MikeC
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11 PM EDT 18 August Update
Dean has weakened in windspeed, but lowered in pressure, so Dean is reorganizing itself. And windspeed should catch up by it tomorrow. There is a very good chance that Dean will be a category 5 system as it approaches Jamaica.
The track has actually gone further left (or west) than previously thought, and the Official Forecast takes it along the Southern part of Jamaica. The windfield is very large with the storm. Jamaica will start seeing the first of Dean overnight, with the eye reaching the island in about 18 hours.
5PM EDT 18 August Update
Dean's forecast remains about the same as before, if not a little southward. Those in the cone of error, especially further out should still watch it. Those north of the cone should be aware and keep up with Dean is doing, but chances are falling that something would happen there.
Intensity is held at the same level, but it appears that it's finishing up it's first eyewall replacement cycle and may get another run of intensification tonight. There are a few other factors (like hati) that may keep it from gaining too much, but it has plenty going for it.
Jamaica, be strong.
3PM EDT 18 August Update
Dean is undergoing an eyewall replacement cycle now, with double (perhaps triple) eyewalls as it reorganizes itself, this unfortunately gives it time to recover from it by the time it gets to Jamaica. The land interaction with Hati may also slow reorganization, or even help to weaken it a bit, but it won't have too great an affect on the system.
The forecast track from 11 seems dead on, and there is no current reason to doubt the track, bad news for Jamaica. The official forecast takes the center of Hurricane Dean directly over Kingston Jamaica and through the entire island.
Beyond that, it appears that the Mexcian landfall is the most probable (Perhaps a clip of the Yucatan), followed by a south Texas hit. Other areas in the gulf have very little chance of seeing something from Dean at this time.
Do you have your own take on what Dean will do? Let us know here.
Discuss preparation, damage reports, and general Island Information here
More to come later, recon aircraft is still flying around in the storm.
Original Update
Hurricane Dean remains a strong Category 4 storm as it moves west northwest through the Caribbean. Hurricane Warnings are up for Jamaica and Hati, and those there should be done preparing, as they will feel the worst of the storm tomorrow.
The future track is fairly consistently moving it slightly north of due west into the Yucatan, however the still insists on a more northerly track, and the storm has moved slightly more north than expected, so there is still reason to watch this system in the Gulf. This afternoon, night and tomorrow is the critical time for many of these model runs. The and other models have been remarkably consistent ant for days now, moving the storm into Northern Mexico. Northern Mexico is the most likely scenario.
There were initialization problems with the wildcard upper level low over Florida, which along with a high west of it, is probably the single biggest concern with the model tracks right now. We'll be watching it to see how the storm progresses throughout the day, and how the forward speed changes.
Intensity of Dean will fluctuate down and up based on all sorts of things, look for dry air, eyewall replacement cycles, and land interaction to cause weakening, and warmer sea surface temperatures to the west of the system to help it gain more intensity.
More to come soon.
Event Related Links:
Jamaican Media
Jamaican Radio (106 Power)
Go Jamaica Hurricane Dean Watch
Jamaica Gleaner (Jamaican Newspaper)
Jamaica Observer (Newspaper)
Nationwide Radio (Hurricane coverage and live reports
starting evening 8/18.)
Jamaican News/Talk 93
Love 101 Radio
Kool 97 Radio
Irie FM Radio
Other
Jamaican Webcam recording... Treasure Beach
Jim Williams will be doing a live show on Dean tonight at hurricane city (8PM EDT)
Jamaican StormCarib Reports
Jamaican Meteorological Service
Guantanamo Bay, Cuba Radar
Southern Cuba Radar (Has Jamaica partially in range
Cuban Radar Mosaic (flhurricane long term recording of this radar)
Martinique Radar Animation Recording
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dem05
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This is a re-post from the previous thread 
I’ve attached an image I created that depicts the upper level features over the and Atlantic Basin. You may want to make a copy to follow along in the discussion. I hope it helps in depicting some of what I am seeing.
I’d also like to repost the Water Vapor Links:
Pacific NW Water Vapor Loop: http://www.goes.noaa.gov/GSSLOOPS/wcwv.html
Atlantic Wide Water Vapor: http://www.ssd.noaa.gov/goes/east/tatl/loop-wv.html
NW Atlantic Water Vapor: http://www.ssd.noaa.gov/goes/east/nwatl/loop-wv.html
CONUS Water Vapor: http://www.goes.noaa.gov/GSSLOOPS/ecwv.html
Well, I have a bag full of wrenches, so I may as well start throwing. Before I do however, I do want to caution that I will not be delving into the models or basing my statements on much of what the models have to say. Traditionally, this is a dangerous game, but with indication that the models are having a tough time in initializing storm intensity, the intensity of the upper level features, and problems with the models racing Dean off probably a bit too fast, I’ve decided not to go much farther in my discussion of them than this. With that said, the models very well may have the correct solution albeit they are not performing as well as one would hope.
The breakdown:
The Florida Upper Level Low is on the move again. From my best estimate, the center is probably right about above my head here in SW FL as I type. It does look like it is now trying to tuck south of the High Pressure Ridge. At some point, I will imagine that the Upper Low will have to either stall or phase out. At this point, it shows no evidence of phasing out, but that may happen in a couple days. Earlier, someone asked about Dean’s forward speed slowdown and how the interaction will affect track. If the Upper Level low had been stationary right now, we would likely expect that Dean would be turning North at some point. However, The Upper Level Low is also moving westward, so I would expect it’s overall influences to resulting a general WNW motion for the next 2-3 days. Dean is probably close enough to feel some of these effects now, but it is also far enough away that I would expect to see subtle fluctuations in forward speed and direction. In other words, Dean slows down a bit, the ULL moves a bit further away, the ridge builds backing a bit and Dean will move slightly faster and a little more westerly…Then Dean will catch up again, slow down and move a bit more WNWerly. In general though, I would not dismiss the Idea that Dean may get closer to Haiti than anticipated. Later on down the road, if the Upper Level low does not phase out and it stalls between 90-95W…I would say that chances for problems in the Eastern Gulf would really increase…Otherwise, the further west it can move before stalling or dissipating will result in problems points west.
Side note/disclaimer: The yellow arrows do not show a forecasted track. They are just there to show the upper air flow ahead of Dean.
Looking at the mid latitude weather systems and the jet stream, there are some other considerations to make. The jet stream over the is not zonal like it was a few days ago. (The jet stream is identified in the pink, the movement of the jet stream is outlined with Green Arrows). The trough over the Northeast US is moving out and being replaced by a ridge. The ridge is highlighted in Blue and this is the feature that the Florida ULL will sweep under. With that said, the ridge IS moving east, and may continue to do so through this evolution. There is a pretty darn good trough entering the Pacific. This trough is probably starting to move the US weather patterns along. At this time, I know the $64,000 question would be…Will that trough get into the Gulf area. Unfortunately, I don’t have an answer for that or if it would have a direct affect on Dean…But it is something to watch, and I have included a link to the Pacific NW Water Vapor Loop. With that said, it is not impossible to assume that the Florida ULL may stall in a couple days as the High Pressure ridge moves east and the Upper Level Low moves around to the SW Side of the ridge. For an additional quirk that may be another wildcard factor…It does appear that the remnants of Erin may also be evolving into a weak upper level low feature. I really can’t say that this would have any ramifications on the overall upper level pattern, but over time, it will be interesting to see if anything unfolds with that.
So that’s basically the way I see it right now…Unfortunately there are more questions than answers, but it is still to early to Pinpoint specific threats and/or dismiss any Gulf Coast possibilities at this point. Keep on tracking…
Edited by dem05 (Sat Aug 18 2007 03:26 PM)
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mr jimmy
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Loc: Spring TX
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Does anyone have a recent pic or link to one of the magificent closeups of the eye of Dean that shows the internal features? Thanks - I lost my old links yet remember the fascinating shots of the eye.
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Allison
Weather Guru
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Loc: Laredo, Texas
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Quote:
Does anyone have a recent pic or link to one of the magificent closeups of the eye of Dean that shows the internal features? Thanks - I lost my old links yet remember the fascinating shots of the eye.
Is this the link you're looking for?:
http://www1.cira.colostate.edu/RAMM/Rmsdsol/TROPICAL.html
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Allison
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pcola
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Loc: pensacola/gulf breeze
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Anyone looking at the model. I don't have much faith in it but it does show a rather robust tropical system heading towards the east coast of FL later in the week, and another near the lesser antilles.
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Erin 95 , Opal 95, Ivan 04, Dennis 05, and that's enough!!!!
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RideTheLightning
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Outstanding observations and excellent information! I agree with your observations. The gulf ULL, and the massive , fast moving pacific trough could have a significant northern shift in the future forecast track. The model runs have obviously been picking up on this.
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scottsvb
Weather Master
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Loc: fl
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There will be them 2 areas to watch but question on the bahamas and florida 1 will be how strong will it really be. shows a trough or weak TS at best. Might be lacking moisture but we will know by monday night.
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R2RICKSTER
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Or this
http://www.nnvl.noaa.gov/cgi-bin/index.cgi?page=items&ser=111962
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Andrew was enough for me!
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Random Chaos
Weather Analyst
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Loc: Maryland
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Looks like an coming up:
805
URNT12 KNHC 181636
VORTEX DATA MESSAGE AL042007
A. 18/16:14:30Z
B. 15 deg 46 min N
069 deg 02 min W
C. 700 mb 2488 m
D. 119 kt
E. 018 deg 8 nm
F. 113 deg 128 kt
G. 018 deg 008 nm
H. 930 mb
I. 9 C/ 3050 m
J. 20 C/ 3046 m
K. 11 C/ NA
L. OPEN S
M. C11
N. 12345/7
O. 0.02 / 2 nm
P. AF304 0604A DEAN OB 21
MAX FL WIND 128 KT N QUAD 16:12:00 Z
NORTH EYEWALL HAS DOUBLE EYEWALL STRUCTURE
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Hugh
Senior Storm Chaser
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Loc: Okaloosa County, Florida
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Looking at the latest recon report, it says:
North eyewall has double eyewall structure
Is this the beginning of an eyewall replacement cycle, which would (I think, anyway) explain the weakening satellite presentation over the last several hours?
(oops, Random Chaos beat me to it!)
Assuming this IS an , it could - COULD - mean a weaker Dean in the short term, but an even stronger Dean in the next couple of days, as it approaches Jamaica.
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Hugh
Eloise (1975) - Elena and several other near misses (1985) - Erin & Opal (1995) - Ivan (2004)
Edited by Hugh (Sat Aug 18 2007 04:41 PM)
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Random Chaos
Weather Analyst
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We have a good microwave overpass:
http://www.nrlmry.navy.mil/tc_pages/tc07/ATL/04L.DEAN/tmi/tmi_85h/1degreeticks/full/Latest.html
Looks like it is undergoing some structural changes.
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weathernet
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Tom -
As you and others here are indicating, very true how so many "little flies in the ointment", may at least minimally impact Dean. Its amazing how intricate and yet related, are the many upstream or downstream weather systems, along with even a slight influence can have on what may or may not be a direct hit on Jamaica ( or other land masses ). A quick footnote on what some of the models are picking up on, regarding a new eventual system east of Florida -
-- It is quite curious how what appears to be some small convective vorticity starting to spin up in the Bahamas. It is in what would appear to be a shear environment on the east side of the ULL over the E. gulf, and yet appears to have a small anticyclonic flow on its eastern side. Probably a transitory low on what appears to be an old frontal trough, which would typically fly off to the N.E., however in light of what most models are picking up on ( rebuilding ridging ), it would be an interesting sub-plot if a small system were to suddenly form off Fla. southeast coast. Though I doubt this will prove to be any kind of a "player" in Dean's evolutionary forward motion, "if" it were to develop I could see some slight and temporary influence on Dean's forward motion.
Andy
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Hugh
Senior Storm Chaser
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Quote:
Looks like it is undergoing some structural changes.
Fascinating image, truly fascinating to me at least.
What does it mean?
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Hugh
Eloise (1975) - Elena and several other near misses (1985) - Erin & Opal (1995) - Ivan (2004)
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scottsvb
Weather Master
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Loc: fl
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With regards to the system that you mentioned about going to (near florida) by next Friday...I can see what could be the feature near 17N and 38W heading wnw near 24mph. Lacking mositure and speed its going could hamper the circulation. Dean already had a moist airmass and a well defined circulation and that didnt inhibit its structure.
Anyways Dean is the main concern and even if its no for Florida or the U.S. in general. Dean is what all us weather Mets and hobbiests should "Gawk" at ( if thats a word) cause this is what we all love about weather and its threatning impacts.
Edited by scottsvb (Sat Aug 18 2007 05:33 PM)
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Genesis
Weather Guru
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The ULL and Ridge presently in place and Trough coming are the flies in the ointment, as noted.
My concern here is that people from Mid-Texas up around to roughly Mobile are basically blowing this off, and people further east are simply ignoring this storm entirely.
While the probabilities favor the 's general solution, I am not yet sold.
With the general premise that Hurricanes move towards the weakest atmospheric feature, a fracture in that ridge or worse, a trough that displaces it (if it gets here in time) could be really ugly. Now add the ULL into that and things potentially get even worse.
The has been all over the place with this storm (http://moe.met.fsu.edu/tcgengifs/) and as recently as 18 hours ago was looking directly at this potential, aiming at the middle of Lousiana! Now its after the SW edge of Texas. This sort of wild fluctuation tells me that the models have a SEVERE problem at present getting a handle on the interaction of these features,
I would not write off this storm in terms of the track holding; we should have a much better handle on this come Sunday, but that means you've only got a couple of days to get your act together! If you need wood or supplies and are in the Gulf - anywhere in the Gulf - DO IT NOW.
I am personally completing preparations for my ability to skedaddle (and I'm near Destin) TODAY. The odds are very low that this storm comes this far to the east, BUT I do not like the uncertainties in the atmosphere right now as the interactions are too complex for me to buy a single solution at the present time.
Further, anything that gets into the Gulf without serious interaction with land first (e.g. not going over much of the Yucatan or much of Cuba - basically shooting the straights) is going to be really bad simply due to oceanic heat content. The Gulf is virtually a HOTTUB right now - up here in the Northern Gulf we've had a couple of solid weeks of near-100F weather with few breaks and surface temperatures are extremely high, with the thermocline breaks being unusually deep. As such I'm deeply concerned about the heat content and thus the fuel available to sustain an extremely strong storm.
Is it really bad if you have a full tank of gas in the car and the storm doesn't come your way?
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vineyardsaker
Weather Guru
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Loc: New Smyrna Beach, FL
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Quote:
Later on down the road, if the Upper Level low does not phase out and it stalls between 90-95W…I would say that chances for problems in the Eastern Gulf would really increase…Otherwise, the further west it can move before stalling or dissipating will result in problems points west.
Let me get that straight: there is still a possibility for Dean to fully change course and actually head for Florida even though all the models point at Texas as only US state where Dean might make landfall?
Or did you mean *Western* Gulf?
If you did mean Eastern Gulf, what is the earliest possible date for such a Floridian landfall?
Thanks!
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Charley(eyewall), Ivan, Jeanne, Dennis, Wilma, Irma, Ian (eyewall), Nicole
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Random Chaos
Weather Analyst
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We have concentric eyewalls now. Definitely undergoing an (Eyewall Replacement Cycle).
078
URNT12 KNHC 181731
VORTEX DATA MESSAGE AL042007
A. 18/17:02:40Z
B. 15 deg 49 min N
069 deg 14 min W
C. 700 mb 2484 m
D. 101 kt
E. 121 deg 007 nm
F. 212 deg 110 kt
G. 121 deg 007 nm
H. 930 mb
I. 11 C/ 3051 m
J. 16 C/ 3052 m
K. 15 C/ NA
L. CLOSED
M. CO 11 22
N. 12345/ 7
O. 0.02 / 2 nm
P. AF304 0604A DEAN OB 27
MAX FL WIND 128 KT N QUAD 16:12:00 Z
MAX FL WIND OUTBOUND 133 KT NE QUAD 17:06:50
CONCENTRIC EYEWALL STRUCTURE
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Hugh
Senior Storm Chaser
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Quote:
We have concentric eyewalls now. Definitely undergoing an (Eyewall Replacement Cycle).
We had concentric eyewalls yesterday (or the day before) as well, I believe. I also believe they were followed by rapid intensification. Could that be the case today? Is the actually coming to a completion?
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Hugh
Eloise (1975) - Elena and several other near misses (1985) - Erin & Opal (1995) - Ivan (2004)
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scottsvb
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First off its not going to stall so you dont have to worry about that. Also the eastern gulf is not out of the possibilities but lets just say its less then 5%.. Central Gulf 20% and Tx about 40%....its looking like Mexico but that is still 4-5 days away. First lets trust the models out to 3 days...by tomorrow nights 0Z runs we will have a very good idea if it will be Tx or Mexico event.
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Clark
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Quote:
We have a good microwave overpass:
http://www.nrlmry.navy.mil/tc_pages/tc07/ATL/04L.DEAN/tmi/tmi_85h/1degreeticks/full/Latest.html
Looks like it is undergoing some structural changes.
Definitely -- and it backs up the earlier recon messages too, particularly the one that said "north eyewall has double eyewall structure." That image shows very well the double -- and you can even make a case for triple -- eyewalls, particularly on the north side of the storm. How fast this occurs will determine whether or not it can seriously tap into the warm eddy south of Hispaniola or if it will merely just have it to support itself today.
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