Potentially dangerous 92L steadily developing; Igor nears hurricane strength

By: Dr. Jeff Masters , 03:04 PM GMT on Σεπτέμβριος 11, 2010

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A tropical disturbance (92L) over the Eastern Caribbean, a few hundred miles south of Puerto Rico, is steadily organizing and appears likely to develop into a tropical depression by tonight or Sunday morning. Satellite loops show an impressive and expanding region of heavy thunderstorms, with good spiral banding and respectable upper-level outflow on all sides. Long range radar out of Puerto Rico shows that heavy rains are now affecting that island, but there is no rotation to the radar echoes evident. However, the rain bands are becoming more intense and more organized. San Juan, Puerto Rico reported a heavy rain squall at 8:44 am this morning, and radar estimates suggest two inches of rain fell in this squall just southeast of San Juan. Wind shear over 92L is low, 5 - 10 knots. The waters beneath are at near-record warmth, 30°C, and these warm waters extend to great depth. Water vapor satellite loops show a large area of dry air lies to the north and west of 92L, and this dry air could interfere with development at times over the next few days.


Figure 1. Morning satellite image of 92L.

Track forecast for 92L
The disturbance is moving west-northwest at 11 mph, and steering currents favor a continuation of this motion for the next three days. Model support for development is scattered. The GFS and NOGAPS models do not develop 92L. The GFDL and ECMWF models predict development, with a track taking 92L into Mexico's Yucatan Peninsula on Wednesday. The HWRF model has a more northwesterly track, taking 92L over the Dominican Republic, Haiti, and Cuba, but this model has been trending too far north in its tracks. I expect 92L will follow a path south of the islands, bringing it near or just south of Jamaica on Monday, then into the Yucatan Peninsula on Wednesday. On this track, the southern Dominican Republic can expect heavy rains of 3 - 6 inches tonight through Monday morning; southern Haiti can expect similar rains Sunday through Monday, and Jamaica and the Cayman Islands can expect heavier rains of 4 - 8 inches Monday and Tuesday. Eastern Cuba will probably escape 92L's heaviest rains in this scenario (Figure 2.)

Intensity forecast for 92L
I can't find any reason to doubt this will be a tropical storm by Sunday or Monday, and potentially a Category 1 or 2 hurricane by Wednesday, if 92L avoids passage over Hispaniola and Cuba. The SHIPS model predicts wind shear will remain low, 5 - 10 knots, through the period, and makes 92L a Category 1 hurricane by Monday night. Water temperatures are certainly warm enough to support development. The main detriment to intensification is likely to be dry air, and 92L could wrap in some of the dry air to its northwest at times, slowing down development. The first Air Force Hurricane Hunter mission into 92L is scheduled for Sunday afternoon, but there will be a research mission by the National Center for Atmospheric Research G-V jet today that will give us valuable information on 92L's large scale environment and potential for development.


Figure 2. Forecast rain amounts from 92L from the 2am EDT Saturday run of the GFDL model. This model predicts most of 92L's heaviest rains will miss Haiti, but will affect Jamaica, the Cayman Islands, and the Yucatan Peninsula. Image credit: Morris Bender, NOAA/GFDL.

Igor
Tropical Storm Igor is very close to hurricane strength, and appears destined to become a large and powerful major hurricane over the Central Atlantic in the days to come. Wind shear is moderate, 15 - 20 knots, waters are warm, 28°C, and Igor has moistened its environment enough to keep the dry air of the Saharan Air Layer (SAL) at bay. Igor will track west under the influence of a strong ridge of high pressure for the next three days, then turn more to the west-northwest in response to the steering influence of a broad trough of low pressure moving across the Western Atlantic on Tuesday and Wednesday. This should allow Igor to pass several hundred miles to the northeast of the Lesser Antilles. In the longer range, Igor may be a threat to Bermuda, and has a slight chance of making landfall on the U.S. East Coast or Canada. Climatology shows that about 10% of all tropical cyclones that have existed at Igor's current position have gone on to hit the U.S. East Coast; these odds are about 10% for Bermuda and 5% for Canada. The forecast steering pattern for the coming two weeks from the GFS model shows a continuation of the pattern we've seen all hurricane season, with regular strong troughs of low pressure moving off the U.S. East Coast. This pattern favors Igor eventually recurving out to sea without affecting any land areas. The odds of Igor hitting land in the U.S. or Canada are probably close to their climatological 10% and 5% probabilities, respectively.

Elsewhere in the tropics
A new tropical wave (Invest 93L) emerged from the coast of Africa yesterday, and is already showing signs of organization. Most of the models predict 93L will develop into a tropical depression 2 - 4 days from now, and NHC is giving 93L a 30% chance of developing by Monday.

Next post
This may be my only post today; I'll have a new post Sunday morning.

Jeff Masters

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Quoting AtHomeInTX:


I'm not sure who Rob Robbin is. Don't think I've listened to the radio since I got cds. Lol. But I'll be keeping an eye out here and there about these systems. If that high holds we'll be in the clear for this 92L anyway. That's some high pressure ridge he showed. That's what we need to watch whether its moving or weakening. Anybody got a link to the steering layers? Anyway fingers crossed. :)


He's a meteorologist out of Lake Charles. He is factual and I've never heard him play a storm more than it is.
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Quoting will40:
Link


those shields look very strong Stef


Yes they do Will. Thanks for the link. :D Hoping they keep us both out of trouble.
Member Since: Αύγουστος 24, 2010 Posts: 0 Comments: 252
Go away!!!!



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770. MZT
Quoting kmanislander:


D-min is the opposite. It is just before sunset wherever a system is.
Just before sunset seems to be when thunderstorm activity is greatest, though. Seems to me that the minimum is around 10PM. That's when people on here pile on about how weak a system looks... then they get to be surprised the next morning!
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Quoting Tazmanian:



thanks



You welcome Taz. It does become quite annoying for some to say fish, without giving something to support that logic. Theirs no time to make light of the situation at hand. Igor is going to be a large major hurricane tracking w to wnw. This is all the Islands and the EC needs right now.
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Quoting plywoodstatenative:
Moonlight so whats the idea on track of Igor. Thats the storm that could play a major role in the track of the system in the caribbean as well as anything else that forms.


Plywood, I've got to look at the basics - there've been so many things said, the models doing whatever and we aren't short on any opinions. I can't see Igor missing the tug of the trough. EC landfall? I'm not thinking so, not at this time, but I guess the chance still remains. As far as 92L - it's a mess, no LLC is clearly evident, scattered convection. It acts like xG who could never get anything going. Still, as it drifts west or wnw I can see the high TCHP values giving it the extra spark it may need to get churning. As far as track then, I'd think he'd ride more northwards on the western periphery of the high weakened by the wake of the trough and the departing Igor. And, who knows really - the ridge may build back in and it may track further west. It's got to develop first - not real sure about it yet.
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Quoting reedzone:
I give Igor a 50% of not recurving out to sea, too many factors and timing is crucial.



I with you on this one. I haven't heard the NHC mention any type of curvature out to sea. But that doesn't mean the possibility isn't there. I just keep hearing a w to wnw track and with Igor being large and a major hurricane soon. It does need to be watched for any suddnen change.
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Link


those shields look very strong Stef
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Both of these storms need to be upgraded.
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Quoting blsealevel:


thats actually a pretty good round about forecast
he is right the Carib. system needs to be watched closely and the high over the North needs to stay put as is.
Thanks for posting that.


You're welcome. And I agree. It needs to be watched. Just a little confused why the GOM Synopsis that Ike just posted says it's weak high pressure. Looked pretty strong on that video.
Member Since: Αύγουστος 24, 2010 Posts: 0 Comments: 252
761. IKE



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Quoting jason2010xxxx:
TROPICAL STORM IGOR big fish storm


According to climatology, you are more than likely correct, remember however if it gets anywhere near 65W and 32.5 N, it can't be considered a fish storm, because that is where Bermuda lies.
Member Since: Σεπτέμβριος 21, 2005 Posts: 10 Comments: 361
Quoting stormwatcherCI:
I think he means Gilbertish in regards to the location 92L is attempting to organize.


But he didn't say "Gilbertish"; he said "glibertish". Twice. Just playin'...)
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758. Vero1
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Quoting AtHomeInTX:


I'm not sure who Rob Robbin is. Don't think I've listened to the radio since I got cds. Lol. But I'll be keeping an eye out here and there about these systems. If that high holds we'll be in the clear for this 92L anyway. That's some high pressure ridge he showed. That's what we need to watch whether its moving or weakening. Anybody got a link to the steering layers? Anyway fingers crossed. :)


here Stef

Link
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Quoting kmanislander:


D-min is the opposite. It is just before sunset wherever a system is.


thanks for your wisdom
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It seems like Igor is going to receive a dry air injection during the next 12 hours????
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Quoting bassis:


So they are going into d-min now?


D-min is the opposite. It is just before sunset wherever a system is.
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Moonlight so whats the idea on track of Igor. Thats the storm that could play a major role in the track of the system in the caribbean as well as anything else that forms.
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Quoting crashingwaves:




I totaly agree here, very well said.



thanks
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Quoting KerryInNOLA:
Igor is a lobster storm. 92L will be a fiddler crab or a shrimp storm.



plzs stop Quoteing him many blogers have him on Ignore
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Quoting aislinnpaps:


I think I'll listen to Rob Robin on the way to work this week. And I'll be lurking here of course and reading.


I'm not sure who Rob Robbin is. Don't think I've listened to the radio since I got cds. Lol. But I'll be keeping an eye out here and there about these systems. If that high holds we'll be in the clear for this 92L anyway. That's some high pressure ridge he showed. That's what we need to watch whether its moving or weakening. Anybody got a link to the steering layers? Anyway fingers crossed. :)
Member Since: Αύγουστος 24, 2010 Posts: 0 Comments: 252
Quoting kmanislander:


D-max is just before dawn wherever a system may be.


So they are going into d-min now?
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I give Igor a 50% of not recurving out to sea, too many factors and timing is crucial.
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Quoting Tazmanian:



and plzs stop Quoteing him




I totaly agree here, very well said.
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744. IKE
SYNOPSIS FOR THE GULF OF MEXICO
430 PM CDT SAT SEP 11 2010

.SYNOPSIS...A COLD FRONT WILL CLIP THE FAR N WATERS LATE SUN
INTO MON. A WEAK SURFACE TROUGH WILL LINGER OVER THE FAR SW GULF
THROUGH WED. A LOW PRES SYSTEM IN THE EASTERN CARIBBEAN WILL
MOVE INTO THE NW CARIBBEAN WED AND THU...POSSIBLY AS A TROPICAL
CYCLONE...INCREASING WINDS AND SEAS IN THE FAR SOUTHERN GULF.
WEAK HIGH PRES WILL DOMINATE THE REMAINDER OF THE GULF THROUGH
THU.
............................................

SYNOPSIS FOR CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N
BETWEEN 55W AND 65W
530 PM EDT SAT SEP 11 2010

.SYNOPSIS...THE REMNANT TROUGH OF GASTON IS FROM 18N84W TO THE
SW CARIBBEAN NEAR 10N80W AND WILL MOVE INTO CENTRAL AMERICA
TONIGHT. LOW PRESSURE NEAR 14N66W WILL DRIFT WNW TO NEAR 16N70W
SUN AFTERNOON...NEAR 17N74W MON AFTERNOON...AND NEAR 18N79W TUE
AFTERNOON.
THERE IS A HIGH CHANCE OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS. TROPICAL STORM IGOR
WELL E OF THE AREA IS FORECAST TO STRENGTHEN TO A HURRICANE
TONIGHT AND APPROACH THE FAR E TROPICAL N ATLC WATERS LATE TUE
INTO WED.
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Quoting bassis:
Refresher on D-max & D-min. Which is the over night in Atlantic


D-max is just before dawn wherever a system may be.
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Quoting AtHomeInTX:
Hmmmm...an interesting prospective on the tropics with a TX/LA slant from Lake Charles, La NWS. Link


thats actually a pretty good round about forecast
he is right the Carib. system needs to be watched closely and the high over the North needs to stay put as is.
Thanks for posting that.
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Quoting AtHomeInTX:
Hmmmm...an interesting prospective on the tropics with a TX/LA slant from Lake Charles, La NWS. Link
Not as fancy but from NWS Houston: 00Z GFS AND ECMWF BOTH INDICATING
THE DISTURBED WEATHER IN THE EASTERN CARIBBEAN TO MOVE VERY SLOWLY
WEST AND TO OVER THE WESTERN CARIBBEAN TUESDAY NIGHT/WEDNESDAY
(ECMWF THE MOST AGGRESSIVE IN DEVELOPING THIS FEATURE) THEN MOVING
OUT INTO THE BAY OF CAMPECHE LATE THURSDAY OR FRIDAY BUT UPPER
RIDGE STILL HOLDING STRONG OVER THE UPPER TEXAS COAST OR NORTHWEST
GULF SO IF IT DOES DEVELOP IT WOULD MOVE WEST INTO MEXICO NEXT
WEEKEND.
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Quoting kmanislander:
Good afternoon folks.

92L has lost a lot of its deep convection today and the 850 vort is not all that impressive. The anticyclone overhead is allowing the cloud deck to fan out nicely and ventilate and the SST is equally conducive for development. The only thing I can see holding it back is that the Eastern Caribbean has never been an area to assist very disorganized systems to develop and become TDs.

Surface pressure with 92L is lowering though and it is closing in on the buoy just to the West which has a current pressure of 1008 and falling. I don't expect to see any significant development from this until about 75W.

Wind Direction (WDIR): E ( 80 deg true )
Wind Speed (WSPD): 9.7 kts
Wind Gust (GST): 11.7 kts
Wave Height (WVHT): 3.6 ft
Dominant Wave Period (DPD): 6 sec
Average Period (APD): 4.4 sec
Atmospheric Pressure (PRES): 29.78 in
Pressure Tendency (PTDY): -0.04 in ( Falling )
Air Temperature (ATMP): 83.1 °F
Water Temperature (WTMP): 86.7 °F
Dew Point (DEWP): 75.2 °F
Heat Index (HEAT): 90.7 °F


Sounds about right.
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Refresher on D-max & D-min. Which is the over night in Atlantic
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Good afternoon folks.

92L has lost a lot of its deep convection today and the 850 vort is not all that impressive. The anticyclone overhead is allowing the cloud deck to fan out nicely and ventilate and the SST is equally conducive for development. The only thing I can see holding it back is that the Eastern Caribbean has never been an area to assist very disorganized systems to develop and become TDs.

Surface pressure with 92L is lowering though and it is closing in on the buoy just to the West which has a current pressure of 1008 and falling. I don't expect to see any significant development from this until about 75W.

Wind Direction (WDIR): E ( 80 deg true )
Wind Speed (WSPD): 9.7 kts
Wind Gust (GST): 11.7 kts
Wave Height (WVHT): 3.6 ft
Dominant Wave Period (DPD): 6 sec
Average Period (APD): 4.4 sec
Atmospheric Pressure (PRES): 29.78 in
Pressure Tendency (PTDY): -0.04 in ( Falling )
Air Temperature (ATMP): 83.1 °F
Water Temperature (WTMP): 86.7 °F
Dew Point (DEWP): 75.2 °F
Heat Index (HEAT): 90.7 °F
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Quoting thewindman:
Hurricane 2010 season killed more FISH than any season in history. It is devastating


Someone found a 'brown' pelican up here... swept up to NS from hurricane Earl.
Methinks Igor wants it back.
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Hurricane 2010 season killed not only FISH than any season in history, but also coral reefs are almost gone....
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Quoting AtHomeInTX:
Hmmmm...an interesting prospective on the tropics with a TX/LA slant from Lake Charles, La NWS. Link


I think I'll listen to Rob Robin on the way to work this week. And I'll be lurking here of course and reading.
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HWRF model does not even turn Igor NW.. Why is everyone here saying "FISH" when in all reality, the ensemble means of the EURO are in huge disagreement with the operational, same with the GFS ensembles? Not a done deal, Igor may miss the trough. The HWRF and EURO/GFS ensembles show a ridge building back after the first trough passes. HWRF steers Igor WNW.
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Hurricane 2010 season killed more FISH than any season in history. It is devastating
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Station 42059 - Eastern Caribbean
15.054 N 67.472 W (15°3'14" N 67°28'19" W)

Wind Direction (WDIR): E ( 80 deg true )
Wind Speed (WSPD): 9.7 kts
Wind Gust (GST): 11.7 kts
Wave Height (WVHT): 3.6 ft
Dominant Wave Period (DPD): 6 sec
Average Period (APD): 4.4 sec
Atmospheric Pressure (PRES): 29.78 in
Pressure Tendency (PTDY): -0.04 in ( Falling )
Air Temperature (ATMP): 83.1 °F
Water Temperature (WTMP): 86.7 °F
Dew Point (DEWP): 75.2 °F
Heat Index (HEAT): 90.7 °F
Member Since: Μάιος 16, 2009 Posts: 1 Comments: 1231
Quoting barbamz:
Though it's a bit off topic: While waiting for development in respect to the future hurricanes you may watch this video about flooding in southern Italy 9/9/2010. Really scaring and fascinating as well (watch it till the end). Unfortunately one person still seems to be missing.
http://www.youtube.com/watch?v=Z7Kb7sq12mo&feature=player_embedded


Holy Cow! Thanks for posting that link. Chilling video. Those cars looked like little matchbook cars. Scary stuff.
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Igor dry air surroundings
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Link

SE of Ponce, PR. Probably a 1007 mslp low given the wind speed.
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NWS HGX:


Early next week the subtropical ridge center drifts eastward. The
models develop a tropical cyclone over the Caribbean...but keep
the system over the Yucatan and the far southern Gulf of Mexico.
As it does so...the high pressure ridge should keep warm days with
little chances for rain over southeast Texas through the middle and
late part of the week.
Member Since: Αύγουστος 26, 2006 Posts: 16 Comments: 4766
Quoting Relix:
Really. I won't get into this "WSW!!!!" discussion, but Igor is moving due west. I would say he's actually around 17.2N now. Just on track. There's no WSW movement as there was none last night. It's due WEST.
ybe it's in peoples heads?
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Quoting washingtonian115:
His track looks like a backwards 7.And you can obviously see what was steering him.Which was probally a big high pressure system.
I don't know what was steering him but that is the first hurricane my children experienced. South Sound(the area kman and stormpetrol live) did not even have a road left.
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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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