Florida disturbance 93L may develop by Thursday; Typhoon Wipha aims at Shanghai

By: Dr. Jeff Masters , 2:05 PM GMT on September 18, 2007

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An area of disturbed weather has developed off the east coast of Florida, in association with a tropical wave interacting with a trough of low pressure. This disturbance has been labeled "93L" by NHC this afternoon. Animations of long-range radar out of Melbourne, Florida and satellite loops show that thunderstorm activity off the Florida coast is increasing, but remains disorganized. Wind shear over the disturbance has fallen from 30 knots to 20 knots today, and is expected to fall below 10 knots by Thursday. The disturbance is moving westward, and will bring heavy rain to Florida and the Bahamas today through Thursday.


Figure 1. Current long range radar out of Melbourne, Florida.

The four reliable computer models for forecasting tropical cyclone genesis all predict that once this area of disturbed weather crosses Florida and emerges into the eastern Gulf of Mexico on Thursday, wind shear will drop enough to allow a tropical depression to form. The path such a storm might take is highly uncertain, and the models have diverged significantly since yesterday's runs. A strong ridge of high pressure is setting up over the eastern half of the U.S., and is expected to remain anchored in place for at least ten days. This is the type of steering pattern we experienced during the Hurricane Season of 2005, and favors westward-moving storms. This ridge will act to steer any developing storm in the Gulf of Mexico towards the west, to the Texas coast, or even west-southwest, to the northeastern mainland Mexico. However, this steering pattern will be complicated by the presence of an upper-level low pressure system over the Gulf of Mexico. This upper-level low is currently forming over northern Florida, and is expected to drift southwestward or westward over the Gulf later this week, and gradually weaken. Depending on the strength and movement of this low, a storm that forms in the eastern Gulf could be steered anywhere from the Florida Panhandle to northeastern Mexico. One model, the NOGAPS, predicts that the storm will move west-southwest into the Bay of Campeche (southwestern Gulf of Mexico), and stall out for many days. The UKMET, GFS, and ECMFW models foresee that the storm will make landfall in Texas or Louisiana Sunday or Monday. The intensity such a storm may reach is also highly uncertain. The NOGAPS model predicts 93L will eventually dissipate over the southwestern Gulf, while the SHIPS intensity model brings 93L to Category 1 hurricane strength by Saturday. All residents along the Gulf of Mexico coast need to consider what actions they might need to take if a hurricane develops in the Gulf this weekend. The highest danger region is from New Orleans westward to Brownsville, Texas. A hurricane hunter airplane is on call for Thursday afternoon.

Remains of Ingrid
The remains of Tropical Storm Ingrid are still kicking up some heavy thunderstorm activity a few hundred miles north of the northernmost Lesser Antilles Islands. There is still a bit a spin evident on satellite loops and this morning's QuikSCAT pass. Wind shear is a hefty 30 knots, and is expected to gradually decline to 10 knots by Wednesday night. If there's anything left of Ingrid then, we will need to watch this area for regeneration.

Tropical wave in the mid-Atlantic
A tropical wave about 750 miles east of the Lesser Antilles Islands is moving west at 10-15 mph. Thunderstorm activity associated with this wave has diminished substantially since yesterday, and any development should be very slow to occur. Wind shear is about 10 knots, and is expected to remain below 15 knots over the next 2-3 days. None of the computer models develop this wave into a tropical depression.

Typhoon Wipha takes aim at China's most populous city
Typhoon Wipha, a formidable Category 4 storm, is poised to make landfall tomorrow just south of China's most populous city, Shanghai. About 14.5 million people live in the city. Over 1 million people have been evacuated so far. Wipha must pass over about 50 miles of land before reaching Shanghai, and will probably be a strong tropical storm or Category 1 hurricane when it passes over or just west of the city. Rainfall amounts of up to seven inches in 24 hours are expected along the path of Wipha, which will cause major flooding problems. Fujian province on China's southeastern coast has sent out 1.41 million text messages to warn the public of the upcoming typhoon, the local flood control headquarters said. The Women's World Cup soccer tournament is going on in China, and the U.S. is supposed to play their final group game tomorrow in Shanghai (8pm Tuesday night China time, 8am EST). World Cup organizers are trying to change the game time to get the game in (and then the teams out of Shanghai) before the storm hits.

Yesterday, Wipha briefly intensified into a super typhoon packing 150 mph winds as it brushed Taiwan. One person was killed there. Wipha is a woman's name in the Thai language.


Figure 2. Radar images of Typhoon Wipha as it passed north of Taiwan. Image credit: Taiwan Central Weather Bureau.

Due to popular request, I'll present a wind shear tutorial in Wednesday's blog.

Jeff Masters

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721. SomeRandomTexan
4:19 AM GMT on September 19, 2007
it looks at is 93L is dying... did wunderground take the invest off of the site? I dont see it there anymore.... maybe there is nothing to worry about after all...
Member Since: August 30, 2007 Posts: 0 Comments: 1857
720. OSUWXGUY
7:28 PM GMT on September 18, 2007
There is also a great deal of mid-level dry air near this low. Looking at the 1KM satellite of the area from weather.cod.edu, you can clearly see an outflow boudary rush out of the convection over the western side of the low.
719. OSUWXGUY
7:23 PM GMT on September 18, 2007
This low off the east coast of FL has an environment that is much more similar to Gabrielle (which struggled to strengthen) than to Humberto!

Humberto had an anticyclone aloft to provide an outlet for air to be pumped out and pressure to fall, and it had very low wind shear (~5 knots or less).

This low has an upper level low in the vicinity, and high shear.

718. ClearH2OFla
7:18 PM GMT on September 18, 2007
Hey all at lunch now. Any chance anything going to whack Tampa
717. LightningCharmer
7:12 PM GMT on September 18, 2007
Sorry, Didn't try to double-post.
Member Since: September 1, 2007 Posts: 0 Comments: 1344
716. LightningCharmer
7:12 PM GMT on September 18, 2007
No expert here but looking at the water vapor imagery, quite a bit of dry air getting sucked into this low from the southwest. Could this be reducing precipitation, and making it harder to see center of circulation than it was earlier on radar?
Member Since: September 1, 2007 Posts: 0 Comments: 1344
715. MTCseadrifter
7:03 PM GMT on September 18, 2007
WiseGuy tell that to Humberto!
Member Since: July 28, 2007 Posts: 0 Comments: 260
714. windsock
7:01 PM GMT on September 18, 2007
Yes Floodman I know. I was in NO for Camille . conditions were pretty bad there that night.
713. WiseGuy
6:56 PM GMT on September 18, 2007
Link

According to above latest surface analysis over the Miami general area, the center of whatever circulation center is right over or just a few miles east of Biscayne Bay.

Link

Latest radar out of Miami above shows about the same thing. And it looks more disorganized than a few hours ago.

Whatever center of circulation there is, it is too close to the coast to significantly develop. If it becomes a TD before ultimate FL landfall, that would be a reach. And unless the system moves to the SW like Katrina did, it will miss most or all of the "loop current". Elsewhere in the GOM, heat potentials are too low for rapid development. Thus, do not expect a major hurricane out of this, wherever it finally landfalls in the GOM.
712. hurricane23
6:55 PM GMT on September 18, 2007
Convection continues to increase...

Member Since: May 14, 2006 Posts: 8 Comments: 13804
711. Michfan
6:53 PM GMT on September 18, 2007
New blog up guys from Dr. M
Member Since: September 7, 2007 Posts: 0 Comments: 1733
710. Cavin Rawlins
6:54 PM GMT on September 18, 2007


yellow=ull
red=COC
Member Since: July 24, 2005 Posts: 407 Comments: 19076
709. mit5000
6:53 PM GMT on September 18, 2007
can we get back to 12-e please!

500
708. StormHype
6:52 PM GMT on September 18, 2007
Where is the COC? From local radar loops is looks off of Miami. From the Water Vapor loop, it looks like Orlando / Tampa area.


The one of tropical concern is the one off miami. The one inland around tampa is the upperlevel low supposedly moving slowly west over time. Note all the dry air on WV on west coast of FL now wrapping into this low. It's this moving west that will allow the developing storm offshore miami to cross the state *eventually* but now it's seems to be allowing it to stay offshore and grow it's convection and even bumping it a bit eastward.
Member Since: May 31, 2007 Posts: 0 Comments: 1204
707. bucsfan0713
6:51 PM GMT on September 18, 2007
Please forego your use of "lol" all of the time. If your comments are funny, people will know. In most likelyhood, things aren't going to be too funny for the next few days anyway. Thank you!


Now thats funny LOL!!!

706. NoviceWatcher
6:50 PM GMT on September 18, 2007
This is an incredible map to see everything in motion all at once.


Link
705. TampaSpin
6:49 PM GMT on September 18, 2007
Iboren that is an ULL that you are looking at....
Member Since: September 2, 2007 Posts: 178 Comments: 20443
704. franck
6:49 PM GMT on September 18, 2007
Is met Roth related to former chairman Greenspan?
Member Since: August 30, 2005 Posts: 0 Comments: 1150
703. centex
6:49 PM GMT on September 18, 2007
SH / Don't disagree and very interested if we can pin down an initial track. Radar is very helpful in these situations.
Member Since: August 10, 2007 Posts: 0 Comments: 3260
702. Cavin Rawlins
6:49 PM GMT on September 18, 2007
Posted By: lborne at 2:47 PM AST on September 18, 2007.
Where is the COC? From local radar loops is looks off of Miami. From the Water Vapor loop, it looks like Orlando / Tampa area.


Thats the upper level low over West FL, the low level center is east of Miami, FL.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
701. Cavin Rawlins
6:48 PM GMT on September 18, 2007
Most of the convection remains north of the center

Member Since: July 24, 2005 Posts: 407 Comments: 19076
700. lborne
6:47 PM GMT on September 18, 2007
Where is the COC? From local radar loops is looks off of Miami. From the Water Vapor loop, it looks like Orlando / Tampa area.
699. cattlebaroness
6:47 PM GMT on September 18, 2007
Houstonstormguy, sorry if I worded it wrong. I was only trying to stave off the folks who say wishcaster,etc. I believe it will be far from a fishstorm. I am very worried. But I have no ability to read these ULL,SST,etc. I just know that warm waters breed bigger storms, and the gulf is warm. I stayed up all night monitoring Humberto and watched it blow up. I believe if this system is out in the gulf just a little bit longer than Humberto it will be a major storm and where ever it hits will have some significant damage to people and things.

Has anyone looked at the blog FitzRoy set up that shows the ages of the different bloggers. It is really interesting. I am just a tatoo toting Granny who was in Buras, NOLA and especially lower 9th ward for 3 plus months after Katrina/Rita. It is a sobering experience and makes you appreciate the size and power of these storms. All I am saying is put some thought into an evac plan if and when the authorities, who I trust, say you are in danger of a hit.
698. TampaSpin
6:46 PM GMT on September 18, 2007
Posted By: Littleninjagrl at 6:44 PM GMT on September 18, 2007.

Posted By: TampaSpin at 6:43 PM GMT on September 18, 2007.

The further this drifts away from florida the longer it has to grow before crossing the State.

What do you mean? Its moving away and then coming back????
Yes the high will build in and force it back over the state.
Member Since: September 2, 2007 Posts: 178 Comments: 20443
697. StormHype
6:45 PM GMT on September 18, 2007
The further this drifts away from florida the longer it has to grow before crossing the State.


Absolutely, and that is what seems to already be happening. Check out the radar loop out of miami and set the loop to 2 hours. Also, check NDBC site for buoy at west end of grand bahama. Wind now 30kts from NE, it was only 9 knots 3 hours ago.
Member Since: May 31, 2007 Posts: 0 Comments: 1204
696. Floodman
6:46 PM GMT on September 18, 2007
windsock, Katrina was three times the size of Camille, a more compact storm...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
695. Michfan
6:46 PM GMT on September 18, 2007
I wouldn't rule out this making a Humberto type of intensification, especially with it moving east at the moment. The COC is basically sitting right on top of the Gulf Stream with nothing but warm water to help feed it. Its initial intensification before it interacts with Southern Florida is going to be very critical as to how strong it gets in the long term i think.

One thing that i haven't seen talked about yet and probably because its an unsure guess is how fast this system is going to move. Slow mover or a nice beeline towards its target? This is going to make for an interesting week!
Member Since: September 7, 2007 Posts: 0 Comments: 1733
693. mit5000
6:45 PM GMT on September 18, 2007
Posted By: aubiesgirl at 6:42 PM GMT on September 18, 2007.

ok i'm not tryin to be a smarta** here I'm just wonderin...what is it that everyone is seeing that has them thinking that 93l could be so bad?..Is it the warm gulf waters? low shear?.. what? I see people already predicting stuff and the thing isn't even a TD yet..edumacate me please!!!


i really dont know!

id much rather us talk about td 12 than td 93l
692. IceSlater
6:45 PM GMT on September 18, 2007
New Blog everyone
Member Since: July 6, 2005 Posts: 0 Comments: 417
691. StormJunkie
6:45 PM GMT on September 18, 2007
Dr M has a new blog up on 93.
Member Since: August 17, 2005 Posts: 26 Comments: 16859
690. houstonstormguy
6:45 PM GMT on September 18, 2007
93l looks to have an Andrew, katrina, rita track. Across south Florida and then into EastTex-LA. High pressure should stear this west after emerging into GOM.
Member Since: September 18, 2007 Posts: 0 Comments: 180
689. blueranch
6:44 PM GMT on September 18, 2007
they broke because the storm was east of the city and when the stronger bands moved over miss back across ne la and pushed the water across the lake NOT from storm surge from the gulf, the other two storms strongest winds were not as far east of the city on the way in and farther west of the metarie levees when they swept back across the lake
688. Littleninjagrl
6:44 PM GMT on September 18, 2007
Posted By: TampaSpin at 6:43 PM GMT on September 18, 2007.

The further this drifts away from florida the longer it has to grow before crossing the State.


What do you mean? Its moving away and then coming back????
Member Since: August 29, 2006 Posts: 0 Comments: 843
687. TheCaneWhisperer
6:44 PM GMT on September 18, 2007
His comment before his departure was "One day, I fear folks are going to go to bed to a tropical storm and wake up to a major hurricane on their doorstep". Highly unlikely in this situation, my comment was intended to be comical. It almost happend with Humbuerto though.
686. GetReal
6:44 PM GMT on September 18, 2007
Observed at: Foots Cay, Foots Cay, Abaco
Elevation: 30 ft / 9 m

Temperature: 78.7 F / 25 C
Humidity: 100%
Dew Point: 79 F / 26 C
Wind: 14.5 mph / 23 km/h from the ENE
Wind Gust: 16.2 mph / 26 km/h
Pressure: 29.77 in / 1008.0 hPa
Heat Index: 83 F / 28 C




The pressure is beginning to fall in the northern Bahama Islands!
Member Since: July 4, 2005 Posts: 204 Comments: 8896
685. bpg16
6:44 PM GMT on September 18, 2007
when do you suspect this storm hits the gulf coast? friday? saturday? want to start making plans to leave ASAP...
684. wxmanfla
6:43 PM GMT on September 18, 2007
Jerry of 1995, same general area, a weak storm but massive flooding in South Florida, see link

http://www.weatherunderground.com/hurricane/at199510.asp
683. TampaSpin
6:43 PM GMT on September 18, 2007
The further this drifts away from florida the longer it has to grow before crossing the State.
Member Since: September 2, 2007 Posts: 178 Comments: 20443
682. aubiesgirl
6:42 PM GMT on September 18, 2007
ok i'm not tryin to be a smarta** here I'm just wonderin...what is it that everyone is seeing that has them thinking that 93l could be so bad?..Is it the warm gulf waters? low shear?.. what? I see people already predicting stuff and the thing isn't even a TD yet..edumacate me please!!!
681. StormHype
6:41 PM GMT on September 18, 2007
I wouldn't pay too much attention to the models initial tracks. Once it gets in the Gulf we should be able to start narrowing it down. Like from 1500 miles of coast line to 750.


Forget the gulf for now, this thing is still moving slightly to the EAST off the EAST coast of FL per the radar loop out of miami during the last 90 minutes. Looks like rapid development per the radar loop.
Member Since: May 31, 2007 Posts: 0 Comments: 1204
680. SlimPBC
6:42 PM GMT on September 18, 2007
Winds are definitely picking up here in Deerfield Beach with no visible storm in the area. I'd estimate 15 mph with intermittent gusts in the 20-25 mph range.
679. Patrap
6:42 PM GMT on September 18, 2007
DocNDswamp's Blog Link
Member Since: July 3, 2005 Posts: 426 Comments: 128639
678. guygee
6:41 PM GMT on September 18, 2007
People let the the levees break. It's people, folks.
Member Since: September 16, 2005 Posts: 0 Comments: 3171
677. Patrap
6:41 PM GMT on September 18, 2007
DocND swamp is here,just go to the directory,hes blogging on 93L
Member Since: July 3, 2005 Posts: 426 Comments: 128639
675. guygee
6:40 PM GMT on September 18, 2007
Interesting, Patrap. I miss DocNDswamp's posts here.
Member Since: September 16, 2005 Posts: 0 Comments: 3171
674. Hhunter
6:39 PM GMT on September 18, 2007
If storm is getting on board this is of concern. will be interesting to see how fast this gets it's act together. Could the moisture from Isabel be helping....
Member Since: August 19, 2007 Posts: 0 Comments: 2973
673. decimus785
6:39 PM GMT on September 18, 2007
let me see,this year only the male names have become a hurricane(dean,felix,humberto) and barry who was not a hurricane was the strongest tropical storm compared with the females tropical storms.
This year is the year of male hurricanes
672. windsock
6:39 PM GMT on September 18, 2007
Yes the levees broke, but what made the levees break? The storm. They did not just break by themselves. The eye did not hit NO, but the storm sure did. Camille's eye hit almost at the same spot , but the levees did not break then. Betsy's eye went right over the city, but they did not break then either. The surge with Katrina was much higher and this caused the break.
671. mit5000
6:38 PM GMT on September 18, 2007
weather channel thing!


Organizing disturbance near Florida

2:10 p.m. ET 9/18/2007
Mark Avery, Meteorologist, The Weather Channel


South
Regional Video

An organizing disturbance just off the coast of southeast Florida is expected to drift westward over the next 36 hours unloading locally heavy downpours on the Sunshine State's peninsula.

Gusty northeast winds and rough surf will batter the east coast of Florida as well as the beaches of Georgia.

Scattered showers and storms will extend northeastward along the Atlantic coast to Virginia.

Farther west, scattered or isolated showers and storms will dot much of Texas and Oklahoma, although nothing particularly heavy is expected.

High temperatures will be mostly in the 80s. The 90s, however, are likely in south and east Texas and much of Louisiana.

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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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