Extremely dangerous Dean heads for Jamaica

By: Dr. Jeff Masters , 3:37 PM GMT on August 18, 2007

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Hurricane Dean put on an impressive round of rapid intensification last night, deepening 49 millibars in just 24 hours. Dean is now a major Category 4 hurricane with 150 mph winds. Reports from Hurricane Hunter aircraft show that Dean has likely peaked in intensity, and may be undergoing an eyewall replacement cycle. The eye has shrunk from 20 miles in diameter yesterday down to 13 miles in diameter this morning. This inner eyewall will probably shrink even more and collapse sometime in the next day, to be replaced by a new outer eyewall 30-40 miles in diameter. Dean's winds may decrease to the lower end of the Category 4 scale, 135-140 mph, if that occurs. The inner eyewall and the new outer eyewall that is forming can be seen on a microwave satellite image from this morning (Figure 1). The 11:02am EDT eye report from the Hurricane Hunters said that the southern portion of the inner eyewall was missing, so the eyewall is probably collapsing now.


Figure 1. Microwave satellite image of Hurricane Dean at 7:31am EDT Saturday August 18. Two small partial rings of strong echoes, marking the boundaries of concentric inner and outer eyewalls, are visible. Image credit: Navy Research Lab.

Dean pounded Martinique, St. Lucia, and Dominica yesterday, and the storm's death toll now stands at three. A 62-year old man died on St. Lucia while trying to save his cow from raging flood waters, and a rain-triggered landslide killed a mother and child in their home in Dominica. Martinique suffered the worst damage, with 100% of the banana crop destroyed, 70% of the sugar cane crop gone, and considerable damage to buildings on the south end of the island. Lesser damage occurred on Dominica and St.Lucia, and overall, it appears that the Lesser Antilles islands were fortunate to get off so lightly.

Puerto Rico
Dean's eye is visible on long range radar out of Puerto Rico. A major spiral band of rain moved over Puerto Rico at about 11am EDT, and will bring up to four inches of rain to the island today. Radar estimated rainfall from the Puerto Rico radar shows up to two inches had fallen as of 1pm EDT. The wind/pressure plot from Buoy 42059 south of Puerto Rico shows that Dean passed just north of that location this morning, bringing wind gusts to 66 knots.

Dominican Republic
The tourist town of Punta Cana on the east tip of the island reported sustained winds of 34 mph, gusting to 46 mph this morning. The capital city of Santo Domingo can expect sustained winds of 40-45 mph today as Dean makes its closest pass to the south. Heavy rains of 1-3 inches in non-mountainous area will create some minor flooding problems in these areas. Mountainous area along the south coast of the Dominican Republic, particularly in the rugged Barahona Peninsula that juts farthest south into the Caribbean, will receive higher rain amounts and are at great risk of life-threatening flash floods.

Haiti
Dean will make a very close passage to the south of Haiti's mountainous southern Peninsula, and the capital city of Port-au-Prince could experience winds just below hurricane force. A Category 4 or 5 hurricane passing so close to Haiti is a serious threat. Deforestation has denuded the mountainsides of protective tree cover, and flood waters will wash down the mountains into populated areas. The only saving grace in this situation may be the relatively rapid forward speed of Dean, which will reduce the amount of rain that will fall, compared to other hurricanes that have affected Haiti.

Jamaica and the Cayman Islands
Jamaica is my greatest concern. A direct hit by Dean would make it the worst hurricane strike on Jamaica for over a century. Jamaica has not received a direct hit by a Category 4 or 5 hurricane since perhaps 1832. The worst strikes of the 20th century were Category 3 Hurricane Gilbert of 1988 and Category 2 Hurricane Charlie of 1951. The Cayman Islands also have much to fear from Dean. Dean could rival Ivan as the Cayman's worst hurricane strike of the past century.

Cuba
Mountainous regions in Cuba area also at risk of dangerous flash flooding from Dean. However, civil defense is so good in Cuba that I don't expect any loss of life. Portions of south Cuba will experience sustained tropical force winds.

Mexico
The models have come into much better agreement this morning on the longer term forecast, and it looks very bad for Cancun and Cozumel. Dean will give those resort areas a pounding like they received from Hurricane Emily (Category 4) in 2005, and Hurricane Gilbert (Category 5) in 1988. Dean will probably not be as bad as Wilma (Category 4) in 2005, since Wilma stalled out over Cancun for three days as a major hurricane. Dean is moving quickly, and will not linger long over any of the regions it strikes.

Texas and Louisiana
Things are looking much brighter for Louisiana, as the GFDL model has come in line with all of the other models in predicting a landfall in Southern Texas or Northern Mexico. It now appears likely that Mexico's Yucatan Peninsula will knock Dean down a category or two before it can approach the Texas coast. The upper level low that was forecast by the GFDL to potentially steer Dean northwards appears to be weakening and moving westwards, out of the way of Dean. You can watch this upper level low on water vapor satellite loops. It is the counter-clockwise spinning region that has moved west off the Florida coast into the eastern Gulf of Mexico. If this low continues to weaken and move westwards, it will not be able to swing Dean northwestwards towards northeast Texas and Louisiana. If Dean does manage to catch up to the upper level low, the counter-clockwise circulation around the upper low will bring some south-to-north winds over Dean that would steer it on a more northerly track into the Gulf of Mexico.

The NOAA jet is scheduled to fly tonight and Sunday morning, so we should have some excellent model runs available Sunday morning and afternoon.

I'll have a short update tonight by 9pm, and a full update Sunday morning by noon. Tonight's update will focus on Jamaica, and I'll post the relevant radar and current condition links to follow the storm's path. I'll talk about Typhoon Sepat, as well.

Jeff Masters

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1841. StormJunkie
3:44 PM GMT on August 19, 2007
Dr. Masters has a new blog up

See y'all there.
Member Since: August 17, 2005 Posts: 26 Comments: 16866
1840. NisSan71
6:17 AM GMT on August 19, 2007
I'm in Santo Domingo right now, just 1 km from the south shore. We had a couple of small rain showers, nothing worse than the typical squall. Right now it's dry, with light breezes-- just enough to make the palm trees flutter. WHERE'S DEAN? Photos and blogs maps show he's right here, right now.
1839. welshcayman
5:15 AM GMT on August 19, 2007
I have just left the local Irish drinking establishment where we have karaoke on a Saturday night.

Popular songs were 'Cruel Summer', 'Rock You Like a Hurricane' and 'I Will Survive'.

You have to love the British/Caymanian sense of humour.

Bottom line in a hurricane is that no-one should die from the wind or rain - we found that out during Ivan.

The one or two days of the actual storm are nothing compared to the lack of power and water after together with the terrible heat, disease and looting.

I wish every island in the caribbean was as fortunate as us to be able to look after it's people during and after the storm to make sure there are minimum casualties.

I still find it amazing that on an island with nowhere to escape to and most of the land is just above sea level it is possible to maintain the safety of the populace as we do.

Goes to show what effort and a bit of money can do to lessen the effects of these systems.

I will be taking a video of the storm outside as long as possible without lashing myself to a palm tree and will upload to youtube and link for you guys as soon as the power comes back up.
1837. tampaENG
3:55 AM GMT on August 19, 2007
Posted By: PBG00 at 12:55 AM GMT on August 19, 2007.

Tomorrow is another day..and it will be more of the same..Have fun. To all those in Deans immediate path, stay safe.


All the "have fun" and "LOL" comments on this blog are odd. If not sick. Either this is a scientific blog about hurricane phenomena or is it a gambling ring about where its going to hit?

Place your bets do we take 3000 in Haiti or 2000 in Jamaica?
200 in Cancun or 110 in Houston?

ta ta - its going to hit me so Im going to bed! LOL

This is neither scientific nor compassionate. Do you think you are in a video game?


Member Since: August 17, 2007 Posts: 0 Comments: 97
1836. BahaHurican
3:41 AM GMT on August 19, 2007
Posted By: whirlwind at 8:41 PM EDT on August 18, 2007. (hide)
where the racism? didnt see anything here.....
plus we are paying for your internet connection and healthcare....

let the show go on...


Dear worldwind,

U are not paying for anything for me (and I doubt u are paying for any of the other Wunderground users, unless they are your family members.)
Duly minused and reported.

Member Since: October 25, 2005 Posts: 19 Comments: 22322
1835. BahaHurican
3:30 AM GMT on August 19, 2007
Posted By: rodrigo0 at 8:30 PM EDT on August 18, 2007.

whirlwind --- There are in fact thousands of white asses in Cancun... but no way... Katrina kills dozens because wind efects in several states... and Wilma, in Mexico only killed 8 people and was worst than Katrina...


People in Cancun and Cozumel got out of the way of the storm. People in the US didn't.

I saw somebody earlier posting "thousands will die" in JA, but I have a feeling people will survive. Their houses may not, but hopefully most people in JA will have enough sense to get out of the way of the worst storm surge and flash flooding.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1834. theBlur
3:22 AM GMT on August 19, 2007
BahaHurican,

It is never a bad idea to be prepared for a storm if you live near the water!
1833. AndyN
2:54 AM GMT on August 19, 2007
Check out this link and see if Dean and the ULL are on a collision course or will the ULL outrun Dean? Link
Member Since: December 29, 2005 Posts: 1 Comments: 551
1832. floridaeast
2:38 AM GMT on August 19, 2007
baha i agree with u!!!!!!!!!
1831. BahaHurican
2:31 AM GMT on August 19, 2007
Also check out the tropical storm force probabilities for the next 120 hours.



I think anybody within the shaded area (i.e. not land or water coloured) should be monitoring Dean closely.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1830. floridaeast
2:27 AM GMT on August 19, 2007
heh all do u all remmeber gean in 2005 when the models had that storm going east away from florida , and what do u think happened. jean made a complety 360 degree turn west right back to florida east coast.
that models for you.
1829. BahaHurican
2:27 AM GMT on August 19, 2007
For people interested in the potential "danger zone", a look at the Mariners' 1-2-3 map might be more informative. Currently it's showing that all of Cuba, the southwestern edge of the Bahamas island chain, and Florida's Keys and Everglades are likely to experience some effects from the storm, even on its current track. (Basically this map is designed to show boaters where NOT to go . . .)
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1828. BahaHurican
2:22 AM GMT on August 19, 2007
Talking about cones of probability, I note that most of the area affected by Erin earlier this week is now in the 5-day cone of probability.

The best advice to anyone living along the western GOM coast is to do your preps and watch for further information. In fact, even though there is a high over the Bahamas, I'm still keeping my eye open, just in case.

I also think about the D & E storms from 2005. Dennis was pretty strong, went one way into the GOM; Emily was stronger, went another way. Both passed through much the same part of the Caribbean that Dean is transversing right now. So it's not like preparing for Dean even if he doesn't come your way is going to hurt much.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1827. CaymanCaneWatch
2:19 AM GMT on August 19, 2007
any thoughts on impact on Cayman? Sitting waiting, Ivan damage was as much water related as wind, any thoughts on possible surge levels.
1826. BahaHurican
2:09 AM GMT on August 19, 2007
VegasRain,

That strike probability map u showed earlier was cool. Looks enough like the hurricane and tropical storm probability maps the NHC does to be easy to follow, too.

Only problem is that people would say, "gee, there's only a 10% probability that it will come my way" and stop watching for advisories . . .
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1825. Wecouldoit
1:50 AM GMT on August 19, 2007
Maybe Jamaica will get the 50 or 75 miles that is needs

http://my.sfwmd.gov/portal/page?_pageid=2854,19644915,2854_19644936:2854_19645082&_dad=portal&_sche ma=PORTAL
1824. floridaeast
1:43 AM GMT on August 19, 2007
This is what iam thinking and also this in in the new update, and posible (Read this )
If Dean does manage to catch up to the upper level low, the counter-clockwise circulation around the upper low will bring some south-to-north winds over Dean that would steer it on a more northerly track into the Gulf of Mexico.
i agree with this quote!!!!!!!!!!!!!!!!!!!!!
1823. StormJunkie
1:40 AM GMT on August 19, 2007
Hey y'all, Dr Masters has a new blog up, come on over
Member Since: August 17, 2005 Posts: 26 Comments: 16866
1822. Masquer08er
1:37 AM GMT on August 19, 2007
Does anyone know of a hurricane having "phobic" reaction to a land mass? I have noticed, on many occasions, a storm's jog parallels a land mass's border. I remember one storm, maybe Ivan, making a half circle around an island. Also, upon landfall, there is frequently a jog of,give or take, 50 miles. It is as if it is trying to avoid land. The recent jog w/sw (whatever) parallel to Haiti made me remember thinking this. Now I'll finally ask some folks who might know.
Member Since: August 16, 2007 Posts: 0 Comments: 397
1821. MelbourneTom
1:36 AM GMT on August 19, 2007
Just looked at the 0045 sat update. Still moving W and I think the eye will pass S of the next projected NHC point. I hope so, we will see.
Member Since: June 2, 2007 Posts: 0 Comments: 619
1820. Fl30258713
1:36 AM GMT on August 19, 2007
Dr Masters has a new blog up ya'll
Member Since: July 24, 2006 Posts: 1 Comments: 987
1819. stormlovr
1:35 AM GMT on August 19, 2007
Fl30258713, glad you found Cantore.
1818. earthlydragonfly
1:34 AM GMT on August 19, 2007
Would anyone agree with that is looks as if the eyewall replacement cycle is over? If so what do we expect next? another night of Rapid intensification or just over all building of the size of the storm?
Member Since: July 1, 2005 Posts: 10 Comments: 1683
1817. HurryKaneKata
1:33 AM GMT on August 19, 2007
Maybe Cantore is still in Hawaii........until Dean gets to the Yucatan at least.
1816. stormlovr
1:33 AM GMT on August 19, 2007
Orange Beach is awesome. Coming back to FL from Alaska has been a BIG adjustment. I forgot how much these storms make me nervous.
1815. Baybuddy
1:32 AM GMT on August 19, 2007
Daphne, Al.
Member Since: June 26, 2006 Posts: 0 Comments: 1115
1814. lowerbamagirl
1:31 AM GMT on August 19, 2007
Posted By: stormlovr at 1:19 AM GMT on August 19, 2007.

Anyone else from FL Panhandle?



Close enough. Orange Beach AL.
Member Since: July 8, 2007 Posts: 0 Comments: 198
1813. Fl30258713
1:31 AM GMT on August 19, 2007
Posted By: stormlovr at 1:24 AM GMT on August 19, 2007.

Watching TWC now ...... Where is Cantore?


I had to zoom in , but I found Jim caught in Dean's eye about an hour ago. ;-)




Jim Cantore found caught in eye of Dean
Member Since: July 24, 2006 Posts: 1 Comments: 987
1811. stormwatcher247
1:29 AM GMT on August 19, 2007
Friv - I don't know if that includes anyone but you!
1810. 1900hurricane
1:27 AM GMT on August 19, 2007
New Blog
Member Since: August 2, 2006 Posts: 46 Comments: 11669
1809. StormJunkie
1:27 AM GMT on August 19, 2007
Evening JG, you in got a safe place staked out? Getting nervous?
Member Since: August 17, 2005 Posts: 26 Comments: 16866
1808. watchinwxnwpb
1:26 AM GMT on August 19, 2007
Dr M put up a new blog a few minutes ago!
Member Since: September 15, 2006 Posts: 0 Comments: 421
1807. StormJunkie
1:24 AM GMT on August 19, 2007
SDF, the eye got real small earlier and was open at one point also cloud filled, supposedly part of an EWRC, although it is not what I am use to seeing with this type of system, and Dean weakened some with the daytime heating as well. As it gets cranked back up the pressure drop comes first. The winds catch up to it later.

oh mighty weather God

lmao, not quite, I'm hear to learn just like y'all. Just been doing it for a few years now...Thanks for the props though ☺

As for intensity tonight, i would expect modest intensification with it getting in to warmer and warmer waters along with the Diurnal max tonight we could see Dean get back up over 150 fairly easily imho. At some point I would expect Dean to doughnut, but that will take either another EWRC, or real completion of this last one.
Member Since: August 17, 2005 Posts: 26 Comments: 16866
1806. VEROBEACHFL1
1:26 AM GMT on August 19, 2007
IMO---i think that dean will be heading on its same WNW course--with lots of directional wobbles---and in the next few updates, end up slightly going NW, AND MORE WNW SOMEWHERE BEFORE the 85W mark. dean is gonna be influenced by the ULL that is moving WSW and the models may show this soon........IMO---- :)
1805. ChuckieTodd
1:25 AM GMT on August 19, 2007
Posted By: stormlovr at 8:24 PM CDT on August 18, 2007.

Watching TWC now ...... Where is Cantore?


He should wear a GPS locator and have a dot on google maps.
1804. JPV
1:25 AM GMT on August 19, 2007
Posted By: TheStormWillSurvive

where is the info that the building has collapsed or is that not true


It's NOT true. There is a FIRE, in an abandoned Manhattan bank building. 2 Firefighters have died however.
1803. thelmores
1:25 AM GMT on August 19, 2007
Myb is good SJ....... but certainly better when all the tourist's leave! LOL

You'll have to come to the new Hard Rock theme part next year! First coaster (the Led Zep) is almost done! :)

I still think Dean may skirt a little S of Jamaica, but I certainly would be "ready" to whatever extent you can be with such a dangerous storm!
Member Since: September 8, 2005 Posts: 0 Comments: 3805
1802. JamaicanGir
1:24 AM GMT on August 19, 2007
good evening SJ
1801. stormlovr
1:24 AM GMT on August 19, 2007
Watching TWC now ...... Where is Cantore?
1800. drj27
1:23 AM GMT on August 19, 2007
what is up on the weather channel always having preg women telling the weather lol
Member Since: August 25, 2006 Posts: 0 Comments: 98
1799. stormlovr
1:23 AM GMT on August 19, 2007
StormJunkie, glad to be here. I enjoy reading all your comments.
1798. dearmas
1:23 AM GMT on August 19, 2007
My husband is in NY and said that it's been on fire since 3pm
Member Since: August 23, 2006 Posts: 0 Comments: 121
1797. stormlovr
1:22 AM GMT on August 19, 2007
PCola; very cool .... I'm in PC Beach.
1796. Fl30258713
1:21 AM GMT on August 19, 2007
Posted By: stormlovr at 1:19 AM GMT on August 19, 2007.

Anyone else from FL Panhandle?


yep, Pensacola
Member Since: July 24, 2006 Posts: 1 Comments: 987
1795. StormJunkie
1:21 AM GMT on August 19, 2007
Welcome aboard storml ☺

Evening fire, not sure what else is out there. All eyes on Dean!
Member Since: August 17, 2005 Posts: 26 Comments: 16866
1794. TheStormWillSurvive
1:20 AM GMT on August 19, 2007
where is the info that the building has collapsed or is that not true
1793. stormlovr
1:20 AM GMT on August 19, 2007
DRJ27, Well Said!
1792. Xion
1:20 AM GMT on August 19, 2007
StormJunkie, what is your take on the storm's intensity and EWRCs and such as of tonight...oh mighty weather God?
Member Since: August 29, 2006 Posts: 0 Comments: 726

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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.