Dr. Jeff Masters' WunderBlog

Omar near hurricane strength; TD 16 slowly strengthening
Posted by: Dr. Jeff Masters, 19:59 GMT le 14 octobre 2008 +2
Tropical Storm Omar is steadily strengthening as it continues to lash northern Colombia, northern Venezuela, Aruba, Bonaire, and Curacao with heavy rains. The latest Hurricane Hunter center fix at 3:06 pm EDT found the pressure had dropped significantly, to 986 mb. The crew reported that heavy thunderstorms were beginning to wrap around the center, which had taken on a better-defined circular shape. Omar is beginning to form an eyewall, and could be a hurricane by morning. Indeed, surface winds reported by the Hurricane Hunters were 70 mph--very close to hurricane strength. Radar from the Netherlands Antilles shows that the rain has organized into spiral bands, but heavy thunderstorm activity is missing on the northwest side of the storm. Satellite loops show the amount of heavy thunderstorm activity continues to increase and organize. Wind shear has fallen to a moderate 10 knots, allowing this increased organization to occur.


Figure 1. Current satellite image of Omar.

The forecast for Omar
The storm is expected to turn northeastward tonight as an upper-level trough of low pressure digs far enough south to pull the storm towards the Virgin Islands and northern Lesser Antilles Islands. Wind shear is expected to remain in the moderate 10-15 knot range over the next three days, and waters will remain warm, 29°C. This should allow Omar to intensify into a hurricane before it moves through the Virgin Islands and northernmost Lesser Antilles Wednesday night. I expect Omar will remain near its current intensity until it completes building an eyewall, which it should happen between 12 am and 6 am EDT Wednesday. At that time, the potential for rapid intensification into a Category 3 hurricane exists. The latest SHIPS model is forecasting that Omar will rapidly intensify over the next 24 hours, arriving in the Virgin Islands Wednesday evening as a borderline Category 2 or 3 hurricane with 110-115 mph winds. The GFDL and HWRF are much less aggressive. They forecast higher shear affecting Omar, and 70-75 mph winds at landfall. Given Omar's current appearance and rather low pressure, landfall Wednesday evening as a Category 2 hurricane looks like a reasonable intensity forecast. I give Omar a 30% chance of being a major Category 3 hurricane at landfall.

Omar's storm surge
If Omar does become a hurricane, wind damage is likely to be the greatest threat from the storm. Storm surge is usually not a problem in the Virgin Islands and northern Lesser Antilles, since these islands are surrounded by deep water, and the surge tends to flow around the islands, rather than be forced up onto the islands. As seen in Figure 2, the maximum storm tide from a mid-strength Category 3 hurricane with 120-125 mph winds is generally in the 3-4 foot range in the Virgin Islands. St. Thomas and Anedega Islands can get a slightly higher surge of 5-6 feet, due to their convex shape facing southwest, which will tend to trap the surge from a northeastward moving hurricane. The down side of having deep water close to shore is that the waves will be high, and the Virgin Islands and northern Lesser Antilles Islands can expect considerable coastal erosion and damage to coastal structure due to high battering waves.


Figure 2. Expected maximum storm tide (storm surge plus a correction for the storm hitting at high tide) for a Category 3 hurricane moving northeast at 12 mph through the Virgin Islands. This is NOT the surge expected from a particular storm, but rather the maximum computed storm tide (Maximum Envelope of Waters, or MEOW) from eleven different simulated hurricanes (with tracks shown in black with arrows). The simulations were done using NOAA's SLOSH model.

Heavy rains from an outer rain band are just south of Puerto Rico and the Virgin Islands, and will move into the islands over the next few hours. This rain should only last a few hours, and the bulk of Omar's rain will not arrive until Wednesday afternoon. Omar should bring heavy rains of 3-6 inches to the easternmost tip of the Dominican Republic on Wednesday, but the rest of Hispaniola should escape heavy rains. All of the Leeward Islands are at risk of total rainfall of 5-10 inches from Omar. Martinique radar shows heavy rains affecting all of the islands north of Martinique.

Links to follow
Puerto Rico radar
Eastern Caribbean buoy 42059
San Juan, Puerto Rico weather
St. Croix, Virgin Islands weather
Martinique radar

Tropical Depression 16 off the coast of Honduras
Tropical Depression 16, near the Honduras/Nicaragua border, continues to slowly organize. The region is under low wind shear, 5-10 knots. Satellite loops show a modest amount of heavy thunderstorms spread out over a large portion of the Western Caribbean. Heavy rains are affecting extreme northeast Nicaragua and northeastern Honduras, and will be pushing into Belize and Mexico's Yucatan Peninsula this evening. So far, rainfall rates in the heaviest thunderstorms over land have been near 1/2 inch per hour (Figure 3). These rains will steadily increase in coverage and intensity as TD 16 continues to organize. This afternoon's Hurricane Hunter mission found 30-35 mph winds and a central pressure of 1004 mb.

The forecast for TD 16
Conditions are favorable for TD 16 to intensify into a tropical storm. The system is expected to track very coast to the coast of Honduras, and this proximity to land should limit intensification potential. A west-southwesterly motion into the northern coast of Honduras is not expected, since the latest set of model runs keeps TD 16 just offshore. However, it would not take much of a deviation in track for TD 16 to make landfall in northern Honduras. Wind shear is forecast to remain low, 5-10 knots, for the rest of the week. As long as the center remains over water within 50 miles of land, slow intensification should occur, and the GFDL and HWRF models are expecting TD 16 to make landfall Thursday morning in Belize as a 50-55 mph tropical storm. If TD 16 manages to move farther from land, more significant intensification could occur, but that doesn't appear likely at this time.

Links to follow
Puerto Lempira, Honduras weather


Figure 3. Estimated rainfall rates from TD 16 at 9:43 am EDT Tuesday, October 13, 2008. Image credit: Navy Research Lab, Monterey.

Nana and the child of Nana
Tropical Depression Nana has been torn apart by wind shear of 30-40 knots. Regeneration is unlikely due to the continued high wind shear expected along its path. The small area of disturbed weather south-southeast of Nana (90L), has also been disrupted by high wind shear, although latest satelite loops show a small amount of heavy thunderstorm activity still clinging to the east side. The shear should prevent either system from redeveloping.

Hurricane Ike relief efforts: Monday 10/13/08 update
From StormJunkie's blog today: Portlight.org is currently preparing the next push of supplies to head to the forgotten populations and disabilities community along the Texas Gulf Coast. Due to the exceptional pricing that U-haul has given us on trucks we have found the cheapest way to transport these goods is to continue to utilize our U-haul deal to transport these goods. We will be delivering many items to these outlying communities early to mid next week. Look for updates on this trip as it happens!

Some of the supplies that are being delivered include 50 manual wheel chairs that were specifically requested by the Houston Mayor of Disabilities. We have also received items from Coleman and Dick's Sporting goods which will be on the truck. A pallet of tents has also been donated by an anonymous person. Some quantity of socks has also been donated. As we receive and secure more items we will continue to update. In the mean time, if any have connections that may be able to help us acquire some of the following items; your timely help is greatly appreciated.


Figure 4. Chief Dickie Uzzle of the Bridge City Fire Department opening supplies sent by Portlight. Supplies were not only needed but also greatly appreciated.

Contributions to the portlight.org charity fund are fully tax-deductible, and will go to provide relief supplies for those smaller communities typically bypassed by the traditional relief efforts. More details can be found at StormJunkie's blog.

I'll have an update Wednesday morning.

Jeff Masters
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351. Seastep 01:47 GMT le 15 octobre 2008    
Quoting Stormchaser2007:
This pop up thing is really annoying me.


switch to 50 per page and it's gone
Member Since: 9 septembre 2008 Posts: 6 Comments: 3406
352. Stormchaser2007 01:47 GMT le 15 octobre 2008    
Quoting Seastep:


switch to 50 per page and it's gone


I did.
Member Since: 9 juin 2007 Posts: 4 Comments: 15248
353. JRRP 01:47 GMT le 15 octobre 2008    
i think 14.6n 68.5w u can see the eye
Link
regreso luego
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354. Beachfoxx 01:48 GMT le 15 octobre 2008    
Evening....

Does anyone know anything about WeatherTap????
Member Since: 10 juillet 2005 Posts: 153 Comments: 29285
355. KEHCharleston 01:49 GMT le 15 octobre 2008    
Quoting Stormchaser2007:


I did.


If it is still giving you the pop up, I would just close out WU and bring it back up.
Member Since: 19 août 2008 Posts: 6 Comments: 2490
356. Seastep 01:49 GMT le 15 octobre 2008    
Quoting Stormchaser2007:


I did.


That's weird. Maybe another tab open?

I'd try closing browser and going back in.
Member Since: 9 septembre 2008 Posts: 6 Comments: 3406
357. RMM34667 01:50 GMT le 15 octobre 2008    
Quoting viman:
I don't think that flooding will be my problem, my altitude of 1400 feet, combined with very saturated soil and lost of big trees(raiforest type trees) will cause for a bad scenario for me. After Marilyn took me and 2 other guys with 3 chainsaws 3 days to cut our way out to the main road. Didn't get electricity to the house for 8 months. Hope this isn't the evil seed of Marilyn.


VIman can you tell me what the time frame is for this storm to hit your area? Have sister who lives on Mahogeny Row near Mendal(??) beach.. I have no idea where that is but she is sick in bed and seems to have no clue what is coming her way. Thanks!
Member Since: 7 septembre 2006 Posts: 5 Comments: 910
358. antonio28 01:50 GMT le 15 octobre 2008    
Quoting JRRP:
i think 14.6n 68.5w u can see the eye
Link


Agree, so is moving N??
Member Since: 15 juillet 2008 Posts: 0 Comments: 799
359. KEHCharleston 01:50 GMT le 15 octobre 2008    
Clear your cache maybe?

What browser do you use?
Member Since: 19 août 2008 Posts: 6 Comments: 2490
360. PR51 01:50 GMT le 15 octobre 2008    
I Think that there will be no inmediate threat with Omar for Puerto Rico, at least for a direct impact. I don't understand why some people are refrerring as to there will be a direct impact with this storm. I think that the effects from this storm will be minimal.
Member Since: 12 août 2007 Posts: 0 Comments: 69
361. Orcasystems 01:51 GMT le 15 octobre 2008    
deleted
Member Since: 1 octobre 2007 Posts: 77 Comments: 26077
363. stormpetrol 01:52 GMT le 15 octobre 2008    
Looks like Omar is starting to take a track more due North, anyone else notice this in last few frames?
Member Since: 29 avril 2007 Posts: 0 Comments: 6400
364. KEHCharleston 01:52 GMT le 15 octobre 2008    
Quoting PR51:
I Think that there will be no inmediate threat with Omar for Puerto Rico, at least for a direct impact. I don't understand why some people are refrerring as to there will be a direct impact with this storm. I think that the effects from this storm will be minimal.

From your keyboard to God's ear.
Of course, if you are wrong......
Member Since: 19 août 2008 Posts: 6 Comments: 2490
365. HurricaneKing 01:53 GMT le 15 octobre 2008    
i dont have time to chat (cal project due in the morning I need to finish.) but it appears to me that Omar is now moving NE. It doesnt appear to still be ene but in no way is it going nne or n. So it's beginning the forecast turn.
Member Since: 6 juillet 2005 Posts: 71 Comments: 2430
366. msphar 01:53 GMT le 15 octobre 2008    
I agree 14.5 68.5 but the is a significant chunk of development on the East side that should be working its way into the center, I think this will cause the mass to wobble.
Member Since: 20 août 2006 Posts: 0 Comments: 258
367. JLPR 01:53 GMT le 15 octobre 2008    
Quoting stormpetrol:
Looks like Omar is starting to take a track more due North, anyone else notice this in last few frames?


I have no idea lol the convection might be playing tricks on us =S
Member Since: 4 septembre 2007 Posts: 36 Comments: 5223
368. Seastep 01:53 GMT le 15 octobre 2008    
Quoting antonio28:


Agree, so is moving N??


I think it is N of forecast.

In my mind, I just expand that cone at PR landfall on the W side to cover PR. It's the cone, not the line, especially at this point.
Member Since: 9 septembre 2008 Posts: 6 Comments: 3406
369. benirica 01:53 GMT le 15 octobre 2008    
Quoting PR51:
I Think that there will be no inmediate threat with Omar for Puerto Rico, at least for a direct impact. I don't understand why some people are refrerring as to there will be a direct impact with this storm. I think that the effects from this storm will be minimal.


I hope you are right, for what its worth...
But I also hope you realize that 1.5 inches of rain in parts of Puerto Rico would devastate flooded areas. Also, remember Vieques and Culebra are a stones throw away from the USVI, where Omar is expected to go.
So... rephrase your argument, because to the people of Vieques and Culebra (and the east coast of PR) this isn't something to ignore.
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370. Chicklit 01:54 GMT le 15 octobre 2008    
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371. HurricaneKing 01:54 GMT le 15 octobre 2008    
So putting the track up. (I've been gone all day.) it appears to be dead on. MAybe a tiny touch north which is ne.
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372. KEEPEROFTHEGATE (Mod) 01:55 GMT le 15 octobre 2008    
Member Since: 15 juillet 2006 Posts: 143 Comments: 40615
373. Snowfire 01:56 GMT le 15 octobre 2008    
Interesting loop of Omar, though it is going out of range in the last frames.
Member Since: 29 juin 2005 Posts: 24 Comments: 300
374. SWFLDigTek 01:56 GMT le 15 octobre 2008    
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375. presslord 01:56 GMT le 15 octobre 2008    
BeachFoxx....sounds like a bar for weather geeks....
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377. CASANOVA7823 01:57 GMT le 15 octobre 2008    
Quoting viman:
what part of st.croix -- i'm on st.thomas -- mountain top
I am located on Clifton Hill, Christiansted; However, I am going to be all over this island throughout the whole ordeal. I will keep posting updates. So far rain has been the main factor since six o'clock. It has not stopped since. No strong winds yet but some gusts associated with heavy rain.
Member Since: 8 juillet 2008 Posts: 0 Comments: 7
378. antonio28 01:57 GMT le 15 octobre 2008    
Quoting Seastep:


I think it is N of forecast.

In my mind, I just expand that cone at PR landfall on the W side to cover PR. It's the cone, not the line, especially at this point.


Yep and move the line 30 or 40 milles to the west.
Member Since: 15 juillet 2008 Posts: 0 Comments: 799
380. Tazmanian 02:00 GMT le 15 octobre 2008    
361. Orcasystems 6:51 PM PDT on October 14, 2008
Complete Refresh Blog
Mirror Site

Tropical Depression ... Nana
Present Satellite picture ... Nana

Tropical Storm ... Omar
Hurricane Hunters TS Omar ... Tracks and Vortex reports
Present Satellite picture ... Omar

Tropical Depression ... 16
Present Satellite picture ... TD 16

Invest ... 90L
Present Satellite picture ... Invest 90L

Present Satellite picture Caribbean
Present Satellite picture GOM
Present Satellite picture Cape Verde
Present Satellite picture Large overall Coverage
CMC 00Z..



do you need to keep re posting that????
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381. Beachfoxx 02:02 GMT le 15 octobre 2008    
Thanks Michael... I went to the site, out of curiosity. But had not heard of it before.
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382. Chicklit 02:03 GMT le 15 octobre 2008    
Member Since: 11 juillet 2006 Posts: 14 Comments: 10254
383. Beachfoxx 02:04 GMT le 15 octobre 2008    
LMAO...

Good to see you press. I got a reply from one of the clothing companies. Will send you an update.
Quoting presslord:
BeachFoxx....sounds like a bar for weather geeks....
Member Since: 10 juillet 2005 Posts: 153 Comments: 29285
384. Chicklit 02:05 GMT le 15 octobre 2008    
Omar looks to be packing a bit of a punch.
Member Since: 11 juillet 2006 Posts: 14 Comments: 10254
385. KEHCharleston 02:06 GMT le 15 octobre 2008    
RE: 380. Tazmanian

Taz!
I like to know when Orca has updated the graphics.


Member Since: 19 août 2008 Posts: 6 Comments: 2490
386. presslord 02:06 GMT le 15 octobre 2008    
Thanks Beach....we're getting another truckload out in a few days....plus a host of direct shipments from around the country....plus we're helping to get some ramps rebuilt for some disabilities groups....
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387. zoomiami 02:06 GMT le 15 octobre 2008    
wow - that is some picture of Omar - thanks for posting chicklit
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388. msphar 02:07 GMT le 15 octobre 2008    
It seems to be ahead of forecast track and slightly to the West/North of the track.
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389. SWFLDigTek 02:08 GMT le 15 octobre 2008    
.
Member Since: 31 août 2008 Posts: 117 Comments: 398
390. Beachfoxx 02:08 GMT le 15 octobre 2008    
No problem... wish I could do more...
Quoting presslord:
Thanks Beach....we're getting another truckload out in a few days....plus a host of direct shipments from around the country....plus we're helping to get some ramps rebuilt for some disabilities groups....
Member Since: 10 juillet 2005 Posts: 153 Comments: 29285
391. SevereHurricane 02:09 GMT le 15 octobre 2008    
Omar reminds me of Hurricane Lenny.
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392. kmanislander 02:09 GMT le 15 octobre 2008    
Hi all

Omar looks like an Octopus !

And, has TD 16 stalled ?
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393. stormwatcherCI 02:10 GMT le 15 octobre 2008    
According to Naval Research Omar's winds are 65 knots which nmake him a hurricane. Pressure 979mb
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394. antonio28 02:10 GMT le 15 octobre 2008    
Ok looks like we are in consensus with the track change closer to PR.
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395. antonio28 02:11 GMT le 15 octobre 2008    
Kamislander what you think Omar will make landfall?
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396. heretolearninPR 02:12 GMT le 15 octobre 2008    
Has anyone looked at the ensemble models. I understand that they are just multiple runs started at various points near where the center is supposed to be. It is curious that all of the models are more west than the GFS. With Ike the models where more symmetrically placed around the white line. I am hoping this means nothing. Any comments?
Member Since: 19 août 2006 Posts: 0 Comments: 229
397. Relix 02:13 GMT le 15 octobre 2008    
I can definitely confirm Omar is going more N and is to the NW, sightly, of the forecast points. Ada Monzon, meteorologist here ("REAL" one, works for NOAA, etc) just said on the radio IT IS moving North of the forecast points and she expects, if the trend ends in 3 hours, for Omar to pass 30 miles east of PR. Now, if it keeps on like that it will be another story.
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398. SWFLDigTek 02:14 GMT le 15 octobre 2008    


See that WU doesn't like the other one...
Member Since: 31 août 2008 Posts: 117 Comments: 398
399. kmanislander 02:14 GMT le 15 octobre 2008    
Quoting antonio28:
Kamislander what you think Omar will make landfall?


Omar appears to be on a NE heading at the moment. If it continues like that I would expect landfall over the eastern one third of PR
Member Since: 19 août 2006 Posts: 0 Comments: 14939
400. luigi18 02:16 GMT le 15 octobre 2008    
Quoting benirica:


I hope you are right, for what its worth...
But I also hope you realize that 1.5 inches of rain in parts of Puerto Rico would devastate flooded areas. Also, remember Vieques and Culebra are a stones throw away from the USVI, where Omar is expected to go.
So... rephrase your argument, because to the people of Vieques and Culebra (and the east coast of PR) this isn't something to ignore.
remenber who knows! better be prepare we are very wet!
Member Since: 21 septembre 2008 Posts: 0 Comments: 452

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About JeffMasters
Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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