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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Quoting Vincent4989:
What to do with Hotwheels:
1.
2.
3. Ignore User


Member Since: Posts: Comments:
Quoting tiggeriffic:


{borrows soap box, opens back up and gets on}
I AGREE!
{steps off soap box, folds up, gives back to Baha}


What she said!
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Quoting CitikatzSouthFL:

No, sweetie, what they are saying is that nothing is threatening the US at this time, the systems (IF they develop)will have to be watched closely because the systems MIGHT OR MIGHT NOT recurve. IT IS WAY TO EARLY TO PREDICT. All 4 S FL weather persons on are saying that "We really need to watch these closely." Now, IF you live in Kansas, and won't be threatened by any storms, I can see where your weather channels just MIGHT say the systems are all going to recurve. Oh, and by the way, the word is MISREPRESENTING, MISREPRESENTATION...not two words and definitely with only one "s".


Yup, thats what ALL the news stations are saying here ... Kansas has tornadoes so I'd be more concerned with that :) And just WHERE did 94 come from?
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Well, gotta admit today looks like fun. 4 circles, all with at least some potential, since they all got invested, and something off the east coast that looks like it snuck in under all the radars again... can I say Bret and Cindy.... again????

Only remember a couple pple saying something about this front as it went through N FL the other day...

Plus not liking this recyling of the storm formerly known as Emily.... btw, seriously doubt it gets named that again.... this is more like the Katrina style cyclogenesis, where part of a formerly followed entity gets mixed in with something else to make a new, stronger, system [think bionic man].

Nothing's set to create impacts in the next little while, but lots of interesting stuff to watch if that's ur cup of tea....
Member Since: October 25, 2005 Posts: 19 Comments: 22565
Quoting kshipre1:
thanks for your answer! I guess I am wondering what does the mb in pressure have to do with spin?

850 MB is simply around 5,000 Feet or so thus 500MB would be higher in the atmosphere and 200MB in the trophosphere!! Thus 850MB Vorticity is spin in the lower levels of the atmosphere!!!
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Quoting kshipre1:
thanks for your answer! I guess I am wondering what does the mb in pressure have to do with spin?


the mb in pressure is an indication of how organized a storm is...the lower the pressure, the more organized...hence...pressure of 1011mb shows there is a disturbance in the weather...drop it to 1005 and typically it would be enuf organization to be condusive to spin...drop it further (under 1000) and it is a top...you can look up old hurricanes (ie andrew, hugo, hazel, etc) and ck the coordinates, they will usually list the mb and strength of storm... it will give you a good idea of what the mb means
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Quoting Floodman:


I've heard that...HAARP temporal displacement side effects can be obviated via the judicious use of dry roasted legumes and hops based brewed beverages...


Sumpin like that...
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Quoting kshipre1:
who in this blog thinks 93L will grow to become a big storm or hurricane, head west and potentially hit the CONUS?


Quoting kshipre1:
who in this blog thinks 93L will grow to become a big storm or hurricane, head west and potentially hit the CONUS?


Not hotwheels
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Quoting TampaTom:


Eat some peanuts and drink some beer before it happens. It will help you recover from the effects...


I've heard that...HAARP temporal displacement side effects can be obviated via the judicious use of dry roasted legumes and hops based brewed beverages...
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79.HOTWHEELS99
You been saying this over and over and over and over all morning.And you wonder why people ignore you,we get your point!!! ****POOF****
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Quoting CybrTeddy:
Good sized Tropical update from me I hope, took a while to type up so I hope you all enjoy!
Very active Atlantic: 4 invests 8/12/11
very informative, nice work.
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who in this blog thinks 93L will grow to become a big storm or hurricane, head west and potentially hit the CONUS?
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Quoting HOTWHEELS99:
ok i wont post anymore but all i can say is what our weather channels have said all morning here that none of these systems will affect the east coast and none should for weeks

No, sweetie, what they are saying is that nothing is threatening the US at this time, the systems (IF they develop)will have to be watched closely because the systems MIGHT OR MIGHT NOT recurve. IT IS WAY TO EARLY TO PREDICT. All 4 S FL weather persons on are saying that "We really need to watch these closely." Now, IF you live in Kansas, and won't be threatened by any storms, I can see where your weather channels just MIGHT say the systems are all going to recurve. Oh, and by the way, the word is MISREPRESENTING, MISREPRESENTATION...not two words and definitely with only one "s".
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Hey guys! I know this is a bit much on the pictures, but these are pictures of the heavy storms earlier this week and the flooding it caused! We've gotten this many times this rainy season now but I decided to post pics of the mos recent stuff. The last picture is me standing in the flood waters right in front of my yard! The yard that is mine is the one that has the mail box and the vehicle on the left.
Member Since: August 21, 2008 Posts: 0 Comments: 7833
thanks for your answer! I guess I am wondering what does the mb in pressure have to do with spin?
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Quoting HOTWHEELS99:
ok i wont post anymore but all i can say is what our weather channels have said all morning here that none of these systems will affect the east coast and none should for weeks


First, I owe you an apology: I went further into the website and found the post you quoted; it doesn't make it any less incorrect or overreaching, but it was there and I apologize for my derision.

Now about saying there's no chance of the current invests effecting the east coast? Possible, but ridiculous to say that this far out...and about not having to worry about anything for weeks? Where did you get that? That is certainly untrue or at the very least a really poor case of tea leaf interpretation
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wow that was some response

LOL
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Quoting BahaHurican:
I have been wondering for a while now what the eventual destination of a system has to do with whether or not it forms or is named by NHC. It is the tree-falling-in-the-forest thing, only more egocentric?... like

If the tree falls in the forest, killing 9 and destroying their home, but I don't hear it fall, does it make a noise? Did it really fall at all?

Sheesh.

How about we agree that if it meets the criteria it gets a name... not whether it's going to hit land... not whether NHC has a quota to meet.... can we keep it simple???

[gets down off soapbox, folds it away for next time]



{borrows soap box, opens back up and gets on}
I AGREE!
{steps off soap box, folds up, gives back to Baha}
Member Since: Posts: Comments:
Wow, I go out for the day and come back to find the tropics have gone crazy. Irene by the start of the week?
I guess it's possible, though somewhat unlikely.

If 95L develops, it will be Franklin, as it'll pretty much have run out of time by late tomorrow. If it fails, my bets are on 92L.
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What to do with Hotwheels:
1.
2.
3. Ignore User
Member Since: November 13, 2009 Posts: 2 Comments: 728
I have been wondering for a while now what the eventual destination of a system has to do with whether or not it forms or is named by NHC. It is the tree-falling-in-the-forest thing, only more egocentric?... like

If the tree falls in the forest, killing 9 and destroying their home, but I don't hear it fall, does it make a noise? Did it really fall at all?

Sheesh.

How about we agree that if it meets the criteria it gets a name... not whether it's going to hit land... not whether NHC has a quota to meet.... can we keep it simple???

[gets down off soapbox, folds it away for next time]

Member Since: October 25, 2005 Posts: 19 Comments: 22565
81. P451 12:21 PM EDT on August 12, 2011

Hey P; problem is you have several "shifts" on the Blog (early am/mid-morning/mid-day/late afternoon/early evening/late evening, etc.) so the same arguments, with different players, is repeated four or five times a day on here.................... :)
Member Since: August 8, 2006 Posts: 0 Comments: 9329
At 132 hours, 92L can be seen as a tropical cyclone SE of Canada and 93L is still weak, just west of the islands:

Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting Floodman:


HAARP, baby! The side effects would be wierd though...the ridge would be gone, but we'd all of us be moved forward to next Tuesday...


Eat some peanuts and drink some beer before it happens. It will help you recover from the effects...
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Quoting CorneliaMarie:
Quoting kshipre1:
dumb question but what does it mean when the 850mb vorticity has increased?



68. Some1Has2BtheRookie 12:15 PM EDT on That is not a dumb question. That is a very good question. ... I have the sole rights to any dumb questions. Fortunately, you did not infringe upon my rights.

Now, would someone with some actual knowledge answer this for them? Please.







it means it used to be 849mb, and now it is 850mb


Lol...That is incorrect...
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting weathermanwannabe:


Hotwheels is quoting a site called central florida hurricane center, dont thingk the guy is misrepresenting TPC...(not nhc)...just fyi
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Central Florida Hurricane Center?

New one on me. 'Specially since I live in Central Florida and do hurricane ed all day...
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Quoting troy1993:
God I wish I can get a group together and just smash the heck of that Texas ridge..anyone else with me?


HAARP, baby! The side effects would be wierd though...the ridge would be gone, but we'd all of us be moved forward to next Tuesday...
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Quoting kshipre1:
dumb question but what does it mean when the 850mb vorticity has increased?



68. Some1Has2BtheRookie 12:15 PM EDT on That is not a dumb question. That is a very good question. ... I have the sole rights to any dumb questions. Fortunately, you did not infringe upon my rights.

Now, would someone with some actual knowledge answer this for them? Please.







it means it used to be 849mb, and now it is 850mb
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81. P451
Quoting mcluvincane:


Too late.... It's already been an eventfull day in the tropics..


The number of blobs is of no interest.

Development of one would be and it has been noted this is unlikely to occur today.

There are plenty of days that make sense to spend time scrutinizing blobs hour to hour. Today is not one of those days.

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Very interesting.. 95L might win the Franklin contest.
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Quoting tiggeriffic:


just got back...sitting at my desk eating sushi and WHAM...sushi hit my puter screen....BWAHAHAHAHA


You need to wipe that up quick, hon...partially masticated tuna roll and wasabi are SOOOO bad for an LCD

LOL
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God I wish I can get a group together and just smash the heck of that Texas ridge..anyone else with me?
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Quoting Floodman:



juuuuust a touch of OCD...LOL


I have CDO...it is like OCD but the letters are in alphabetical order just as they should be.... :)
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Good sized Tropical update from me I hope, took a while to type up so I hope you all enjoy!
Very active Atlantic: 4 invests 8/12/11
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Quoting MississippiWx:


I'm thinking 8 year old because of the hot wheels name.

12z GFS keeps 93L weak through 90 hours and doesn't develop any of the other 3 AOIs:



That's bad on a number of levels...
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Quoting Floodman:


Uh, I was just on their website trollboy; they quote the NHC TWO verbatim...by the way, when trying to mimic the NHC it;s best ot try and proofread a little...LMAO

And with that, the group heard a resounding **POOF!** and the annoyance was gone


just got back...sitting at my desk eating sushi and WHAM...sushi hit my puter screen....BWAHAHAHAHA
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72. HCW
92L 93L 94L and 95L







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Quoting PrivateIdaho:


you mean HFAARP.



juuuuust a touch of OCD...LOL
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Quoting kshipre1:
dumb question but what does it mean when the 850mb vorticity has increased?


That is not a dumb question. That is a very good question. ... I have the sole rights to any dumb questions. Fortunately, you did not infringe upon my rights.

Now, would someone with some actual knowledge answer this for them? Please.
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Quoting JNCali:

 Sorry Some1.... I'm all in with a missing DARPA Falcon Hypersonic Technology Vehicle 2 which undoubtedly carried a mobile HAARP unit.l


OH NO! And JNCali takes the hand...
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Quoting kshipre1:
dumb question but what does it mean when the 850mb vorticity has increased?

It means that on the surface vorticity or (spin) is becoming more pronounced which in turn means development chances are more likely!!
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Quoting kshipre1:
dumb question but what does it mean when the 850mb vorticity has increased?


Means the low level COC has strengthened
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Quoting JNCali:

 Sorry Some1.... I'm all in with a missing DARPA Falcon Hypersonic Technology Vehicle 2 which undoubtedly carried a mobile HAARP unit.l


you mean HFAARP.
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Quoting Floodman:


Either a troll or an 8 year old; not worthy of comment


I'm thinking 8 year old because of the hot wheels name.

12z GFS keeps 93L weak through 90 hours and doesn't develop any of the other 3 AOIs:

Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting P451:
SAL, Dry Air, Wind Shear.

Four poorly organized AOIs.

It's going to be an uneventful day in the tropics.


Too late.... It's already been an eventfull day in the tropics..
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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.