Claudette hits Florida; Ana approaches Puerto RIco; Bill becomes our first hurricane
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
Reader Comments
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Agreed. However, in the unlikely (read: very unlikely) event that it makes it into the vicinity of Florida, and traverses the very warm Gulf Stream, the longwave trough could conceivably generate a poleward outflow channel by ventilating the northern side of the circulation, possibly allowing rapid intensification, and then a high end Category 4, or even a weak Category 5, would be possible.
That is just speculation on my part though, but trough interactions have been known to rapidly intensify hurricanes (i.e. Charley).
well, i guess we have some capable folks online here tonite that can answer our questions better than I can, i believe!
but if you watch the image you'll see that there's a sort of hole on top of bill, not the big ol' circle that's on the left of it. I guess that's the weakness... and maybe the erosion is the green spots starting to show on the right ridge itself.
For sure, we saw this very clearly with Felicica when she was rapidly intensifying.
Yes, there is a small weakness along ~51W, but it currently has not been strong enough to erode the ridge to its west. It is forecast to strengthen, erode a large portion of the ridge to its west(essentially the eastern part of the ridge should be eroded), allowing Bill to turn more NW and N between the two areas of High Pressure in the North-East Atlantic.
the U!
aren't the U and the Gators rivals? hmm ...
Yep, they sure are! :)
Here, let me use my sloppy handwriting and MS paint to show you all visually what is "forecast" to happen with Bill and the High pressure areas. Give me a few minutes.
Used to be, but since the degradation in one of the aforementioned programs, not much reason to really consider it a rivalry. Plus, the two schools haven't been meeting each other lately. Any team in FL is a rival however.
whats WV?
don't worry, i think this is the first time in two days i've been able to have an answer to my doubts and questions on the ridge weakness!
this darn thing becomes too hectic, and i believe sometimes full of kids...
this is a good hour for it :)
i suppose that suspect degraded program isn't on the gator's side of the field...?
uhh, that's a negative.
Here you see the two areas of high pressure. You also see the mysterious "weakness".
Here you see that the weakness will erode the eastern portion of the western area of high pressure, allowing Bill to turn towards the north-west and eventually the north.
That is only what is currently forecast, things can change, but it actually looks as if the weakness has begun to have an effect on the subtropical ridge, as in the last 3-hour update of the Layer Mean Wind analysis, the subtropical ridge was moved slightly westward. We'll have to see if this continues.
lol
hey hurricanefcaster... i ain't as touchy as other ppl around here, no need to worry (about what you said when you first quoted me).
im planning on taking my first met classes in january, as im applying for computer engineering college and there is an associate's degree in meteorology.
im passionate about this - and i think you are, too!
thanks for your info.
Nite all
im still concerned, but ... i believe that ridge has to move east if bill has any chance of threatening our islands.
Well Bill is moving WNW as we speak and has already reached 15N, therefore even if it were to continue its current motion it would miss the leeward islands. It would have to take an actual turn towards the west for anyone to become concerned with an impact to the leewards, and a turn towards the west isn't meteorologically logical (No pun intended) at this point, so I wouldn't be very concerned.
Oh really? That's cool! Should be an interesting associate's! Yes, I am absolutely passionate, I've had a passion for weather since about the 6th grade, and had decided to study it by about 8th or 9th. :)
that's one badass animation. thanks
i live in one of those islands lol so puny... right to the left of the image...
we're definitely not in the clear.
It's so funny that you mentioned Madden, because guess what game I have in my Xbox 360 that is turned on as we speak, sitting next to me? :)
Lol, thanks for the kind words.
Is this strictly because of how quickly that ridge will be eroding? Because surely it won't be heading directly for that high off the eastern US coast that it is forecast to plow through.
my first cane was Hugo in 1989, i was 7... rode it out in Puerto Rico. Ever since then I've been hooked on hurricanes, so to speak. top it off, im a cast-die surfer lol ...
how is that met school you're attending? the minuses about USA colleges in my opinion is how to pay for them ... :(
the credit-hour cost in mayaguez is ... $40 per credit lol
well, those things aren't static, they move... so ...
speaking of which, is there an animation link to the steering layers?
go pack go!
this is the link i have on that
Well, yes, I gathered that much. It's just - it's hard to imagine them moving that much. But I will just wait and see.
And, the 6:15 GOES image is in, the eclipse is over, and... a move to the north! I'm glad to see it above 15N
Tomorrow we see major hurricane Bill.
I have to go quick, but here is a link to the site and an image:
Link
What do you think? I know that the high pressure systems interacting with Hurricanes at close distances can result in both weakining, is that true?
Bill isn't quite north enough to significantly "feel" the weakness yet, and the weakness isn't strong enough to completely steer Bill. Bill is currently being affected by a few steering mechanisms: He's not being allowed North by the ridge, and he's attempting to move poleward, thus the WNW motion. Until that High moves out of the way, he will not be able to move N or NE, thus he moves as far towards the N as he can, which is WNW at the moment.
(The reason he's trying to move poleward is complicated, involving precession of an object with angular momentum. A Hurricane precesses because of the rotation of the Earth. Since Hurricanes have angular momentum with respect to the Earth's axis, when they gain latitude they experience a conservation of that angular momentum and experience an acceleration to the east. Thus, a Hurricane moving WNW, experiencing a force from the west(A.K.A. an acceleration towards the east) will tend to move NW, N, and then NE until it is forced towards the Poles. When a Hurricane moves towards the Poles the distance to the Earth's axis decreases and it conserves angular momentum by increasing velocity.)
Low pressure (Bill) cannnot go through HIGH pressure it must go around High pressure. Therefore as Bill moves West the western edge of the High erodes allowing Bill to move up the left side of the High.
nice update! very nice
looks like shear is weakening for billy
It's an excellent school. Yes I completely understand the costs are extraordinary! I was lucky enough to earn a scholarship from UM, so we only have to pay 2-3K out of pocket per year, where tuition is $35,500 per year. (~$1,400 per credit hour)
You have to manually animate the Layer Mean Wind Analyses, click the + or - 3 HR button.
i dont think i understand...
are you asking why shear has a negative impact on a hurricane?
yeah, i kind of got it. thanks!
I was asking why the map constucters put red on the wind shear charts, shouldnt they put green on the map because its a good thing that the hurricane will die?'
ok! how did you earn that scholarship? :) grades?
lol
yeah... i guess that makes sense!
red is pretty much universal for intensity, force, stop, danger... and green for go... at least on the western world, we can say (dare we say) the States and it's territories.
So i guess they're shooting for a Red as Intense and greener for less and less.
The shear is forecast to remain low or neutral for at least 24 hours.
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