92L still a threat to develop; record SSTs continue in the tropical Atlantic

By: Dr. Jeff Masters , 13:44 GMT le 10 septembre 2010

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A tropical disturbance (92L) over the Lesser Antilles Islands lost most of its heavy thunderstorms last night, due to an infusion of dry air. However, 92L has redeveloped a moderate amount of heavy thunderstorm activity this morning, and remains a threat to the Caribbean--though not as great a threat as it appeared yesterday. Satellite loops show that 92L's heavy thunderstorms are slowly growing in areal coverage, and are becoming more organized. St. Lucia reported sustained winds of 33 mph this morning in a heavy rain squall, and heavy rain showers and gusty winds can be expected throughout the southern Lesser Antilles Islands today. Martinique radar shows that heavy rains are now affecting that island, but there is no rotation to the radar echoes evident. Surface observations indicate that pressures continue to fall at a number of stations in the Lesser Antilles, but no surface circulation is evident in the wind reports. A strong flow of upper level easterly winds is creating a moderate 10 - 20 knots of wind shear on the south side of 92L. The waters 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 over the northern Caribbean, and this dry air could interfere with development over the next few days.

Forecast for 92L
The disturbance is moving westward at 5 mph, but steering currents favor a more west-northwest motion Saturday. Lower shear lies over the Central Caribbean, away from the coast of South America, so any northward component of motion will allow for more significant development. There is drier air to the north, but 92L is steadily moistening the atmosphere in the Caribbean, so dry air may not be a problem for it. Model support for development is less than it was yesterday. The GFS and NOGAPS models do not develop 92L. The HWRF, GFDL, and UKMET models predict development, with a track taking 92L into the Dominican Republic on Sunday as Tropical Storm Julia. These models predict the storm will continue west-northwest, affecting Haiti, Eastern Cuba, Jamaica, and the Southeast Bahamas early next week. The ECMWF model foresees a more southerly track, taking 92L into Mexico's Yucatan Peninsula seven days from now.

Residents of the northern Lesser Antilles Islands and Puerto Rico should anticipate the possibility of heavy rains from 92L affecting their islands on Saturday and Sunday, though most of the action will probably stay south and west. The southern Dominican Republic should see heavy rains of 3 - 6 inches on Sunday and Monday from 92L, and Haiti, Jamaica, and eastern Cuba should anticipate similar rains on Monday and Tuesday. Should 92L make a direct hit on the Dominican Republic, it could destroy the storm, though. NHC is giving 92L a 40% chance of developing into a tropical depression by Sunday, which is a reasonable forecast. The first Air Force Hurricane Hunter mission into 92L is scheduled for Saturday morning, but there will be two research missions into the storm today that will give us valuable information on 92L's large scale environment and potential for development.


Figure 1. Morning satellite image of 92L.

Igor
Tropical Depression Igor has survived a bout with high wind shear, and is now in an environment of moderate 10 - 20 knots of shear that should allow for steady strengthening. Waters are warm, 28°C, and the Saharan Air Layer (SAL) is probably not close enough to Igor to prevent development. The models continue to predict development of Igor into a hurricane 2 - 4 days from now. Igor will track west to west-northwest over the next week, with long range forecasts from the GFS and ECMWF models putting the storm several hundred miles northeast of the Lesser Antilles Islands about 6 - 8 days from now. 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 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
The GFS and ECMWF models predict the development of a new tropical wave off the coast of Africa 3 - 6 days from now.

August SSTs in the tropical Atlantic set a new record
Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes had their warmest August on record, according to an analysis I did of historical SST data from the UK Hadley Center. SST data goes back to 1850, though there is much missing data before 1910 and during WWI and WWII. SSTs in the Main Development Region (10°N to 20°N and 20°W to 80°W) were 1.23°C above average during August, beating the previous record of 1.01°C set in August 2005. August 2010 was the 7th straight record warm month in the tropical Atlantic. The five warmest months in history for the tropical Atlantic have all occurred this year; June 2005 comes in sixth place, and August 2010 in seventh. As I explained in detail in a post on record February SSTs in the Atlantic, the Arctic Oscillation (AO) and its close cousin, the North Atlantic Oscillation (NAO), are in large part to blame for the record SSTs, though global warming and Atlantic Multidecadal Oscillation (AMO) also play a role.

The Bermuda-Azores High was weaker than average during August, which drove slower than usual trade winds over the tropical Atlantic. These lower trade wind speeds stirred up less cold waters from the depths than usual, and caused less evaporational cooling than usual, allowing August SSTs to remain at record warm levels. The Bermuda-Azores High and its associated trade winds are forecast to be at near-average strength during the next two weeks, according to the latest run of the GFS model. This means that Atlantic SST anomalies will continue to stay at record warm levels during September, significantly increasing the odds of major hurricanes in the Atlantic.


Figure 2. The departure of sea surface temperature (SST) from average for September 9, 2010. Note the area of cool anomalies off the U.S. East Coast, due to the passage of Hurricane Earl. Cool anomalies are also evident east of Bermuda, due to the passage of Hurricane Danielle. Image credit: NOAA/NESDIS.

Next post
I'll have an update Saturday morning.

Jeff Masters

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3007. hercj
Quoting StormW:


Yeah...I know...wish I was back.

Senior why is it guys like us spend half our career thinking about retiring and when we do always wish we were back in. I think about it all the time.
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MiamiHurricanes09 what is your take on 92L, 93L, and Igor..do you see one of these systems threatening the United States because I just checked the latest computer models for Igor and some of the models show Igor bending west at the end of their run. Plus a pattern shift is suppose to take place late next week so what affect will that have on Igor and 93L?
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Quoting aquak9:


pens bandaids neosporin can-opener gasoline

q-tips deodorant soap toilet-paper

coffee-filters fresh water

deck of cards


Hi Aqua, well it appears you about summed it up with the priorities! LOL

good morning to you.
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Quoting 954FtLCane:
my question is, what are the chances that 93L will hit Florida? Should I start hording beer now?
Based on the latest dynamical envelope, you shouldn't worry about it as it appears to be more like a Jamaica-Yucatan threat. Nonetheless, just monitor the situation.

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Well living in S. fl. it's always nice to have a few extra cold ones on supply they never go to waste besides it's also football season they come in handy.
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Quoting StormW:
Latest RGB loop shows Igor looking to build an eyewall:

LINK


I noticed on the water vapor this morning Igor appeared to have an eye...or a "dry spot" in the center of the circulation...
but on your link now, sure enough..an eye is forming..I am afraid Igor is going to be a powerful storm...
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Quoting MiamiHurricanes09:
The convective organization of 92L has really improved over night. Given the current environmental conditions, and if the convection can persist throughout the day, I would not rule out the development of a tropical depression later today.



93L currently located near the coast of Africa is also a very vigorous tropical wave and is accompanied by a well-defined mid to lower level circulation. Once it fully emerges, the development of a tropical depression during the next 48 hours it likely.



Both could develop by tonight if trends continue.
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2999. aquak9
Quoting wunderkidcayman:
ok guys help me what do I need to get I have one my list already generator TV PS3 computer Beers corned beef cand tuna alot of jamaican blue mountain coffee my office papers (tracking maps (surface map and advisorys)(as they come out) couple ref.books)


pens bandaids neosporin can-opener gasoline

q-tips deodorant soap toilet-paper

coffee-filters fresh water

deck of cards
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2998. ackee
Question when will Recon Investgate 92L ?
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The convective organization of 92L has really improved over night. Given the current environmental conditions, and if the convection can persist throughout the day, I would not rule out the development of a tropical depression later today.



93L currently located near the coast of Africa is also a very vigorous tropical wave and is accompanied by a well-defined mid to lower level circulation. Once it fully emerges, the development of a tropical depression during the next 48 hours is likely.

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2995. hercj
Quoting StormW:


Only one beer!

Morning Senior Chief. I did get the call. On the 13th of September and was back at MCAS Beaufort SC on the 18th. I was at grad school at FSU.
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Quoting 954FtLCane:
my question is, what are the chances that 93L will hit Florida? Should I start hording beer now?


Chances appear relatively low right now, but just keep an eye on it. No reason to worry too much as of now.
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Quoting Cayman2010:


If you live in a hurricane zone then it niether paranoia nor enthusiasm that should lead you to monitor sites for up to date information. It is responsibility.

And the 'handful' that do keep themselves updated can lead to hundreds or potentially thousands of others being updated.
Thank you. I am definitely not paranoid gut if someone in Cayman is I really do understand where they are coming from. Grand Cayman is only about 24 miles long and 7 miles wide and 6 years ago Ivan hit us as a major hurricane. No-one who was not here knows what we went through.
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my question is, what are the chances that 93L will hit Florida? Should I start hording beer now?
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Check out the lastest GFDL, HWRF, NOGAPS, and NGFDL models for Igor:

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Quoting wunderkidcayman:
ok guys help me what do I need to get I have one my list already generator TV PS3 computer Beers corned beef cand tuna alot of jamaican blue mountain coffee my office papers (tracking maps (surface map and advisorys)(as they come out) couple ref.books)
a gallon of appleton vx for your nerves LOL
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I know it is almost impossible to tell time frames for these storms, but do any of you have any idea, even a general guesstimate, on how long it will take for either one to get to a point where we may have some sort of an idea if either one could make a US landfall? The tracks for 92L seem to be kind of all over the place and what I've seen for Igor has him spinning off into the Atlantic.




~Never forget 9/11~
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2983. USCGLT
Quoting StormW:


Ditto that.

I had just dropped off my son for school, and heard it on the radio. I had just retired from the Coast Guard June 01, of that year.

Really thought I would have gotten "that" phone call.


You have really been gone 9 years?? Man where does time go, seems like yesterday you were at MLC!
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Quoting dwpearson:
any chance this new system heads near Louisiana?
\Yes there are chances, but there are chances for the entire gulf. Monitor advisories and go from there.
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ok guys help me what do I need to get I have one my list already generator TV PS3 computer Beers corned beef cand tuna alot of jamaican blue mountain coffee my office papers (tracking maps (surface map and advisorys)(as they come out) couple ref.books)
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2980. Patrap

2977. KanKunKid


Maybe the 18Z will offer a trend or another route. But one has to be prepared, for this is the meat of the season,and Calamity never waits for Humans.

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2979. Hhunter
from mexico to florida and islnds before them need to be alert of large system 92l
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Imagine yourself in Haiti.... Still, no roof, no shelter, no guaranteed food supply for the day. After you wake up, you have to look for water for you and your family.... Any medical condition? Forget about medicines, they are unreachable.... And now this....92L or maybe Julia, planning to visit us....
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2975. ackee
92L does look really serious if devlops further here in jamaica storms treaten us around the 11 to 13 sepetmeber has been deadly Gilbert and Ivan althought seem like might just be dealing with a weak TS OR TD
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2974. USCGLT
Quoting StormW:
Good morning!


The measure of how good the morning is would be the amount of "consumtion" last night, no?
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2973. hydrus
It would be nice if this happened..Link
Member Since: 27 septembre 2007 Posts: 1 Comments: 22294
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14 N and 63.6 W on Navy site and WU Home page.

Back later
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any chance this new system heads near Louisiana?
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2969. Patrap
92L Floater - Rainbow Color Infrared Loop
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2968. Grothar
Quoting StormW:


If a Hurricane is strong enough, and is oriented in such a way, with a ridge to it's north (i.e. riding the southern periphery, and the ridge is strong enough), it can in effect "pump the ridge" in a manner of speaking. This is what we speak of when we say a strong hurricane can modify it's environment directly around it.

IF a strong hurricane can be situated such, as to send the outflow N and NW of itself, it "can" reinforce the ridge to it's north somewhat, as the latent heat from the outflow will have the tendency to strengthen that portion of the ridge. When this happens, you can keep a WNW to NW motion longer...this also can aid a very strong hurricane to "bust" a trof, if the trof is not as deep.


Thanks StormW. That is the best explanation I have heard on that. Should answer a lot of people's question on the subject.
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2967. Patrap
92L

RGB




WV




Rainbow

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we will never foget those that died and those that gave thier lives to save other, we will pray for them, by the way this was the day we had our national disaster many dont understand what happened here there was lives lost and our complete infrastructre was desimated and billions of $ in damage, so we suffered under different cicumstances 9/11
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Quoting stormwatcherCI:
That is not nice. He who feels it knows it and we have had more than our share of hurricanes and even major hurricanes so that does not make anyone here paranoid, just cautious.


If you live in a hurricane zone then it niether paranoia nor enthusiasm that should lead you to monitor sites for up to date information. It is responsibility.

And the 'handful' that do keep themselves updated can lead to hundreds or potentially thousands of others being updated.
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2964. Patrap
.."Pump up da volume,"..
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Current motion with 92L looks to be about 300 degrees, or mid way between WNW and NW. That is fairly steep and if it continued it would take the system somewhere between Jamaica and Haiti IMO. Of course, with no well defined center at this time trying to pin down a future track is difficult at best.
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Quoting Chicklit:

I was on the tennis court with my team (think it was Tuesday morning). One of our members who didn't play was home watching tv. She drove down to the courts in tears. It had started pouring. We all stopped and went to a diner. We didn't want to split up until we figured out what was going on...One of the women had a son who worked in the World Trade Center. Turns out he had taken that morning off to go surfing.


And the reason he went surfing was because of a hurricane swell. Amazing how fate works....

Be grateful for every minute!
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2961. Hhunter
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2960. Patrap
12z Early Cycle NHC model tracks
Invest92
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)





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2959. Grothar
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Looking forward to the doc's post on 92L, looks like the real deal. Hurricane Cleo flashback.
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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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