Three Atlantic disturbances to watch

By: Dr. Jeff Masters , 2:40 PM GMT on October 03, 2007

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A low pressure system over the southern Gulf of Mexico (90L) has developed a large surface circulation covering most of the Gulf of Mexico, but is not a threat to develop rapidly. This morning's QuikSCAT pass shows this circulation nicely, with top winds of 35 mph to the southeast of the center. Satellite loops show that 90L's heavy thunderstorm activity has decreased since yesterday. Water vapor satellite loops show a large upper-level low pressure system also covers the entire Gulf of Mexico, with two embedded swirls. This upper level low has a cold core and is wrapping plenty of dry air into 90L. These factors, plus the very large size of the surface circulation of 90L, will keep any development of the storm slow. A Hurricane Hunter aircraft is scheduled to investigate the system Thursday afternoon, if necessary. Today's flight was canceled.

The latest computer model runs continue to point to a landfall Thursday night or Friday morning near the Louisiana/Texas border. I don't see 90L becoming a hurricane, and I give equal chances of 90L arriving at the coast as a tropical disturbance, tropical depression, or tropical storm.


Figure 1. Today's line up of tropical disturbances to watch.

Disturbance 92L east of the Bahamas
Of greater concern to me is an area of heavy thunderstorm activity associated with a surface trough of low pressure (92L) that has developed just east of the Bahama Islands. This morning's QuikSCAT pass showed an east-west oriented zone of converging winds at 27N between 69W and 72W, but no surface circulation. Satellite loops show a large area of disorganized thunderstorm activity that is not getting better organized. This disturbance is under about 10-15 knots of wind shear. Wind shear is expected to remain ten knots or less over 92L for the next five days. The computer models expect 92L will move slowly west-southwest over the Bahamas, then the Florida Straits or Cuba during the next three days. By Saturday, the GFS and ECMWF models predict a tropical depression could form in the Western Caribbean or southern Gulf of Mexico. The NOGAPS and UKMET model forecast that development Monday is more likely. These are the highest heat content waters in the Atlantic, and with a upper-level anticyclone with light wind shear expected to set up over the disturbance, the potential exists for a hurricane to form from 92L next week. The Hurricane Hunters are scheduled to investigate 92L Thursday afternoon.

Disturbance 91L between Africa and the Lesser Antilles
A tropical wave (91L) near 9N, 41W, midway between Africa and the Lesser Antilles Islands, has gotten better organized this morning. This morning's QuikSCAT pass showed a wind shift associated with the wave, but no closed circulation. Satellite loops show a modest area of heavy thunderstorm activity that is not well-organized. The disturbance is headed west at 10-15 mph, and is expected to take a more west-northwesterly track Thursday.

Wind shear is about 10 knots over the wave, and is forecast to remain below 15 knots until Thursday night. This may allow for some slow development. However, beginning Thursday night, wind shear is expect to increase and remain 20-30 knots through Sunday. This should prevent further development.

I'll have an update Thursday morning at the latest.

Jeff Masters

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2037. flaboyinga
2:43 PM GMT on October 04, 2007
Have 90 and 92 brought any significant rainfall to the W coast of Fla yet? Someone mentioned a while back tha the fire danger was going to be high if y'all didn't get a soaker before the fall dry season kicked in.
2036. moonlightcowboy
2:38 PM GMT on October 04, 2007
Good morning.

Latest SFC Analysis
Member Since: July 9, 2006 Posts: 184 Comments: 29610
2035. flaboyinga
2:31 PM GMT on October 04, 2007
It's been raining here in SE GA most of yesterday,
all night, and now most of the morning. My german shepherd ate his dog house a while back and now he's wanting to replace it with an Ark. (I haven't found a steel dog house to replace it with yet.)
2034. IKE
2:19 PM GMT on October 04, 2007
20-30 knots of shear over 92L...that'll keep it in check for awhile.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
2032. SamTeam
2:18 PM GMT on October 04, 2007
New Blog
Member Since: September 22, 2007 Posts: 0 Comments: 213
2031. OSUWXGUY
2:18 PM GMT on October 04, 2007
Ivansvrivr-

Yeah...I was looking at that strong ridging pushing in from the NE as well. It looks to me that the dryest air should stay just east of the Central Bahamas...I still think development could occur somewhere between there and Cuba.

See that big push of dry air headed for Bahamas out of N.E on W.V.loop? That should favor development S. of Cuba too.
2030. IKE
2:16 PM GMT on October 04, 2007
The tropical floater on 92L has the COC near 26N, and 73W at 1011 mb's.....

Link
Member Since: June 9, 2005 Posts: 23 Comments: 37860
2028. flaboyinga
2:14 PM GMT on October 04, 2007
Ivans, the cat may be staying at 8 lbs because of the spare lives it gives up when you let it drive the Buick. lol
2025. Ivansvrivr
2:08 PM GMT on October 04, 2007
Agreed Patrap. The folks who made the Scat are some of the best of the best. Too bad they didn't make 2 while they were doing the project.
2024. Ivansvrivr
2:05 PM GMT on October 04, 2007
See that big push of dry air headed for Bahamas out of N.E on W.V.loop? That should favor development S. of Cuba too.
2023. Patrap
2:04 PM GMT on October 04, 2007
QuickSCAT humming along on its lone transmitter. Its a tough Bird ..now way passed it design Orbital Life.A real tribute to its builders and designers. WE need another scatterometer on Orbit. Thats a given.
Member Since: July 3, 2005 Posts: 428 Comments: 129762
2022. Ivansvrivr
2:02 PM GMT on October 04, 2007
Patrap, Is Cig smoking man up there replacing the Duracells in the quickscat?
2021. Patrap
2:02 PM GMT on October 04, 2007
I just link the Models...That is about all I can give ya on that...
Member Since: July 3, 2005 Posts: 428 Comments: 129762
2020. bellestarr
2:01 PM GMT on October 04, 2007
1971. Patrap 8:30 AM CDT on October 04, 2007
mm5fsu45b 2007100400 Forecast slp Java Animation

Link

Can you tell how long 92L is supposed to stall out over the Yucatan?
2019. HIEXPRESS
2:00 PM GMT on October 04, 2007
CPC on Intraseasonal Oscillations: "During the summer these oscillations have a modulating effect on hurricane activity in both the Pacific and Atlantic basins."
Member Since: October 13, 2005 Posts: 4 Comments: 2156
2018. ROVtroll
1:59 PM GMT on October 04, 2007
StormW, great synopsis. Knew I could understand you, but thats because u are a Coastie, I was too for a little bit. Best station was Guam, on a bouy tender!
former ET3, USCG
2017. Patrap
1:59 PM GMT on October 04, 2007
QuickSCAT Pass Atlantic
12:53 UTC descending Pass

Link



Member Since: July 3, 2005 Posts: 428 Comments: 129762
2016. PensacolaDoug
1:58 PM GMT on October 04, 2007
Morn'n all.
Good analysis Storm!
Member Since: July 25, 2006 Posts: 0 Comments: 659
2015. Patrap
1:57 PM GMT on October 04, 2007
GOES WV Loop Of Atlantic,GOM 92L
Click to ENlarge
Link
Member Since: July 3, 2005 Posts: 428 Comments: 129762
2014. Ivansvrivr
1:56 PM GMT on October 04, 2007
Good morning Storm. off to read Storms update, be right back
2012. disasterguy
1:55 PM GMT on October 04, 2007
Thanks Storm
2011. Ivansvrivr
1:54 PM GMT on October 04, 2007
"Yukatan and Honderas have been a magnet this year"

I'm leaning that way, until big Bertha Bermuda high breaks down later in season. Or until something develops and proves me wrong.
2010. Floodman
1:53 PM GMT on October 04, 2007
Good morning, StormW
Member Since: August 2, 2006 Posts: 10 Comments: 9922
2009. HIEXPRESS
1:53 PM GMT on October 04, 2007
Winter weather report - Ice time.
The NHL Tampa Bay Lightning open their season tonight against the New Jersey [dust] Devils.

MJO 10/3/07
Member Since: October 13, 2005 Posts: 4 Comments: 2156
2008. Hhunter
1:52 PM GMT on October 04, 2007
Interesting analysis stormw. Kinda sums up the problems challenges of trying to figure out 92L...
Member Since: August 19, 2007 Posts: 0 Comments: 2974
2007. Ivansvrivr
1:51 PM GMT on October 04, 2007
Anybody who breeds bengals. They are wild and not legal in all states. Must ge 5 gens from parent leopard to be cosidered "domestic" this ones only 2/
2006. saltydog1111
1:50 PM GMT on October 04, 2007
I can't believe we've had this many systems in the Gulf without something major blowing up!!! Unbelievable!!!!!
Member Since: July 24, 2007 Posts: 0 Comments: 133
2005. hurricanehanna
1:50 PM GMT on October 04, 2007
Thanks for the update Storm! Good job as usual!
Member Since: September 5, 2007 Posts: 0 Comments: 3488
2004. Patrap
1:50 PM GMT on October 04, 2007
GFDL has a end solution of 988MB..

Link
Member Since: July 3, 2005 Posts: 428 Comments: 129762
2003. disasterguy
1:49 PM GMT on October 04, 2007
Heavy duty shear for 92L this morning.
2002. houstonstormguy
1:49 PM GMT on October 04, 2007
Ivansvrivr 1:46 PM GMT on October 04, 2007
Fidel may send 92 on down to see is pal Hugo.


lol. Not sure that far south but I agree 92L could pull a Mitch. Yukatan and Honderas have been a magnet this year
Member Since: September 18, 2007 Posts: 0 Comments: 180
2001. OSUWXGUY
1:49 PM GMT on October 04, 2007
Good morning everyone! Time to see what everyone has been writing
2000. Hhunter
1:48 PM GMT on October 04, 2007
UGH i don't like the GFDL latest run..
Member Since: August 19, 2007 Posts: 0 Comments: 2974
1998. newt3d
1:47 PM GMT on October 04, 2007
92L still doesn't look too great, but my gut feeling is that something has to at least try to form underneath that large, moist, anti-cyclone that's built up around the Bahamas/Cuba. It's a decently favorable environment that is just missing some semi-organized surface spin.
Member Since: October 6, 2005 Posts: 0 Comments: 90
1997. Ivansvrivr
1:46 PM GMT on October 04, 2007
Fidel may send 92 on down to see is pal Hugo.
1996. Floodman
1:46 PM GMT on October 04, 2007
Hey, Ivamn, where does one acquire such a cat, if that question may be asked? I'd like to train it to do my job, so I can spend my time in here...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
1995. Ivansvrivr
1:44 PM GMT on October 04, 2007
JP I hear you, just won't be sold on development in bahamas until named. Too many non events in bahamas so far this year.

Mitch was in deep tropics, but conventional wisdom at the time was that development in that area always moves NW into GOM, usually turning N.E into FL. Mitch remnant eventually did cross FL as tropical dep. or storm. (or so thae cat tells me.)
1994. Floodman
1:44 PM GMT on October 04, 2007
Yikes! All the models are doom and gloom this morning...and of course, the CMC is forecasting the end of the world...about 168 hours out, huh?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
1993. Hhunter
1:42 PM GMT on October 04, 2007
Link

This loop shows pretty well where the current low pressure center of 92L is. Quite a big area. It will be interesting to see where, when and if this forms.

Member Since: August 19, 2007 Posts: 0 Comments: 2974
1992. felixemartinez
1:39 PM GMT on October 04, 2007
I see another counter-clockwise swirl shooting out to the NW at 26.1N, 71.5W during the last few frames here:

http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html
1991. LADobeLady
1:38 PM GMT on October 04, 2007
cmc 2007100400 Forecast slp Java Animation

Pat I really don't like that scenario. However, I feel good that it's the CMC doing it LOL
Member Since: July 29, 2005 Posts: 21 Comments: 794
1990. houstonstormguy
1:38 PM GMT on October 04, 2007
Passing CMC 1mg xanax to CMC and to cat, while taking one. 92 wants mozy on to greener pastures south of Cuba.


No worries Ivan...Fidel has a good beat on it
Member Since: September 18, 2007 Posts: 0 Comments: 180
1989. Ivansvrivr
1:38 PM GMT on October 04, 2007
The cat ate it. That cat is fully grown and only weighs 6 pounds. Eats 4 times as much as other 11 lb domestic.
1988. weathermanwannabe
1:36 PM GMT on October 04, 2007
1955. SEFL 9:22 AM EDT on October 04, 2007
Okay, I am going to Tallahassee this weekend to watch the 'Noles beat up on North Carolina State. My question is are any of you going to be able to gin up weather that will mess up the weekend? Will 92L suddenly shoot north on the back of that low that 90L couldn't use? Or is there a yet undefined/unknown event lurking off the gulf coast ready to devastate the panhandle? :)

I live in Tally and will be at the game and right now; it looks all clear to me (for some good Football & Beer!).......
Member Since: August 8, 2006 Posts: 0 Comments: 9400
1987. HIEXPRESS
1:36 PM GMT on October 04, 2007
...full frontal nudity.
Member Since: October 13, 2005 Posts: 4 Comments: 2156

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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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