Tropical Depression 15 forms; new Caribbean disturance a threat to develop

By: Dr. Jeff Masters , 2:58 PM GMT on October 13, 2008

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Tropical Depression Fifteen has formed this morning, and is already bringing flooding rains to the Virgin Islands and Puerto Rico. This morning's QuikSCAT pass showed a well-defined closed surface circulation, but did not scan the eastern portion of the storm, where the heaviest thunderstorms are. Eastern Caribbean buoy 42059 is in the heavy thunderstorm region to the east of 98L's center, and winds there were sustained at 20-26 mph this morning. Satellite loops show an impressive amount of heavy thunderstorm activity that is increasing in intensity and coverage. Wind shear is a high 20 knots over the disturbance, due to strong upper level winds out of the west. These strong winds are keeping 98L's heavy thunderstorms pushed over to the east side of the center of circulation. The storm is a little too far from Puerto Rico radar to see rotation of the rain. The rain area is poorly organized, with no spiral rain bands evident. However, radar from the Netherlands Antilles does show spiral bands beginning to develop on the south side of the depression. Dominican Republic radar was down this morning.


Figure 1. Current satellite image of TD 15. Image credit: NOAA.


Figure 2. Current radar-estimated rainfall from 98L.

The track forecast for TD 15
The storm is drifting slowly northwestward, and this motion is expected to continue through Tuesday. A upper-level trough of low pressure is forecast to position itself to the north of Puerto Rico by Tuesday. The counter-clockwise flow of air around this trough should draw TD 15 to the northeast across Puerto Rico or the eastern Dominican Republic on Wednesday. Up to five inches of rain has already fallen over the Virgin Islands and eastern Puerto Rico (Figure 2), and additional heavy rains of 5-10 inches are likely over these islands through tonight. Heavy rains of 5-10 inches per day will likely spread to the eastern Dominican Republic and the northern Lesser Antilles Islands by Tuesday morning, and continue through Wednesday night. Over Puerto Rico, isolated rain amounts in excess of 20 inches are possible before the storm clears the islands by Thursday. It currently appears that Haiti will only get 1-3 inches of rain from TD 15.

The intensity forecast for TD 15
Wind shear is expected to fall to the moderate 10-20 knot range over the next three days, and waters will remain warm, 29°C. This should allow 98L to intensify into a tropical storm by Tuesday. The HWRF and GFDL models both intensify TD 15 into a hurricane before it hits Puerto Rico on Wednesday. This seems overly aggressive, given the moderate 10-20 knots of wind shear expected. The SHIPS model forecast and official NHC forecast of a strong tropical storm hitting the island on Wednesday is more reasonable. A Hurricane Hunter aircraft will investigate the storm this afternoon.

Links to follow
Puerto Rico radar
Eastern Caribbean buoy 42059
San Juan, Puerto Rico weather

Nana
Tropical Storm Nana, the fourteenth named storm of this busy Atlantic hurricane season, formed yesterday over the middle Atlantic Ocean. Nana is one of those "blink and you'll miss it" storms, as high wind shear of 30 knots is in the process of tearing the storm apart. The UKMET model did a nice job forecasting the development of this storm, up to a week in advance.

New disturbance in the Southwest Caribbean (99L)
An area of disturbed weather (99L) has formed in the Southwest Caribbean, off the coast of Nicaragua. The region is under a low to moderate amount of wind shear, 5-15 knots. The NOGAPS model forecasts the development of a tropical depression in this region by Thursday. The model predicts the storm will move northwest and threaten Honduras, the Cayman Islands, the Yucatan Peninsula, and western Cuba by early next week. I put the odds a tropical depression forming in this region by Wednesday in the moderate range (20-50%).

Saturday's update on Hurricane Ike relief efforts
I got this very nice email Friday, giving appreciation for all those who helped out through the portlight.org Hurricane Ike charity effort:


I just wanted to express my sincere gratitude, on behalf of the City of Houston, the Mayor, and our community partners over at TIRR/Memorial Hermann, for all of your involvement in bringing medical supplies and equipment together to help Texans with disabilities affected by Hurricane Ike. I can't tell you how much we all appreciate the fact that you so quickly mobilized and leveraged such a tremendous amount of support to bring these needed items to Houston and other Texas cities.

An email simply doesn't do justice to the generous spirit and initiative that you, Paul Timmons, and your partners took to make this happen, nor to our gratitude. However, I just want you to know that we think about you all in appreciation every single day over here, and there are many who are directly benefiting from your generosity.

By the way, Paul Timmons mentioned that it looks like another shipment of 30-50 wheelchairs can be sent over here. All I can say is wow! Thank you for not forgetting about us, and for realizing that we still have a lot of needs here that we are trying to meet - even 4 weeks after the hurricane.

Again, please accept my sincere thanks. I hope that you have a wonderful weekend!

Michelle Colvard, MPH
Executive Director
Mayor's Office for People with Disabilities

Contributions to this highly worthy 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 this afternoon, between 3pm-4:30pm EDT.
Jeff Masters

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508. KBH
9:48 PM GMT on October 13, 2008
orca, what's your take on the centre of TD15. Two separate areas of TS activity look like they are developing. Is between the two a likely are for lowest central pressure? I'm guessing, don't have the models and charts
Member Since: August 28, 2008 Posts: 0 Comments: 278
507. KBH
9:38 PM GMT on October 13, 2008
latest noaa sat shows centre to the north, but plenty of TS activity to the south, but there is no indication of flood watches for non US territories. A near stationery TD15 over the islands is very bad news considering the amount of rains in the area for the last week
Member Since: August 28, 2008 Posts: 0 Comments: 278
506. Orcasystems
9:33 PM GMT on October 13, 2008
Complete Refresh Blog
Mirror Site

Awake again :)
Member Since: October 1, 2007 Posts: 81 Comments: 26516
505. antonio28
9:21 PM GMT on October 13, 2008
Orca any news??
Member Since: July 15, 2008 Posts: 0 Comments: 799
504. BahaHurican
9:16 PM GMT on October 13, 2008
Afternoon, everybody.

It's certainly getting pretty interesting here all of a sudden; 4 areas to watch at one time. . .

I'm thinking if we see a Fujiwara dance it will be between Nana and 90L. . . . may revitalize Nana, too.
Member Since: October 25, 2005 Posts: 19 Comments: 22728
502. stillwaiting
9:15 PM GMT on October 13, 2008
ECMWF is starting to do that "thing" it was doing last week/not looking so great for the west coast of FL,I have a "gut feeling" that 99L is going to grow into a monster,maybe even a major...and if it gets into the gulf and there's that front coming in this weekend?????..WEST coast FL make sure you have all your hurricane supplies,the season is not over and oct. is the month when we are most vounerable to a TC......
Member Since: October 5, 2007 Posts: 20 Comments: 4970
501. plywoodstatenative
9:14 PM GMT on October 13, 2008
75, I think mother nature is waking up yet again. took a 2 week break and now all heck is breaking loose in the carib./CV Area
Member Since: November 15, 2005 Posts: 16 Comments: 4189
500. hurricanemaniac123
9:14 PM GMT on October 13, 2008
NEW BLOG!
Member Since: September 21, 2008 Posts: 9 Comments: 688
499. 7544
9:10 PM GMT on October 13, 2008
local mets says they will be watching 99l as it heads north and could be a promblem for so fla too early to say for sure stay tuned by the way there is no o storm yet right
Member Since: May 6, 2007 Posts: 0 Comments: 6874
497. plywoodstatenative
9:09 PM GMT on October 13, 2008
Naples, I would like to know why it is after what you went through with Wilma. That you want another storm of her caliber to hit South Florida. There are enough people on here from south florida, that everytime you mention red alert this or red alert that, the blog goes nuts. Stick to the facts, not any false truths or rhetoric that you hear please.
Member Since: November 15, 2005 Posts: 16 Comments: 4189
496. KEEPEROFTHEGATE (Mod)
9:08 PM GMT on October 13, 2008
Quoting sammywammybamy:
I think it is over for s.fla... Oviosully a another Year we get a break .. this year it has been tex and carolinas
its not over today is the start of the final peak pulse in the activity scale and should continue for the next 7 to 10 days with most developement taking place in carb
99l may give ya a run and 90l is up to something as well omar should get drawn ne ward over pr as a hurricane before it get to pr and it may be quite a surprize to its strengh hold on things may get a little trickey
Member Since: July 15, 2006 Posts: 178 Comments: 56059
495. AstroHurricane001
9:08 PM GMT on October 13, 2008
Quoting KBH:
here is the report from wunderground (current)
Grantley Adams, BR (Airport)
Updated: 50 min 43 sec ago
79 °F / 26 °C
Light Showers Rain
Humidity: 94%
Dew Point: 77 °F / 25 °C
Wind: 5 mph / 7 km/h / 2.1 m/s from the SSW
Pressure: 29.77 in / 1008 hPa (Steady)
Visibility: 4.3 miles / 7.0 kilometers
UV: 1 out of 16
Clouds: Mostly Cloudy 1200 ft / 365 m
Mostly Cloudy 30000 ft / 9144 m
(Above Ground Level)
Elevation: 184 ft / 56 m

and here is the one from barbados weather.org (current)
ESE - E at 15-35 km/h. Sea: Slight to moderate in open water, swells 1.0 - 1.5m.

Meteorologist: Cameron Burke

Valid from October 14 to October 17, 2005

can someone explain?

"Valid from October 14 to October 17, 2005"??

Quoting naplesdreamer28:
Red alert for FL, Omar after hitting Cuba.

Huh? Omar? FL? Cuba? What?
Member Since: August 30, 2008 Posts: 8 Comments: 2835
494. SpicyAngel1072
9:02 PM GMT on October 13, 2008
Quoting plywoodstatenative:
The problem is when you mention anything along the lines of Florida when it pertains to storms, everyone automatically thinks about a storm nailing Florida.


Is this why no one answered my post?
Member Since: September 1, 2008 Posts: 0 Comments: 315
493. billy305
9:02 PM GMT on October 13, 2008
Quoting sammywammybamy:
I think it is over for s.fla... Oviosully a another Year we get a break .. this year it has been tex and carolinas
Fay.....4 times....Ring a bell?
492. AstroHurricane001
9:01 PM GMT on October 13, 2008
I hope the hurricane hunter investigates both TD 15 and the Nicaragua system. This would help get new data for both. Also where is Dr. M's new blog?
Member Since: August 30, 2008 Posts: 8 Comments: 2835
489. plywoodstatenative
8:58 PM GMT on October 13, 2008
The problem is when you mention anything along the lines of Florida when it pertains to storms, everyone automatically thinks about a storm nailing Florida.
Member Since: November 15, 2005 Posts: 16 Comments: 4189
488. stormdude77
8:56 PM GMT on October 13, 2008
487. KBH
8:55 PM GMT on October 13, 2008
here is the report from wunderground (current)
Grantley Adams, BR (Airport)
Updated: 50 min 43 sec ago
79 °F / 26 °C
Light Showers Rain
Humidity: 94%
Dew Point: 77 °F / 25 °C
Wind: 5 mph / 7 km/h / 2.1 m/s from the SSW
Pressure: 29.77 in / 1008 hPa (Steady)
Visibility: 4.3 miles / 7.0 kilometers
UV: 1 out of 16
Clouds: Mostly Cloudy 1200 ft / 365 m
Mostly Cloudy 30000 ft / 9144 m
(Above Ground Level)
Elevation: 184 ft / 56 m

and here is the one from barbados weather.org (current)
ESE - E at 15-35 km/h. Sea: Slight to moderate in open water, swells 1.0 - 1.5m.

Meteorologist: Cameron Burke

Valid from October 14 to October 17, 2005

can someone explain?
Member Since: August 28, 2008 Posts: 0 Comments: 278
486. Dar9598
8:54 PM GMT on October 13, 2008
of course Michaelistl
485. benirica
8:54 PM GMT on October 13, 2008
Unfortunately, stationary also gives it more time over the water to develop and strengthen.
Member Since: August 3, 2006 Posts: 0 Comments: 1143
484. HadesGodWyvern (Mod)
8:53 PM GMT on October 13, 2008
you're welcome
Member Since: May 24, 2006 Posts: 52 Comments: 46914
483. extreme236
8:53 PM GMT on October 13, 2008
Quoting bwt1982:


How do you figure Smart Guy...I said in my Opinion that the hurricane season is over for SOUTH FLORIDA...Wow, how many times do I have to say it.And I will say it again, In my opinion the hurricane season seems to be over for SOUTH FLORIDA. Not the GOM, not Texas, not the open Atlantic but for South Florida. It's just an opinion, nothing scientific, no studies just an opinion. I know about Wilma, because I experienced her first hand.Just an opinion.It's just funny how all the models can take a storm a certain direction but there are always a few clowns that have to say well if this happens and this happens it make a 180 turn and head this way, something everyone calls wishcasting and it's ok. I merely say as an opinion I think we are safe in S. Fla and everyone wants to flame me for it. But that shows the maturity on here.


You may have meant South Florida but at one time you clearly did not specify that. I guess it was just a misunderstanding then.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
482. benirica
8:53 PM GMT on October 13, 2008
Quoting foggymyst:
What is the implication for TD15 becoming stationary?


What do you mean?
It wont change the over all track. If anything, it may mean that it wont go to the Dominican Republic because it wont make it further west before heading North and North East towards PR and/or the USVI and BVI.
Member Since: August 3, 2006 Posts: 0 Comments: 1143
481. Stormchaser2007
8:52 PM GMT on October 13, 2008
Quoting HadesGodWyvern:
StormChaser

NRL Tropical Cyclone Support Page


Thanks Hades...I appreciate it.
Member Since: June 9, 2007 Posts: 4 Comments: 15950
480. HadesGodWyvern (Mod)
8:51 PM GMT on October 13, 2008
StormChaser

NRL Tropical Cyclone Support Page
Member Since: May 24, 2006 Posts: 52 Comments: 46914
479. foggymyst
8:51 PM GMT on October 13, 2008
What is the implication for TD15 becoming stationary?
Member Since: September 23, 2008 Posts: 0 Comments: 383
478. Stormchaser2007
8:50 PM GMT on October 13, 2008
Quoting HadesGodWyvern:


Sorry but im looking at the NRL site and the FNMOC site but I dont see that TCFA. Can I have the link to that please?
Member Since: June 9, 2007 Posts: 4 Comments: 15950
477. extreme236
8:49 PM GMT on October 13, 2008
Quoting Stormchaser2007:


TCFA for which system?


For 99L
Member Since: August 2, 2007 Posts: 19 Comments: 19234
476. bwt1982
8:49 PM GMT on October 13, 2008
Quoting CybrTeddy:
bwt1982, how does it feel to know how dead wrong you prediction of the season ending early feels?


How do you figure Smart Guy...I said in my Opinion that the hurricane season is over for SOUTH FLORIDA...Wow, how many times do I have to say it.And I will say it again, In my opinion the hurricane season seems to be over for SOUTH FLORIDA. Not the GOM, not Texas, not the open Atlantic but for South Florida. It's just an opinion, nothing scientific, no studies just an opinion. I know about Wilma, because I experienced her first hand.Just an opinion.It's just funny how all the models can take a storm a certain direction but there are always a few clowns that have to say well if this happens and this happens it make a 180 turn and head this way, something everyone calls wishcasting and it's ok. I merely say as an opinion I think we are safe in S. Fla and everyone wants to flame me for it. But that shows the maturity on here.
Member Since: September 29, 2008 Posts: 0 Comments: 143
475. 7544
8:48 PM GMT on October 13, 2008
tropic storm watch now for pr and the virgin islands
Member Since: May 6, 2007 Posts: 0 Comments: 6874
474. HadesGodWyvern (Mod)
8:47 PM GMT on October 13, 2008
Member Since: May 24, 2006 Posts: 52 Comments: 46914
472. KEEPEROFTHEGATE (Mod)
8:47 PM GMT on October 13, 2008
Quoting Stormchaser2007:


TCFA for which system?
15L/TD/O
Member Since: July 15, 2006 Posts: 178 Comments: 56059
471. HadesGodWyvern (Mod)
8:46 PM GMT on October 13, 2008
A LOW PRESSURE CENTER LOCATED NEAR 13.6N 82.5W IS CURRENTLY
ENCOUNTERING WEAK SHEAR OF SOUTHWESTERLY WIND AND SEA WATER
TEMPERATURES OF 82 TO 85 F. THE AREA OF LOW PRESSURE WILL SLOWLY
TRACK NORTHWARD TOWARDS A MORE CONDUCIVE AREA FOR TROPICAL CYCLONE
FORMATION FAVORING DEVELOPMENT OVER THE NEXT 24 TO 48 HOURS.
Member Since: May 24, 2006 Posts: 52 Comments: 46914
470. plywoodstatenative
8:45 PM GMT on October 13, 2008
Keeper, you have a TCHP for the area that TD 15 and 99L are located in?
Member Since: November 15, 2005 Posts: 16 Comments: 4189
469. 7544
8:44 PM GMT on October 13, 2008
99l is moving north
Member Since: May 6, 2007 Posts: 0 Comments: 6874
468. plywoodstatenative
8:43 PM GMT on October 13, 2008
Masters does not mention anything about Florida. The farthest that he puts our southwestern carib. disturbance is into western Cuba. Remember the mountainous terrain in Cuba, has a habit of bouncing storms either way. So lets not get all of us in Florida worried, when there has been no OFFICIAL statement made as to where its future track lies.
Member Since: November 15, 2005 Posts: 16 Comments: 4189
467. Stormchaser2007
8:42 PM GMT on October 13, 2008
Quoting KEEPEROFTHEGATE:
T.C.F.A


TCFA for which system?
Member Since: June 9, 2007 Posts: 4 Comments: 15950
466. benirica
8:42 PM GMT on October 13, 2008
It isnt moving south, it isnt moving at all.
Not any change to the actual track.
Member Since: August 3, 2006 Posts: 0 Comments: 1143
465. KEEPEROFTHEGATE (Mod)
8:41 PM GMT on October 13, 2008
darkness falls with it comes dmax should get real interesting real
Member Since: July 15, 2006 Posts: 178 Comments: 56059
464. Dar9598
8:41 PM GMT on October 13, 2008
This week could be very busy with the possibility of 3 named storm:
Omar
Paloma
Rene(another"Four Letter Name Storm")
463. plywoodstatenative
8:41 PM GMT on October 13, 2008
This is where the satellite images that I am finding are coming from: Link
Member Since: November 15, 2005 Posts: 16 Comments: 4189
462. pottery
8:41 PM GMT on October 13, 2008
Hi, DDR. Good point.
I'm out for a while.........
Member Since: October 24, 2005 Posts: 0 Comments: 24883
461. DDR
8:40 PM GMT on October 13, 2008
Interesting stuff in the mid atlantic,NANA might absord 90L?
Member Since: April 27, 2007 Posts: 14 Comments: 1729
460. kingzfan104
8:39 PM GMT on October 13, 2008
459. benirica
8:39 PM GMT on October 13, 2008
...TROPICAL DEPRESSION NEARLY STATIONARY...

AT 5 PM AST...2100 UTC...A TROPICAL STORM WATCH HAS BEEN ISSUED FOR
PUERTO RICO AND THE U.S. VIRGIN ISLANDS.

AT 5 PM AST...2100 UTC...THE GOVERNMENT OF THE DOMINICAN REPUBLIC
HAS ISSUED A TROPICAL STORM WATCH FOR THE EXTREME EASTERN PORTION
OF HISPANIOLA FROM ISLA SAONA TO CABO ENGANO.

AT 5 PM AST...2100 UTC...THE GOVERNMENT OF THE BRITISH VIRGIN
ISLANDS HAS ISSUED A TROPICAL STORM WATCH FOR THE BRITISH VIRGIN
ISLANDS.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE
INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR LOCAL WEATHER OFFICE.

AT 500 PM AST...2100Z...THE CENTER OF TROPICAL DEPRESSION FIFTEEN
WAS LOCATED NEAR LATITUDE 14.8 NORTH...LONGITUDE 69.9 WEST OR ABOUT
355 MILES...570 KM...SOUTHWEST OF SAN JUAN PUERTO RICO AND ABOUT 185
MILES...295 KM...NORTH-NORTHWEST OF CURACAO.

THE DEPRESSION IS STATIONARY AND LITTLE MOTION IS EXPECTED DURING
THE NEXT 24 HOURS. THEREAFTER...A NORTHEAST TRACK WITH AN INCREASE
FORWARD SPEED SHOULD BEGIN...BRINGING THE CENTER VERY NEAR PUERTO
RICO OR THE VIRGIN ISLANDS ON WEDNESDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHER
GUSTS. THE DEPRESSION COULD BECOME A TROPICAL STORM TONIGHT OR
TUESDAY. AN AIR FORCE RECONNAISSANCE AIRCRAFT IS CURRENTLY
APPROACHING THE DEPRESSION.
Member Since: August 3, 2006 Posts: 0 Comments: 1143
458. plywoodstatenative
8:38 PM GMT on October 13, 2008
Puerto Rico's RGB Of TD 15:
Member Since: November 15, 2005 Posts: 16 Comments: 4189

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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.

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