


probly the only place where calling someone a weatherstudent is derogatory... :O)
Member Since: August 22, 2006 Posts: 2 Comments: 1983
Quoting WPBHurricane05:


He's just gaining some latitude...trying to get out of the ITCZ. He should hit the southern periphery soon and turn more toward the W/WNW.

I really hope that you and the rest of the models are right, I really am. I went back and looked at some historical storms from that point and they were all over the place. I can't imagine that some of those crazy tracks were predicted. Granted technology has come a long way, but it's not so great that we have a TD in the gulf today where yesterday it ws not expected. Highs, lows, steering currents, etc. 5 days out...I just don't trust.
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Quoting Funkadelic:


I know models could go back and forth, but I can assure you that bill will recurve. During the night he started moving WNW, that was a bit pre-mature. Therefor he is already north of the forcast points, if anything the NHC track will be even more north east at 5:00pm.


The euro called this a few days ago with a quick recurve away from any significant impacts on the the northern islands.In all honesty i did not buy such a recurve but once again euro in my view proves its top notch when handling synoptics.Heres a glance at the 12z guidance on bill.
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Can someone please tell me what will make Bill curve, and didn't stormW say the high was going to build more westward or something.
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Quoting btwntx08:

fishcaster on bill u will be wrong imo


don't know why he thinks TD4 will only be a weak TD, NHC brings this up to 60 mph. Quite a rapid strengthening. I guess its his opinion though..

Not sure though how he can determine this season an all bark no bite, and that Bill will curve out to sea even though its over a week out.. can I borrow that crystal ball 23? :)
Member Since: August 10, 2009 Posts: 3 Comments: 672
Quoting ALCoastGambler:
I remember that mobilegirl. You and Patrap were the only 2 on that one I believe.May have been a few more but not many

Herd that the coc was in the southern part of the covection. Could this be one of those side-winder type storms?
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I have to agree with the others who post and are thinking that Bill is going to curve and go out to sea. Bill will keep strengthening and will curve and go out to sea. Bill may have some type of effect(s) on Bermuda (maybe rain and wind or either one) but Bill is going to curve and miss the lower 48 states JMHO.
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Have a good day y'all. Everyone in harms way take care.
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Quoting weatherwatcher12:
According to the ADT the center is in the extreme south of the convection.


of what? td4?
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Quoting MississippiWx:
Could be just temporary, but TD4 looks to be headed towards Pcola on radar. Could be the ridge building in like the Mobile NWS Office was referring to this morning.

TD 4 Radar


I agree. If she does a loop, I would not be surprised.
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Quoting mobilegirl81:

I saw that earlier, but did not want to get ridiculed like the blob over swfl.


hey, you guys did a wonderful job... i definetly didn't ridicule you... maybe was reluctant to give a public back-pat :D lol

nah i think i commented. who knows i was a bit drunk the whole day yesterday.

well... bill... since i woke up and gettin up to date with 5am and 11am advisories... ive been crying FISH.

still too low and too due west to discredit tho.

ana... poor ana, since her birth so troubled. i think i'll make a small ceremony when and if she passes puerto rico, maybe some cake and candles, something.

td4... has stronger barbs than ana lol
Member Since: August 22, 2006 Posts: 2 Comments: 1983
Quoting HurricaneKyle:
Recon going in shortly, if they find a stronger system than expected, expect a special advisory.
i will keep u posted, i willpost all the observations.
___________________________________________________________________

Right now Bill is moving WNW to get out of the ITCZ. It should continue it's westward movement later today.
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How's the drought been in the Panhandle this year? Is TD4 going to be beneficial for you guys?
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XtremeHurricanes.com Update:

The XtremeHurricanes.com team is not in position to provide live webcam coverage of TD#4 (Claudette.)

We will provide future updates when conditions warrant.

Disclaimer: If you are being affected by a landfalling TC of any size, never leave a safe, sheltered area to venture outside into the storm. Tropical TCs of any size will cause fatalities by rising waters, flying debris, and falling trees/poles.
Member Since: August 26, 2006 Posts: 10 Comments: 3684
Quoting Orcasystems:


Log into your router someday.. the software is there in any decent router to spoof your mac address.


yea, been a while, my ignorance increases with time, I'm sure the IP stack has gotten a lot more complicated, since my days doing Firewall setup and NAT, I know sites like this keep a log, I'm sure, if they had to, a senior network engineer and some investigator working together could probably work out who did what.
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Quoting mobilegirl81:

I saw that earlier, but did not want to get ridiculed like the blob over swfl.
I remember that mobilegirl. You and Patrap were the only 2 on that one I believe.May have been a few more but not many
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I was on the road when Ana and Bill formed but today is the 16th and the "average" start date for a late August season is August 14th;...Looks like Mother Nature just threw the switch on the 14th....Facinating.
Member Since: August 8, 2006 Posts: 0 Comments: 9132
According to the ADT the center is in the extreme south of the convection.
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00z ECMWF

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Could be just temporary, but TD4 looks to be headed towards Pcola on radar. Could be the ridge building in like the Mobile NWS Office was referring to this morning.

TD 4 Radar
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Recon going in shortly, if they find a stronger system than expected, expect a special advisory.
Member Since: August 10, 2009 Posts: 3 Comments: 672
does the ecmfw still show development of a wave off of Africa???
Quoting Funkadelic:


No weatherstudent, oh my bad I mean Canesrule1 you are not in danger in any way, shape, or form...
ROFLMAO! For real or are you just messing with me? LOL
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Bill almost a hurricane

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting julia78:
I think Miami, FL (again) is going to dodge these storms... I am just so sick of these news stations always telling us to prepare when the models are already showing it curving up... It really is difficult to shift around all your plans around their forecasts... Now I make my plans around the models on wunderground! I think again, we aren't going to be lucky this year :)
better to be cautious and shift your plans than to be a possible casualty
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Quoting hurricaster:
Been viewing the visible sat and TD4 has shifted dramatically westward over the past hour or so. Starting to feel the effect of high pressure to the north. This one could get a little more interesting than expected.

Link

I agree.
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XtremeHurricanes.com Update:

The XtremeHurricanes.com team is not in position to provide live webcam coverage of TD#4 (Claudette.)

We will provide future updates when conditions warrant.

Disclaimer: If you are being affected by a landfalling TC of any size, never leave a safe, sheltered area to venture outside into the storm. Tropical TCs of any size will cause fatalities by rising waters, flying debris, and falling trees/poles.
Member Since: August 26, 2006 Posts: 10 Comments: 3684
XtremeHurricanes.com Update:

The XtremeHurricanes.com team is not in position to provide live webcam coverage of TD#4 (Claudette.)

We will provide future updates when conditions warrant.

Disclaimer: If you are being affected by a landfalling TC of any size, never leave a safe, sheltered area to venture outside into the storm. Tropical TCs of any size will cause fatalities by rising waters, flying debris, and falling trees/poles.
Member Since: August 26, 2006 Posts: 10 Comments: 3684
Quoting Funkadelic:


I know models could go back and forth, but I can assure you that bill will recurve. During the night he started moving WNW, that was a bit pre-mature. Therefor he is already north of the forcast points, if anything the NHC track will be even more north east at 5:00pm.


He's just gaining some latitude...trying to get out of the ITCZ. He should hit the southern periphery soon and turn more toward the W/WNW.
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Quoting Babsjohnson:
Look off the coast of Belize. Is that the D storm?

I saw that earlier, but did not want to get ridiculed like the blob over swfl.
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TD4 composite radar
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Quoting Blog:Several of the longer range models show Bill passing near Bermuda or Nova Scotia, Canada.


Once again i ask this quest a few days ago, as bill starts turning up in my direction, nova scotia, how likely is it it will fall below hurricane strength before it makes landfall? I'm really not looking forward to a repeat of hurricane juan, a tree fell on my house...
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Quoting julia78:
I think Miami, FL (again) is going to dodge these storms... I am just so sick of these news stations always telling us to prepare when the models are already showing it curving up... It really is difficult to shift around all your plans around their forecasts... Now I make my plans around the models on wunderground! I think again, we aren't going to be lucky this year :)


The problem is the more and more that these storms "cry wolf" the more people are hesitant to prepare for the next threat. Eventually the wolf eats the sheep. You have to prepare EVERY time. Its a pain in the a-- but you still have to do it.
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Quoting PensacolaDoug:




It's a meteorlogical fact that ANA can't strenghten until she's been wriiten off by everyone.


If she's a Tropical Storm with that one cluster of thunderstorms on her center, more power to her. But I doubt she is and and that dry air just won't let anything get going.

However, if she goes south of the islands and makes it into the Gulf of Mexico in a few days, things could get interesting.

Guess we will see with RECON later.
Member Since: July 6, 2005 Posts: 5 Comments: 580
Been viewing the visible sat and TD4 has shifted dramatically westward over the past hour or so. Starting to feel the effect of high pressure to the north. This one could get a little more interesting than expected.

Link
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Look off the coast of Belize. Is that the D storm?
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Quoting julia78:
I think Miami, FL (again) is going to dodge these storms... I am just so sick of these news stations always telling us to prepare when the models are already showing it curving up... It really is difficult to shift around all your plans around their forecasts... Now I make my plans around the models on wunderground! I think again, we aren't going to be lucky this year :)


What else are they going to talk about? The Marlins?
Member Since: July 14, 2006 Posts: 0 Comments: 574
How about just ignore them and carry on with the discussion? Very simple to click "HIDE".
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Quoting rainraingoaway:
Good morning all.

I just love watching what Mother Nature can do.

Hopefully TD4/Claudette? is simply a rainmaker with no troubles. I know Texas could use something like that coming in- just NOTHING worse.


We sure could use the rain here in South Central Texas - but after seeing what Ike did to Galveston - thanks, but no thanks. We'll get our rain from El Nino - hopefully enough to bust the droughts of the last two years. The tropical systems just flood the area - not really beneficial like you'd think as the water just rushes out of here.

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I just want to know if I am still in danger o one of these system's making landfall here in Miami, FL?
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Well; gonna clear out a few items in case we get some rain in Tally from TD4 and will be back later to keep Yall posted on conditions here. If it keeps tracking NW, the Big Bend might just get a few wind gusts and some rain but from the looks of the Radar, the rest of the Panhandle to Mobile is in for a good soaking later today.....WW
Member Since: August 8, 2006 Posts: 0 Comments: 9132

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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.