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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A vigorous low level circulation can be seen spinning just west of the convection in 94L...a little gain in convection and we could have TD7:

Member Since: July 15, 2006 Posts: 17 Comments: 10282
Quoting KoritheMan:


They always bring up 2005. Just ignore it.

http://www.youtube.com/watch?v=XU5tgLQDVrs&featu re=fvsr

I brought up the sat. loop of 2005 to show how incredible the cyclogenesis was that year but more importantly to show how many different circumstances can instigate a storm during prime conditions.

This is well worth watching if you have not yet.

Should be interesting when this ridge builds over the Hudson Bay region in a few weeks if the model Levi pointed out comes to fruition.

Same setup as some classic storms from 2005.

And no I am not proclaiming this season as prolific as 05....
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1157. Grothar
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Given with it's shape, I'm surprised that 93L gave out a shape that is offensive to some people, especially religious ones.
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92L is gonna whack Bermuda.
Member Since: September 2, 2006 Posts: 110 Comments: 6877
1153. Grothar
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17.8n45.3w has been re-evaluated&altered for 92L's_12amGMT_ATCF
17.8n45.1w, 18.6n46.9w, 19.1n48.7w are now the most recent positions

11.3n30.3w has been re-evaluated&altered for 93L's_12amGMT_ATCF
11.3n30.0w, 11.3n31.5w, 11.6n32.6w are now the most recent positions

25.0n53.6w, 24.7n54.7w, 24.6n55.5w have been re-evaluated&altered for 94L's_12amGMT_ATCF
24.6n5.43w, 25.0n55.4w, 2.54n56.1w, 25.7n57.1w are now the most recent positions

Starting at 12August_12amGMT and ending at 13August_12amGMT

The westernmost grouping of red dots represents 94L's path,
the middle grouping represents 92L's path,
and the easternmost grouping represents 93L's path.

Copy&paste 25.2n52.7w, 24.6n54.3w, 25.0n55.4w, 25.4n56.1w, 25.7n57.1w, bda, 16.2n41.4w, 17.0n43.3w, 17.8n45.1w, 18.6n46.9w, 19.1n48.7w, vxe, 11.0n26.5w, 11.2n28.4w, 11.3n30.0w, 11.3n31.5w, 11.6n32.6w into the GreatCircleMapper to make your own map to fiddle with.

The previous mapping (for 12August_12pmGMT)
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Quoting tiggeriffic:


okie dokie then i really didn't miss much then, lol, SSDD...trying to figure the reasoning behind turning 92 unless they are thinking 94 will cut a path, but didn't think any of them were really strong enuf to do that at this point...guess time will tell...
Nawp... was a pretty lowkey day.... I'm more interested in tomorrow, to see what kind of interaction we'll see between 92 and 94.... could be interesting. Plus 93L should start to make some improvements in the next 12 to 24....

Anyway, I'm starting to droop here, like a wilting flower... think I'll get into bed.... may get on long enough to see the 2 a.m. if I'm still awake...

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George Noory is The Source of All Significant Knowledge
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1149. j2008
AL, 92, 2011081218, , 186N, 469W, 30, 1011, DB,
AL, 92, 2011081300, , 191N, 487W, 25, 1013, DB,
Good rise in pressure and a drop in wind speed. Gotta keep an eye on 92L, I dont know how much longer the blog can handle systems teasing us.
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ok...off to bed...so tired feels like there is sand in my eyes...i hate workin 12s lol
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The real storm that hit hawaii real bad
Member Since: July 25, 2010 Posts: 0 Comments: 2636
Quoting Matt74:
George Noory is a total wak job!


A total wak job with millions of listeners and dollars.
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Quoting spathy:


Looks like my # are a little too high.
But my ratio seems on target.
for whatever nogood reason, I didn't get mine on the blog.... so I must go uncontesting this year.... bummer....
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Quoting BahaHurican:
Hey, tig.... did anybody catch u up? I went over to ossqss's blog to see what was on the contest list he has over there...

Anyhoo... today... we had 4 circles at the beginning.... then at 11 a.m. they made 95L into TD6.... kept 93L the same, downgraded 92L to 30%, and brought 94L [the one that is Emily remnants] up to 30%.

Only one expected to have any long-term land impact is 93L.... everything else basically forecast to either fizzle or head out to sea.

Insert regular blog bickering and lower than average blog jokes.... that's about it...


okie dokie then i really didn't miss much then, lol, SSDD...trying to figure the reasoning behind turning 92 unless they are thinking 94 will cut a path, but didn't think any of them were really strong enuf to do that at this point...guess time will tell...
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Quoting KoritheMan:


Yep.


thanks but i was looking for something like a gif
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Quoting tiggeriffic:


hey baha...poppin in for a few before i hit the bed... workin that 12 today wore me out lol... wanna fill me in on the skinny with our train...short version is ok lol...dont think my eyes could handle going thru multiple pages tonight lol
Hey, tig.... did anybody catch u up? I went over to ossqss's blog to see what was on the contest list he has over there...

Anyhoo... today... we had 4 circles at the beginning.... then at 11 a.m. they made 95L into TD6.... kept 93L the same, downgraded 92L to 30%, and brought 94L [the one that is Emily remnants] up to 30%.

Only one expected to have any long-term land impact is 93L.... everything else basically forecast to either fizzle or head out to sea.

Insert regular blog bickering and lower than average blog jokes.... that's about it...
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Good Night, I leave you with 92L.
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I'm out for the night, and most of the weekend, everyone.

Be back Sunday evening.
Member Since: July 6, 2010 Posts: 113 Comments: 32249
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Well, I guess my first guess was right...NHC keeping it as a Tropical Depression. That being said...It may not make it to TS status.
Member Since: July 6, 2010 Posts: 113 Comments: 32249
Quoting KoritheMan:


Hardly "tough" if you ask me.
Lol

Quoting Levi32:


In addition to Kori's post, there was also Hurricane/Typhoon Ioke in 2006, one of the longer tracks that there is transversing multiple Pacific basins.



Dora in 1999 had a long track as well:

Interesting to see such a long period of due west with Dora's track. Several thousand miles of straight west.
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Tropical Depression SIX Storm Archive
...TROPICAL DEPRESSION MOVING TOWARD THE OPEN NORTH ATLANTIC OCEAN...
11:00 PM EDT Fri Aug 12
Location: 36.6°N 61.3°W
Max sustained: 35 mph
Moving: ENE at 22 mph
Min pressure: 1010 mb
Member Since: September 2, 2006 Posts: 110 Comments: 6877
Quoting tropicfreak:


Ignore him, god why do the trolls keep coming and coming, sad that they have nothing better to do than to stir up trouble.
They keep coming because people keep replying to them or quoting them.
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STILL A TROPICAL DEPRESSION
Member Since: July 6, 2010 Posts: 113 Comments: 32249
Quoting KoritheMan:


Well, about three days ago, the GFS was indicating the possibility of a trough split, so it's something to keep an eye on for sure (although it has since backed off on that solution).

I personally think it will be entirely inconsequential, however, as the associated singular energy, if there is one, is very weak within the models. Nonetheless, it might move slow enough underneath the ridge so that it least warrants attention.
okay because I saw that the front could stall and some people were worried that this maybe the first GOM game changer down the road and could be our next invest real soon
Member Since: July 25, 2010 Posts: 0 Comments: 2636
Quoting TropicalAnalystwx13:
Chances are, it will be declared as Franklin at 11PM. However, it won't hang on to the name for long.
You think so? I'm thinking it remains a TD until 5 or 11a.m.
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Quoting presslord:


almost nuthin'...just didn't make it out to da beach


lots of thunder and black clouds in S. Windermere, but only a sprinkle of rain...heard ladson got upwards of 4 inches...
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Quoting ncstorm:
whats with all the "fish storms" wanting to come back?



That's a big ouchie for Bermuda, GFS takes it right over it.
Member Since: September 2, 2006 Posts: 110 Comments: 6877
1123. ncstorm
Quoting wunderstorm87:

I believe the weaker the storm is the better chance it has of rotating around the ridge. Otherwise it's much more likely to be absorbed by the trough and carried northeastward.

This is why you will note some models like the GFDL on 94L show a stronger curve and at the same time a weaker storm.


Okay thanks!
Member Since: August 19, 2006 Posts: 13 Comments: 15643
Quoting tiggeriffic:


hey ya Press...did you get much of that afternoon storm that rolled thru today? i know Ladson area got slammed from what i heard


almost nuthin'...just didn't make it out to da beach
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CZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT FRI AUG 12 2011

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

1. DISORGANIZED CLOUDINESS AND A FEW SHOWERS ARE ASSOCIATED WITH AN
AREA OF DISTURBED WEATHER LOCATED ABOUT 500 MILES SOUTH OF ACAPULCO
MEXICO. DEVELOPMENT...IF ANY...OF THIS SYSTEM IS EXPECTED TO BE
SLOW TO OCCUR DURING THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD
AT 10 TO 15 MPH. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...
OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

2. CLOUDINESS AND SHOWERS HAVE INCREASED IN ASSOCIATION WITH A WEAK
AREA OF LOW PRESSURE LOCATED ABOUT 975 MILES SOUTHWEST OF THE
SOUTHERN TIP OF BAJA CALIFORNIA. ENVIRONMENTAL CONDITIONS APPEAR
MARGINALLY CONDUCIVE FOR SOME GRADUAL DEVELOPMENT OF THIS SYSTEM
DURING THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS A LOW CHANCE...10
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES WEST-SOUTHWESTWARD TO WESTWARD AT 10 MPH.


ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER KIMBERLAIN
NNNN
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Quoting spathy:


Yes he did.
Gotta go check it out...
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Quoting presslord:


yea...I saw one as a teenager.....scared thew snot outta my cousin and me...


hey ya Press...did you get much of that afternoon storm that rolled thru today? i know Ladson area got slammed from what i heard
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1118. Levi32
Quoting OCF:
A question inspired by post 1001: has there ever, historically, been an extremely long track Pacific tropical cyclone? That is, declared in the EPAC region, staying far enough south, holding together through the Central Pacific, continuing into the WPAC, and making or nearing landfall in Asia (Philippines, Japan, etc.)? It seems very, very unlikely, and we'd probably only know of cases since satellite monitoring - but maybe it's not completely impossible?


In addition to Kori's post, there was also Hurricane/Typhoon Ioke in 2006, one of the longer tracks that there is transversing multiple Pacific basins.



Dora in 1999 had a long track as well:

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Chances are, it will be declared as Franklin at 11PM. However, it won't hang on to the name for long.
Member Since: July 6, 2010 Posts: 113 Comments: 32249
I still think 98E would be a threat to Hawaii



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Quoting TropicalAnalystwx13:
It'll be a tough decision for the NHC for whether or not to declare TD Six Franklin. It has lost its organization over the past few hours.




Ahh! My eyes!
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Quoting BahaHurican:
Did he do it again this year?


hey baha...poppin in for a few before i hit the bed... workin that 12 today wore me out lol... wanna fill me in on the skinny with our train...short version is ok lol...dont think my eyes could handle going thru multiple pages tonight lol
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Quoting KoritheMan:


Hardly "tough" if you ask me.


but, I didn't ask you.

nah, j/k :P
Member Since: July 6, 2010 Posts: 113 Comments: 32249
Quoting ncstorm:


so if 92L follows the projected path forecasted by the models, it might come back again for a second round?

I believe the weaker the storm is the better chance it has of rotating around the ridge. Otherwise it's much more likely to be absorbed by the trough and carried northeastward.

This is why you will note some models like the GFDL on 94L show a stronger curve and at the same time a weaker storm.
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Quoting TropicalAnalystwx13:
It'll be a tough decision for the NHC for whether or not to declare TD Six Franklin. It has lost its organization over the past few hours.





Hardly "tough" if you ask me.
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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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