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

By: Dr. Jeff Masters , 10. syyskuuta 2010 klo 13:44 (GMT)

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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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3207. sflawavedude
12. syyskuuta 2010 klo 00:22 (GMT)
.
Member Since: 3.06.2010 Posts: 0 Comments: 131
3206. catastropheadjuster
11. syyskuuta 2010 klo 16:35 (GMT)
Quoting kuppenskup:


Ok man. Hopefully I didnt get myself blocked for community standards but I just had to get it off my chest


what the heck it this. Do u have 2 personalities? answering yourself doesn't sound to good.
Member Since: 24.08.2006 Posts: 21 Comments: 3648
3201. crashingwaves
11. syyskuuta 2010 klo 15:59 (GMT)
Igor will put everyone on the EC, sitting on the edge of their seats. My question is, if Igor continues on a w to wnw track how does he recurve? I don't see any mention from the NHC of it. Looks like were in for a treat.
Member Since: 8.07.2008 Posts: 0 Comments: 158
3200. blsealevel
11. syyskuuta 2010 klo 15:42 (GMT)
Here's the projections up to 7 day's out incase
anyones intreasted.

Member Since: 23.08.2008 Posts: 0 Comments: 1918
3199. Vero1
11. syyskuuta 2010 klo 15:32 (GMT)


Member Since: 21.07.2008 Posts: 4 Comments: 2233
3198. blsealevel
11. syyskuuta 2010 klo 15:30 (GMT)
5 days Out

Member Since: 23.08.2008 Posts: 0 Comments: 1918
3197. kuppenskup
11. syyskuuta 2010 klo 15:26 (GMT)
Quoting kuppenskup:

Im just tired of people in high positions who once you dont agree with their viewpoint they turn on you and this happens to be one of those times. We're just offering an opinion on what we see and all of a suddent were called clowns and get ignored. What's all that about?


Well I know you for example everytime a storm forms you wanna know when it's gonna hit South Florida. That's all you care about and you promote that. That's not what were here for. Were here to monitor these systems and offer and educated guess not to wishcast a storm.
Member Since: 26.08.2009 Posts: 0 Comments: 411
3196. kuppenskup
11. syyskuuta 2010 klo 15:24 (GMT)
Quoting kuppenskup:


What are you talking about? Dr Masters is a highly respected individual who is open to any opioion. There are just people on here who jump the gun on everything. This Blog would be worthless if it wasnt for Dr Masters.

Im just tired of people in high positions who once you dont agree with their viewpoint they turn on you and this happens to be one of those times. We're just offering an opinion on what we see and all of a suddent were called clowns and get ignored. What's all that about?
Member Since: 26.08.2009 Posts: 0 Comments: 411
3194. kuppenskup
11. syyskuuta 2010 klo 15:22 (GMT)
Quoting kuppenskup:


Well Dr Masters it looks like you have everyone on ignore who doesnt agree with your opinion or who offers a different point of view. Correct?


What are you talking about? Dr Masters is a highly respected individual who is open to any opioion. There are just people on here who jump the gun on everything. This Blog would be worthless if it wasnt for Dr Masters.
Member Since: 26.08.2009 Posts: 0 Comments: 411
3193. kuppenskup
11. syyskuuta 2010 klo 15:19 (GMT)
Quoting StormW:
Hey gang,
Can you do me a favor and ignore this clown? I have him on ignore, and am getting pretty tired of seeing his garbage!


Quoting pipelines:


that's not a depression. Where is the surface circulation? Doesn't have one. What about the mid level circulation? Very ill defined. This is a convective tropical blob at the moment. A lot of pretty convection doesn't mean anything if there is next to no rotation present.


Well Dr Masters it looks like you have everyone on ignore who doesnt agree with your opinion or who offers a different point of view. Correct?
Member Since: 26.08.2009 Posts: 0 Comments: 411
3192. crashingwaves
11. syyskuuta 2010 klo 15:17 (GMT)
Quoting WeatherNerdPR:
Why are people's comments hidden? I keep pressing Show all but nothing happens.



I've done the same thing and nothing. Could be a glitch or something. Who knows....
Member Since: 8.07.2008 Posts: 0 Comments: 158
3191. help4u
11. syyskuuta 2010 klo 15:14 (GMT)
Igor is a fish!Just like Earl and the rest,everything in Atlantic heads north and in gulf west to mexico.Pattern has not changed all season even though everyone keeps saying next week it will change.This has been going on for 6 weeks now, and nothing major even close.This is why people pay no attention when their really is a storm, been told before and nothing happens.
Member Since: 18.09.2006 Posts: 0 Comments: 1257
3190. MZT
11. syyskuuta 2010 klo 15:13 (GMT)
Moving to The New Dr Masters Blog Post
Member Since: 24.09.2005 Posts: 0 Comments: 793
3189. AtHomeInTX
11. syyskuuta 2010 klo 15:13 (GMT)
Quoting WeatherNerdPR:
Why are people's comments hidden? I keep pressing Show all but nothing happens.


When that happens to me I have to exit out of WU then come back in. That usually resets it to show all for me. :)
Member Since: 24.08.2010 Posts: 0 Comments: 459
3188. pipelines
11. syyskuuta 2010 klo 15:13 (GMT)
Quoting StormW:
Hey gang,
Can you do me a favor and ignore this clown? I have him on ignore, and am getting pretty tired of seeing his garbage!


Quoting pipelines:


that's not a depression. Where is the surface circulation? Doesn't have one. What about the mid level circulation? Very ill defined. This is a convective tropical blob at the moment. A lot of pretty convection doesn't mean anything if there is next to no rotation present.


Funny, I'm about to be higher qualified than storm in terms of qualification in meteorology in a year after I get my degree in atmospheric science next fall.
Member Since: 10.07.2008 Posts: 0 Comments: 225
3187. CalTex
11. syyskuuta 2010 klo 15:11 (GMT)
Quoting CajunTexan:
Another day in the season of 2010,
Which systems will lose and which ones will win,
Some are concerned with 92L's convection,
Others still waiting for Gastons resurection,
Will 92L go to Mexico, Fla, or out to sea,
But on its way out good luck to Haiti,
Where Igor is traveling conditions are hell,
and right behind him comes 93L,
Tropics heating up with 3 systems to track,
Maybe for the blog it'll bring sanity back.






Awesome...
Member Since: 7.09.2010 Posts: 0 Comments: 138
3186. GeoffreyWPB
11. syyskuuta 2010 klo 15:11 (GMT)
Has a TCFA been issued for 92L?
Member Since: 10.09.2007 Posts: 0 Comments: 10589
3184. MZT
11. syyskuuta 2010 klo 15:09 (GMT)
TropicalAnalystwx13, my "Spidey sense" proved correct - LOL
Member Since: 24.09.2005 Posts: 0 Comments: 793
3183. saltwaterconch
11. syyskuuta 2010 klo 15:08 (GMT)
Call me a skipping cd but I still say that 92l/futer julia has been talked about for 3 days and it is still just an invest. Meanwhile there is a 70 mph storm that IS going to be a major cane that has been written off because all storms this year at that latitude have curved out to sea. Ok climatology says that only 20% of storms at that lat go on to hit the east coast. However if i point a loaded weapon at you and tell you that there is only a 20% chance of you getting hit will you stand there. The answer is is a most certain no!!!!
Member Since: 17.08.2008 Posts: 0 Comments: 92
3182. tropicfreak
11. syyskuuta 2010 klo 15:08 (GMT)
Quoting TropicalAnalystwx13:
Lets see how 92L does in low Wind Shear, no Dry Air, and TCHP values over 100 in the W CAR.

May try to pull a Wilma.


Except for the nearly stationary movement part.
Member Since: 2.09.2006 Posts: 110 Comments: 6814
3181. pipelines
11. syyskuuta 2010 klo 15:08 (GMT)
Quoting Hurricanes101:


Could be the NHCs description of a broad area of low pressure, added to the fact that the surface maps have shown the low for about 2 days now


to be a low doesn't require a surface circulation. If there was a defined surface circulation, it would already be declared a depression.
Member Since: 10.07.2008 Posts: 0 Comments: 225
3180. MiamiHurricanes09
11. syyskuuta 2010 klo 15:08 (GMT)
I would not rule out the development of yet another tropical depression later today into tomorrow from 93L.

Member Since: 2.09.2009 Posts: 130 Comments: 21032
3179. MZT
11. syyskuuta 2010 klo 15:08 (GMT)
I would think we'll see a new Dr Masters post soon. He usually chimes in after an 11AM update and indicates his level of agreement with the NHC
Member Since: 24.09.2005 Posts: 0 Comments: 793
3178. TropicalAnalystwx13
11. syyskuuta 2010 klo 15:08 (GMT)
NEW BLOG!
Member Since: 6.07.2010 Posts: 109 Comments: 30298
3176. tropicfreak
11. syyskuuta 2010 klo 15:07 (GMT)
Quoting Hurricanes101:


it would be TD 12


Oh sorry lol.
Member Since: 2.09.2006 Posts: 110 Comments: 6814
3175. HurricaneSwirl
11. syyskuuta 2010 klo 15:07 (GMT)
Wow was away all day yesterday. Igor was 35 mph last time I checked. 92L was at 30% while 93L didn't exist or even have a circle yet. Things sure have picked up.
Member Since: 7.07.2008 Posts: 2 Comments: 3237
3174. CybrTeddy
11. syyskuuta 2010 klo 15:07 (GMT)
Quoting Hurricanes101:


it would be TD 12


Correct.
Member Since: 8.07.2005 Posts: 259 Comments: 23018
3173. TropicalAnalystwx13
11. syyskuuta 2010 klo 15:06 (GMT)
Lets see how 92L does in low Wind Shear, no Dry Air, and TCHP values over 100 in the W CAR.

May try to pull a Wilma.
Member Since: 6.07.2010 Posts: 109 Comments: 30298
3172. mrsalagranny
11. syyskuuta 2010 klo 15:06 (GMT)
Quoting StormW:


Thank you! I'm doing ok. Yes, I did...mentioned a more zonal, flatter pattern for a brief period.

How are you?
Doing great.Looks like I was paying attention in class.LOL
Member Since: 6.06.2010 Posts: 0 Comments: 851
3171. tropicfreak
11. syyskuuta 2010 klo 15:05 (GMT)
Quoting pipelines:


that's not a depression. Where is the surface circulation? Doesn't have one. What about the mid level circulation? Very ill defined. This is a convective tropical blob at the moment. A lot of pretty convection doesn't mean anything if there is next to no rotation present.


It does have a surface circulation.
Member Since: 2.09.2006 Posts: 110 Comments: 6814
3170. GeoffreyWPB
11. syyskuuta 2010 klo 15:04 (GMT)
Member Since: 10.09.2007 Posts: 0 Comments: 10589
3169. MZT
11. syyskuuta 2010 klo 15:04 (GMT)
The image from StormW's blog: Look to the far right... appears there is a wave not even on the African continent yet... about to land on Somalia. Things are really queued up.

Member Since: 24.09.2005 Posts: 0 Comments: 793
3168. TropicalAnalystwx13
11. syyskuuta 2010 klo 15:04 (GMT)
I expect it to be classified at 5PM today:

Member Since: 6.07.2010 Posts: 109 Comments: 30298
3167. CaicosRetiredSailor
11. syyskuuta 2010 klo 15:04 (GMT)


Note the "M"s
Member Since: 12.07.2007 Posts: 0 Comments: 5984
3166. hunkerdown
11. syyskuuta 2010 klo 15:04 (GMT)
Quoting MrstormX:


Miami, those are pretty meager. This could be reminiscent of an '05 system.
If it forms as it seems, I don't see it being the "compact" system you call it (that is if you mean "small" when you say "compact"). I could see this blow up as a rather large, substantial system depending on the track.
Member Since: 15.08.2008 Posts: 0 Comments: 2515
3164. ShenValleyFlyFish
11. syyskuuta 2010 klo 15:03 (GMT)
Quoting MrstormX:
Tell me that's not a Tropical Depression.



Thats not a tropical depression. Happy now? ;)
Member Since: 9.09.2007 Posts: 36 Comments: 4687
3163. MiamiHurricanes09
11. syyskuuta 2010 klo 15:03 (GMT)
Quoting pipelines:


What's your evidence of this?
The NHC stated yesterday evening that an aircraft investigating the system found a well-defined surface circulation. Satellite imagery along with microwave agree that a surface circulation is present, it is just broad at the time being.
Member Since: 2.09.2009 Posts: 130 Comments: 21032
3162. Hurricanes101
11. syyskuuta 2010 klo 15:03 (GMT)
Quoting pipelines:


What's your evidence of this?


Could be the NHCs description of a broad area of low pressure, added to the fact that the surface maps have shown the low for about 2 days now
Member Since: 10.03.2010 Posts: 1 Comments: 7233
3161. TampaSpin
11. syyskuuta 2010 klo 15:02 (GMT)
Gotta run. I for sure would not worry about Igor to much as the real player for now is soon to be JULIA from Invest 92L. Looks like a Tx./La. storm coming to me as Julia should turn toward the North when it enters the BOC/GOM. Just my opinion. Later all!
Member Since: 2.09.2007 Posts: 177 Comments: 20430
3160. WeatherNerdPR
11. syyskuuta 2010 klo 15:02 (GMT)
Why are people's comments hidden? I keep pressing Show all but nothing happens.
...
Never Mind.
Member Since: 7.07.2010 Posts: 0 Comments: 5521
3159. Hurricanes101
11. syyskuuta 2010 klo 15:02 (GMT)
Quoting tropicfreak:
I would not be surprised if 92L becomes a TS today let alone TD 11.


it would be TD 12
Member Since: 10.03.2010 Posts: 1 Comments: 7233
3158. hunkerdown
11. syyskuuta 2010 klo 15:01 (GMT)
Quoting TampaSpin:
Misses Trough


Misses Trough


See's an opening.



I hope we get the later of the 3 models.
for "missing" the trough, they all seem to impart a prominent NW turn a little too early from what I see at the moment. I just don;t see that trough having THAT MUCH influence on him at this point. A gradual WMW movement yes, but not a pronounces NW turn like that. Stay tuned...
Member Since: 15.08.2008 Posts: 0 Comments: 2515
3157. pipelines
11. syyskuuta 2010 klo 15:01 (GMT)
Quoting Hurricanes101:


It does have a surface circulation


What's your evidence of this?
Member Since: 10.07.2008 Posts: 0 Comments: 225

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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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