Extremely dangerous Dean heads for Jamaica
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
Reader Comments
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"My concern here is that people from N Texas up around to Mobile are basically blowing this off."
NOT A CHANCE HERE!
after Ivan, NO WAY,
all I know if it stays CAT 4 or 5, it won't matter if I am in appilachicola , P cola , Mobile, or NOLA, it's gonna be BIG enough to get us all!
below is time at 30 second intervals, and the wind speed in kts at the time (max 10 second winds during the 30 second period) from HH reports when going into the eye.
232830 102
232900 102
232930 108
233000 105
233030 106
233100 110
233130 116
233200 115
233230 113
233300 117
233330 113
233400 106
233430 102
233500 106
233530 113
233600 117
233630 115
233700 062
233730 020
233800 007
normally it should have picked up with out drops until a max right before entering the eye, but since it has concentric eyewalls, this is not the case.
No way skye, how could surface pressure at the spot be 697 with 26mph winds...
the states lucked out big. we got our cat 5 now lets hope the rest of this season is a bust..i think it will be
how will this be a bust? its mid august, now if it were mid september, maybe. although we could have a couple storms in the next week or so, so maybe you should wait and say that later
whipster - straight line storms
That graphic showed ONE straight line storm in the last century.
ya sure it has a great track record..tell that to the people of mexico who now have 48 hrs less to prepare for this monster if they listened to the POS. DIE GFDL DIE.
Posted By: wederwatcher555
the gfdl is worse than the cmc lol. at least the cmc had mexico what 3 days ago? this POS takes 3 runs today to finally figure it out
What's your problem? GFDL has had a very good record for the last several years. If I remember correctly it was the only model, of the big four, to predict Katrina's landfall correctly.
Either way, these long range forecasts can change on a dime anyway. I think that you are putting WAY too much stock into their accuracy. It's still a fledgling science as far as I'm concerned.
BTW, let's see the model that predicted Ivan's path correctly...
6.4 / 940.1mb/124.6kt
ADT is messing with my mind.
The Weakening Flag is still on, but some of the T# estimates are rising.
6.3 6.3 6.4 6.4
as compared to
6.3 6.3 6.2 6.2
6.3 6.3 6.3 6.3
the last two times.
Jamaica Radar!!
http://www.metservice.gov.jm/radarpage.asp
"All the models are only 66% better than CLP5 in 3 days. After 5 days they are no better."
[...]
Good point tampaENG, and that was one of the major points of Dr. Masters very last blog. That tells you something about the attention span of a couple of the crowing roosters in this otherwise informative and relatively laidback blog today.
BTW, major pieces of the GFDL have gone into the HWRF as it evolves, so think of it as a more sophisticated upgrade to the GFDL, not really a completely new model.
Acually, the GFS did!
Our prayers and thoughts are with all those affected by Dean and other hurricanes this season. I also hope that the feeder bands that are heading towards the south and central Bahamas do not cause any loss of life to areas still getting back to normal after the storms two years ago. Blessings to Jamaica, Cayman, Haiti, Cuba and the Bahamian islands of Inagua, Crooked Island, Acklins and Mayaguana.
All the best to all
mybahamas
this thing isnt going to hit the nothern gulf coast at all...all who think so are wishcasters at their best...unfortunantly this is mexicos problem after poor jamaica gets beat up by it...southern texas still has that slight chance....but i doubt they will get anything more than rain and blustery conditions...ts force winds...of course they dont even need that at this point....
LOL... famous last words. There is NO telling where it will end up yet. Give it 2-3 more days before making such bold statements.
Hmmm - please post a link
Link
BTW, let's see the model that predicted Ivan's path correctly...
Acually, the GFS did!
Interesting, even the loop back into the Eastern Coast, over Florida and back into the Gulf? Or just where the landfall was?
Slower hurricaines are more likely to recurve.
Storms accellerate as they recurve.
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