An African wave worth watching; 2nd warmest June on record

By: Dr. Jeff Masters , 1:51 PM GMT on July 17, 2009

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There's finally a African tropical wave worth mentioning, in what has been a very inactive June/July period for African waves with a potential to develop. A tropical wave near 12N 36W, about 1200 miles west of the coast of Africa, is triggering some modest heavy thunderstorm activity over the open ocean as the storm moves west at 10 - 15 mph. NHC designated this wave 97 L at noon today. Wind shear is a modest 15 knots over the disturbance, which is low enough to allow some slow development over the next few days. As long as the disturbance stays south of Puerto Rico's latitude (18°N), wind shear should remain low enough to allow development. However, there is a substantial amount of African dust and dry air surrounding the system on its west and north sides. This dry air will retard development, and may be able to completely disrupt the disturbance at some point over the next 3 - 4 days. None of the computer models develop the disturbance. The National Hurricane Center is giving this system a low (less than 30% chance) of developing into a tropical depression in the next 48 hours.


Figure 1. The first African wave of 2009 worth watching.

Second warmest June on record
The globe recorded its second warmest June on record, 0.02°C short of the record set in 2005, according to the National Climatic Data Center. The period January - June was the fifth warmest such period on record. Global temperature records go back to 1880. The most notable warmer-than-average temperatures were recorded across parts of Africa and most of Eurasia, where temperatures were 3°C (5°F) or more above average. The global ocean Sea Surface Temperature (SST) for June 2009 was the warmest on record, 0.59°C (1.06°F) above the 20th century average. This broke the previous June record set in 2005. The record June SSTs were due in part to the development of El Niño conditions in the Eastern Pacific. If El Niño conditions continue to strengthen during the coming months, we will probably set one or more global warmest-month-on-record marks later this year. The last time Earth experienced a second warmest month on record was in October 2008.


Figure 1. Departure of temperature from average for June 2009. Image credit: National Climatic Data Center.

June sea ice extent in the Arctic 4th lowest on record
June 2009 Northern Hemisphere sea ice extent was the 4th lowest since 1979, according to the National Snow and Ice Data Center. The record June low was set in 2006. This summer's melt is lagging behind the melting in the summer of 2007, which set the record for the lowest amount of summer sea ice in the Arctic. Forecasts of summer Arctic sea ice melt made in early June by two teams of German scientists put the odds of a new record sea ice minimum this year between 7% and 28%. With the amount of sunlight in the Arctic now on the wane, it appears unlikely that we will set a new record sea ice minimum in 2009. This year will probably have the 2nd or 3rd least sea ice extent on record come September, when the melting season ends. The ice-free seas that nearly surround Greenland now have contributed to temperatures of 2 - 3°C above average over the island over the past ten days. With clear skies and above-average temperatures likely over most of the island for at least the next week, we can expect near-record July melting over portions of the Greenland Ice Sheet this month.

Northwest Passage likely to open for the third consecutive year
The fabled Northwest Passage is more than half clear now, and has a good chance of melting free for the third consecutive year--and third time in recorded history. The first recorded attempt to find and sail the Northwest Passage was in 1497, and ended in failure. The thick ice choking the waterways thwarted all attempts at passage for the next four centuries. Finally, in 1905, Roald Amundsen completed the first successful navigation of the Northwest Passage. It took his ship two-and-a-half years to navigate through narrow passages of open water, and his ship spent two cold, dark winters locked in the ice during the feat.

We can be sure the Northwest Passage was never open from 1900 on, as we have detailed ice edge records from ships (Walsh and Chapman, 2001). It is very unlikely the Passage was open between 1497 and 1900, since this spanned a cold period in the northern latitudes known as "The Little Ice Age". Ships periodically attempted the Passage and were foiled during this time. The Northwest passage may have been open at some period during the Medieval Warm Period, between 1000 and 1300 AD.


Figure 3. Ice extent as measured by an AMSR-E microwave satellite sensor on July 15, 2009. Most of the famed Northwest Passage (red lines) has melted out. Image credit: University of Bremen.

References
Walsh, J.E and W.L.Chapman, 2001, "Twentieth-century sea ice variations from observational data", Annals of Glaciology, 33, Number 1, January 2001 , pp. 444-448.

I'll have an update on the African tropical wave at least once this weekend if the system doesn't fall apart.

Jeff Masters

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You know the tropics are dead when we wonder whether something is classified as a wave or not.
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Look to the bottom of the page of this Discussion. The forecaster, Cohen, who is really good, I think, is debating over whether to call something a tropical wave.
Link

(I quoted him earlier.)
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How long till this thing gets deemed 95L?
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Shear actually does look favorable in the path of our wave over the next 72hrs. The shear in the Caribbean gets unfavorable, but then favorable by 72hrs.
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Quoting BurnedAfterPosting:
...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 33W S OF 18N MOVING W NEAR 10 KT. THIS
WAVE COINCIDES WITH LOW TO MIDDLE LEVEL CYCLONIC CIRCULATION
BASED ON RECENT SATELLITE IMAGERY. THE QUIKSCAT PASS AROUND
16/2045 UTC INDICATED CYCLONIC CURVATURE IN THE FLOW NEAR THE
SURFACE IN THE VICINITY OF THIS WAVE. SCATTERED MODERATE
CONVECTION IS FROM 8N-14N BETWEEN 31W-36W.

Yes it is a tropical wave Chicklit

oh, thnx. taking a break now.
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112. Chicklit

It is deemed a wave. Has been since coming off of Africa.
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Quoting Chicklit:
Another interesting comment JM made was that the system has to stay below 18 latitude.
I don't get how that shear is going to move out that quickly...but it (still officially not a wave) will travel about 10 degrees in two days.

Shear Map


If you remember 456 talking about a monsoonal trough, different from a wave but similar. Read the wind shift and embedded depression sections.
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...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 33W S OF 18N MOVING W NEAR 10 KT. THIS
WAVE COINCIDES WITH LOW TO MIDDLE LEVEL CYCLONIC CIRCULATION
BASED ON RECENT SATELLITE IMAGERY. THE QUIKSCAT PASS AROUND
16/2045 UTC INDICATED CYCLONIC CURVATURE IN THE FLOW NEAR THE
SURFACE IN THE VICINITY OF THIS WAVE. SCATTERED MODERATE
CONVECTION IS FROM 8N-14N BETWEEN 31W-36W.

Yes it is a tropical wave Chicklit
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According to the 8 AM NHC Discussion, it's still not officially deemed a tropical wave...Here's more info on what qualifies:
Tropical Wave Characteristics and Model Depiction

Based up the orientation, vorticity, location, time of year, speed, ummm direction. It looks like a tropical wave.
If it looks and walks like a duck...quacks, what's wrong with calling it a duck?!
Jeeze. Did somebody sneeze on some SAL?
Call it a wave, for Pete's sake!
(I don't get it...)
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Quoting jurakantaino:
Is interesting to see the reactions here "from the "extreme right fellows" when Dr. Master discusses in his blog and provide outstanding information about Global warming. Talking about objectivity! ha,ha,ha.


yeah so giving one half of the data only the ground measurements, and not the satilites is very objective?!!?! spoken like a true liberal
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Hey Chuck, good to see you.

That would be greatly appreciated, as it always is!
Member Since: August 17, 2005 Posts: 26 Comments: 16874
Quoting cg2916:
What are the qualifications for an area to become an Invest?


The NHC wants additional specialized information such as cyclone specific models or microwave satellite information.
Member Since: September 23, 2005 Posts: 15 Comments: 11409
chuck what do you think about what NWS is saying at it will be later tonight time frame 12-midnight
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Quoting AllStar17:


Vorticity is continuing to increase with our AOI. When will they label it 95L???


My guess would be not until they are sure it's going to be able to overcome the dry air and shear makes a move to lower values ahead. A lot of ocean to travel before it impacts any landmass.
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I must admit that I find conspiracy theorists of all kinds amusing.
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Quoting Chicklit:
Another interesting comment JM made was that the system has to stay below 18 latitude.
I don't get how that shear is going to move out that quickly...but it (still officially not a wave) will travel about 10 degrees in two days.

Shear Map


It is a wave. The TWD was talking about the feature behind it, around 25W maybe not being a wave.
Member Since: September 23, 2005 Posts: 15 Comments: 11409
Morning SJ and CHS - looks like an active afternoon - but the weekend now looking much better

SJ - how's Portlight going - time to do another story?
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102. IKE
Hey TampaSpin...this from the good doctor...

As long as the disturbance stays south of Puerto Rico's latitude (18°N), wind shear should remain low enough to allow development.


Member Since: June 9, 2005 Posts: 23 Comments: 37860
What are the qualifications for an area to become an Invest?
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100. MahFL
I was on Cape Cod last week. Provincetown is erm "intersting"......
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Quoting TheCaneWhisperer:


It's a bunch of bull if you as me, let em' be.

Bill Gates should be stripped of his billions and forced to start from scratch again. That will give him something to do.

No, I think Bill Gates should give me $500 for every time I forward this e-mail, because Microsoft and AOL are testing a new e-mail tracking technology. ;)
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Chicklit the area at 35W is a tropical wave

the are behind it is not, that is where the surface trough is
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In SHARP contrast, NASA UAH MSU satellite assessment had June virtually normal (+0.001C or 15th coldest in 31 years) and RSS (+0.075C or 14th coldest in 31 years). This is becoming a habit.


exactly... but again there is bias in this blog. Satilites are much more accurate then ground measurements but Dr. which definatly has the resources doesnt put that in his blog... force it down our throats...
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75. The CIMSS product for SAL is not the best representation for dust imo. CIMSSs SAL product includes both "dust" and "dry air" which portrays dust as being more heavily concentrated. The EUMETSAT's dust product has additional channels and is better optimized for depicting particles in the atmosphere.

The CIMSS, since it measures "both" dry air and dust, inaccurately reflects a "dust concentration" imo. If there's a great deal of dry air their graphic product implies that there is a heavier concentration of dust than what actually exists. If you compare the two, and I do, EUMETSAT's product rarely depicts heavy concentrations as often as CIMSS. To me, this is quite noticeable and when you see a deep color with EUMETSAT's, the CIMSS site is almost completely orange and expansive.
Member Since: July 9, 2006 Posts: 184 Comments: 29610
You can't see dust in a water vapor image.
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Here's the Wikipedia Definition:
Tropical Wave
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Good Morning Folks and great analysis on the wave Dr. M; while it looks marginally promising in terms of some persistent convection, it would certainly start to suck in a lot of dry air if it started to develop so it looks like a losing battle right now unless it is able to expand a nice moisture sheild in the West and NW areas...However, it will certainly moisten the middle passage a bit for the next ones that may follow. When NHC mentioned it it struck me that the "no troipcal development is expected over the next 48 hours" rule makes total sense....When you combine persistent convection and low shear for over 24 hours or so on an area of interest, then you start to take notice. Welcome back from your "hibernation" Dr. M.
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Quoting weatherwatcher12:
It also has some good 850mb vorticity associated with it.



Vorticity is continuing to increase with our AOI. When will they label it 95L???
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Thanks Doc.
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Someone call Mayor Nagan !
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Another interesting comment JM made was that the system has to stay below 18 latitude.
I don't get how that shear is going to move out that quickly...but it (still officially not a wave) will travel about 10 degrees in two days.

Shear Map
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Quoting jeffs713:


That is one potential drawback, yes.

There is also the whole "some things live in colder water at depth" issue, and "where does the hot water go" issue, and "this is meant to make money how?" issue.


It's a bunch of bull if you as me, let em' be.

Bill Gates should be stripped of his billions and forced to start from scratch again. That will give him something to do.
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It also has some good 850mb vorticity associated with it.

Member Since: May 16, 2009 Posts: 1 Comments: 1231
Bill Gates' hurricane supression technique will not work. Especially if the hurricane is a large one, it can just cycle out the cool waters caused by his technique, and it can spin the warm waters into its center.
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The dust really isn't that bad. Take a look at this (our system is the one closest to the left).
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Quoting cg2916:
FIrst half of September quiet, wait a minute... this model isn't working. It won't forecast an organized hurricane, which I find strange. I give up.


The CFS is for synoptic-scale events. Also, something that forecasts out several hundred hours isn't going to have the resolution needed to "see" a storm. That is just a matter of computing power.
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Fishinfool made a post here on the Dr's previous blog, I come here to learn and maybe see what other people see as far as why things in weather the way they do. I don't assume they are here to get reactions or anything, yes they are some who do that of course but you learn that by asking them questions and if they don't answer you move on. Just seems more on more if someone has a different opinion from the group and to ask why, that person is baiting the blog, do we all think the same way? I doubt it so lets hear other people's thoughts and maybe learn a thing or two maybe from it. Just my two cents.
Member Since: July 7, 2005 Posts: 0 Comments: 5417
Quoting StormJunkie:
Morning all

Welcome aboard chsintern

Sure had some nasty ones yesterday. Got a couple of lightening pics...decent but not great. Rain was around too long for me to get the really good shots.

Really sticky out this morning, so I wouldn't be surprised to see more this afternoon. Hopefully not as nasty as yesterday.


Not bad. Yea it is sticky the dewpoint is already 75 at AP. Could be internesting.
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Quoting weatherwatcher12:


Weak area of SAL around


Wow some strong SAl's in Carribean N of Cuba. There is a wave ahead of it that should take care of some of the SAL.
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Is interesting to see the reactions here "from the "extreme right fellows" when Dr. Master discusses in his blog and provide outstanding information about Global warming. Talking about objectivity! ha,ha,ha.
Member Since: July 31, 2008 Posts: 0 Comments: 730
Quoting TheCaneWhisperer:


Hurricanes use the heat energy pulled from the ocean and vent it into the atmosphere. So technically if all your doing is shoving the warm water around by pulling cool water up from depth wouldn't the ocean eventually heat up more than it should?


That is one potential drawback, yes.

There is also the whole "some things live in colder water at depth" issue, and "where does the hot water go" issue, and "this is meant to make money how?" issue.
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Morning all

Welcome aboard chsintern

Sure had some nasty ones yesterday. Got a couple of lightening pics...decent but not great. Rain was around too long for me to get the really good shots.

Really sticky out this morning, so I wouldn't be surprised to see more this afternoon. Hopefully not as nasty as yesterday.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
Photobucket

Here's a better graphic.
Member Since: July 9, 2006 Posts: 184 Comments: 29610
Quoting philliesrock:
I'll post this again in case people missed this in the other blog...Euro has a huge 600dm ridge in the Atlantic. It's 240 hours out, but imagine if that were to verify with a tropical system.



Hey long time no see. How are you doing?! gosh it has been a year.
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Weak area of SAL around
Member Since: May 16, 2009 Posts: 1 Comments: 1231
I will never watch TWC, especially if Alexandra Steele is on there.
Isn't she also on "Days of Our Lives?"
lol
I think the SAL JM is referring to is the bright orange stuff further west.
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Quoting growe:
Again, some objectivity needs to be injected into this "nth warmest month on record" headline. Although the NCDC did indeed state this, it must be pointed out that other measurements (from UAH) that rely on satellite data rather than the ground-based (and therefore patchy) measurements used by NCDC find that the global temperature for June was exactly equal to the 1971-2000 average and therefore that there is essentially no global warming. Thus the NCDC measurements are again an outlier and must be treated with extreme skepticism. For a more balanced view of June's temperatures, see here.

The huge differences between the various measurements of current global temperatures do also beg the question of how anyone can say what temperatures were in prehistoric times, if they can't even agree what they are in the present.


I totally agree, but the land-based temperature stations have been proven to be improperly placed and not maintained; therefore, they cannot be used as accurate providers of actual temperature. Three-quarters of the U.S. based stations are improperly placed and/or not maintained. Also, station drop-out from globally cool areas is on the increase and, consequently, not factored into the entire global average.

See:
http://wattsupwiththat.com/2008/03/06/weather-stations-disappearing-worldwide/

http://static.cbslocal.com/station/wbz/wbz/2009/may/SurfaceStations.pdf
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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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