Two African waves, 92L and 93L, worth watching

By: Dr. Jeff Masters , 2:59 PM GMT on August 11, 2011

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An African wave is near 13°N 35°W, about 700 miles west-southwest of the Cape Verde Islands. This system, (Invest 92L), is moving west to west-northwest at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands early next week. Recent visible satellite loops show that 92L has less heavy thunderstorm activity near where it is trying to develop its circulation center than yesterday. Water vapor satellite loops that a large area of dry air lies just to the west of 92L, but the atmosphere in the immediate vicinity of 92L is moist. Even so, the decline of heavy thunderstorm activity since yesterday implies that dry air is probably working its way into 92L. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 15 knots affecting 92L. Sea surface temperatures are 26.5° - 27°C, which is very close to the 26.5°C threshold usually needed to support a tropical storm.


Figure 1. Morning satellite photo of Invest 92L and Invest 93L.

Forecast for 92L
Low to moderate wind shear of 5 - 15 knots is predicted along 92L's path over the coming three days, which should allow the storm to organize, assuming it can shut out any incursions of dry air that might intrude. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show weak development or no development of 92L, and NHC gave 92L a 30% chance of developing into a tropical depression by Saturday morning in their 8am outlook. A steady west to west-northwest motion for 92L is predicted by all of the models, which would put the storm in the vicinity of the northern Lesser Antilles Islands by Sunday. On Saturday and Sunday, 92L is expected to enter a region where an upper-level low pressure system will bring high wind shear of 20 knots to the storm, which should slow development. This upper-level low is also expected to turn 92L more to the northwest, so the storm is likely to pass north of the Lesser Antilles, though may pass close enough to give heavy rains to the northernmost islands. It is too early to know if 92L will recurve out to sea and potentially threaten Bermuda, or continue to the northwest towards the U.S. East Coast.

93L
An African wave that emerged off the coast of Africa is near 10°N 22°W, a few hundred miles south of the Cape Verde Islands. This system, (Invest 93L), is also moving west at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands near the middle of next week. Recent visible satellite loops show that 93L has a decent amount of heavy thunderstorms, but this activity is not well organized. There is not much spin associated with 93L yet. 93L is fairly well-protected from dry air to its north and west. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 20 knots affecting 93L. Sea surface temperatures are 27.5°C, which is one degree above the 26.5°C threshold usually needed to support a tropical storm.

Forecast for 93L
Moderate wind shear below 20 knots is predicted along 93L's path over the coming five days, which should allow the storm to steadily organize. 93L is about 600 miles east of 92L, which is close enough that the two systems may interfere with each others' organization. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET), have only one model, the GFS, that is indicating significant development of 93L. This model brings 93L near the northern Lesser Antilles Islands by Wednesday. NHC gave 93L a 20% chance of developing into a tropical depression by Saturday morning in their 8am outlook. Due to moister air, the potential for less wind shear, and a more southerly track, 93L is probably a greater threat to the Lesser Antilles than 92L.

Jeff Masters

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WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1000 AM EDT FRI 12 AUGUST 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 13/1100Z TO 14/1100Z AUGUST 2011
TCPOD NUMBER.....11-073

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY: LOW LEVEL INVEST
AT 14/1800Z NEAR 24.0N 59.0W.
3. REMARKS: FOLLOW-ON FLIGHT ON 15 AUG AT 18Z NEAR 28N 64W. THEN
12 HOURLY REQUIREMENTS AFTER THAT. POSSIBLE TASKING ON
SUBSEQUENT ATLANTIC SYSTEM ON 16 AUG. ---CORRECTED
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Quoting dc8mech:
haarp


Why did you announce haarp? Because I saw something really strange, too.
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Independent of which of the AOI's actually develop this time around, sheer is really low out there from the Mid-Atlantic all the way into the Caribbean and Gulf. With the exception of potential dry air/SAL issues, it will be interesting if this general trend continues into late-August and the September peak (or longer into October if a La Nina cold bias emerges).

Link
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1706. KEEPEROFTHEGATE (Mod)
Quoting aquak9:


dude- how many tv's do you have?
my guess 4 but useless with no brain
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1705. nigel20
Good morning everyone. I see we have four areas of interest today.
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Quoting hydrus:
ECMWF..93 heading west through the Caribbean..Link


yeah...then the east coast...
im at work, anyone have models for 94L? when i signed on it didn't have any graphics...just wondering movement, speed, etc
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1702. dc8mech
haarp
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Nobody expects... the Spanish Inquisition.
12.4n30.1w, 12.5n31.0w, 12.7n32.0w, 12.9n33.0w, 13.3n34.5w, 13.6n35.7w, 14.0n37.3w have been re-evaluated&altered for 92L's_12pmGMT_ATCF
12.4n30.3w, 12.8n32.1w, 13.3n33.9w, 13.9n35.6w, 14.6n37.4w, 15.4n39.4w, 16.2n41.4w, 17.0n43.3w, 17.8n45.3w are now the most recent*positions

10.6n22.5w, 10.8n24.0w, 11.0n25.6w have been re-evaluated&altered for 93L's_12pmGMT_ATCF
10.6n22.8w, 10.8n24.6w, 11.0n26.5w, 11.2n28.4w, 11.3n30.3w are now the recent positions

94L's_12pmGMT_ATCF
95L's_12pmGMT_ATCF


Starting at 11August_12pmGMT and ending at 12August_12pmGMT so that
92L's, 93L's, 94L's, and 95L's coordinates span the same 24hours

The westernmost grouping of red dots represents 95L's path,
the 2nd(western)grouping of red dots represents 94L's path,
the 3rd(eastern)grouping represents 92L's path,
and the easternmost grouping represents 93L's path.

Copy&paste 30.4n74.0w, 31.4n72.4w, 32.5n70.6w, 33.6n68.8w, 34.8n66.8w, bgi, 14.6n37.4w, 15.4n39.4w, 16.2n41.4w, 17.0n43.3w, 17.8n45.3w, vxe, 10.6n22.8w, 10.8n24.6w, 11.0n26.5w, 11.2n28.4w, 11.3n30.3w, bda, 26.0n50.9w, 25.5n51.8w, 25.2n52.7w, 25.0n53.6w, 24.7n54.7w, bda into the GreatCircleMapper to make your own map to play with.

The previous mapping (for 11August_12pmGMT)

* 15.2n39.0w, 15.8n40.6w, 16.3n42.1w, 16.8n43.7w were once again reevaluated&altered to
15.4n39.4w, 16.2n41.4w, 17.0n43.3w, 17.8n45.3w after the original 12August_12pmGMT posting
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1700. aquak9
Quoting HOTWHEELS99:
all the weather stations here out of florida are all saying that 92 and 93 will most likely recurve out to sea if they even develop and 2 big fronts that will push down off the east coast next week should also help tear them apart next week and recurve them that was on channel 3 5 and 9 and channel 13 at 945am


dude- how many tv's do you have?
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1699. KEEPEROFTHEGATE (Mod)
2011 Storms
All Active Year


Atlantic
95L.INVEST
94L.INVEST
93L.INVEST
92L.INVEST

East Pacific

Central Pacific

West Pacific
13W.THIRTEEN

Indian Ocean

Southern Hemisphere
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1698. KEEPEROFTHEGATE (Mod)
Fleet Weather Center Norfolk Tropical Feed
No Active Tropical Warnings in the Atlantic, Caribbean, or Gulf of Mexico
By Maritime.CDO@navy.mil (FWC-N CDO) from Fleet Weather Center Norfolk Virginia. Published on Fri, Aug 12, 2011.

As of Fri, 12 Aug 2011 13:45:01 GMT
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Quoting TampaTom:


Fuji Film


Here in SE Fla we called what Jeanne did the FujiWAMA!
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1696. MTWX
Quoting MahFL:
The drought in TX got worse, Exceptional went up from
73.49% to 78.26%.



the numbers are for the last week. I don't think theyy have taken into account the rain yesterday.... Definetley not "drought busting", but some areas received 3-4".

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93L doesn't look that good. At least for the time being. 92L on the other hand looks better than yesterday.
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Good Morning...

The most immediate concren of the 4 invests would likly be 94 as it is moving in WSW and could be a threat to the eastern seaboard. It has a nice low level spin with a modest SW shear. With the trough in the NE US it would likely move WSW and then curve.

93 overall is possibly the most dangerous threat in the next two weeks as it could become a major headache to the islands and the eastern seaboard. We expect the trough in the NE US trough thru next week but could lift later the period allowing a west/northwest track.
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1692. MTWX
Morning all!! I see we now have 2 more invests to watch!! going to be fun trying to follow all the comments and try not to get what storms people are talking about confused with each other!
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1691. hydrus
Quoting wunderkidcayman:

and has it hitting me and Jamaica by FRI/SAT/SUN time frame
Could easily be a major hurricane if that track comes to fruition.
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Although it's unlikely at all 4 invests get named, if they do, that would put us on pace to have some Greek Alphabeting.
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Quoting barbamz:

Yeah, we're doom all together, certainly. Otherwise, welcome here; hope you like it, though we don't have a real summer this year.


Summer? I'd hardly call this spring! Brrrrrr.
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1688. hydrus
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Quoting hydrus:
ECMWF..93 heading west through the Caribbean..Link

and has it hitting me and Jamaica by FRI/SAT/SUN time frame
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1686. hydrus
ECMWF..93 heading west through the Caribbean..Link
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1685. ncstorm


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1684. Thrawst
Quoting CybrTeddy:
Morning! Its a 4 way race to Franklin today, looks like 95L and 92L are in the lead.


Could be an interesting couple days ahead of us...
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who left the crayon box out last night?
off to hide the red crayons!
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1682. Matt74
Quoting AtHomeInTX:


I was just going to say that. A long way out. But I wouldn't hate this.



Neither would I.
Member Since: June 21, 2011 Posts: 0 Comments: 329
Morning! Its a 4 way race to Franklin today, looks like 95L and 92L are in the lead.
Member Since: July 8, 2005 Posts: 259 Comments: 23627
1679. emcf30
What the heck. Signed on this morning to check the status of 93L and see you have 3 oranges and 1 lemon. This place is fixing to turn upside down.
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What is the most named/ invest at once inthe Atantic basin ?
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1677. barbamz
Quoting largeeyes:


Only Hanna affected me in 4 years in NC. Move to Germany, 2 months later 95L is pointing at me. Sheesh.

Yeah, we're doom all together, certainly. Otherwise, welcome here; hope you like it, though we don't have a real summer this year.
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that would be surprising especially given the high pressure pattern that is supposed to set up
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1674. hydrus
92 looks alot different then yesterday..
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1673. hydrus
The S.W. Caribbean may have something brewing soon...NOGAPS has a tendency to overdo that region though..
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Quoting barbamz:


Wow, Invest 95 is heading directly to my place in Germany. Should I buy some plywood???
Good morning, btw.


Only Hanna affected me in 4 years in NC. Move to Germany, 2 months later 95L is pointing at me. Sheesh.
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Quoting stormwatcherCI:
Link

It opened for me.

Thanks, you are right just had an old bookmark, when the FSU site did not open I started thinking about conspiracy theories. For some reason I always go back to the FSU site, just like it's presentation. It was probably all the users from here checking out the four invests that crashed the FSU site!
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there is a floater now on 94L..looks decent for a newly invested system.
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1667. MahFL
Despite recent rains, the area of Florida abnormally dry is 83.29 %. Indeed today I smell smoke in downtown JAX.
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1666. HCW
I wouldn't be shocked if we have a new circle in the GOM after the cold front stalls Sunday in the GOM :)
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1665. hydrus
GFS model shows storms recurving. Link
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Good Morning Everyone! Man!!!! I just woke up and a friend of mine tells me they have 4 invests!! One word WOW! The way the map looks with the invest kinda resembles a trough coming off the east coast. Lol. But Gro u made a good point people better be ready because the African Train Waves are coming!!! U wanna see a preview of 2005, Here we go!! Everybody needs to pay close attention to every storm starting now.
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Quoting Huracaneer:
Tried this morning to get to the FSU model site at moe.met.fsu.edu and it times out. Is it just me or is their site down? Also having trouble reaching the Allan Huffman's model site, can't even find the page. Can anybody reach these? Four invests on the Atlantic and I can't reach my favorite sites! The horror!
Link

It opened for me.
Member Since: October 9, 2008 Posts: 0 Comments: 8279
Quoting PolishHurrMaster:
4 invests! Is it the record?

Probably not. I think I saw five invests a few years ago.
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1661. hydrus
Quoting Grothar:
You think the Atlantice is active now, just wait and look at the wave train


Right now it looks a lot like 1995...
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1659. SaraGal
Quoting Grothar:
You think the Atlantice is active now, just wait and look at the wave train




Ok, Gro -- fess up! You're using your fancy new photoshop program :)
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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.