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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I'll have a new post by 1pm Saturday.

Jeff Masters

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1410. msphar
Putting a name on storms is good for Insureance companies. I get no joy out of those events but they certainly get financial benefits.
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1409. WxLogic
Watch the disturbed region as NE of PR as a piece of energy attempts to break off from 94L:





If it's successful at such then we could have 96L coming soon.
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Quoting AussieStorm:

We could have Gert, Harvey and Irene by this time next week.


Morning all... looks like this GFS run posted a couple of spots down from me puts whatever 93L becomes on SW FL's door in about 10 days...

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Quoting AussieStorm:
Franklin looks better than Emily ever did.




Looks like Dmax did its job on Franklin.

Wouldn't surprise me if it was a 50 mph storm.
Member Since: September 2, 2006 Posts: 110 Comments: 6878
Quoting Stormchaser2007:
Exposed LLC.

Another weak system on the way?


NHC will have it named Gert in the next 48hrs.
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94L close-up

**FULL-RES

Member Since: June 9, 2007 Posts: 4 Comments: 15947
Quoting Stormchaser2007:
More rain anyone?



What a swing from Texas to Florida from 00z to 6z. That is why I dont believe anything in the models after 144 hours.
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Exposed LLC.

Another weak system on the way?

Member Since: June 9, 2007 Posts: 4 Comments: 15947
Quoting WxLogic:
Good Morning... we got Franklin. This should be an interesting week.

We could have Gert, Harvey and Irene by this time next week.
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1400. msphar
I started skiing Snowbird in the winter of the first gas crisis, 1973. I have skied there every year ever since. Sometimes powder mountain, or snow basin or sundance or BCC but generally we stay at the Cliff on Snowbird. great snow, great steeps. Still I prefer the velvety body of the sierra powder over all.
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More rain anyone?

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1398. WxLogic
Good Morning... we got Franklin. This should be an interesting week.
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Franklin looks better than Emily ever did.

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Quoting largeeyes:
Whats the effect of Franklin and the front going to be on Europe next week?


Leaves may be momentarily disturbed, hairstyles ruffled and the odd anorak covered with a light dusting of moisture.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
Whats the effect of Franklin and the front going to be on Europe next week?
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Quoting LightningCharmer:


Good Morning!

Good Point! Even the so called, "Fish Storms" are not really fish storms at all, they don't really affect fish but they do affect maritime interest. Perhaps, they should be called, "Ship Storms" or "Maritime Storms?"

Looking really busy in Atlantic with more to come. Africa is really busy wave-making.

Keep a close eye, and review your hull and/or hunker plans. Patrap and other bloggers here have excellent resources and links on preparedness. Don't wait till the lines at the grocery stores and supply stores are out the door into the parking lots.

NOAA Preparedness Page


Great point! Most would consider Franklin a complete fish storm. But as Aspectre pointed out with the Great Circle Mapper earlier, a str8 line projection would indeed have Franklin hitting land. Albeit that's a straight line projection, and most likely subject to change, it go's to show that what most would consider "fish" storms have that potential to hit the most obscure, of pieces of land.

Shouldn't ever call anything a fish, till it's in the far North Atlantic graveyard, otherwise, someone may in fact feel it, in someplace and someway.
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1393. msphar
I think there is something like 4 or 5 million people on Puerto Rico with most of them concentrated in the Northeastern part. although there people all over that island in every nook and cranny. The little islands to its East and South all seem to have a bunch of people living and visiting on them too.
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Quoting msphar:
I get to salt lake, more specifically Little Cottonwood Canyon about twice a year. I enjoy the heck out of it, just not its SLC modern airport, I liked the old one much better.


It's a small world indeed LCC! And yes, bring back the old! Some changes just aren't for the better!
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6Z GFS Not good with rain over places who don't need it. Looks to pull north thru Haiti. Link
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1389. msphar
no worries At Home I think 93 will never reach the GOM and that your drought will break soon. I remember living through a 7 year drought in Calif in the 1990s it was awful. Now it rains too much in the desert where I call home.
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Quoting msphar:
I dont like the sound of "hitting some islands" theres a lot of people lives and property on those "some islands", including some of mine.


Good Morning!

Good Point! Even the so called, "Fish Storms" are not really fish storms at all, they don't really affect fish but they do affect maritime interest. Perhaps, they should be called, "Ship Storms" or "Maritime Storms?"

Looking really busy in Atlantic with more to come. Africa is really busy wave-making.

Keep a close eye, and review your hull and/or hunker plans. Patrap and other bloggers here have excellent resources and links on preparedness. Don't wait till the lines at the grocery stores and supply stores are out the door into the parking lots.

NOAA Preparedness Page
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Quoting msphar:
I dont like the sound of "hitting some islands" theres a lot of people lives and property on those "some islands", including some of mine.


Ok. I'll try one more time. That's why I said I hoped it was wrong. :)
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1386. msphar
I get to salt lake, more specifically Little Cottonwood Canyon about twice a year. I enjoy the heck out of it, just not its SLC modern airport, I liked the old one much better.
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Quoting Neapolitan:
First night/day RGB split of Franklin. He did blossom last night. Pretty impressively, in fact...

Franklin
I agree. The diurnal maximum really helped this system, that in combination with baroclinic support from the troughing towards the northeast was just enough to push the system to Franklin. Should be able to intensify into a modest tropical storm should it continue to fire intense thunderstorm activity before encountering stronger upper-level winds and cold surface temperatures.
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1384. msphar
93 is sort of spread all over the eastern atlantic
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Quoting msphar:
My routing really sucked but the price was right. San Juan to Atlanta to Baltimore to Salt Lake the finally to Reno. Seemed to take forever.


I hope you got a chance to see some of Salt Lake City! As beautiful as it gets on it's outskirts, not a lot of spots compare! Got fam there, and it's one of the few fam get-to-gathers I look forward to and habitually attend!
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morning all.

I see we have ts franklin this morning just as I suspected. Any change on 94L, 93L or 92L?
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1381. msphar
I dont like the sound of "hitting some islands" theres a lot of people lives and property on those "some islands", including some of mine.
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Quoting wunderkidcayman:
hey guys I noticed something with 93L(93L's NW quad) convection is starting to flare up(on the NW quad) which is now reaching 40W I am thinking that 93L nakid days will soon be over


If so, and so soon, odds are, fish or at least north of the Leewards she'll/ he'll a go. But, as I said earlier, hopefully no deal until somewhere in a Texas vicinity, and then just a rainmaker, no trouble maker! *Fingers crossed!*
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Quoting AtHomeInTX:


Sorry I meant strengthen fast. It looked to me that model showed a stronger storm hitting some islands.


That would make sense. A stronger 93L would be pulled north, into P.R. or other northern areas. A weaker one would push closer or onto the South American Coast, as depicted by some models. Who knows, in reality. We're still several days from whatever will be, and only Ma Nature knows which way that shoe drops.

Best bet, just watch the models, and pay heed to the NHC and other pertinent orgs.
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hey guys I noticed something with 93L(93L's NW quad) convection is starting to flare up(on the NW quad) which is now reaching 40W I am thinking that 93L nakid days will soon be over
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1377. msphar
My routing really sucked but the price was right. San Juan to Atlanta to Baltimore to Salt Lake the finally to Reno. Seemed to take forever.
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First night/day RGB split of Franklin. He did blossom last night. Pretty impressively, in fact...

Franklin
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Quoting nocaneindy:


I'm by far no expert, but judging from the post's I've read on here thus far in '11, I'd say folks in that area could use a nice reprise from any moisture. But in a tropical moisture fetch way of understanding, those in Texas would most likely be impacted from a system in the P.R. or south vicinity. So it's a fine line. Maybe we could luck out and a mere wave impact P.R./ Hispainola, with a minimal precip value. Then cruise into the gulf and meet just enough favorable conditions to achieve T.S. status and move slow enough to bring beneficial rains and not enough for any real flooding issues. Then a wash and repeat a week or 2 later. Drought breaker baby!

My wishes for you in the dried out, great state of Texas anyway! From Indiana with love and prayers!


Thanks! Hope you get your cool down fast. :)
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1374. msphar
On a flight route, from Baltimore to Salt Lake, we had a consistent 75 to 100 mph head wind. Straight west to east.
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Quoting msphar:
I don't understand what you mean by "bottom out fast"

It looks to me like its starting to climb a bit.


Sorry I meant strengthen fast. It looked to me that model showed a stronger storm hitting some islands.
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1372. msphar
Puerto Rico has been quite wet this summer. It needs no rain any more. Let Texas have it all.
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Another name. Do wonder if it'll end up a bit like 1936...

Still, cricket's the main thing of the day. Going to the top of the world. ;)
Member Since: August 23, 2008 Posts: 7 Comments: 5300
Quoting msphar:
I flew over Indiana the other day this week. Don't remember much of the air there.


Hot and Humid, at ground level anyway. Was smack dab in high pressure, and hot! Not too bad now though, much more reasonable high/lows for the area. Jet stream dip = I'm happy!
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Quoting msphar:
NOGAPS seems to have a thing about Eastern Puerto Rico this year. I hope it is wrong again.


I'm by far no expert, but judging from the post's I've read on here thus far in '11, I'd say folks in that area could use a nice reprise from any moisture. But in a tropical moisture fetch way of understanding, those in Texas would most likely be impacted from a system in the P.R. or south vicinity. So it's a fine line. Maybe we could luck out and a mere wave impact P.R./ Hispainola, with a minimal precip value. Then cruise into the gulf and meet just enough favorable conditions to achieve T.S. status and move slow enough to bring beneficial rains and not enough for any real flooding issues. Then a wash and repeat a week or 2 later. Drought breaker baby!

My wishes for you in the dried out, great state of Texas anyway! From Indiana with love and prayers!
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1367. msphar
For me every degree of latitude gained is a win with 93L
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1365. msphar
I don't understand what you mean by "bottom out fast"

It looks to me like its starting to climb a bit.
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Quoting msphar:
NOGAPS seems to have a thing about Eastern Puerto Rico this year. I hope it is wrong again.


Looks to me for that to come about 93l would have to bottom out fast to get pulled that far north. So I hope it's wrong too. Because if anything is going to become strong I hope it just goes out to sea.
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1363. msphar
I flew over Indiana the other day this week. Don't remember much of the air there.
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1362. Walshy
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Well to burn one off one of them in a complete weather related post, here ya go!

For Central Indiana, KIND forecast area, this was the hottest July in 75 years and the driest July in recorded history. As a person who feels personally insulted when the mercury rises over 75-80F, the past month was a exercise of torture. Born in Louisiana, I'd much rather live in Artic conditions as opposed to any other. Coincidentally, I just may get that ironic chance in the near term! Wish me luck!! But to the point, it was way too very hot these past 6 weeks or so. For you guys in the south, I just don't get how ya can do it, year in and out. Props from a lightweight in Indiana on having that "we just deal with it" attitude.

Here's to an early fall, early winter, and blessed be, early snows!!!
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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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