Hurricane Dean

[Cookie]

i didnt realise how many small islands thier are!

[crimsone]

i didnt realise how many small islands thier are!

Understandable! The people living on them probably don't realise how many Scotland has either

[crimsone]

Category 2 now... Oddly enough, the NHC seem to have put the pressure back at 979 mb (an error?... or was 970 an error?...)

REPEATING THE 500 PM AST POSITION...14.0 N...56.5 W. MOVEMENT

TOWARD...WEST NEAR 23 MPH. MAXIMUM SUSTAINED WINDS...100 MPH.

MINIMUM CENTRAL PRESSURE...979 MB.

0300 UTC - 991 mb

0900 UTC - 987 mb

1500 UTC - 979 mb

1800 UTC - 970 mb

2100 UTC - 979 mb

It seems bizarre that a stengthening hurricane hasn't deepened in the last 6 hours while becoming Cat 2. I wonder what's going on? I note the discussion says that there's fluctuation between 979 and 974... assuming that the reading three hours ago is wrong, then 974 would be believable to me... Something just doesn't seem quite right to me... dry air perhaps?

Edited August 16, 2007 by crimsone

[January Snowstorm]

Where's Mondy??

He would be loving this

[tcc]

Category 2 now... Oddly enough, the NHC seem to have put the pressure back at 979 mb (an error?... or was 970 an error?...)

0300 UTC - 991 mb

0900 UTC - 987 mb

1500 UTC - 979 mb

1800 UTC - 970 mb

2100 UTC - 979 mb

It seems bizarre that a stengthening hurricane hasn't deepened in the last 6 hours while becoming Cat 2. I wonder what's going on? I note the discussion says that there's fluctuation between 979 and 974... assuming that the reading three hours ago is wrong, then 974 would be believable to me... Something just doesn't seem quite right to me... dry air perhaps?

Maybe it's something to do with the EWR? (Eye Wall Replacement). Wouldn't this affect the pressure slightly?

Still looks like a hit to the Yucatan then, hoping for a gradual curve to the north! However obviously I wouldn't wish this to hit anywhere, it's going to be nasty and all over the news in a few days time!

[crimsone]

Still looks like a hit to the Yucatan then, hoping for a gradual curve to the north

It's still a possibility.

Where's an update from KW when you need one?

[Cookie]

Where's Mondy??

He would be loving this

he got banned sadly

[Somerset Squall]

Maybe it's something to do with the EWR? (Eye Wall Replacement). Wouldn't this affect the pressure slightly?

From what I understand an eye wall replacement will cause a pressure rise- I don't think Dean has had one or is going through one though. A mystery- perhaps it is just an error.

Dean center has weakened just a touch since 12pm as a little dry air has become entrained into the southern side of the circulation and the eye has breifly weakened again.

A quote from KW earlier- perhaps this may be the reason for the pressure fluctuation?

Edited August 16, 2007 by Somerset Squall

[Cookie]

dean has made BBC NEWS

The Atlantic season's first hurricane is rapidly approaching the islands in the eastern Caribbean, the US National Hurricane Center (NHC) says.

It says Dean has top sustained winds of 100mph (160km/h), making it a Category Two hurricane.

A hurricane warning has been issued for Martinique, Guadeloupe and other French dependencies, and also for Dominica and St Lucia.

The hurricane centre was some 305 miles (490km) east of Martinique at 2100 GMT.

http://news.bbc.co.uk/1/hi/world/americas/6950626.stm

[Roo]

i didnt realise how many small islands thier are!

Yes, and by now all the bigger boats will have run in front of the storm to other islands, the planes and anything else will have left, the water and electricity will have been turned off and the buildings will have their windows and doors boarded up. Those with flimsy houses will have gone to the shelters (usually old stone churches).

Those islanders are now just sitting it out, tuning into the radio and hoping it doesn't hit too hard.

My thoughts are with them

Edited August 17, 2007 by Roo

[Iceberg]

A quick update.

Pressure looks to have increased after the eye collapsed yesterday evening, minimum recorded pressure was 969 and it probably went below this before recon entered, however a gradual increase in pressure led to 979 by the time the 10.00pm advisory was issued. As to why the eye collapsed ?, it could be down to a number of reasons and these things happen all the time.

The tight banding of Dean however means that an fully formed eye is not needed for an upgrade to a CAT 2. Pressure leakage is kept minimal. The collapsing eye has also led to an expansion of the TS and Hurricane strength wind fields

Currently Dean is looking good but not fantastic, an eye wall is in place but there is no eye.

All models, Meto, ECM, GFDL, HWRF etc being dean to a boardline CAT 5 or above, it's also looking increasingly that there will only be a brief flirt with cancun before re-intensification in the GOM and most likely a Texas hit.

If Dean is to develop it needs to improve it's outflow particularly as it moves over the high octane water after the Islands, if it gorges itself it will struggle to maintain any kind of low pressure.

Edited August 17, 2007 by Iceberg

[Iceberg]

Thinking a bit more I am confident a new larger eye will develop over the next 6 hrs.

HWRF and GFDL take a direct CAT 4 hit on Jamica, a Boarderline CAT 5 on Cancun and a monster CAT 5 to North Texas.

[kold weather]

Its interesting to talk about why the eye collapsed though its a little hard to know for sure, foward speed may be a slight issue as of now with some weak shear present thanks to a ULL to the NW, though note it is only weak shear and is only going to slow strengthenig over the next 24hrs, not stop it.

It should also be noted that now its in much higher heat content the eye probably has collapsed in response to this and will re-form once the pressure has adjusted to this new fuel source IMO.

For what its worth a new eye is starting to show signs of forming with the eyewall still open on its southern side, as you say its not bad looking right now and suspect its just sorting out its inner core a little, we could well see further strengthening over the next 6-9hrs if that eye can become stronger but that is a fairly big if given its reent difficulties of getting one. I suspect the next real wave of development into a cat-4 will begin in about 18-24hrs time once its sorted its inner core out a little better.

Anyway currently aobut 2-3hrs away from passing close to Martinique and we are looking at hurricane force winds getting into the island very soon with the western side of the hurricane moving and its in this mass of convection that you'll see the hurricane force winds getting going. We are looking at 80-90mph gusts I suspect in Martinique will be in the northern quadrant which is the strongest part of the system esp given its foward speed at the moment.Will no doubt be a storm surge as well which may be quite noteable tohugh i don't know the topography of the island very well I have to admit. Still looking like a strong hit.

After that Jamacia is going to have to watch Dean very closely and could see Ts force gusts even in the outer bands over S. PR if it picks up more latitude.

Longer term and it still looks like a very powerful hurricane will move west through the caribbean and in western Caribbean Dean has a deent chance of becoming close to category-5 if not actually a category-5. not certain yet and its going to depend on timings but as I've said before many systems have done it over there and Dean would probably be a cat-4 by the time it reaches there, the extra boost may help it in terms of heat content.

Models are still very divided however on track even if they all agree on Dean becoming a very powerful hurricane. The ECM is still quite far south but is still going for a strong hurricane hitting Belize with it heading exactly due west between 96-144hrs. CMC and nogaps also go with the ECM but these two aren't all that great with these systems. GFS has shifted northwards but is a compramise between the southerly and northerly models with landfall just south of Texas after making first landfall in mid-Yucatan.

The most northerly models in GFDL and the UKMO have Dean hitting Texas and barely hitting the Yucatan at all which would not be a good thing given the strength Dean will be at that point. Right now its very hard to know which model is right. The key feature will be the action of the ULL in the gulf between 96-120hrs and its track as well as the strength of the ridge and how quickly it breaks down. Its hard to know which model is right though I do suspect the ECM is a touch too far south.

As stated before the models nearly all make Dean a very powerful hurricane. HWRF for example takes Dean down to aobut 920mbs before hitting Jamaica in about 72hrs time before dropping down to at least 912mbs before clipping the Yucatan. The GFDL does similar and gets down to about 916mbs beofre reaching the Yucatan as a powerful cat-5. It does look sadly like a NE Yucatan hit is the most likely option for landfall with this system but thats still a good 3-5 days away yet and more over possibly a Cancun hit.

Edited August 17, 2007 by kold weather

[Iceberg]

Latest :

ESTIMATED MINIMUM CENTRAL PRESSURE 976 MB

EYE DIAMETER 15 NM

MAX SUSTAINED WINDS 85 KT WITH GUSTS TO 105 KT.

A bigger eye seems to be forming/available.

Latest from Matinique.

Wind from the NE (040 degrees) at 33 MPH (29 KT) gusting to 59 MPH (51 KT) (direction variable)

Pressure 999mb

Edited August 17, 2007 by Iceberg

[kold weather]

By the way here is the latest forecast track, some small changes on the systems forecast

1:Strength has been upped, now going for 125kts before a landflall in NE Yucatan, which would be a 145mph and a mid-range category-4

2:The system is 1 degree further north on this mornings advisory compared to the advisory 6hrs ago.

Anyway here is the latest track in graphical form:

By the way Iceberg, I agree though the eyewall is still fairly open though I'm noting that radar is showing the eastern side now getting stronger over the last few hours. However ther eis no real way to know how well the eye is bar microwave imagery passes and I can't find any of Dean that is recent though the NHC probably does have that and so I suppose we'll just have to trust their better judgement. i'm sure Vis.imagery will give a better indicayion as to how well developed any eye presently is, I can't imagine it being that well developed right now but it is still very much developing its inner core still.

Dean is going to skirt just south of Martinique with hurricane force winds on the southern side of the islands and hurricane force gusts on the northern side of the island barring any jogs or wobbles which would change the exacts of the hurricane again.

(ps weak shear plus dry air intrusion into western semicircle of convection is to blame for the general lack of organisation, expected to ease in about 24hrs tohugh like I thought it might)

Edited August 17, 2007 by kold weather

[January Snowstorm]

he got banned sadly

What a disgrace

Dunno what he did but he offered so much to the hurricane thread every year

Bring back mondy!!

Edited August 17, 2007 by January Snowstorm

[Gray-Wolf]

Still looking at the predicted track makes me wonder that if it's forward movement is impeded in any way then it's 'turn north' could lead it into the Gulf proper. We saw a few years back just how quickly things can deepen in the seas off Yucatan.

[kold weather]

Its a real risk Gray-wolf, the GFDL goes mighty close to do what you mention with the modelf roecasting to skim the yucatan as a 160kts cat-5 with a central pressure of 912mbs according to the GFDL of course. Take a look at this, sure to scare anyone in Texas I'm sure:

http://moe.met.fsu.edu/tcgengifs/gfdl/2007...an04l/slp21.png

The UKMO also takes the system further north into the gulf of Mexico.

It does appear that the models are slowly shifting northwards, its noted in the discussion that the models have been slightly overdoing the upper high to the systems north and the models now should have much better data ran into them which may explain why some models are a little further north so far today.

Dean now SSE of Martinique by about 12-15 miles with the NWquadrant hitting currently, highest winds should be recieved in the next 2hrs or so then the risk of hurricane force winds, esp ion the northern sid eof the island decreases thanks to its small wind radius.

By the way I think the winds should be lowered to 80kts given the fairly messy core and I suspect the NHC will do that if the core doesn't sort itself out over the next 3-6hrs. Eyewall is still very open which may be caused by that light shear and dry air intrusion which is probably being caused by having a decent inflow from the south for a short time taking in some air from South America. Indeed this actually weakened Ivan for a short time. As I said these aren't serious problems but they will limit development needed to take it that step up, though it is expected to take that step tomorrow and once it gets that little bit further north as expected then it should get gonig een better. Best development will occur in the W.caribbean where near record breaking heat content values are present.

Edited August 17, 2007 by kold weather

[tcc]

Obviously from a purely selfish point of view, I hope it does turn north enough to not have and adverse effect around the Yucatan. However I'm fully aware that if it does it will be very nasty for the Texans (or god forbid anywhere near New Orleans!)

[kold weather]

Well thats logical tcc, of course on the systems current track if it does miss Yucatan then a Texas landflal is very possible. I suspect given the set-up right now its gonig to have a very hard time totally missing the Yucatan and I have to admit the models are suggesting that its NE Yucatan that is going to get hit and probably hit hard, maybe not quite as badly as with Wilma but you never know. Hope for your sakes it misses but starting to get closer to the time when that becomes more of a hope then an expectation.

By the way Martinique currently now in the NE eyewall where the strongest winds are being registered. Indeed Le Lamentin on the Sw side of island recorded a 89mph wind gust just now. Obviously these high wind gusts have had an impact because over the last 15 mins Martinique radar has gone down. St.Lucia by the way also reporting 55-65mph gusts just about on the southern eyewall. We won't know how much damage will have been done till this eveing probably but at least if theres one good thing its 24mph forward speed is helping Dean to move out of the way pretty quickly.

By the way, recon is flying now into Dean, on the outskirts it appears of the deeper convection. highest winds of 60kts at flight level, about 50kts at the surface very roughly. (note ths is not decoded but there is plenty of decoders out there if you look!)

http://asp1.sbs.ohio-state.edu/text/tropic...tic/URNT15.KNHC

Edited August 17, 2007 by kold weather

[Iceberg]

pressure at 991 gusts to 77Kt and sustained winds of 44Kt so far recorded at Martinique.

Recon finding some very low pressure and good winds,

Eye looks to be forming again but still slightly open, I'd expect further recon to find a period of intensification is underway. Looking better on Sat as well.

AF304 0404A DEAN HDOB 10 20070817

104400 1438N 06132W 6969 03060 9921 +107 +101 059078 080 060 006 00

104430 1437N 06131W 6961 03054 9908 +109 +093 061079 081 058 009 00

104500 1436N 06130W 6968 03038 9919 +093 +093 062082 083 059 050 03

104530 1434N 06129W 6960 03035 9894 +103 +103 056080 083 062 044 03

104600 1433N 06128W 6959 03028 9899 +088 +088 057071 074 061 017 03

104630 1432N 06127W 6966 03009 9893 +081 +081 061072 072 062 048 03

104700 1431N 06126W 6965 02994 9854 +101 +101 057074 075 063 007 03

104730 1429N 06125W 6966 02976 9820 +110 +110 054071 072 067 010 00

104800 1428N 06124W 6961 02955 9786 +117 +117 046066 068 072 010 00

104830 1426N 06123W 6971 02919 9740 +137 +137 047060 064 072 009 00

104900 1425N 06122W 6960 02913 9690 +165 +117 039045 050 067 007 03

104930 1424N 06120W 6972 02879 9685 +153 +110 033034 039 054 005 03

105000 1423N 06119W 6969 02879 9685 +143 +121 059013 018 026 005 03

105030 1422N 06117W 6966 02880 9693 +136 +117 121004 006 013 005 00

105100 1421N 06116W 6969 02891 9702 +139 +110 203011 016 027 006 03

105130 1419N 06115W 6968 02898 9710 +139 +123 212026 034 052 007 03

105200 1418N 06113W 6960 02927 9747 +123 +123 212046 052 064 018 00

105230 1417N 06112W 6974 02932 9990 +085 +999 210068 075 071 024 05

105300 1416N 06111W 6980 02946 9990 +066 +999 201080 083 068 032 01

105330 1415N 06110W 6946 03010 9885 +073 +073 203075 076 071 018 01

$$

Edited August 17, 2007 by Iceberg

[kold weather]

Recon just went through the developing eye though may have just missed the lowest pressure. Needless to say Dean is a good bit deeper then the NHC expected, lowest pressure found so far has been 969mbs on the last run through the core.

Highest winds so far has come from this ob:

104530 1434N 06129W 6960 03035 9894 +103 +103 056080 083 062 044 03

83kts would equal about 75kts at the surface based on a 90% reduction which would be used as it went through the eyewall.

Would expect to see 85-90kts in the Ne eyewall but we'll see when it goes through.

Dean looking pretty good on Vis, just lacking an eye really right now, once it gets that then it could develop quite well I suspect given the pressure is already fairly low. h we'll see what recon says when the vortex message comes through. I don't think we'll see any real strengthening beyond what we have now till tonight at the earliest but what is possible is the NHC have underdone the pressure and so may have underestimated the winds as well at the moment.

Edited August 17, 2007 by kold weather

[January Snowstorm]

Thanks for the updates guys.

Anyone got the latest sat picture?

[kold weather]

Latest vortex message, the eyewall is a good deal more developed then IR led on overnight, hence why I wanted to find a microwave pass, much better at showing these features!

968

URNT12 KNHC 171105

VORTEX DATA MESSAGE AL042007

A. 17/10:50:30Z

B. 14 deg 22 min N

061 deg 18 min W

C. NA mb 2841 m

D. 72 kt

E. 313 deg 008 nm

F. 064 deg 083 kt

G. 318 deg 018 nm

H. 970 mb

I. 11 C/ 3052 m

J. 17 C/ 3060 m

K. 11 C/ NA

L. CLOSED WALL

M. E07/17/15

N. 12345/7

O. 0.02 / 2 nm

P. AF304 0404A DEAN OB 04

MAX FL WIND 83 KT NW QUAD 10:45:00 Z

Finally the Martinique radar is back up and is showing a better looking eyewall then before with an eye starting to become better defined as well now, Vis. imagery showing just small hints of this now, not as good looking as this time yesterday mind you!

( Edit---12.40pm---Eye is now starting to show better on the newest Sat.Imagery, maybe about to deepen quite rapidly despite what I thought before based on recon and Vis.imagery. Dean also has a great outfow channel right now on its eastern side)

(ps, Recon just found winds of 80kts at the surface in one of the eyewalls with pressure down to 976mbs.)

Edited August 17, 2007 by kold weather

[Keepster]

he got banned sadly

why?