Sea ice in the Arctic continues its record decline, thanks to unusually cloud-free conditions and above-average temperatures. For August 21, the National Snow and Ice Data Center estimated that fully one third of the Arctic ice cap was missing, compared to the average levels observed on that date from 1979-2000. Sea ice extent was 4.92 million square kilometers on August 21, and the 1979-2000 average for the date was about 7.3 million square kilometers. Arctic sea ice has fallen below the record low absolute minimum of 4.92 million square kilometers set in 2005 by about 8%, with another 3-5 weeks of the melting season still remaining. Reliable records of sea ice coverage go back to 1979.
Figure 1. Extent of the polar sea ice on August 21, compared to the average for the date from the 1979-2000 period (pink line). Image credit: National Snow and Ice Data Center.
With one third of the Arctic ice cap already gone, and another month of melting to go, we need to consider what effect this will have on weather, climate, and sea level rise. Well, we don't need to worry about sea level rise, since the polar sea ice is already in the ocean, and won't appreciably change sea level when it melts. However, the remarkable melting of the ice cap will likely lead to unusual weather patterns this fall and winter. The lack of sea ice will put much more heat and moisture into the polar atmosphere, affecting the path of the jet stream and the resultant storm tracks. Expect a much-delayed arrival of winter to the Northern Hemisphere again this year, which may lead to further accelerated melting of the ice cap in future years.
Last week, I remarked that the most recent images from the North Pole webcam show plenty of melt water and rainy conditions near the Pole. It turns out that was misleading, since the webcam is on a ship that was headed towards the pole, but had not reached it. There have been rainy conditions at the Pole this summer, and there is some open water there, but this is not uncommon in summer. Shifting ice frequently opens up leads (cracks) with open sea water at the Pole. It was one of these open leads that British swimmer Lewis Gordon Pugh swam in for 18 minutes this July to draw attention to global climate change.
Figure 2. Total rainfall from August 10-22 as estimated by NASA's TRMM satellite.
Midwest flooding
To get an idea of the magnitude of the flooding that has hit the Midwestern U.S. during the past ten days, take a look at the total amount of rain from August 10-22 (Figure 2). We can blame Tropical Storm Erin for the rain in Texas and Oklahoma (up to 11 inches), and for the nine flooding deaths that occurred in those states. However, the unbelievable rain amounts in excess of 20 inches in Minnesota and Wisconsin were primarily due to a frontal system--with the help of some copious moisture pumped northwards by the counter-clockwise circulation around Erin while it spun over Oklahoma.
Tropical update
There are no threat areas in the Atlantic to discuss. Two of our four reliable forecast models, the NOGAPS and ECMWF, are predicting that a tropical depression could form off the coast of Nicaragua on Sunday. The models forecast that this system would move inland over Nicaragua and Honduras by Monday.
I'll have an update on Saturday morning.
Jeff Masters
Bulldozer trying to clear sand and debris from Norman Manley Highway(Airport Road)
The flood is over, now the cleanup
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to do whatever it is they have been conspiring to do...
Don't forget GW-as in G Dubya...
The lower graphic in the post about the "false" SAL west of Mexico is quite impressive - such a great difference in SSTs on a relatively small area. La nina coming?
While I'm at it my thanks go to all of you experts, StormJunkie, Weather456, H2PV, IKE, texascanecaster, etc (can't remember all the names yet). I really appreciate your readiness to explain these complexe phenomena to laymen like me. This is one of the reasons why this site is so addictive.
I can go to sleep now with a good conscience since I've learnt something new today. ;-)
I think...
...two tropical waves started off the coast of Africa; one soon labeled Invest90L, which would become Dean. The tropical wave following Invest90L was suppressed by a dust storm coming off of Africa.
Remnants of that dust storm have been chasing after Dean ever since, though it was never fast enough to catch up before Dean's collapse.
I'll gladly back up what I say with facts, but only if you will listen to it. I am not a person to waste my breath on people who won't listen, so don't expect me to provide every piece of data like STL does UNLESS you will listen.
And yes, it is true that the ones who say it'll be active get praise, and I guess that isn't fair. But all signs point to that. Dean just dissipated two days ago. Give it a freaking chance, my word. I will agree with LLJ that we don't know till the season is over.
If you are going to call it inactive, fine, but use facts. Unlike some people here, I'll listen to them.
Cold Core Lows (Upper Level Lows)
In comparison to its enviroment, this low is most intense and coldest in the upper troposphere. It is therefore weaker at lower levels and can be hard to find below 500 mb. Subisdence is confined to the center and low level lifting is found on the Eastern ppheriphy of the circulation. A line of cold low may comparise the tropical upper trospheric trough or TUTT for short.
W456
I'll list some characteristics of subtropical cyclones later.
If you are going to call it inactive, fine, but use facts. Unlike some people here, I'll listen to them.
K'Man, agree with most of what you say but somehow the last bit of logic is flawed But by whom, I not sure.
How can one call it inactive before the fact. i.e. it ain't over til is over. No facts to prove it at the moment. Can't prove a negative.
Or, the correlary, how can one call it ACTIVE before the fact also. Not really any more facts to prove that either, til it's over.
And please, don't anybody on this blog point to any BS computer models. Because I'll blow you off in 2 seconds.
You are right on one thing, most, NOT ALL, are idiots. Most don't avail themselves of the basic information they have on hand and couldn't tell you which way the wind is blowing if it was spitting rain and dust in their face.
If we do get some development from the wave that's likely to come offshore tomorrow or Monday, wouldn't the presense of that low likely influence the new system to move north rather than west?
Or, the correlary, how can one call it ACTIVE before the fact also. Not really any more facts to prove that either, til it's over.
Well, you can prove an active season will likely (not will, but will LIKELY) take place by looking at the overall weather pattern both now and in the future. Also, years that have had similar conditions in the Atlantic were also quite active, like this one, and I'm sure people wrote that season off since a tropical cyclone didn't occur until relatively close to September after the first one formed. La Niña was present in 1999 as well, and this year has behaved similarly thus far, and has generally the same conditions as 1999 did. That's one fact you can use to say this season has a good chance to be active.
On the other hand, this year reminds me of 1993, because of the dates in which the storms up to the E storm formed. Not to say this will be like 1993, but it sure reminds me of it so far as far as formation dates go.
If we were to get an anomalous warming of the equatorial East Pacific this year (it would have to be a rapid warming), and had a neutral ENSO phase with a warm-bias or an El Niño, I would say this season will be inactive. However, there are no signs currently pointing to an El Niño this year, although there may be one in 2008, according to some models, but they are just models, and are not gospel.
At any rate, we have already had one big storm this year -- Dean, and it is the 9th most intense Atlantic hurricane on record. So this season is by no means a bust, nor is it over. There are likely going to be many more storms once the upward MJO pulse kicks in, and MJO won't make or break the season either, just help supress and/or ramp up activity.
It only takes one storm to make the season busy for the community affected. Tell the people affected by Dean it's been quiet -- they'd tell everyone real quick like it hasn't been.
Nothing new tropical wise.
Hey Extreme!
Nothing new tropical wise.
Ok. I was just looking over the page to see what everyone was talking about when I was gone. So, a few models develop that CV wave?
The only low I see in the central Atlantic is an extra-tropical storm above 40N. The ridge is forecast to build back in below this low.
extreme, you left for a few hours and are asking if anything new is happening? Isn't that kind of, eh...pointless? No offense, but it's just odd to me.
Yeah its kind of odd. But, you know how things can be in the tropics, they can change all the time. Blobs can pop up in a matter of hours lol. And we all know how fun blob watching is lol
WMO International Workshop on Tropical Cyclones-November 2006
A good "talking points" summary if you wish to limit your GW discussion to tropical cyclones.
Link has surely been up here before. If so, sorry, here it is again.
Link
extreme236, where can I get an animated loop for that African wave? I can't seem to find one. I saw the CV wave via the tropical page on here, but I haven't seen a loop. Can you help?
Link
try this link. click on circled area you want to view the satillites on and then once you click on one of the circles you get a bunch of boxes of specific areas. click on the box that says west africa and you will get a bunch of images such as infrared. then you click the various java animations or whatever other loops it lets you open
I don't see a lot of complacency. When Amystery suggested not too much activity going forward, he was jumped on pretty good.
Thanks, extreme.
Your welcome :)
Anyway, not what I would call complacency.
2000: September 10th
2001: September 7th
2002: September 5th
2003: August 25th
2004: August 25th
2005 (outlier): July 21st
2006: September 3rd
Statement on Tropical Cyclones and Climate Change from the
WMO International Workshop on Tropical Cyclones-November 2006
A good "talking points" summary if you wish to limit your GW discussion to tropical cyclones.
Link has surely been up here before. If so, sorry, here it is again."
Talk about wishcasting.
The low res models show substantially weaker simulated models and the high res only show some increase in intensity. Where the relationship to SST's have been examined the relationship dependence is much weaker.
So they deduce from that their models are flawed/broken and they go on to predict an increase in cyclone intensity.
Someone wanted their funding on that one.
Only posted to apply focus to some central issues.
Let the debate rage...from there.
However I totally agree with your cynicism and real world view of research.
]
Lat25
Only posted to apply focus to some central issues.
Let the debate rage...from there.
However I totally agree with your cynicism and real world view of research."
If you read it, you see where they contradict themselves.
Our research is based on models....
....our models are flawed because they don't agree with what we want them to say
...we are going to override what our models say and make up our own predictions.
edit; I added something to try and make what I wanted to say clearer. ;-)
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