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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We'll see...
News to me. Roads outbound weren't too busy today. Wouldn't surprise me tho. I left a day earlier than I thought I needed to for Rita, still took me 3 hours to drive an hour north, and that thankfully was a short trip.
The sad part is, it's supposed to be 'better' this time, but I'm not so certain. A large portion of it seems to be contingent upon evac zones, and letting people closer to the coast leave first.
Like -that- is going to happen.
http://www.h2-pv.us/wiki_100mpg/img/wiki_up/20070818_2315._04LDEAN_130kts.jpg
President Bush has signed a pre-landfall emergency disaster declaration for Texas, allowing the federal government to immediately send people, equipment and supplies to the state when Dean makes landfall there.
Who says it's making landfall there?
Is Jamaica gonna be spared? Dean jogged south for a short time.
I don't know what they were showing - probably the Rita evac. Or just the usual traffic in Houston lol - but no evac has been called in Houston and to say that an evac in process is irresponsible
"Can Dean get so big and powerful that it affects it's own course --things like lows, trough, shear, won't matter? Is it folk lore or is it true that hurricanes like to go to the higher latitude? Wouldn't Dean be lured to the warmest water in the Gulf which is more in the middle?"
surfmom- Large hurricanes can affect relatively weak systems around them, but they cannot stand up for long against strong troughs or highs coming down from the mid-latitudes.
Hurricanes do tend to gain latitude as they progress though the Atlantic basin. A hurricane will travel WNW in the Northern Hemisphere even if the steering flow is calm. But a strong high will overwhelm this effect and push the storms west or even southwest on occasion.
Hurricanes do not seek out warm water, but are more likely to develop in very warm water.
Hope this helps.
Dean is powerful enough to create its own environment inside the larger environment of highs and lows that determine its path - so yes, bigger hurricanes can push things around them a bit - but they still will obey the laws of physics - or in this case - fluid dynamics.
Dean does not sense or follow the warm water patterns in the ocean. It can't move its path toward warmer waters - it is guided by the larger patterns in the atmosphere. During hurricane season in the Atlantic, the western Caribbean and the Gulf of Mexico frequently have high TCHP or tropical cyclone heat potential. Meaning that these areas have deep layers of very warm water which is available to feed a tropical system. Since many tropical systems move over these waters during the season, it is something that is taken into account when trying to predict hurricane intensity.
The warmest water isn't necessarily in the middle of the Gulf of Mexico. There is an overall current - the Caribbean Current that flows west bringing warm water from the Equatorial Current (at the equator between the North Atlantic and South Atlantic) into the Caribbean and then there is another current in the Gulf of Mexico- the Loop Current. The Loop Current in the Gulf of Mexico is much like its name. It makes a loop into the Gulf of Mexico before the warm water flows into the channel between Florida and the Bahamas. The Loop Current sometimes extends all the way up to Louisiana or it can get cut short and move water right into the Straits of Florida. The Loop Current is always changing position and size in the Gulf of Mexico.
Hope that helps.
#1- That is an irresponsible post...no one knows exactly where it will end up yet.
#2- If stating an OPINION on knowing where it will or will not go makes a person a "wishcaster", you are being hypocritical by saying yourself it will not go here or there.
#3-Guess that makes you a wishcaster also!
http://www.brownsvilleherald.com/news/island_79410___article.html/storm_residents.html
isnt stormtop the same person as stormkat?
It's someone different. This ST has his name in all caps....the original didn't.
Posted By: watchingnva at 8:13 PM EDT on August 18, 2007. 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....
#1- That is an irresponsible post...no one knows exactly where it will end up yet.
#2- If stating an OPINION on knowing where it will or will not go makes a person a "wishcaster", you are being hypocritical by saying yourself it will not go here or there.
#3-Guess that makes you a wishcaster also!
I agree
It was a surfer buddy of mine who insisted that Charlie was headed for port Charlotte - even I didn't believe him, now I listen to the experienced locals who have a "feel" but I don't ignore the hard science either
I worked in the Caribbean, for a short while, and some of the locals could predict when a storm was coming, and for how long it would last, down to the minute. Better that ANY Weatherman ever could.
I've also witness how the weather in the Caribbean can drastically change in a matter of seconds.
Those making all these predictions, with so much bravado and certainty, are being foolish. It's still too early to tell where this thing will end up.
Alot of things have to happen, The High building in and the ULL that will cross in front of Dean..... So lets all wait and see what will happen in 2 - 3 days.... Then we go from there..
Taco :0)
BeenThere in Miami: True the upper level flow constrains the storms but warm waters due increase intensity which changes the atmosphere which changes the ULL flow pattern which changes the storms. So there may be an indirect effect of some sort!
What the process for getting someone to address all this racism?
Hit the lil red mark on the right
--as for now--we will watch dean wibble wobble along in all sorts of misdirections-- WNW. WSW,DUE west etc........
Minimum surface pressure of 918mb? Is this recent? This is catergory 5-caliber if it is true. Could very well be the case--satellite presentation has improved dramatically over the past 6 hours and the west side of the storm is looking fuller and healthier. Also note the south-of-forecast track in the last 3 frames. Probably just a wobble, but it could mean Jamaica is on the NE side of the eyewall and the worst case scenario for surge...
And that is based on todays models runs, based on todays weather data. Tomorrows input data could yield a different center line and a three day confidence error that includes much of Texas coast and perhaps even Louisiana.
The closer we get to the time of landfall the more confidence we can have that the models will be on target. This graph shows how our confidence in landfall location prediction changes with the number of days out.
Dean will actually make landfall in Seattle... after blasting right across Mexico like he was Ponce deLeon... then a brief drink of the Pacific before swinging north to listen to some grunge.
BET ON IT!
Seriously... no-one has any idea where it's going to hit... they're all guessing. Until about this time next week, anyone who lives in a vulnerable area needs to be aware of it... and get outta the way if it gets close... that's all.
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