Claudette hits Florida; Ana approaches Puerto RIco; Bill becomes our first hurricane

By: Dr. Jeff Masters , 2:10 PM GMT on August 17, 2009

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Tropical Storm Claudette made landfall at about 1:15 am EDT near the eastern end of Santa Rosa Island, just southeast of Fort Walton Beach in Florida. Claudette's top winds were around 50 mph. A Personal Weather Station in Eastpoint, FL recorded sustained winds of 49 mph, gusting to 66 mph last night. So far, the rain from Claudette has had a tough time penetrating inland (Figure 2). Heavy rains of 3 - 4 inches have been confined to a narrow strip of coast, and Claudette is unlikely to cause any major flooding. Apalachicola received just over 4 inches of rain so far from Claudette. Radar animations out of the Florida Panhandle show that heavy rains continue along the coast in association with a main spiral band of Claudette, and these rains will gradually subside today.


Figure 1. Radar reflectivity image of Tropical Storm Claudette as it approached landfall just southeast of Fort Walton Beach shortly after midnight on 8/17/09.

The tropics featured a rare triple threat the past two days--simultaneous named storms beginning with the letters A, B, and C. The last time this occurred was in the slow-starting 1984 hurricane season, when Tropical Storms Arthur, Bertha, and Cesar were all active on September 1. This year's A, B, and C storms all got their names in just a 33 hour span. This is not a record, since in 1995, three tropical storms--Humberto, Iris, and Jerry--got their names in a 27-hour span (thanks to NOAA's Ryan Sharp for looking up this stat).


Figure 2. Total precipitation estimated by radar for Claudette, as of 3:28pm EDT 8/17/09.

Ana not dead yet
Tropical Depression Ana continues to cling to life, and is now approaching landfall in Puerto Rico. Radar animations from the San Juan, Puerto Rico radar show a surface circulation just southeast of the island, with some low-level spiral banding trying to develop to the south. Recent satellite images also show a rejuvenation of the heavy thunderstorm activity near Ana's center, as the storm regroups from being nearly torn apart yesterday. Ana has already dumped up to 4 inches of rain along the north coast of Puerto Rico, according to radar-estimates.

It is unlikely that Ana will survive past today, however, since the storm will move over both Puerto Rico and the rugged terrain of Hispaniola. The high mountains of these islands should act to disrupt the relatively small and fragile circulation of Ana. None of the computer models foresee that Ana will survive passage over Hispaniola. The Dominican Republic can expect 3 - 6 inches of rain from Ana, and Haiti can expect 1 - 3 inches.


Figure 3. Total precipitation estimated by radar from Ana for Puerto Rico.

Bill becomes the first Atlantic hurricane of 2009
Hurricane Bill continues to gather strength, and is now the first hurricane of the 2009 Atlantic hurricane season. An eye has appeared on visible and infrared satellite imagery, and Bill is displaying an impressive symmetry, with plenty of low-level spiral banding.

Wind shear is low, 5 - 10 knots, and is forecast to be in the low range through Wednesday. With Sea Surface Temperatures only 27°C today, substantial intensification may not occur until Tuesday and Wednesday, when SSTs warm to 28 - 29°C and ocean heat content sharply increases. By Thursday, Bill is expected to leave the favorable upper-level wind environment it currently finds itself in, and moderate shear of 15 - 20 knots may limit further intensification.

Water vapor satellite imagery shows that there is a modest trough of low pressure in the upper atmosphere near 50°W longitude, that Bill is currently approaching. All of the computer models except the UKMET predict that this trough will be strong enough to turn Bill more to the northwest so that the hurricane misses the Lesser Antilles Islands. The UKMET predicts the trough will not affect Bill much, and that the hurricane will pass through or just north of the islands on Thursday. For now, the UKMET solution is being discounted, since the trough at 50W appears substantial enough on satellite imagery to be able to turn Bill more to the northwest.

A much larger trough of low pressure is expected to develop along the U.S. East Coast late this week, turning Bill even more to the northwest. Most of the models predict Bill will pass very close to Bermuda on Saturday as a result. The HWRF model predicts Bermuda will receive a direct hit at Category 4 strength. Until Bill interacts with the small trough at 50°W, it is too early to be confident of the potential threat to Bermuda. By Tuesday, we should have a much better idea of the threat. Likewise, I would like to see the UKMET model come around in line with the other models before dismissing the possible threat to the U.S. East Coast. It currently appears that Bill will miss the U.S. East Coast, but that a strike on the Canadian provinces of Newfoundland or Nova Scotia is possible.

I'll have an update Tuesday morning, or possibly this afternoon.

Jeff Masters

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Quoting extreme236:


The eye had shown itself on the previous image. Obscured again now.


Yeah I saw that. Ive been lurking for a few hours.

Its seems that the inner core hasnt become well defined enough to support an eye.
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Bill is forcast to split between the two highs and thats why you are seeing the Bermuda high building to the west as forcast!!
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3022. JLPR
Quoting StormW:


Well, until I can see the updated steering layers in the a.m., I still feel at the moment he should pass north of there, if he looks like he could get closer, I'll have it in my synopses.


thanks
I will keep a close watch on your updates =D
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Quoting Drakoen:
WARNINGS NEED TO BE PUT UP FOR SOUTH AMERICA!~~~~


stop being such a smart ass
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Quoting Dakster:


Alright. Dr. Lyons, why do you say he is rapidly intensifying when it looks to all of us here at the Wunderground that he is injesting dry air and not intensifying?

TWC forecasting is usually several hours behind 'real time' observations. jmo
Member Since: July 11, 2006 Posts: 14 Comments: 11423
3019. Dakster
Apparently, someone has hacked Drakeon's account, again.. Either that he is smoking some wierd stuff.
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Quoting extreme236:


Doubtful. It filtered out worse yesterday.


I agree, gonna take more than dry air to weaken this one.
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Quoting pearlandaggie:




"panicing" just looks wrong....kind of looks like pan icing...LOL


that's why...you left the "k" out of "panicking"...i knew something looked fishy! :) damn, Engrish is hard! hahaha
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t-20 minutes until f5 mania hahaha
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3014. Drakoen
WARNINGS NEED TO BE PUT UP FOR SOUTH AMERICA!~~~~
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Quoting Stormchaser2007:


Theres no way for it to make it into the Caribbean.



i wont agree with that. I don't like how Bill's heading SW.
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Quoting StormW:


Well, you get a net effect...if you average it out, the ridge pushing him sort of south, the trof trying to bring him north, and the flow around the building ridge (westward?), you get the current slow down, and current motion.



will the surrounding dust affect only his strength, or his movement as well? if it weakens him, is he less likely to be "steered" by the aforementioned factors?
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It seems Bill is not strengthening and is on track to move to the SOUTH of its next forecast point. I would expect another left shift in the track for Bill at 11.
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Night all, thanks for the fun!
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Quoting MelbourneTom:
Good size wedge of dry air starting to enter. Bill may actually begin to weaken.



Doubtful. It filtered out worse yesterday.
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Quoting theshepherd:
Hmmm?
Maybe Bill slowed down to visit the deepest heat vent in the Atlantic?



Again.

Very old sat images there.
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Quoting Weather456:


tell that to dr lyons. he says bill is rapidly intensifying. :)


456 are you worried at all?
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Quoting surfsidesindy:


I can't imagine having been there for IKE. We've been through Frances and Jeanne, but nothing like what you guys went through with IKE.


yeah, it really sucked. i've never seen anything like it...and we got off with only light damage!

Quoting kmanislander:


Probably a cross between being paranoid and panicing !


"panicing" just looks wrong....kind of looks like pan + icing...LOL
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I want a skippy in my lunch!
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3003. Dakster
Quoting Weather456:


tell that to dr lyons. he says bill is rapidly intensifying. :)


Alright. Dr. Lyons, why do you say he is rapidly intensifying when it looks to all of us here at the Wunderground that he is injesting dry air and not intensifying?
Member Since: March 10, 2006 Posts: 0 Comments: 10796
Quoting Stormchaser2007:


Yes

But not here.

This is more recent.


The eye had shown itself on the previous image. Obscured again now.
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Good size wedge of dry air starting to enter. Bill may actually begin to weaken.

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Quoting indianrivguy:


I wonder why that is.. anyone know?


Surprisingly, not much lightning occurs in the inner core (within
about 100 km or 60 mi) of the tropical cyclone center. Only around a
dozen or less cloud-to-ground strikes per hour occur around the eyewall
of the storm, in strong contrast to an overland mid-latitude mesoscale
convective complex which may be observed to have lightning flash rates
of greater than 1000 per hour (!) maintained for several hours.
Hurricane Andrew's eyewall had less than 10 strikes per hour from the
time it was over the Bahamas until after it made landfall along Louisiana,
with several hours with no cloud-to-ground lightning at all (Molinari et
al. 1994). However, lightning can be more common in the outer cores of
the storms (beyond around 100 km or 60 mi) with flash rates on the order
of 100s per hour.

This lack of inner core lightning is due to the relative weak nature
of the eyewall thunderstorms. Because of the lack of surface heating
over the ocean ocean and the "warm core" nature of the tropical cyclones,
there is less buoyancy available to support the updrafts. Weaker updrafts
lack the super-cooled water (e.g. water with a temperature less than 0 C
or 32 F) that is crucial in charging up a thunderstorm by the interaction
of ice crystals in the presence of liquid water (Black and Hallett 1986).
The more common outer core lightning occurs in conjunction with the
presence of convectively-active rainbands (Samsury and Orville 1994).

One of the exciting possibilities that recent lightning studies
have suggested is that changes in the inner core strikes - though the
number of strikes is usually quite low - may provide a useful forecast
tool for intensification of tropical cyclones. Black (1975) suggested
that bursts of inner core convection which are accompanied by increases
in electrical activity may indicate that the tropical cyclone will soon
commence a deepening in intensity. Analyses of Hurricanes Diana (1984),
Florence (1988) and Andrew (1992), as well as an unnamed tropical storm
in 1987 indicate that this is often true (Lyons and Keen 1994 and Molinari
et al. 1994).

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Another 35 minute wait until the new advisory on Bill..don't think much will change, probably move a little to the west.
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Quoting Weather456:


tell that to dr lyons. he says bill is rapidly intensifying. :)


Well apparently hes not looking at MIMIC and recent microwave images.

Also the presentation isnt impressive at all.

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2997. JLPR
Quoting Weather456:
WHCA31 TAPA
TROPICAL CYCLONE ALERT STATEMENT NUMBER 5
ANTIGUA AND BARBUDA METEOROLOGICAL SERVICE
5:00 PM ECT MON AUGUST 17 2009


THIS IS FOR THE LEEWARD ISLANDS AND THE BRITISH VIRGIN ISLANDS


THE MET OFFICE IS CLOSELY MONITORING THE PROGRESS OF HURRICANE BILL WHICH IS NOW LOCATED IN THE CENTRAL, TROPICAL, NORTH ATLANTIC OCEAN ABOUT 1000 MILES EAST-SOUTHEAST OF THE LEEWARD ISLANDS AND 1200 MILES EAST-SOUTHEAST OF THE BRITISH VIRGIN ISLANDS. THE SYSTEM POSES NO IMMEDIATE THREAT TO THE AREA AT THIS TIME. ON ITS PRESENT TRACK, BILL IS FORECAST TO PASS TO THE NORTHEAST OF THE CARIBBEAN, AWAY FROM ANY LAND MASS. HOWEVER, RESIDENTS SHOULD MONITOR THE SYSTEM AS A SHIFT TO THE LEFT OF THE FORECAST TRACK COULD BRING BILL DANGEROUSLY CLOSE TO THE ISLANDS. BULLETIN TRACK SATELLITE

FORECASTER DESTIN


Well thats not good =P
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Quoting StormW:


This is why Bill has slowed down. Yes, the weakness still has some pull, but mainly to his N and NNE, while to his NW, the ridge is beginning to build in somewhat, pushind down on him right now, and keeping his motion around 280-285.


Hi, I'm a lurker and have always enjoyed reading your comments. This ridge that you speak of...was it always in the forecast? Meaning the timing and it's magnitude?
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Let's see if there is a slight westward shift at 11:00 p.m. EST.
Photobucket
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Quoting HurricaneJoe:


Evening futuremet. I'm guessing you've read up, what's your opinion on this whole "shift to the west" deal?


No I have not. If Bill is moving west, then it is probably just another wobble. Do not focus in mere one or two frame images.
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Hmmm?
Maybe Bill slowed down to visit the deepest heat vent in the Atlantic?

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Time for the Wild Bill Show.. Pull up your chairs and keep your eyes glued to the screen.. You haven't seen nothing yet! LOL
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Quoting Stormchaser2007:


Its not doing any intensifying.

Not now at least.


tell that to dr lyons. he says bill is rapidly intensifying. :)
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Quoting DestinJeff:
eye evident on this image:



Yes

But not here.

This is more recent.
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Quoting futuremet:
Little lightning in Bill, which is typical for tropical cyclones



I wonder why that is.. anyone know?
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Quoting DestinJeff:
eye evident on this image:



are you sure it's really "evident"?? LOL...looks like a burned out pixel! :)
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2986. Relix
See? NHC is never overly dramatic with track changes or putting out warnings. There's no need right now.
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Quoting pearlandaggie:
2958. WTF is "paranoic"?? LMAO


Probably a cross between being paranoid and panicing !
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2962. Mossyhead.

Thanks, makes sense I guess.

This has been a really interesting last few weeks.
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For all those out there acting like the XTRAP is the tool of Satan, it's a really handy reference point. Take a look at it now. It's basically pointing WNW, right? So next time u look at it, if it's still pointing in the same direction, u've had no real change in direction of movement. This I expect to continue w/ Bill, for example, for another 12 - 24 hrs. If on the next run, however, u notice that the Xtrap is now pointing at, say, Cape Hattaras (sp), u can be pretty sure that the storm has moved to the NW instead of NNW. It is a primative tool, but useful.
Member Since: October 25, 2005 Posts: 19 Comments: 22734
Quoting pearlandaggie:


well, i'd DEFINITELY rather be in ECFL than in Surfside, Texas :)


I can't imagine having been there for IKE. We've been through Frances and Jeanne, but nothing like what you guys went through with IKE.
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Quoting GatorWX:


well with all due respect, they are part of the Caribbean lol


Depends on which part of the islands.
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Anything is possible in the tropics.
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2978. ackee
quick poll where is bill moveing now ?
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2977. funeeeg
Hi all, been lurking so far this year. Have a look a this,<a href="http://cimss.ssec.wisc.edu/tropic2/real-time/storm.php?&basin=atlantic&sname=03L&zoom=4&img=1& vars=1111100000000000000000&loop=0" target="_blank">Link> click on SWIR and you can see that Bill is bang on the NHC forecast track. Can't see any jog West.
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2976. JLPR
Quoting StormW:


Not too strong, but enough to probably, pull him away from the current weakness, and keep him possibly WNW for a little while longer, until the second weakness begns to erode the ridge in a few days.


Then by what you say do you believe it could end up a little closer to the NE islands?
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Quoting futuremet:
Little lightning in Bill, which is typical for tropical cyclones



Evening futuremet. I'm guessing you've read up, what's your opinion on this whole "shift to the west" deal?
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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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