Four invests in the Atlantic; fair weather in Arctic to drive rapid sea ice loss

By: Dr. Jeff Masters , 3:38 PM GMT on August 12, 2011

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It's a busy day in the tropical Atlantic, with the National Hurricane Center tracking four areas of interest (Invests.) None of these systems is a danger to any land areas over the next three days. The disturbance of most concern is the one farthest from land, a tropical wave that emerged from the coast of Africa two days ago. This wave, (Invest 93L), is located about 500 miles southwest of the Cape Verde Islands, and is moving westward at 15 - 20 mph. Recent visible satellite loops show that 93L has lost some of its heavy thunderstorms since yesterday, and the system is poorly organized, though there is a good deal of spin to the system. There is dry air to its north that is interfering with development. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing high wind shear in excess 20 knots affecting 93L, which has undoubtedly contributed to the storm's loss of organization. Sea surface temperatures are 27.5°C, which is one degree above the 26.5°C threshold usually needed to support a tropical storm.


Figure 1. Morning satellite photo of the four Invests in the Atlantic today.

Forecast for 93L
High wind shear above 20 knots is predicted along 93L's path through Saturday afternoon, followed by a drop to the moderate range, 10 - 20 knots, for the succeeding four days. This should allow the storm to organize over the weekend. 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 40% chance of developing into a tropical depression by Sunday morning in their 8am outlook. Given 93L's recent struggles, I'd put these odds at 30%.

92L
An African wave midway between the northern Lesser Antilles Islands and the coast of Africa, near 18°N 45°W, is moving west-northwest at 20 mph. This system, (Invest 92L), is being given a 40% chance of development by NHC. Recent visible satellite loops show a modest amount of heavy thunderstorm activity, but no signs of a surface circulation. A Windsat pass from 8:04 am EDT this morning also showed no surface circulation, and noted top winds of around 35 mph. Water vapor satellite loops show that a large area of dry air surrounds 92L, and this dry air is causing problems for the storm. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 20 knots affecting 92L. Sea surface temperatures are 27 - 27.5°C, which is a degree above the 26.5°C threshold usually needed to support a tropical storm.

Forecast for 92L
Moderate wind shear of 10 - 20 knots is predicted along 92L's path over the coming five days, which should allow the storm to organize if it can handle the dry air surrounding it. 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 40% chance of developing into a tropical depression by Sunday morning in their 8am outlook. A steady west-northwest motion for 92L is predicted by all of the models, which should make the storm miss the Lesser Antilles by a comfortable margin. However, Bermuda may be at risk from 92L next week.

94L
A broad low pressure system about 700 miles northeast of the northern Lesser Antilles Islands has developed a small amount of heavy thunderstorm activity, and may be a threat to become a tropical depression early next week. This system, (Invest 94L), is currently headed west-southwest at 10 mph, but is expected to turn northwest later today. Recent visible satellite loops show some spin to the cloud pattern at middle levels of the atmosphere, but no signs of a surface circulation. This system is also battling dry air, which is keeping the its heavy thunderstorms relatively meager. The SHIPS model is showing moderate wind shear of 10 - 20 knots affecting 94L. Sea surface temperatures are 28°C.

Forecast for 94L
Moderate wind shear of 10 - 20 knots is predicted along 94L's path over the coming five days, which should allow slow development, if it can handle the dry air surrounding it. None of our reliable models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show no development of 94L, and NHC gave 94L just a 20% chance of developing into a tropical depression by Sunday morning in their 8am outlook. Bermuda is the only land area that needs to be concerned with 94L.

95L
The final invest out there is an area of disturbed weather along on old frontal boundary several hundred miles off the coast of North Carolina. This sytem, Invest 95L, is headed northeastwards out to sea, and is not a threat to any land areas.



Figure 2. Arctic sea ice extent on August 11, 2011, was the 2nd lowest on record for the date. The Northeast Passage and Northwest Passage (southern route) were both ice-free. Image credit: UIUC Cryosphere Today.

Arctic sea ice poised to undergo record decline in mid-August
A strong high pressure system with a central pressure of 1035 mb has developed over the Arctic north of Alaska, and will bring clear skies and warm southerly winds to northeast Siberia and the Arctic during the coming week, accelerating Arctic sea ice loss. Widespread areas of northeastern Siberia are expected to see air temperatures 4 - 12°C (7 - 22°F) above average during the coming week, and the clockwise flow of air around the high pressure system centered north of Alaska will pump this warm air into the Arctic. Arctic sea ice extent, currently slightly higher than the record low values set in 2007, should fall to to its lowest extent for the date by the third week of August as the clear skies and warm southerly winds melt ice and push it away from the coast of Siberia. This weather pattern, known as the Arctic Dipole, was also responsible for the record sea ice loss in 2007, but was stronger that year. The weather conditions that led to the 2007 record were quite extreme--one 2008 study led by Jennifer Kay of the National Center for Atmospheric Research showed that 2007's combination of high pressure and sunny skies in the Arctic occur, on average, only once every 10 - 20 years. The 2011 summer weather pattern in the Arctic has not been nearly as extreme as in 2007, but the total sea ice volume has declined significantly since 2007, leading to much loss of old, thick, multi-year ice, making it easier to set a new low extent record with less extreme weather conditions. The GFS model is predicting that the Arctic Dipole will weaken by 8 - 15 days from now, with cloudier weather and weaker high pressure over the Arctic. This should slow down the rate of Arctic sea ice loss to very near the record low values observed in 2007. It remains to be seen if 2011 Arctic sea ice extent will surpass the all-time low set in September 2007; it will be close, and will depend on the weather conditions of late August and early September, which are not predictable at this time. It is already possible to sail completely around the North Pole in ice-free waters through the Northeast Passage and Northwest Passage, according to sea ice maps maintained by the UIUC Cryosphere Today website. This marks the fourth consecutive year--and the fourth time in recorded history--both of these Arctic shipping routes have melted free. Mariners have been attempting to sail these passages since 1497. This year, the Northeast Passage along the north coast of Russia melted free several weeks earlier than its previous record early opening.

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Jeff Masters

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also notice a possible new disturbance north of Puerto Rico !!! The NAM model agrees !!!
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Quoting CaicosRetiredSailor:


...Franklin the storm
or
Franklin the forecaster?

lmao
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Morning Aqua and all friends,I love me some dunkin donuts original blend whole bean ground up strong with milk and lotsa sugar.Watching the tropics this morning from the DelMarVa peninsula:)
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Quoting WeatherNerdPR:
Franklin, you look like a big fat puffball.


...Franklin the storm
or
Franklin the forecaster?
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1507. 900MB
Quoting 900MB:


I have faith in 92L! It has spin, convection (be it off center East), and it is in 29 degree + waters. Just have no idea where it's going. NHC says W/NW, but I don't see how this doesn't pull a quick exit stage right eventually.


Ha, first post all year and I get my invests confused! Change that comment to 94L dang it. That's where I am putting my chips, 94L. Arrgghh!
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94L (center) and 92L (lower right):
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Possible invest 96L?:

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1503. aquak9
Pookie- if it comes your way, just send it up this'aways when you're done. But if it heads towards Texas- they can keep every drop.

Nice pic, Nea.
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1502. 900MB
Quoting tropicfreak:
92L seems to have a decent spin.


I have faith in 92L! It has spin, convection (be it off center East), and it is in 29 degree + waters. Just have no idea where it's going. NHC says W/NW, but I don't see how this doesn't pull a quick exit stage right eventually.
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Franklin, you look like a big fat puffball.
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1500. hulakai
friendly, informative blog this morning, it was a pleasure dropping by. That cloud moving out of Africa (1485) may be our next AOI if/when it gains some latitude. Everybody else seems to be wandering aimlessly and impotenly out to sea which is fine. Surfing crowd could use a little more juice tho.
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92L hanging by its fingernails:

AL, 92, 2011081312, , BEST, 0, 195N, 532W, 25, 1013, DB, 34, NEQ, 0, 0, 0, 0, 1014, 125, 60, 0, 0, L, 0, , 0, 0, INVEST, M,
Member Since: November 8, 2009 Posts: 4 Comments: 13457
Quoting Neapolitan:

Naples. This was at Vanderbilt Beach in front of the very-very, too-too, "Stop taking pictures or we'll call the cops" Ritz Carlton. ;-)


You show 'em Neo, a strike for the little people taking pics at their beach ;)

I'm just up the coast a ways in St. Pete, but we haven't got a cloud in the sky. Even afternoon showers looking unlikely up here at the moment. But I suppose if 93L comes our way, we'll be getting plenty of moisture.
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1497. ncstorm
CMC..94L and 93L..both CMC and GFS in agreement for this run anyway about a West florida landfall for 93L and riding up the east coast..this seems like Emily all over again..



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Quoting Neapolitan:

Indeed. I was down at the water before dawn, and had a couple of good candidates, but nothing panned out. Here's a sample:

Clouds

Maybe next time...

I'm about to go down to the water.... there is a 300x100 mile storm coming from the north about an hour and a half from Austin now with 0% chance of rain, go figure.

That DirectTV whale guy has me competing to get MY carp to come out of the water. Right now they'll only stick their heads out a few inches to pluck Doritos.
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Quoting aquak9:
Well, Pookie, it was worth a try. If ya can't have coffee without chaos, what else is there to hope for?

Funny, someone posted the little pre-K storm. I was just thinking about how pathetic it was in it's formative days.


Indeed Aquak9, that sounds like the title of a self-help book or something, "Coffee without Chaos".

Scary to think that that became Katrina, good to keep in mind while looking at some of the other systems out there, and how small and helpless they appear now.

Well, I'm out of coffee, and it's time for me to head out into the heat for a bit to water plants, since it looks like we're not getting any rain today. Nice chatting with y'all and I'll see you on the flip side.
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Quoting HurricanePookie:


Beautiful shot Neo, where you at in Florida?

Naples. This was at Vanderbilt Beach in front of the very-very, too-too, "Stop taking pictures or we'll call the cops" Ritz Carlton. ;-)
Member Since: November 8, 2009 Posts: 4 Comments: 13457
92L seems to have a decent spin.
Member Since: September 2, 2006 Posts: 110 Comments: 6874
Quoting Neapolitan:

Indeed. I was down at the water before dawn, and had a couple of good candidates, but nothing panned out. Here's a sample:

Maybe next time...


Beautiful shot Neo, where you at in Florida?
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Quoting HurricaneSwirl:
FWIW, 6 years ago today was the beginning of Katrina.



SHHHHHHH
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1488. IKE

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1487. aquak9
Well, Pookie, it was worth a try. If ya can't have coffee without chaos, what else is there to hope for?

Funny, someone posted the little pre-K storm. I was just thinking about how pathetic it was in it's formative days.
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Quoting FLdewey:
Kind of messy out there today... tropical farm team.

Much of Florida is ripe for waterspouts today... woop woop. Taking the kids on a hunt.

Indeed. I was down at the water before dawn, and had a couple of good candidates, but nothing panned out. Here's a sample:

Clouds

Maybe next time...
Member Since: November 8, 2009 Posts: 4 Comments: 13457
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A good time to throw out the ACE tutorial for the uninitiated.

Quoting Neapolitan:

2002 was an average year; the season ended at 12-4-2, with an additional two TDs. (But one of those hurricanes was Lili, which killed people throughout the Caribbean before making landfall in Louisiana.)


More referring to the initial statement rather than anything else.

An early starting season is not a certainly of an active season, though it is often a good indicator. There have been a few seasons which started off with a bang then faded somewhat after. Others just ramped up further. I suspect we'll know in about 6 weeks which category this season falls into.

No season before started off with four storms of which none reached hurricane status, of course.
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Quoting stormhank:
I fully beleive the 9 hurricanes forecast for this season could happen, last year Danielle didnt form until after Aug 20th and we seen how busy the season was afterwards,, I also beleive 92l n 93l laid down more moisture for the next waves comin off africa so they will probably have a better chance at developing.


Does this mean you don't think 93L will develop? I agree it's looking a bit weak at the moment, but my understanding (admittedly limited) is that it'll get some more favorable conditions tomorrow, should it survive.
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Quoting shadoclown45:
Just a question, is there any website where i can access all the past noaa cone, and wind probabilities maps given out each advisory?


This is the closest I could find. Link

edit ok his is better. lol
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Quoting shadoclown45:
Just a question, is there any website where i can access all the past noaa cone, and wind probabilities maps given out each advisory?


Link When you select a storm/year the graphics archive link is at the top.
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1478. IKE
Day 74.
109 to go.
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I fully beleive the 9 hurricanes forecast for this season could happen, last year Danielle didnt form until after Aug 20th and we seen how busy the season was afterwards,, I also beleive 92l n 93l laid down more moisture for the next waves comin off africa so they will probably have a better chance at developing.
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1476. IKE

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Quoting Cotillion:


Gaze eyes and thoughts back to 2002 and you'll find your answer.

That is the only season to do that, however.

2002 was an average year; the season ended at 12-4-2, with an additional two TDs. (But one of those hurricanes was Lili, which killed people throughout the Caribbean before making landfall in Louisiana.)
Member Since: November 8, 2009 Posts: 4 Comments: 13457
Quoting shadoclown45:
Just a question, is there any website where i can access all the past noaa cone, and wind probabilities maps given out each advisory?

Link
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FWIW, 6 years ago today was the beginning of Katrina.

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Quoting prcane4you:
How many fish storms this year? All of them.

the season is far from being over, Mother nature is just firing warning shots. Be prepared or be warned.
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Mother nature wants her MJO back .
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Levi said last night he does not expect development with 93L until it is in the area of 40-50W. Not there yet . NHC says conditions could become more favorable for development in a few days which again would be between 40-50W.
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Just a question, is there any website where i can access all the past noaa cone, and wind probabilities maps given out each advisory?
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Aqua, you say I'm asking for alot? All I asked for was some eggs. Look at Nea's request.....LOL Now that's a lil picky....lol Morning Nea
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Quoting aquak9:
EEEWWWW!!! CocaCola for breakfast?? T'Freak you're scarin' me!

HurricanePookie- if you're still here? I did a CoffeeCast a few weeks back, like a palm reading defined by the coffee you drink. Wanna hear yours?


Morning Aqua. I only get donuts like once a week. Bummer. :( And I don't drink coffee. I'm a coca cola gal. Lol.
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Quoting aquak9:


You drive a dependable car, that you keep quite clean. Your home is orderly, and you look at expiration dates on everything you purchase. You don't like loud, noisy, self-centered people.

Yeah?


Good try, but alas, only partly correct. I DO drive a dependable car and I don't like loud, noisy, self-centered people (who does, really?).

But I like to live on the edge, and play fast and loose with expiration dates (just a suggestion, really), and my home, and garden are generally chaos. The coffee ritual is my one real attempt to instill order.

I follow the weather obsessively, mostly because I garden and need to know when to water my plants, and when to protect them from the cold. And of course, I keep an eye on the tropics because I live in Florida and that's just a good idea, even if I do live in "magically" protected Pinellas county. Thus my interest in this blog, and 93L.
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The water vapor loops show the only significant pocket of dry air South & West of our three invests. We may be be close to the point where dry air will no longer choke out these African waves. From what I read on here, MJO is supposed to be back sometime next week.
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Quoting AussieStorm:
1439. tropicfreak

Poll time!
What will 92L be at the next advisory?
A.20%
B.30%
C.40%
D.50%

What will 93L be in the next advisory?
A.20%
B.30%
C.40%
D.50%
What will 94L be in the next advisory?
A.20%
B.30%
C.40%
D.50%
How strong will Franklin be?
A.40 mph
B.45 mph
C.50 mph
D.60 mph
Will there be any new circles? If so where
A.Yes
B.No
How many fish storms this year? All of them.
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Quoting stormhank:
Pardon me if Im wrong ,but I cant recall the last season where the first six named storms were all TS's so if all the hurricane forecasts hold true that means most of the remaining named storms for this year could possibly be our worst storms before the season ends, I also see the MJO is showin alot of upward motion between now and the end of the month for the eastern atlantic and Africa so the big boys/girls may make their appearance before August ends


Gaze eyes and thoughts back to 2002 and you'll find your answer.

That is the only season to do that, however.
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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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