Hurricane Hunters find 50 - 60 mph winds in disturbance 92L north of Puerto Rico

By: Dr. Jeff Masters , 8:54 PM GMT on August 25, 2009

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The tropical wave (92L) a few hundred miles north of Puerto Rico is generating a large area of surface winds of 50 - 60 mph, according to the latest information from the Hurricane Hunters. Top winds seen so far at their flight level of 1,000 feet were 69 mph, which would make 92L a strong tropical storm if it had a surface circulation.
However, the aircraft has not found a surface circulation, and the satellite appearance shows virtually no change in the amount, intensity, or organization of the storm's thunderstorm activity. Wind shear has dropped to the moderate range, 15 - 20 knots this afternoon, but the upper low 92L is moving underneath is dumping cold, dry air into the region. Dry air continues to get ingested into 92L's thunderstorms, creating strong downdrafts that are robbing 92L of heat and moisture. These downdrafts are creating surface arc clouds that spread out from where the downdraft hits the ocean surface. NHC continues to give 92L a high (greater than 50% chance) of developing into a tropical depression by Thursday afternoon.

The forecast for 92L
As 92L moves underneath the center of the upper low on Wednesday morning, the upper low is expected to weaken, and wind shear is expected to decline to the low range, 5 - 10 knots. However, the upper-level low will continue to dump dry, cold air into 92L through Thursday afternoon, slowing down development. By Thursday night, when 92L should be several hundred miles off the coast of northern Florida, the upper-level low may be weak enough and far enough away that 92L will find itself in a region with light upper level anticyclonic winds, which would favor more rapid development. However, this favorable environment will not last long, since a strong trough of low pressure will be approaching the U.S. East Coast on Friday. This trough will bring high wind shear of 20 - 30 knots by Friday night. This trough should be strong enough to turn 92L to the north. The models disagree substantially on how close 92L will be to the coast at that time. One camp of models, including the NOGAPS, Canadian, UKMET, and ECMWF models, predict 92L will pass very close to the Outer Banks of North Carolina on Friday night or Saturday morning. The GFS, GFDL, and HWRF models keep 92L several hundred miles out to sea. Both sets of models bring 92L north-northeastwards on Saturday, with a track over Massachusetts or Nova Scotia. The intensity forecast for 92L is problematic, since it's eventual strength depends upon how quickly it manages to become a tropical depression. Given that 92L will find itself in a favorable environment for strengthening for about 36 hours this week, and marginal for the remainder of the week, I give the system these odds:

10% chance of never getting a name.
20% chance of becoming a weak tropical storm (40 - 50 mph winds).
40% chance of becoming a strong tropical storm (55 - 70 mph winds).
30% chance of attaining hurricane strength.

Elsewhere in the Atlantic
The ECMWF and UKMET models predict the development of a tropical wave coming off the coast of Africa late this week. The GFS model no longer shows this.

I'll have an update Wednesday morning.

Jeff Masters

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Quoting StormW:


Grab plenty of toilet paper!



lol
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LOLOLO Storm !!
Quoting StormW:


Grab plenty of toilet paper!


lol
Member Since: Posts: Comments:
Quoting 900MB:
1. Rut-roh!
2. 60 mph before it even has a surface low? What happens when it organizes for real?
3. SHIPS now forecasting strong Cat 2!
4. From D.C. to Maine a Cat 2 is like a Cat 4 in GOM.
5. Buy stock in Home Depot quick if a cat 2 hit Long Islnad and NE!

P.S. Storm- what's your take?


Dont get your knickers in a twist dude!!
Member Since: September 3, 2008 Posts: 0 Comments: 602
483. OBXNC
hey guys and gals ...

you know, this may seem weird ... but it may make sense to some ...

i'm a native of a coastal community (Outer Banks, NC) that is pretty hurricane-savvy. Sometimes it just "feels" like your year to get hit, and that has been the consensus of the locals around here since before hurricane season began this year ... it just kinda feels like we are going to get a storm this year ...

by no means saying it will be 92L, of course ... but my mother and i were talking about it today (she manages a vacation rental company on Hatteras Island), and she agreed that "it feels like our year"

(just cause i feel like i have to disclaim everything - i'm not saying 92L will be an isabel ... lol ... )

i often wonder if the "feeling" is because the weather patterns that set up that allow storms to strike us are similar, and locals in coastal communities sense that ... do i make any sense?

i dunno ... just a musing on a muggy and still tuesday night on the OBX ...
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Quoting 900MB:
1. Rut-roh!
2. 60 mph before it even has a surface low? What happens when it organizes for real?
3. SHIPS now forecasting strong Cat 2!
4. From D.C. to Maine a Cat 2 is like a Cat 4 in GOM.
5. Buy stock in Home Depot quick if a cat 2 hit Long Islnad and NE!
Why?
Member Since: August 19, 2008 Posts: 6 Comments: 2490
Quoting 900MB:
1. Rut-roh!
2. 60 mph before it even has a surface low? What happens when it organizes for real?
3. SHIPS now forecasting strong Cat 2!
4. From D.C. to Maine a Cat 2 is like a Cat 4 in GOM.
5. Buy stock in Home Depot quick if a cat 2 hit Long Islnad and NE!

P.S. Storm- what's your take?


Joe Bastardi? Is that you?
Member Since: September 22, 2005 Posts: 18 Comments: 2342
478. 900MB
1. Rut-roh!
2. 60 mph before it even has a surface low? What happens when it organizes for real?
3. SHIPS now forecasting strong Cat 2!
4. From D.C. to Maine a Cat 2 is like a Cat 4 in GOM.
5. Buy stock in Home Depot quick if a cat 2 hit Long Islnad and NE!

P.S. Storm- what's your take?
Member Since: June 11, 2006 Posts: 0 Comments: 684
Quoting StormW:
?466. stormwatcherCI 9:51 PM EDT on August 25, 2009
Quoting Hurricane009:
It means that the MJO will not be as active as what it is starting to go in to this week
Not a very clear explanation. What does it mean as far as what results


Post 462.

Thanks. I saw that after I typed my question.
Member Since: October 9, 2008 Posts: 0 Comments: 8373
Quoting Hurricane009:
It means that there will be cold, dry air in place and that any tropical wave that comes off africa will have a difficult time developing into anything
Thanks. It's clearer now. So when it is in a downward motion it is more difficult for anything to form ?
Member Since: October 9, 2008 Posts: 0 Comments: 8373
The National Hurricane Center started running computer forecast models on the wave and right now the system is forecast to move closer to the southeast United States before turning to the north and eventually the northeast. As of this morning, the models put the developing system on a path somewhat similar to that of "Hurricane Bill." However, if the projections are correct, it would come closer to our coastline before making the turn to the north. There are many uncertainties at this point so check back for information in the coming days.

This statement was from our local forecaster Craig Moeller, here in Virginia.I sure hope if this does become a Tropical storm, that we have enough warning to start preparing for it. I sure wouldn't want it in my backyard before the alerts come out.
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We have a had a great couple of days here on the gulf coast, low humidity and almost record lows at night. For August...fabulous!
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Quoting Skyepony:
Fresh quikscat..no west wind


Click on the pic & select from the decending pass (most current) if you want to see the part south of this one..nothing there though.


As long as there's no closed circulation it should follow a general WNW direction:



Also if it keeps being disorganized I won't be surprised to see further W shifts but not by much due to the trough on the E CONUS.
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469. JLPR
Quoting Skyepony:


This one has that & more..

Link


great
thanks :0)

also some strong winds in there but no closed low


the 12.5km resolution off Africa was skipped >:| I wanted to see that one =P
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468. bwat
Quoting NCHurricaneHunter18:
Post 450....... Where at in NE NC do you live? I live in Edenton


New Hope....in between Hertford and E. City.
Member Since: August 18, 2009 Posts: 0 Comments: 353
Quoting StormW:


If you could please...take a gander at comment number 4 on my blog.
You might also want to check out #1 on Hurricane009's blog.
Member Since: October 4, 2007 Posts: 0 Comments: 200
Quoting Hurricane009:
It means that the MJO will not be as active as what it is starting to go in to this week
Not a very clear explanation. What does it mean as far as what results ?
Member Since: October 9, 2008 Posts: 0 Comments: 8373
Post 450....... Where at in NE NC do you live? I live in Edenton
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I'm beginning to believe that this system should be classified as a subtropical storm. I think the only reason the NHC has not done so is the fact that a STS so far south is almost unheard of.

Can anyone else recall an STS forming south of 30N?
Member Since: September 22, 2005 Posts: 18 Comments: 2342
The system remains a surface trough of low pressure.
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461. Skyepony (Mod)
Quoting JLPR:
anyone has a good Ukmet model site?
im still missing that one =P


This one has that & more..

Link
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Looks like a legitimate post to me Storm. Hey I think I hit the center of 92L a couple of hours ago thanks to some of the questions I asked Storm W last year so if any of you questions don't be afraid to ask Storm. I don't want to put words in his mouth but the only stupid question is the one that's not asked. Now repeating yourself endlessly with the same question or comment is another story.
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459. CUBWF
Good evening adrian, I have your blog in my favorites, and I think you can find everything someone need. I recomend you Connie.
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Thank you all for your info and patience with me....I probably will ask a million more stupid questions, just put me on ignor if I become too annoying!! Thank you all!! Have a great evening.....
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457. JLPR
anyone has a good Ukmet model site?
im still missing that one =P
Member Since: Posts: Comments:
455. Skyepony (Mod)
Fresh quikscat..no west wind


Click on the pic & select from the decending pass (most current) if you want to see the part south of this one..nothing there though.
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Quoting StormW:


I try not to speculate that far out. It's possible, given the forecast of a negative NAO. But then we have to add in the downward motion of the MJO after the first week of September.


What is the downward motion of MJO? What does that mean?
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Update Spaghetti models



AOI

AOI

AOI

AOI
Member Since: October 1, 2007 Posts: 81 Comments: 26511
450. bwat
Quoting stormobserver:
Still hard to get excited about 92L--unless all the models are wrong. And it seems unlikely to get above Cat 1 intensity.


To be honest, I'm more worried about the precip, rather than the wind event. Here in NE NC we have had more rain this summer than I can remember. Wish I could send some of this rain to others in the blog that need some.
Member Since: August 18, 2009 Posts: 0 Comments: 353
Quoting stormobserver:
Still hard to get excited about 92L--unless all the models are wrong. And it seems unlikely to get above Cat 1 intensity.
So, Cat 1 can't do any damage or what ?
Member Since: October 9, 2008 Posts: 0 Comments: 8373
Hi StormW,

From what you are seeing could things livin up in the Carribean and GOM in September? Thanks.
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442. Skyepony (Mod)
So Vamco is dead.. Been around so long.. Never harassed land. Had a big beautiful eye. Been meaning to dig up the MIMIC. Never really noticed eyewall replacement. They never ran SHIPS on him..Would have liked to have seen his Annular Hurricane Index. Was incredible to see the big eye there earlier today with the rest faded..like an old mancane.
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Quoting connie1976:
..another stupid question...sorry again....but where do you all find the updated models besides the one on Tropical / Hurricane page...


You can get the SFWMD Model Plots HERE and for further variety you can you my links page.

Adrian
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Quoting hurricane23:


Not to sure...Recon leaves @ midnight so well see what they find.Moving at 20mph this thing could reach the southern bahamas vicinity tommorow.


Thanks. Always appreciate your analysis and perspective.
Member Since: August 10, 2005 Posts: 0 Comments: 2146

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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.