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 JeffMasters:
I updated the blog to include the high winds found by the Hurricane Hunters. I bumped up my odds of it becoming a hurricane, too. Still, there is nothing resembling a closed surface circulation that the hurricane hunters are able to find, or visible on satellite.

Jeff Masters


Thanks for the update Doc. Using the area of lowest pressure as the potential center, the strongest winds have been displaced to the north, similar to a subtropical system. Any chance this could be the case?
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Max Mayfield just mentioned that the hunters are going to fly west from what I can tell towards the smaller blowup to the west around 22.5 & 67, i thought that might look a little interesting but not an expert here by any stretch
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Quoting amd:
this could be subtropical storm danny at anytime. Winds out of the WNW at San Juan according to this buoy:

Link

Interestingly, an area of much lower shear is located just north of Puerto Rico.

Link

Why Subtropical?
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86. JeffMasters (Admin)
I updated the blog to include the high winds found by the Hurricane Hunters. I bumped up my odds of it becoming a hurricane, too. Still, there is nothing resembling a closed surface circulation that the hurricane hunters are able to find, or visible on satellite.

Jeff Masters
This storm seems to be taking the same path Bill just did....
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actually subtropical systems do get named now
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000
AGXX40 KNHC 251909
MIMATS

MARINE WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL


SW N ATLC...
COMPLEX TROPICAL WAVE ACROSS THE SW N ATLC BETWEEN 60W AND 67W
CONTINUES TO INTERACT WITH UPPER TROUGH AND PAIR OF VORTS TO ITS
W...ALIGNED N TO S ALONG 67/68W...AND IS PRODUCING A BROAD AND
ELONGATED AREA OF SCATTERED MODERATE TO DEEP CNVTN. SAHARAN AIR
THAT HAS WRAPPED AROUND THE FAR W OF THE WAVE IS AIDING IN
PRODUCING SQUALLS AND HUGE OUTFLOW BOUNDARIES W OF 68W RACING
AWAY FROM THE WAVE. AN EVENING QUIKSCAT PASS YESTERDAY SHOWED
SEVERAL NON RAIN FLAGGED VECTORS WITH GREATER THAN 34 KT WINDS
OCCURRING WITHIN AND TO THE N OF THIS BROAD AREA OF CNVTN...BUT
THERE WERE NO MORNING SCATTEROMETER PASSES TODAY TO ASSIST.
REGARDLESS...GALE FORCE WINDS ARE LIKELY OCCURRING IN A NARROW
BAND ACROSS THE NRN SEMICIRCLE OF THE BROAD LLVL TROUGHING
ASSOCIATED WITH THIS WAVE AND IS EXPECTED TO PERSIST WITH IT
THROUGH 48 HOURS BEFORE WEAKENING. ACCOMPANYING SEAS ARE LIKELY
IN EXCESS OF 15 FT NOW AND SHOULD BUILD IN A DYNAMIC FETCH TO
AROUND 18 FT NEXT 24-36 HOURS. WE STILL PREFER A SOLUTION FOR
THE MOVEMENT OF THIS FEATURE MORE TOWARD THE WNW AS PER RECENT
ECMWF FORECASTS...THROUGH 48 HOURS...BEFORE TURNING MORE NW
48-72 HOURS. THE MORNING STLT PRESENTATION SUGGESTED A SFC LOW
TRYING TO DEVELOP ACROSS WRN PORTIONS OF THIS WAVE...WHEREAS
GLOBAL MODEL GUIDANCE WAS UNANIMOUS IN TRYING TO DEVELOP A LOW
ACROSS THE SE PORTION OF THE WAVE THE PAST FEW DAYS. THIS ALSO
MOVES US TOWARD A MORE WNW MOTION. STLT IMAGERY DOES NOT LOOK AS
GOOD THIS AFTERNOON WITH LESS ORGANIZATION...AND AN ELONGATED
AREA OF CNVTN...LIKELY COINCIDENT WITH THE WIND AND WAVE FIELD.
THIS BROAD AREA OF 20-25 KT WINDS...AND NARROW BAND OF 30-35 KT
WINDS AND SEAS IN EXCESS OF 12 FT WILL SLIDE WNW THROUGH LATE
WED AND MAINTAIN VERY ROUGH CONDITIONS. WWIII GUIDANCE FOLLOWS
THE GFS WIND FIELD...WITH BOTH OF THESE MODELS PRODUCING HIGHEST
WINDS AND SEAS 3-8 DEGREES NE OF OUR POSITIONS. THIS SYSTEM
SHOULD LIFT OUT OF THE AREA FRIDAY...WITH HIGH PRES BRIEFLY
BUILDING INTO THE AREA AHEAD OF THE NEXT LARGE TROPICAL WAVE.

REFER TO LATEST TROPICAL WEATHER OUTLOOK...MIATWOAT...FROM NHC
ON THIS EVOLVING TROPICAL WAVE...AS WELL AS THE HIGH SEAS
FORECASTS FROM TAFB...MIAHSFAT2.

WARNINGS
ATLC...
.GALE WARNING N OF 22N FROM 63W TO 73W...
.GALE WARNING EXPECTED WED AND WED NIGHT WITHIN 180 NM NE OF LOW
PRES CENTER...

CARIBBEAN...
.NONE.

GULF OF MEXICO...
.NONE

$$
FORECASTER STRIPLING

Member Since: July 15, 2006 Posts: 169 Comments: 53296
This system reminds me of Hanna last year.
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Quoting jeffs713:

I think it has a partial circulation, with it strong in some sections, but until it fully closes off, it won't be named anytime soon.


Agreed. I'll go out and say we may have a subtropical storm. It really does need to close off a LLC, though, before the NHC will name it. 8 p.m. will be interesting. I gotta head out, see y'all later.
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000
FZNT23 KNHC 252130
OFFNT3

OFFSHORE WATERS FORECAST FOR THE SW AND TROPICAL N ATLANTIC AND
CARIBBEAN SEA
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 PM EDT TUE AUG 25 2009


AMZ088-260330-
SYNOPSIS FOR THE SW N ATLC INCLUDING THE BAHAMAS
530 PM EDT TUE AUG 25 2009

.SYNOPSIS...HIGH PRES RIDGE FROM 32N65W TO NW BAHAMAS WILL
WEAKEN AND DRIFT N THROUGH FRI AS A STRONG AND COMPLEX TROPICAL
WAVE MOVES NW ACROSS THE BASIN THROUGH FRI. A TIGHT PRES GRADIENT
BETWEEN LOW PRES ASSOCIATED WITH THE WAVE NEAR 24N67W 1010 MB AND
HIGH PRES TO THE N IS RESULTING IN AN AREA OF GALE FORCE WINDS N
AND NE OF LOW. THE LOW...POSSIBLY A TROPICAL CYCLONE...MOVING WNW
AT 18 KT IS FORECAST TO REACH NEAR 25N71W BY WED MORNING...NEAR
28N73W WED NIGHT...THEN TURN TO THE N AND ACCELERATE TO NEAR
29N74W BY EARLY THU EVENING...AND MOVE N OF THE AREA INTO FRI
WITH GALE CONDITIONS SHIFTING INTO THE N AND NE PORTIONS OF THE
THROUGH THU NIGHT. RIDGE WILL BUILD W ALONG THE NORTHERN WATERS
FRI THROUGH SUN.

FORECASTER AGUIRRE


$$

Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting jeffs713:

I think it has a partial circulation, with it strong in some sections, but until it fully closes off, it won't be named anytime soon.

Yep, I was going to say something like that.

It appears to be an open near-cane.
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77. amd
this could be subtropical storm danny at anytime. Winds out of the WNW at San Juan according to this buoy:

Link

Interestingly, an area of much lower shear is located just north of Puerto Rico.

Link
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I would definitely like to see all the observations once the flight is over. Might be easier to pick out a pattern then. (if there is one)
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Quoting stormwatcherCI:
Pressure in the Central Caribbean right now 1008 mb and falling. Notice the are just east of Nic/Hond is very convective. Any chances something forms here ?


I'm not really sure. Just noticed how the NOGAPS hung onto it for a while. So far the 18z Nam and GFS seem to bring a lot of moisture through there. But I can't tell what it means.
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Quoting atmoaggie:


Did you see that on SFMR obs? Is there any way they were over land or shallow water at the time?

Nevermind...so long as you guys are talking about the ob at 24.633N 64.383W.
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I do believe jeffs713 is correct...let that bad boy close off
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OFFNT3

OFFSHORE WATERS FORECAST FOR THE SW AND TROPICAL N ATLANTIC AND
CARIBBEAN SEA
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 PM EDT TUE AUG 25 2009


AMZ088-260330-
SYNOPSIS FOR THE SW N ATLC INCLUDING THE BAHAMAS
530 PM EDT TUE AUG 25 2009

.SYNOPSIS...HIGH PRES RIDGE FROM 32N65W TO NW BAHAMAS WILL
WEAKEN AND DRIFT N THROUGH FRI AS A STRONG AND COMPLEX TROPICAL
WAVE MOVES NW ACROSS THE BASIN THROUGH FRI. A TIGHT PRES GRADIENT
BETWEEN LOW PRES ASSOCIATED WITH THE WAVE NEAR 24N67W 1010 MB AND
HIGH PRES TO THE N IS RESULTING IN AN AREA OF GALE FORCE WINDS N
AND NE OF LOW. THE LOW...POSSIBLY A TROPICAL CYCLONE...MOVING WNW
AT 18 KT IS FORECAST TO REACH NEAR 25N71W BY WED MORNING...NEAR
28N73W WED NIGHT...THEN TURN TO THE N AND ACCELERATE TO NEAR
29N74W BY EARLY THU EVENING...AND MOVE N OF THE AREA INTO FRI
WITH GALE CONDITIONS SHIFTING INTO THE N AND NE PORTIONS OF THE
THROUGH THU NIGHT. RIDGE WILL BUILD W ALONG THE NORTHERN WATERS
FRI THROUGH SUN.

FORECASTER AGUIRRE


$$
Member Since: July 15, 2006 Posts: 169 Comments: 53296
71. IKE
18Z GFS @ 78 hours....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Stoopid1:


I'm in the same boat, but readings have been too consistent over too large an area to just contribute it to downdrafts or equipment error.


Could be mis-calibration of the SMFR... but flight level are high at only 1K feet, so... I'm just scratching my head on this one.
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Quoting Drakoen:
I have a hard time believing that thing has 60mph winds


Did you see that on SFMR obs? Is there any way they were over land or shallow water at the time?
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Quoting Stoopid1:


I'm in the same boat, but readings have been too consistent over too large an area to just contribute it to downdrafts or equipment error.

I think it has a partial circulation, with it strong in some sections, but until it fully closes off, it won't be named anytime soon.
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Quoting Drakoen:
I have a hard time believing that thing has 60mph winds


I'm in the same boat, but readings have been too consistent over too large an area to just contribute it to downdrafts or equipment error.
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Quoting Drakoen:
I have a hard time believing that thing has 60mph winds


Yep...nothing out of the west either, huh? We're missing a piece here
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Quoting Drakoen:
I have a hard time believing that thing has 60mph winds


Agree
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http://weather.noaa.gov/pub/data/raw/fz/fznt23.knhc.off.nt3.txt


AMZ088-260330-
SYNOPSIS FOR THE SW N ATLC INCLUDING THE BAHAMAS
530 PM EDT TUE AUG 25 2009
.SYNOPSIS...HIGH PRES RIDGE FROM 32N65W TO NW BAHAMAS WILL
WEAKEN AND DRIFT N THROUGH FRI AS
A STRONG AND COMPLEX TROPICAL
WAVE MOVES NW ACROSS THE BASIN THROUGH FRI.
A TIGHT PRES GRADIENT BETWEEN LOW PRES ASSOCIATED WITH

THE WAVE NEAR 24N67W 1010 MB AND HIGH PRES TO THE N
IS RESULTING IN AN AREA OF GALE FORCE WINDS N AND NE OF LOW.

THE LOW...POSSIBLY A TROPICAL CYCLONE...MOVING WNW
AT 18 KT IS FORECAST TO REACH NEAR 25N71W BY WED MORNING...

NEAR
28N73W WED NIGHT...

THEN TURN TO THE N AND ACCELERATE TO NEAR
29N74W BY EARLY THU EVENING...

AND MOVE N OF THE AREA INTO FRI
WITH GALE CONDITIONS SHIFTING INTO THE N AND NE PORTIONS OF THE
THROUGH THU NIGHT. RIDGE WILL BUILD W ALONG THE NORTHERN WATERS
FRI THROUGH SUN.
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Readings have covered a substantial area and have been consistent, and reduction factors have been appropriate, so I guess the readings are legit. All 92L needs to be now is close off a low level circulation and it will be a TS.
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I have a hard time believing that thing has 60mph winds
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Quoting homelesswanderer:


The models had been showing something like this for days. The NOGAPS the farthest north with a stronger system in the S. GOM. But they seem to have come off of it. The Nam showed something making it to the NW Caribbean. Haven't looked at them recently though.
Pressure in the Central Caribbean right now 1008 mb and falling. Notice the are just east of Nic/Hond is very convective. Any chances something forms here ?
Member Since: October 9, 2008 Posts: 0 Comments: 8279
Quoting homelesswanderer:


The models had been showing something like this for days. The NOGAPS the farthest north with a stronger system in the S. GOM. But they seem to have come off of it. The Nam showed something making it to the NW Caribbean. Haven't looked at them recently though.


Thats what rare said yesterday and I rode him like a rented mule...I probably should feel bad...but I dont :)
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Quoting Skyepony:
With the flight level winds they are finding I don't see the surface winds as an error. SFMR or % calculation you get plenty of TS strength winds.


Kinda starting to remind me of Kyle from last year. Once they closed off a center it went straight to a TS.
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Quoting Seastep:
No winds from any sort of W, yet, though.

Weird.


Open circulation...
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Quoting stormpetrol:
I know all the attention is on 92L, but I think ex93L may have split with LLC crossing into the EPac and the MLC emerging off Honduras into the NW Caribbean becoming a separate system in itself with a potential for development, jmo


The models had been showing something like this for days. The NOGAPS the farthest north with a stronger system in the S. GOM. But they seem to have come off of it. The Nam showed something making it to the NW Caribbean. Haven't looked at them recently though.
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Quoting homelesswanderer:
I don't know if the timing of the front down here would have anything to do with the timing of the trough in the NE. But here's what my NWS had to say about it in SW La.

LAWN WORK MAY NEED TO BE COMPLETED EARLY THIS WEEK AS RAIN CHANCES
WILL RAMP UP FRIDAY THROUGH THE WEEKEND THANKS TO A SLOW MOVING
CANADIAN COLD FRONT MOVING IN FROM THE NORTHWEST AND CREEPING
THROUGH BEFORE STALLING OFF THE COAST EARLY NEXT WEEK.

Of course this is what they said about the last one but it just didn't make it this far. Lol. But we're glad of em anyway. :)
front is surpose to stall with whatever forms trapped into a n ward movement as a rex block sets up just south of greenland preventing systems from going ene as well
Member Since: July 15, 2006 Posts: 169 Comments: 53296
55. Skyepony (Mod)
With the flight level winds they are finding I don't see the surface winds as an error. SFMR or % calculation you get plenty of TS strength winds.
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Quoting largeeyes:
Thanks Dr. M. Eastern NC is watchin!


OBXer's EAT THESE STORMS FOR BREAKFAST!
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is it 1030pm yet school day bedtime call

lol
Member Since: July 15, 2006 Posts: 169 Comments: 53296
I don't know if the timing of the front down here would have anything to do with the timing of the trough in the NE. But here's what my NWS had to say about it in SW La.

LAWN WORK MAY NEED TO BE COMPLETED EARLY THIS WEEK AS RAIN CHANCES
WILL RAMP UP FRIDAY THROUGH THE WEEKEND THANKS TO A SLOW MOVING
CANADIAN COLD FRONT MOVING IN FROM THE NORTHWEST AND CREEPING
THROUGH BEFORE STALLING OFF THE COAST EARLY NEXT WEEK.

Of course this is what they said about the last one but it just didn't make it this far. Lol. But we're glad of em anyway. :)
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Darn eddye school just started and you already want out
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I know all the attention is on 92L, but I think ex93L may have split with LLC crossing into the EPac and the MLC emerging off Honduras into the NW Caribbean becoming a separate system in itself with a potential for development, jmo
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Sounds like Dolly all over again.
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Quoting largeeyes:
Couldn't those just be downdrafts from the big thunderstorms?


Very likely. Or some sort of calibration error. I'm having a hard time buying those readings.
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Couldn't those just be downdrafts from the big thunderstorms?
Member Since: August 22, 2006 Posts: 0 Comments: 1451
Quoting zebralove:
can anyone tell me where to see more stuff cycloneoz may have posted? He said he was getting some great video of Bill, but his blog hasnt been updated in 58 days. Does he post his stuff somewhere else? I was really interested to see what he had. thanks


Ive seen him on youtube. :)
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the HH this found a 58kt winds in 92L
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Quoting gordydunnot:
23 a little easy on the caps but this has been the situation the whole season,that's why there has only been one real storm so far.


Claudette does not count? It was the first storm of the Atlantic to kill a US resident.

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No winds from any sort of W, yet, though.

Weird.
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Quoting eddye:
it coming to florida finally we get a system this year finally yeah
who's coming to fla not 92l sorry to tell ya
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Test # 3
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53 knots
(~ 60.9 mph)
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IMO, I give 92L a 60-80% chance of becoming a TD, a 50-70% chance of becoming a TS (most likely Danny) and a 20-40% chance of becoming a hurricane.
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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.