Caribbean Disturbance 92L Moving Over the Yucatan; Erin Forms Off of Africa

By: Dr. Jeff Masters , 2:40 PM GMT on August 15, 2013

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The tropical wave in the Western Caribbean near the Yucatan Peninsula (92L) is growing more organized this morning, after an evening when it lost most of its heavy thunderstorm activity. Satellite loops show a modest-sized area of heavy thunderstorms that are increasing in intensity and areal coverage, but there are a no signs of a surface circulation. Winds at surface stations in the Western Caribbean also do not show a surface circulation. The highest surface wind reports this Thursday morning were at Western Caribbean buoy 42056 about 140 miles east southeast of Cozumel, which had east winds of 25 mph, gusting to 34 mph, at 10 am EDT. Wind shear is a moderate 10 - 20 knots over the the wave, which should allow slow development today until its west-northwest movement at 10 - 15 mph carries it over the Yucatan Peninsula Thursday afternoon. Four hurricane hunter flights were scheduled to fly into 92L today--an Air Force mission tasked to provide a center fix early this afternoon, two NOAA P-3 missions aimed at collecting real-time radar data to feed into the HWRF model, and a flight by the NOAA jet to collect dropsonde data around the periphery of 92L. However, all of these flights were cancelled, given that 92L did not organize as much as much as it could have.


Figure 1. MODIS satellite image of Invest 92L taken at 12:30 pm EDT Thursday August 15, 2013. Image credit: NASA.

Forecast for 92L
92L will trek across the Yucatan Peninsula Thursday evening and arrive in the Southern Gulf of Mexico on Friday, when it will have the opportunity to strengthen. The 06Z Thursday SHIPS model forecast predicts that 92L will remain in an area of low to moderate wind shear through Saturday, and ocean temperatures will be a favorable 29 - 30°C. The topography of the Southern Gulf of Mexico's Bay of Campeche can aid in getting a storm spinning more readily, but 92L may be far enough north that this influence will be negligible. Given all these factors, 92L should be able to become at least a tropical depression by Saturday, A trough of low pressure over the northern Gulf of Mexico will dip down by Saturday evening over the Central Gulf of Mexico, potentially increasing wind shear to a high 20 - 30 knots, stalling any further intensification. This trough may also be able to pull the storm northwards to a landfall between Eastern Louisiana and the Florida Panhandle, as the 00Z Thursday run of the European model is suggesting. This would bring a plenty of tropical moisture into the Southeast U.S., resulting in a large area of 4+" of rain. However, the other models show a more westerly track for 92L, with landfalls possible in Texas or Mexico south of the Texas border, and there is high uncertainty where 92L may go once it enters the Gulf of Mexico. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave 92L a 50% of developing by Saturday, and a 60% chance of developing by Tuesday.


Figure 2. MODIS satellite image of Tropical Storm Erin taken at 10:30 am EDT Thursday August 15, 2013. At the time, Erin had maximum sustained winds of 40 mph. Image credit: NASA.

Tropical Storm Erin
The season's fifth named storm of the year, Tropical Storm Erin, has formed over the far Eastern Atlantic off the coast of Africa. Erin is over warm waters of 27°C and is under a moderate 10 - 15 knots of wind shear, which should allow continued development today and Friday. Erin is a small storm, as seen on satellite loops. The 12Z Thursday SHIPS model forecast predicts that wind shear will be low to moderate for the next five days, which favors development. However, the waters beneath Erin will steadily cool to a marginal 26°C by Friday, and the atmosphere will steadily get drier, as the storm encounters the Saharan Air Layer (SAL), discouraging development. Erin's west-northwest motion will cut the storm off on Sunday from a moist source of air to its south--the semi-permanent band of tropical thunderstorms called the ITCZ (Inter-Tropical Convergence Zone.) The storm should weaken beginning on Sunday, which would result in Erin turning more to the west as the east-to-west blowing surface trade winds begin to dominate the steering of the shallower storm. We may see a situation like occurred for Tropical Storm Dorian in late July--intensification to a 60 mph tropical storm, followed by a slow decay and dissipation. The latest run of the GFS model calls for Erin to dissipate well before reaching the Lesser Antilles Islands.

Typhoon Utor dissipates
Typhoon Utor has dissipated after hitting Southeast China about 150 miles southwest of Hong Kong on Wednesday as a Category 1 storm with 90 mph winds. The typhoon is being blamed for 1 death in China, and sank a 21-person cargo ship off the coast. In the Philippines, where Utor hit as a Category 4 storm with 140 mph winds on Monday, 8 deaths are being blamed on the storm, and damage is estimated at $20 million.

Jeff Masters

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so far this year five lowgrade TS and no hurricanes maybe its a year of the tropical storms
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Quoting 729. Patrap:
Thats not true in any sense.

That poster is just yanking ya chain.

Here in NOLA, its Thursday.

Dat bout covers it.



**Sigh*** I'm too gullible...
Member Since: June 26, 2013 Posts: 0 Comments: 1817
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Quoting weatherrx:
Our local officials here in south Louisiana are issuing warnings about the upcoming storm forecast to hit south Louisiana, which has put a strain on our retail stores. Gas is getting hard to come by and food and water is still available but not much to choose from, I picked up a couple cans of chief boy R D ravioli and thats about it. All I can say at this point is hunker down and be safe.

First, it's a good idea to buy things before a storm coming. Second, what part of south Louisiana are you in? I can find no warnings of any type being issued by the Louisiana EMA nor any parish EMA. There is also nothing in the news about any panic buying in south Louisiana. I may be wrong, but your post sounds like trolling, and that's a bad thing to do when it's storm season.
Member Since: October 2, 2004 Posts: 0 Comments: 13067
Looks better.
Member Since: August 2, 2010 Posts: 0 Comments: 1411
Funny how so many don't agree with current positions by NHC.
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Quoting 733. LAbonbon:


I was actually referring to the 'Tropical Development Index' graphic. But I do appreciate the other ones...w/ the exception of that NAM one you posted in the wee hours :)
oh yeah now I remember..they didn't like the graphs..its ok..to each his own I guess.
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735. VR46L
Quoting 717. CaribBoy:


I feel even more frustrated when the rain skirts me... (remember Dorian's remains :s :s)


Looks like the next two will be similar well according to the GFS ..
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Quoting 716. sar2401:

I think this is Barry II. Once this "thing" gets back into the Gulf, most of the energy will go left into Mexico. There will be enough leftover convection to give central and south Florida some rain but I can't see any scenario where whatever tropical type storm 92L becomes gets any further east the the TX/MX border. 92L has had plenty of time to get organized and all its done is become a more elongated trough.
that's a good point also..we'll have a better idea tomorrow when this leaves the land..im really looking forward to the 8am update tomorrow..see what that says.
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Quoting 725. LargoFl:
no I cant remember either..probably they meant the pics I post are mainly precip and not how windy its going to be,,my fear for up there isn't wind..at worst it will be a TS..folks can handle that easily..its flooding im worried about..days of heavy downpours from that cold front then getting days of tropical rains on top of it..so I post mostly precip models.


I was actually referring to the 'Tropical Development Index' graphic. But I do appreciate the other ones...w/ the exception of that NAM one you posted in the wee hours :)
Member Since: June 26, 2013 Posts: 0 Comments: 1817
Quoting 724. sar2401:

Since it may have been all they had in the world, they probably didn't consider it "crap". I hope I'm never in such a position,
didn't mean literal crap.
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Quoting 728. LAbonbon:


weatherrx, what parish are you in?


Troll Parish.
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Quoting 695. hurricanes2018:
we will have lots of fish storm if there start at 15 north!! next tropical wave gong to start at 16 north..that is still to far north..


Very annoying/depressing/boring pattern if it continues into september
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Thats not true in any sense.

That poster is just yanking ya chain.

Here in NOLA, its Thursday.

Dat bout covers it.

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Quoting 722. weatherrx:
Our local officials here in south Louisiana are issuing warnings about the upcoming storm forecast to hit south Louisiana, which has put a strain on our retail stores. Gas is getting hard to come by and food and water is still available but not much to choose from, I picked up a couple cans of chief boy R D ravioli and thats about it. All I can say at this point is hunker down and be safe.


weatherrx, what parish are you in?
Member Since: June 26, 2013 Posts: 0 Comments: 1817
Quoting 676. Relix:
Wave at 40W should get a honorary 10% :P! Erin looks boring to me; at the pace its going it will be north of the islands easily. I don't get CaribBoy... here in PR its been a rainy summer; nonstop. I don't want more rain! Yet there's a t-wave coming up and the one at 40W which seems pretty darned strong.


Yes, but PR has been WAYYYYYY wetter than St.Barths/St.Maarten/Anguilla in the N Leewards. So I can understand your opinion.
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Maybe I'm crazy, but doesn't kind of look like the circulation is actually NE of the Yucatan?
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Quoting 713. LAbonbon:


Hey Largo - a few days back someone posted in respone to this graphic that they weren't really fond of it. I've always liked it, as it seems pretty straightforward to me. But I can't recall the rationale that was posted. Something like it didn't give a complete picture of conditions?...dunno. Do you remember the blogger's thoughts on this?
no I cant remember either..probably they meant the pics I post are mainly precip and not how windy its going to be,,my fear for up there isn't wind..at worst it will be a TS..folks can handle that easily..its flooding im worried about..days of heavy downpours from that cold front then getting days of tropical rains on top of it..so I post mostly precip models.
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Quoting centex:
Did actually evac for Rita? The evacs made for a sight in Austin when they arrived and moved into all the schools. They were easy to spot with all the crap strapped to the top of there cars.

Since it may have been all they had in the world, they probably didn't consider it "crap". I hope I'm never in such a position,
Member Since: October 2, 2004 Posts: 0 Comments: 13067
Quoting 718. MississippiWx:
Here is what is currently happening with 92L. It still has a little work to do before consolidating into one area of focused low pressure/vorticity, but it is getting better with time. The most concentrated area of vorticity seems to be where I have the "L", but there is also a bit of a surface trough extending to the south of it as winds are still converging along the axis there. To the south of that yellow axis I drew, winds are convincingly out of the west and they move cyclonically thereafter. I believe the surface low will continue consolidating where red L is and it should keep moving off to the WNW. What happens once it emerges in the Gulf will be determined by the influence of the upper low to the north at first. If it stays tangled with it, it will have a difficult time wrapping convection around the surface low as it would remained sheared and have dry stable air pulled into the surface low. If enough convection can get going, the latent heat production might be able to kill of the upper low since it is not a very potent one. The future of 92L is still murky and still wreaks of persistent struggles, but it will have an opportunity to get going over the Central Gulf if it can shed the upper low and continue consolidating its surface low.



Very nice-sounding evaluation.
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Our local officials here in south Louisiana are issuing warnings about the upcoming storm forecast to hit south Louisiana, which has put a strain on our retail stores. Gas is getting hard to come by and food and water is still available but not much to choose from, I picked up a couple cans of chief boy R D ravioli and thats about it. All I can say at this point is hunker down and be safe.
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Here is a really nice hi rez full globe image from Eumetsat, focused on Africa, with Erin and the waves behind it:

Link
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Looks like my call of the NHC going down to 50% was correct. And As I have been saying, it will most likely drift west into BOC since it is weaker and only become a TD at best/lowgrade TS.
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It actually looks like there is dual centers on satellite imagery and based on the surface observations; one west of Cozumel and one over Belize.
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Here is what is currently happening with 92L. It still has a little work to do before consolidating into one area of focused low pressure/vorticity, but it is getting better with time. The most concentrated area of vorticity seems to be where I have the "L", but there is also a bit of a surface trough extending to the south of it as winds are still converging along the axis there. To the south of that yellow axis I drew, winds are convincingly out of the west and they move cyclonically thereafter. I believe the surface low will continue consolidating where red L is and it should keep moving off to the WNW. What happens once it emerges in the Gulf will be determined by the influence of the upper low to the north at first. If it stays tangled with it, it will have a difficult time wrapping convection around the surface low as it would remained sheared and have dry stable air pulled into the surface low. If enough convection can get going, the latent heat production might be able to kill of the upper low since it is not a very potent one. The future of 92L is still murky and still wreaks of persistent struggles, but it will have an opportunity to get going over the Central Gulf if it can shed the upper low and continue consolidating its surface low.

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Quoting 672. VR46L:


I hope you get some ! I remember how frustrated you get with no rain!


I feel even more frustrated when the rain skirts me... (remember Dorian's remains :s :s)
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Quoting LargoFl:
..thanks,,im thinking charley..how wrong they were on where it was coming in..sometimes these storms just defy logic and do what THEY want to do..well keeping a good eye on this one for sure.

I think this is Barry II. Once this "thing" gets back into the Gulf, most of the energy will go left into Mexico. There will be enough leftover convection to give central and south Florida some rain but I can't see any scenario where whatever tropical type storm 92L becomes gets any further east the the TX/MX border. 92L has had plenty of time to get organized and all its done is become a more elongated trough.
Member Since: October 2, 2004 Posts: 0 Comments: 13067
Quoting 703. seminolesfan:
Where is StormTrackerScott?

It is rare to not see his smiling face on our lovely community blog space.
he was here this morning
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Quoting 703. seminolesfan:
Where is StormTrackerScott?

It is rare to not see his smiling face on our lovely community blog space.
StormTracker Scott is looking for the troll he missed.
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Quoting 692. LargoFl:


Hey Largo - a few days back someone posted in respone to this graphic that they weren't really fond of it. I've always liked it, as it seems pretty straightforward to me. But I can't recall the rationale that was posted. Something like it didn't give a complete picture of conditions?...dunno. Do you remember the blogger's thoughts on this?
Member Since: June 26, 2013 Posts: 0 Comments: 1817
Quoting 710. louisianaboy444:


Do you feel like it can keep any circulation in tact while crossing the Yucatan?


It pretty much formed the one it has now near/on land. We'll see if it can maintain any lower level circulation which is becoming more apparent on visible satellite imagery.
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Quoting 708. Drakoen:


A couple of westerlies shown


Do you feel like it can keep any circulation in tact while crossing the Yucatan?
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Quoting 702. daddyjames:


Models scream? Wow, that's a first. ;)


XD
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Quoting 701. Skyepony:
Fresh ASCAT higher res & coastal..


A couple of westerlies shown
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Quoting 671. RitaEvac:


Wow, I have a cousin on the blog
Did actually evac for Rita? The evacs made for a sight in Austin when they arrived and moved into all the schools. They were easy to spot with all the crap strapped to the top of there cars.
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706. VR46L
LSU Water Vapour



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Quoting 669. whitewabit:


That's only one model run .. let wait and see ..


Though 6Z, 12Z and 18Z models have trended north overall....
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Quoting 690. Stormchaser2007:
"Meh-rin"

Another recurve.Boring times ahead.
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Where is StormTrackerScott?

It is rare to not see his smiling face on our lovely community blog space.
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Quoting 665. CaribBoy:


Just watch the 18Z models.. they all scream fish. That's boring, I hope the 40W disturbance will do something


Models scream? Wow, that's a first. ;)
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701. Skyepony (Mod)
Fresh ASCAT higher res & coastal..
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Quoting 668. Gearsts:
Will bring alot of rain.


COOL!!
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Quoting 686. Gearsts:


My fingers are crossed.. I'm waiting impatiently
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Quoting 683. CybrTeddy:
The sudden increase in intensity is probably in response to a shift westwards into the western GOMEX by the 18z models.

Yep! Majority of these take this to the southwestern gulf not central gulf. Coordinates for the central gulf are around 25n and 90w give or take. Also shear there in the sw gulf is very favorable atm compared to the central gulf.
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Member Since: June 24, 2012 Posts: 0 Comments: 130
Quoting 690. Stormchaser2007:
"Meh-rin"



Fairly nice structure.
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we will have lots of fish storm if there start at 15 north!! next tropical wave gong to start at 16 north..that is still to far north..
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Quoting 676. Relix:
Wave at 40W should get a honorary 10% :P! Erin looks boring to me; at the pace its going it will be north of the islands easily. I don't get CaribBoy... here in PR its been a rainy summer; nonstop. I don't want more rain! Yet there's a t-wave coming up and the one at 40W which seems pretty darned strong.
Where do you see that.Another elongated spin?
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Quoting 419. opal92nwf:

I think we are bound to get something really interesting before Dec. 1st. Maybe the equivalent of a Frederic:

Or an Eloise:


I was not born yet... but Frederic (1979) sure was an interesting storm in the N Leewards! It was a slow and wet Strong TS/Low Cat 1. 400 mm of rainfall fell in my area during that storm!!

Much more interesting than fast moving sheared busts like Chantal.
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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.