Two African waves that may develop

By: Dr. Jeff Masters , 10. elokuuta 2011 klo 16:59 (GMT)

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Hello everyone, it's Jeff Masters back with you again after a long stretch of vacation. Now that the peak part of hurricane season is upon us, I'll be with you every day for the next few months, in what promises to be an unusually active Atlantic hurricane season. We've got several threats to talk about today, most notably a strong African wave near 12.5°N 30.5°W, about 400 miles west-southwest of the Cape Verde Islands. This system, dubbed Invest 92L by NHC, 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 is beginning to develop a surface circulation, and heavy thunderstorms are slowly building along the western edge of the center. However, a separate area of heavy thunderstorms lies 400 miles to the east, just south of the Cape Verde Islands, and this blob is interfering with consolidation of the center near the blob of heavy thunderstorms at 30.5°W. Water vapor satellite loops show that a large area of dry air from Africa lies just to the west of 92L, but the atmosphere in the immediate vicinity of 92L is moist, so dry air is currently not a problem for the storm. The SHIPS model is diagnosing low shear, 5 - 10 knots, over 92L, but the University of Wisconsin CIMSS analysis shows that moderate shear of 10 - 20 knots is 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. Noon satellite photo of Invest 92L.

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 steadily 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 little or no development of 92L, and NHC gave 92L just a 20% chance of developing into a tropical depression by Friday morning in their 8am outlook. Given the recent improvement in the satellite appearance of 92L, I would put these odds at 30%. 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 may pass north of the Lesser Antilles. 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.


Figure 2. NASA MODIS image taken at 10:40am EDT 8/10/11 of the tropical wave emerging from the coast of Africa. The GFS model is predicting this system will develop into a tropical storm early next week. Image credit: NASA.

Tropical wave emerging from the coast of Africa
A strong tropical wave currently emerging from the coast of Africa near 8°N has a modest amount of spin and heavy thunderstorm activity associated with it, and has the potential to develop early next week once it moves past the Cape Verde Islands. The GFS model has been developing this system into a tropical storm in several of its recent runs. A westerly track towards the Lesser Antilles is expected by the GFS model.

Jeff Masters

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1628. wund
15. elokuuta 2011 klo 13:09 (GMT)
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Member Since: 28.07.2011 Posts: 0 Comments: 4
1627. ILwthrfan
11. elokuuta 2011 klo 15:07 (GMT)
Quoting P451:


Yeah the new surge of SAL isn't helping either pushing in from behind.

If 92L does develop it clearly won't be for days.

93L on the other hand...

93L will have to contend with SAL as well, maybe even more than 92L. Look at the flow off the coast of West Africa, west south west. 93L could very well ingest quit a bit of dry air in the coming days. It would not all surprise me if it took 4-5 days out from now for these waves to really get going.
Member Since: 2.02.2010 Posts: 0 Comments: 1403
1626. nrtiwlnvragn
11. elokuuta 2011 klo 15:02 (GMT)
OLD BLOG
Member Since: 23.09.2005 Posts: 13 Comments: 10466
1625. tropicalweather2011x
11. elokuuta 2011 klo 15:00 (GMT)
WOW!! HIGH!
Member Since: 10.08.2011 Posts: 0 Comments: 139
1624. tropicalweather2011x
11. elokuuta 2011 klo 14:57 (GMT)
Member Since: 10.08.2011 Posts: 0 Comments: 139
1623. presslord
11. elokuuta 2011 klo 14:56 (GMT)
Quoting SAINTHURRIFAN:
Well I will try this a 3rd time.I think a troll must be deleting all my osts.Ten posts and no reply?Hey i cant be that unpopular lol.Here we go.Good morning Ike and Aquak.Press lord isnt it amazing that


Good mornin'!
Member Since: 13.08.2007 Posts: 0 Comments: 10458
1622. angiest
11. elokuuta 2011 klo 14:55 (GMT)
Quoting AussieStorm:

Most of those 6.0+ quakes were off the coast of Japan.


Yes, they continue to get moderately large aftershocks.
Member Since: 26.08.2006 Posts: 16 Comments: 4766
1621. CybrTeddy
11. elokuuta 2011 klo 14:52 (GMT)
Good morning Saint..
Member Since: 8.07.2005 Posts: 259 Comments: 23012
1620. SuperYooper
11. elokuuta 2011 klo 14:51 (GMT)
Quoting SAINTHURRIFAN:
Well I will try this a 3rd time.I think a troll must be deleting all my osts.Ten posts and no reply?Hey i cant be that unpopular lol.Here we go.Good morning Ike and Aquak.Press lord isnt it amazing that


LOL, he only got half your post this time. ;^)
Member Since: 18.08.2010 Posts: 14 Comments: 1601
1619. AussieStorm
11. elokuuta 2011 klo 14:49 (GMT)
Quoting Neapolitan:

Unusual, but not unheard of, I guess. Since the monster earthquake in Japan, there have been 70 6.0 or larger quakes on the planet: 21 in March, 14 in April, 5 in May, 10 in June, 19 in July, and--so far--just one in August. It's definitely a bit of a drought. But there were two on May 15, then none until June 1, so we've another week to go before equaling that seismic lull...

Most of those 6.0+ quakes were off the coast of Japan.
Member Since: 30.09.2007 Posts: 9 Comments: 15749
1618. AussieStorm
11. elokuuta 2011 klo 14:48 (GMT)
Quoting SAINTHURRIFAN:
Well I will try this a 3rd time.I think a troll must be deleting all my osts.Ten posts and no reply?Hey i cant be that unpopular lol.Here we go.Good morning Ike and Aquak.Press lord isnt it amazing that

Good Morning Saint :-)
Member Since: 30.09.2007 Posts: 9 Comments: 15749
1617. SuperYooper
11. elokuuta 2011 klo 14:47 (GMT)
Quoting Neapolitan:

Unusual, but not unheard of, I guess. Since the monster earthquake in Japan, there have been 70 6.0 or larger quakes on the planet: 21 in March, 14 in April, 5 in May, 10 in June, 19 in July, and--so far--just one in August. It's definitely a bit of a drought. But there were two on May 15, then none until June 1, so we've another week to go before equaling that seismic lull...


I saw that gap there also. Two weeks, from what I gathered, is the usual gap. All the while, pressure builds...........oooohhhhhhh..........
Member Since: 18.08.2010 Posts: 14 Comments: 1601
1615. SuperYooper
11. elokuuta 2011 klo 14:43 (GMT)
Quoting P451:


Are we DOOM?

If so, where?

West coast US? New Madrid?

We're the ones that haven't popped in a long time.


True. AK had a 6-7 mag 2 months ago and that is where I would place money for one again. Higher? Yeah we are due but so are a lot of other places. I would place higher bets on something in Europe...Iceland or the Med before us. Not a lot of money though. Gotta be a volcano ready to go in the Med somewhere which is usually proceeded by a quake of some sort.

Yeah, we are probably DOOM.
Member Since: 18.08.2010 Posts: 14 Comments: 1601
1614. RitaEvac
11. elokuuta 2011 klo 14:43 (GMT)
The records continue to fall and the situation across the state is becoming increasingly desperate for rainfall. Some of the record are just amazing on the drought and shows how bad things have become!


Locally the strong heat ridge remains in place with yesterday being the tenth straight day at or above 100…we will do it again today and likely again Friday. The streak to break the 1980 record is 14 and to tie it would be on Sunday. It would appear that the ridge may weaken just enough over the weekend to drop 1-3 degrees off the high temperature which would support 98-101 across the region, so it is in question if the current 100 degree streak will be broken or tied.

Heat:

Below is some comparison data to the summer of 1980 (hottest summer ever for TX) and 2011 for the number of days at or above 100:



College Station: 43 (1980), 38 (2011)

Huntsville: 43 (1980), 45 (2011)

Conroe: 22 (1980), 27 (2011)

BUSH IAH: 32 (1980), 21 (2011)

Hobby: 8 (1980), 6 (2011)

Dallas: 69 (1980), 47 (2011)

Waco: 63 (1980), 59 (2011)

Austin Mabry: 32 (1980), 57 (2011), record year is 69 in 1925

Del Rio: 56 (1980), 63 (2011), record year is 78 in 1953

San Antonio: 31 (1980), 33 (2011), record year is 59 in 2009


Number of consecutive days at or above 100 degrees:

Dallas: 42 (1980), 40 (2011)

Waco: 42 (1980), 42 (2011) *Today will break this record*

BUSH IAH: 14 (1980), 10 (2011)


So far for August of 2011, most of the climate sites in SE TX are on their way to breaking their hottest monthly temperature FOR ANY MONTH by 2-3 degrees!


Drought:

Things are bad and getting worse by the day with respect to water supply, vegetation, and agricultural impacts. The impacts to agriculture and livestock are approaching severe levels with cattle running out of drinking water from drying creeks and ponds. Vegetation has stopped growing and died in many ranch areas with feed being trucked into from the central plains for cattle. We are really getting into a bad situation quickly and we desperately need widespread rainfall. The majority of irrigation currently is just to keep vegetation alive at this point and with increasing water conservation measures likely vegetation already stressed is going to suffer even more.



Houston has now gone 198 days between 1.0 inch rainfall events breaking the previous record of 192 days from 1917-1918



Only 6.36 inches of rain has fallen in the last 191 days for the City of Houston (IAH) making this by far the driest Feb-Aug 10 period ever. This breaks the previous record by an astounding 6.25 inches of rainfall…that is an amazing record!!! At Hobby Airport for the same time period the record is being broken by 5.17 inches!



The period from August 2010 to August 2011 is now the driest 1-year period ever for the City of Houston.



Water Supply:

For the first time since the drought of 1988 the City of Houston is going to be requesting emergency releases from Lake Conroe to help stabilize the rapid fall that is occurring on Lake Houston (the primary water supply for the City of Houston). This is only the third time ever this action has been required. Water intake pipes on Lake Houston are getting dangerously low to becoming exposed and causing damage to the water supply system. With this action likely next week, the City of Houston will move to Stage 2 water conservation (mandatory water restrictions). This is going to have a significant impact on the lake levels at Conroe as releases begin, and the lake will begin to fall due to the releases that are going to be required to help stop the rapid decline on Lake Houston.



Lake Somerville and Lake Texana are now close to 50% of their capacity and falling. Lake Somerville has lost an astounding 11% of its capacity in the last 3 weeks!



Outlook:

I have really no good news, as any rains over the next 48 hours will likely be focused west of SE TX. 14 day outlook continues to feature below normal rainfall unless something can develop and threaten from the tropics.



NOAA issued a La Nina Watch this week suggesting that the return of cooling in the central Pacific may once again result in La Nina conditions this fall-winter-spring….if this happens rainfall will average below normal through much of this winter and this drought will only worsen if we do not get some kind of tropical system in the next 2 months.

Member Since: 14.07.2008 Posts: 1 Comments: 9625
1613. OracleDeAtlantis
11. elokuuta 2011 klo 14:43 (GMT)
Quoting P451:


Looks like the energy got split. A model run days ago had this happening but much further west than it occurred and a new tight system forming and rolling WSW towards the SE US Coastline.

I wouldn't put much into it honestly. It would just circle right back up on out of here if anything came of it.

66 hours, Emily:






Quoting beell:


I would say no. There is a long-advertised shortwave along 50-51W breaking a somewhat weak A/B ridge in half. The models respond by bringing 92L towards this weakness. Some runs have even hinted at a weak trough split here and a subsequent area of vorticity ahead of 92L drifting to the SW into the Caribbean. That part seems pretty iffy.

700mb @ 18Z
click to enlarge




It does appear that her energy got split, looking at the imagery posted above.

That's at least half of her moisture circling around the big High, and some of her vorticity.

It's interesting, anytime one tries to do this, even if it's just part of the energy. The left over moisture is significant, at the least.
Member Since: 27.08.2009 Posts: 0 Comments: 489
1612. Neapolitan
11. elokuuta 2011 klo 14:39 (GMT)
Quoting SuperYooper:
There have been no earthquakes, world wide, above a 7 magnitude in over a month and nothing above a 6 for a week now. Unusual given recent activity.

Unusual, but not unheard of, I guess. Since the monster earthquake in Japan, there have been 70 6.0 or larger quakes on the planet: 21 in March, 14 in April, 5 in May, 10 in June, 19 in July, and--so far--just one in August. It's definitely a bit of a drought. But there were two on May 15, then none until June 1, so we've another week to go before equaling that seismic lull...
Member Since: 8.11.2009 Posts: 4 Comments: 13276
1610. tropicfreak
11. elokuuta 2011 klo 14:34 (GMT)
Quoting P451:


Yeah the new surge of SAL isn't helping either pushing in from behind.

If 92L does develop it clearly won't be for days.

93L on the other hand...


You sound a lot like pottery lol.
Member Since: 2.09.2006 Posts: 110 Comments: 6814
1609. Hugo7
11. elokuuta 2011 klo 14:34 (GMT)
Quoting P451:


Looks like the energy got split. A model run days ago had this happening but much further west than it occurred and a new tight system forming and rolling WSW towards the SE US Coastline.

I wouldn't put much into it honestly. It would just circle right back up on out of here if anything came of it.

66 hours, Emily:






Still looks to me like Emily is trying to come back around again.
Member Since: 1.06.2011 Posts: 0 Comments: 64
1606. beell
11. elokuuta 2011 klo 14:29 (GMT)
Quoting OracleDeAtlantis:
She's back ....

Emily has decided to go another round?

That is what's left of her, correct?





I would say no. There is a long-advertised shortwave along 50-51W breaking a somewhat weak A/B ridge in half. The models respond by bringing 92L towards this weakness. Some runs have even hinted at a weak trough split here and a subsequent area of vorticity ahead of 92L drifting to the SW into the Caribbean. That part seems pretty iffy.

700mb @ 18Z
click to enlarge


Member Since: 11.09.2007 Posts: 137 Comments: 15325
1605. ackee
11. elokuuta 2011 klo 14:27 (GMT)
92L really not looking Good just seem like its puropse was get rid of the dry air for 93L
Member Since: 15.07.2008 Posts: 0 Comments: 1341
1604. AussieStorm
11. elokuuta 2011 klo 14:26 (GMT)
Quoting SQUAWK:


Isn't it a little early to be calling that?

I wished he'd give it a break, the system hasn't even formed yet and he's calling fish. It's only an INVEST.
Member Since: 30.09.2007 Posts: 9 Comments: 15749
1603. SAINTHURRIFAN
11. elokuuta 2011 klo 14:26 (GMT)
Well I will try this a 3rd time.I think a troll must be deleting all my osts.Ten posts and no reply?Hey i cant be that unpopular lol.Here we go.Good morning Ike and Aquak.Press lord isnt it amazing that
Member Since: 20.08.2005 Posts: 5 Comments: 706
1602. sandbarhappy
11. elokuuta 2011 klo 14:26 (GMT)
Quoting HurricaneDean07:
Presslord,
Yep, have visited Galveston in the moddle of July every year since 2003, and its amazing how much they've built back, though tourism has sadly plumeted and may not return to where it was for years...


I am a resident of Galveston and I beg to disagree. The middle of July happens to be the slowest time - we get such crowds for the 4th and there is a slump right afterwards. If you look at hotel occupancy and beach counts, we are back where we were before Ike, and higher on the holidays.

That said, if you drive off the main drag, you will still see many blue roofs (most now shredded) and derelict buildings. Whereas tourism has recovered, the population has not and the economy is keeping things down. It is a great time to buy property on the island.
Member Since: 26.08.2010 Posts: 0 Comments: 5
1600. Jedkins01
11. elokuuta 2011 klo 14:25 (GMT)
Quoting portcharlotte:
Right..I see very little difference from last year..it's either Mexico or out to sea



I agree, that is the dominant pattern in place. Although obviously storms could still go elsewhere, those seem like the main paths again.
Member Since: 21.08.2008 Posts: 0 Comments: 6867
1599. portcharlotte
11. elokuuta 2011 klo 14:24 (GMT)
Fron the death ridge to the Artic freeze ridge..
I think Noaa should attack the "Death Ridge" with some kind of atmospheric weapon of some sort..


Quoting RitaEvac:


With another high that will put us in the Deep Freeze
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1598. ackee
11. elokuuta 2011 klo 14:24 (GMT)
I think 93L percent could be up to 30% by 2pm
Member Since: 15.07.2008 Posts: 0 Comments: 1341
1597. CybrTeddy
11. elokuuta 2011 klo 14:24 (GMT)
Morning StormJunkie! Glad to see you.
Member Since: 8.07.2005 Posts: 259 Comments: 23012
1596. SQUAWK
11. elokuuta 2011 klo 14:22 (GMT)
Quoting JasonIsCoolman:
FISH STORM!!!


Isn't it a little early to be calling that?
Member Since: 9.12.2008 Posts: 0 Comments: 2498
1594. RitaEvac
11. elokuuta 2011 klo 14:22 (GMT)
Quoting portcharlotte:
On Xmas day..a "Blue Norther" will destroy the high!




With another high that will put us in the Deep Freeze
Member Since: 14.07.2008 Posts: 1 Comments: 9625
1592. RitaEvac
11. elokuuta 2011 klo 14:20 (GMT)
Also my hope is by October we have some fronts come down and stall over the state and have deep tropical moisture coming in from the BOC and get widespread heavy training rains. I bet that's what will happen too.
Member Since: 14.07.2008 Posts: 1 Comments: 9625
1591. portcharlotte
11. elokuuta 2011 klo 14:19 (GMT)
On Xmas day..a "Blue Norther" will destroy the high!


Quoting RitaEvac:
The TX ridge has been around since March, it's doomed to fail at some point
Member Since: 7.09.2008 Posts: 0 Comments: 703
1590. atmoaggie
11. elokuuta 2011 klo 14:19 (GMT)
Quoting StormJunkie:
Hey Aussie & Zoo, good to see y'all...And you too CT

Michael is doing well; being a bit of the pain in the arse on days he wakes up on the wrong side of the bed. Seeing as how he's 2.5 and thinking he can get away with testing me ;-)

nrti, great to see you around as well ;)
Well, greetings earthling.
Member Since: 16.08.2007 Posts: 6 Comments: 12461
1589. portcharlotte
11. elokuuta 2011 klo 14:17 (GMT)
True..it can change ...I have noticed though that sometimes when when get a very strong tropical system recurve it starts a pattern. It seems to leaves a subtle weakness in the ridge or the region and all other follow to some degree. We'll see


Quoting tropicfreak:



Yeah but that pattern won't certainly last long. Come on now, you're going to say the same thing next year. We are still relatively early in the season, so anything can happen.
Member Since: 7.09.2008 Posts: 0 Comments: 703
1588. divdog
11. elokuuta 2011 klo 14:17 (GMT)
Quoting RitaEvac:
The TX ridge has been around since March, it's doomed to fail at some point
maybe in november
Member Since: 22.08.2008 Posts: 0 Comments: 755
1587. Matt74
11. elokuuta 2011 klo 14:16 (GMT)
Quoting RitaEvac:


I expect it to crack by next month
Let's hope so. I would take a storm right now if that is gonna be the only way to get any beneficial rain. I'm sure alot of people around here would agree.
Member Since: 21.06.2011 Posts: 0 Comments: 329
1586. RitaEvac
11. elokuuta 2011 klo 14:14 (GMT)
Quoting cmahan:


Uhm... bullcr*p. I grew up in Houston and was just down there a couple weekends ago. Happy to leave some of my dollars behind on the Island and had a great time doing it.


Uhm, you're a local too, not from another state
Member Since: 14.07.2008 Posts: 1 Comments: 9625
1585. tropicfreak
11. elokuuta 2011 klo 14:13 (GMT)
Quoting portcharlotte:
Right..I see very little difference from last year..it's either Mexico or out to sea




Yeah but that pattern won't certainly last long. Come on now, you're going to say the same thing next year. We are still relatively early in the season, so anything can happen.
Member Since: 2.09.2006 Posts: 110 Comments: 6814
1584. RitaEvac
11. elokuuta 2011 klo 14:13 (GMT)
The TX ridge has been around since March, it's doomed to fail at some point
Member Since: 14.07.2008 Posts: 1 Comments: 9625
1583. cmahan
11. elokuuta 2011 klo 14:12 (GMT)
Quoting RitaEvac:


Never has had tourism, Galveston really doesnt have anything to offer.


Uhm... bullcr*p. I grew up in Houston and was just down there a couple weekends ago. Happy to leave some of my dollars behind on the Island and had a great time doing it.
Member Since: 7.09.2010 Posts: 0 Comments: 155
1582. portcharlotte
11. elokuuta 2011 klo 14:11 (GMT)
Right..I see very little difference from last year..it's either Mexico or out to sea

Quoting AussieStorm:
From The Northeast Quadrant
This is the current upper air pattern, which is somewhat similar to last year, though the negative NAO that kept the storms from reaching the U.S. in 2010 is not as strong in 2011. Still, with this pattern and with storms potentially forming so far east like they did last year, odds are that most, but not all, will still recurve. You will identify that trend as the models start hooking right once 92L and 93L have defined low level centers.
Member Since: 7.09.2008 Posts: 0 Comments: 703
1581. JrWeathermanFL
11. elokuuta 2011 klo 14:10 (GMT)
Hard thing to remember, but what is your opinion on the best looking invest this season that never became a TS?
Member Since: 19.07.2011 Posts: 8 Comments: 1635
1580. RitaEvac
11. elokuuta 2011 klo 14:10 (GMT)
Quoting Matt74:
With the ridge over us we won't have to worry about one.


I expect it to crack by next month
Member Since: 14.07.2008 Posts: 1 Comments: 9625
1579. earthlydragonfly
11. elokuuta 2011 klo 14:09 (GMT)
Quoting JrWeathermanFL:

I know what it means.


Just helping with the spelling..
Member Since: 1.07.2005 Posts: 10 Comments: 1681

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About JeffMasters

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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