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:


I did...in my 11:15 synopsis.


Thanks Storm. Just read it.
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437. bwat
Quoting connie1976:
..another stupid question...sorry again....but where do you all find the updated models besides the one on Tropical / Hurricane page...

Link Others may have better sites for you, but this is the one I use.
Member Since: August 18, 2009 Posts: 0 Comments: 338
Quoting JupiterFL:


Someone posted that a little earlier. If the new position is correct, do you think this will have much bearing on the overall track. TIA


Not to sure...Recon leaves @ midnight so well see what they find.Moving at 20mph this thing could reach the southern bahamas vicinity tommorow.
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434. Skyepony (Mod)
Quoting Alockwr21:
Seems like the models keep going west with 92L


CMC has really seen this one from five days before it began. Almost precisely consistent. Was a hair left on the 12z run as to where it made the near 90º turn north.
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..another stupid question...sorry again....but where do you all find the updated models besides the one on Tropical / Hurricane page...
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431. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #73
EXTRATROPICAL LOW, FORMER VAMCO (T0910)
9:00 AM JST August 26 2009
=========================================

At 0:00 AM UTC, Extratropical Low, Former Vamco (988 hPa) located at 51.0N 169.0E has 10 minute sustained winds of 45 knots with gusts of 65 knots. The low is reported as moving northeast at 40 knots

THIS IS THE FINAL TROPICAL CYCLONE ADVISORY FROM THE JAPAN METEOROLOGICAL AGENCY
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430. Skyepony (Mod)
Nowcoast is an easy way to see self updating satellite & surface observations. Zoom in, check the wind box on the right. Several south winds south of 92L.
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what does el nino mean for a florida winter?
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Seems like the models keep going west with 92L
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Quoting hurricane23:


Speaking of track SSD dvorak position was @ 22.5N 67.1W which is South and west of the 0Z initialization for the track guidance.


Someone posted that a little earlier. If the new position is correct, do you think this will have much bearing on the overall track. TIA
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Ascat caught half of the tropical wave.

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so any GOM storms?
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Quoting Relix:


It's been ridiculously hot the whole day but man... the night is... wow... almost unbearable.


Wow. I would have thought that you would have a little bit more breeze. Its just about as bad here but we at least have a little wind to cool us down.
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Quoting StormW:


Doin' good! You?

Yea...I'm watchin' over that a way!


I am well also. We have had some wicked lightening here recently, has scared the crap out of me a few times. Walked out the door into the lanai at the same time it cracked. Heart failure! LOL
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Quoting JupiterFL:


Watch it Orca they may call you a Kook as well.

May??
ROFLMAO, there are those on here who call me a lot worse :)
Member Since: October 1, 2007 Posts: 81 Comments: 26493
I'm sorry I thought that you were referring to something someone posted about me....now I'm the crazy one...lol....sorry...
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Wow, StormW- looks like you're becoming something of a met. star! Congrats on the success, I have more respect for your forecasts than any others on this site by far.
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Quoting GeoffreyWPB:
StormW...of all the storms you have analyzed, which one surprised you the most as far a major track change?


Speaking of track SSD dvorak position was @ 22.5N 67.1W which is South and west of the 0Z initialization for the track guidance.
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Quoting connie1976:


what am I? I'm a mother two boys, who is paranoid about hurricanes, but loves to watch them anyway.... I do not understand all of these maps people post, so I ask a lot of questions...isn't that what this blog is for? are you the owners?


??
Member Since: October 1, 2007 Posts: 81 Comments: 26493
414. Relix
Quoting JLPR:
92L is sucking the air from PR =\
currently : S 3 MPH
effectively making this night ... hot! =\

84 °F
Humidity: 74 %
Wind Speed: S 3 MPH
Barometer: 29.92"
Dewpoint: 75 °F (24 °C)
Heat Index: 92 °F (33 °C)


It's been ridiculously hot the whole day but man... the night is... wow... almost unbearable.
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Quoting Orcasystems:


Me thinks it might be


Watch it Orca they may call you a Kook as well.
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Quoting Orcasystems:


Me thinks it might be


what am I? I'm a mother two boys, who is paranoid about hurricanes, but loves to watch them anyway.... I do not understand all of these maps people post, so I ask a lot of questions...isn't that what this blog is for? are you the owners?
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Just needs convection and a well defined circulation and then I think they will pull the Trigger for Danny. Track wise, It's all about timing, but if that High is strong to the north, those major models like EURO could be on to something. Yes a trough is going to come, but which will be stronger, the high or the trough? We should know in about a few days from now.
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Quoting KEHCharleston:
yep. We can hope that this is not the case. Time will tell.


Me thinks it might be
Member Since: October 1, 2007 Posts: 81 Comments: 26493
hard to believe we have been through 13 invests now in the atlantic after such a "quiet" start
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406. JLPR
92L is sucking the air from PR =\
currently : S 3 MPH
effectively making this night ... hot! =\

84 °F
Humidity: 74 %
Wind Speed: S 3 MPH
Barometer: 29.92"
Dewpoint: 75 °F (24 °C)
Heat Index: 92 °F (33 °C)
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting hydrus:
My 2 cents, the weather all over has been strange.I travel quite a bit and everywhere I go the locals say the weather has changed a lot,and it is not how it use to be.Some of these people are 80 years old and lived these areas there whole lives.

I know exactly what you mean, I meet people from all over and they say very much what you have said. Hope it is not the sign of the times!
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StormW...of all the storms you have analyzed, which one surprised you the most as far a major track change?
Member Since: September 10, 2007 Posts: 0 Comments: 10578
Quoting palmbaywhoo:

what is that? the second time today you have brought it up? relax a little, no ones out to get you


Ok. You are probably right.
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Quoting stormpetrol:

I'll be 45 in November and I can never remember it being this hot in Grand Cayman, CI. and I never been away for more than 2 weeks during the Summer and those years were very few & far between.
My 2 cents, the weather all over has been strange.I travel quite a bit and everywhere I go the locals say the weather has changed a lot,and it is not how it use to be.Some of these people are 80 years old and lived these areas there whole lives.
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Hey Storm, how are ya? Looks like we might get a little more action here in the near future. The next wave off Africa looks like a bigun.
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Something "fishy" going on?! :)
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careful stormw, it may not be him, it could be a wolf in sheeps clothing lol... maybe jfv or eddye
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Very cool Storm!! ....but your famous too!! ..most people who come to this blog look for you too!..
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Quoting StormW:


Storm.

(j/k)

Thomas...or I go by Tommy...like the rock opera.


haha alright, Tommy, thanks :P
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Quoting stormpetrol:
I just noticed on the loop 92L looks like its shrinking without losing convection, Is it trying to tighten up and close off?


shear is dropping, so the storms arnt getting spread out as much.
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Quoting StormW:


If you could please...take a gander at comment number 4 on my blog.
Another fan it seems. You are a highly respected gentleman and your views are well appreciated.
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Funny Invest 92L showed on the Home page with 45 mph winds, but no named system, reminds me of Dolly!
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Quoting extreme236:


I'd say we have a good shot at seeing Danny after the recon tomorrow afternoon...gonna need a good 24 hours to organize some more as the shear drops.


I Agree..that wave nearing the African coast looks intense. I'm more concerned about that as far as in the long term.
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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.