One third of Arctic ice cap now missing; Midwestern floods; tropical update

By: Dr. Jeff Masters , 12:46 PM GMT on August 24, 2007

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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

After Hurricane Dean (sprinter)
Bulldozer trying to clear sand and debris from Norman Manley Highway(Airport Road)
After Hurricane Dean
Findlay Ohio flood (prairieview)
The flood is over, now the cleanup
Findlay Ohio flood

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397. weathermanwannabe
4:27 PM EDT on August 24, 2007
As I mentioned yesterday, it will be an interesting second half of the season given the current lack of any viable tropical systems during the peak of the season. Notwithstanding what may develop in September (it was very active in 2005 as we know all too well), as the stonger cold fronts start to come down and cool off the waters in October, there will probably be a greater chance of "sub-tropical" and cold core systems if this becomes a "late season"....For right now, the Western Caribbean/GOM is one big pot of moisture and there is a lot of dry air just north of the ITCZ so I would not expect any CV waves to have the juice to develop over the next week..........The Carib/GOM will probably present the chances of development in the immediate short term......
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396. georgia325
8:29 PM GMT on August 24, 2007
Hey guys, I lurk on here all the time but, rarely post. Don't know enough yet:) I had a question. Africa looks like it has quite a bit of activity on it this afternoon. Is everything that rolls off the continent considered a wave?
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395. plylox
8:32 PM GMT on August 24, 2007
Posted By: extreme236 at 8:32 PM GMT on August 24, 2007.
Posted By: plylox at 8:30 PM GMT on August 24, 2007.

does anyone have a link to the history of tropical storm Erin. Its origination and track before landfall near Port Aransas. All info will be appreciated. Homeschool Project.Thanks!

Try checking wikipedia.org-they have some good tropical info


YES that is the info I need. THANK YOU!!!
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394. extreme236
8:32 PM GMT on August 24, 2007
Posted By: JLPR at 8:28 PM GMT on August 24, 2007.

wow im bored
not even a intersting blob in the Atlantic


JLPR look harder! lol. we have some sfc lows that are spinning around. we got a blob near panama. but yes, its boring waiting for them to either form, or not form lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
393. extreme236
8:31 PM GMT on August 24, 2007
Posted By: plylox at 8:30 PM GMT on August 24, 2007.

does anyone have a link to the history of tropical storm Erin. Its origination and track before landfall near Port Aransas. All info will be appreciated. Homeschool Project.Thanks!


Try checking wikipedia.org-they have some good tropical info
Member Since: August 2, 2007 Posts: 19 Comments: 19234
392. plylox
8:28 PM GMT on August 24, 2007
does anyone have a link to the history of tropical storm Erin. Its origination and track before landfall near Port Aransas. All info will be appreciated. Homeschool Project.Thanks!
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391. extreme236
8:26 PM GMT on August 24, 2007
hmm...interesting. the nogaps model shows the current low pressure off the east coast disipating and shows something else coming off virginia and possibly developing
Member Since: August 2, 2007 Posts: 19 Comments: 19234
390. JLPR
8:27 PM GMT on Agosto 24, 2007
wow im bored
not even a intersting blob in the Atlantic
-_-
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388. Relix
8:23 PM GMT on August 24, 2007
Wow, suddenly its so quiet....
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386. extreme236
8:18 PM GMT on August 24, 2007
UKM appears to pick up on a weak system hitting nicaragua as well. perhaps only a TD or weak TS. which means we have:

1)Nogaps
2)cmc
3)emcwf
4)perhaps ukm

4 models hinting at development. 4 models hinted at dean developing as well...
Member Since: August 2, 2007 Posts: 19 Comments: 19234
385. IKE
3:17 PM CDT on August 24, 2007
Posted By: extreme236 at 3:17 PM CDT on August 24, 2007.
Posted By: IKE at 8:15 PM GMT on August 24, 2007.

Posted By: extreme236 at 3:12 PM CDT on August 24, 2007.
why do you say that ike? but this time include the low pressures near the azores and the virginia coast. about 3 models develop something near nicaragua


Just don't think they'll be any named system until September...models aren't picking up on anything that's a near certainty like Dean was.

There's only 7 days until September.

yes, but as you said, there are 7 days left. a lot can change from now to then lol


If I'm wrong, I won't be like SK and not admit it on here. LOL.
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384. extreme236
8:17 PM GMT on August 24, 2007
to me, they are just low pressures, but tomorrow, if they persist and look more impressive, then i might think there something more
Member Since: August 2, 2007 Posts: 19 Comments: 19234
383. Inyo
8:12 PM GMT on August 24, 2007
Instead of creating more clouds, individual tropical warming cycles that served as proxies for global warming saw a decrease in the coverage of heat-trapping cirrus clouds,


hmm... less cirrus = drought? I'd rather have the heat.
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382. Weather456
8:16 PM GMT on August 24, 2007
Posted By: extreme236 at 8:14 PM GMT on August 24, 2007.

so perhaps two subtropical systems? lol


Well according to the models, they can be wrong and they can be right but the only way to know is by watching.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
381. extreme236
8:16 PM GMT on August 24, 2007
Posted By: IKE at 8:15 PM GMT on August 24, 2007.

Posted By: extreme236 at 3:12 PM CDT on August 24, 2007.
why do you say that ike? but this time include the low pressures near the azores and the virginia coast. about 3 models develop something near nicaragua


Just don't think they'll be any named system until September...models aren't picking up on anything that's a near certainty like Dean was.

There's only 7 days until September.


yes, but as you said, there are 7 days left. a lot can change from now to then lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
380. latitude25
8:12 PM GMT on August 24, 2007
"Posted By: Dakster at 8:06 PM GMT on August 24, 2007
Couldn't we be in a natural warm cycle?"

More than likely.

It wasn't that long ago that Great Britain almost put France out of the wine/grape business.
Then it got too cold for grapes to grow in Great Britain, and France recovered.
Member Since: August 24, 2007 Posts: 0 Comments: 3654
379. IKE
3:13 PM CDT on August 24, 2007
Posted By: extreme236 at 3:12 PM CDT on August 24, 2007.
why do you say that ike? but this time include the low pressures near the azores and the virginia coast. about 3 models develop something near nicaragua


Just don't think they'll be any named system until September...models aren't picking up on anything that's a near certainty like Dean was.

There's only 7 days until September.
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378. extreme236
8:14 PM GMT on August 24, 2007
so perhaps two subtropical systems? lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
377. sammo
8:12 PM GMT on August 24, 2007
Posted By: icepilot at 6:15 PM GMT on August 24, 2007.
Jesus, study physics before you make comments about the physics of a process

- water expands when heated duh - But I don't think it will be enough to raise sea levels significatly

water contracts when cooled until the ice crystals form at which time it expands as air is trapped in the crystal matrix.


Water doesn't expand because of air trapped in the crystal matrix. It reaches maximum density at around 4 degrees C, and as it gets colder, it expands again. When ice crystals form, the angle between the two Hydrogen bonds goes from about 105 degrees (when liquid and gas) out to 120 degrees due to the attractions between the Oxygen and Hydrogen atoms as they get close to one another to form the hexagonal crystal. Therefore, the molecules take up more space in crystalline form.
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376. Weather456
8:07 PM GMT on August 24, 2007
Also, the CMC has the low near the US East Coast become subtropical. Also the GFS

What an interesting system.
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375. extreme236
8:11 PM GMT on August 24, 2007
why do you say that ike? but this time include the low pressures near the azores and the virginia coast. about 3 models develop something near nicaragua
Member Since: August 2, 2007 Posts: 19 Comments: 19234
373. extreme236
8:09 PM GMT on August 24, 2007
Posted By: Weather456 at 8:07 PM GMT on August 24, 2007.

Well according to cyclone phase diagrmas from CMC and GFS a low pressure area in the vicinty of the 1003 mb low is expected to become a shallow warm-core system i.e. subtropical system.


The one in the central north atlantic west of the azores? if that is the one you are talking about then i think the only way it really could develop is as a subtropical system similiar to vince
Member Since: August 2, 2007 Posts: 19 Comments: 19234
371. IKE
3:08 PM CDT on August 24, 2007
Posted By: StSimonsIslandGAGuy at 3:04 PM CDT on August 24, 2007.
excluding the low off Virginia and the low west of the Azores, do you think a tropical storm will be named before the end of the month?


No.
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370. extreme236
8:04 PM GMT on August 24, 2007
Posted By: StSimonsIslandGAGuy at 8:04 PM GMT on August 24, 2007.

excluding the low off Virginia and the low west of the Azores, do you think a tropical storm will be named before the end of the month?


I think so. With that convection near panama, which is in a favorable enviroment would be to me the most imminent feature, as it may develop before it hits nicaragua
Member Since: August 2, 2007 Posts: 19 Comments: 19234
369. Melagoo
8:07 PM GMT on August 24, 2007
none ... I guess I'll go into photo mode
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368. Weather456
8:02 PM GMT on August 24, 2007
Well according to cyclone phase diagrmas from CMC and GFS a low pressure area in the vicinty of the 1003 mb low is expected to become a shallow warm-core system i.e. subtropical system.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
366. Dakster
8:01 PM GMT on August 24, 2007
Sullivanweather,

It was to illustrate a point... Sometimes it takes a ridiculous metaphor to get a point across..

I've heard of the cycles and it was actually my point. A million years ago human were not here and we had ice ages and warm periods. Couldn't we be in a natural warm cycle?

I really didn't mean to get the whole GW debate ramped up again...
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365. Melagoo
8:04 PM GMT on August 24, 2007
... any storms brewing?
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363. extreme236
8:02 PM GMT on August 24, 2007
I'm thinking that the low off the east coast has the better chance of developing
Member Since: August 2, 2007 Posts: 19 Comments: 19234
362. Weather456
7:58 PM GMT on August 24, 2007
Posted By: extreme236 at 7:57 PM GMT on August 24, 2007.

TWC was talking about some non tropical low in the atlantic somewhere. they said they are watching it to see if it can get tropical characteristics. im still trying to figure out where this low pressure is lol. there are a few low pressures so im trying to figure out which one there talking about


Me too, i think its the one off the US East Coast
Member Since: July 24, 2005 Posts: 407 Comments: 19076
361. extreme236
8:00 PM GMT on August 24, 2007
well it is a fairly strong low pressure. 1003mb, so if it did get tropical characteristics it could develop
Member Since: August 2, 2007 Posts: 19 Comments: 19234
359. sullivanweather
7:51 PM GMT on August 24, 2007
Posted By: Dakster at 7:35 PM GMT on August 24, 2007.

When the earth was ice free in the past what was that blamed on? I'm sure the dinosaurs weren't driving gas powered engines...

Ohh and how or what started the Ice Age and how did it end?



You surely aren't serious!

It's folks that say rather silly things such as 'dinosaurs didn't drive SUV's' that make the rest of those that are skeptical have a bad name.

Furthermore have you ever heard of Milankovitch cycles?
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358. extreme236
7:57 PM GMT on August 24, 2007
if you think about it though, it is super quiet as there is some action out there. right now there are a few wait and see features to monitor. a few models develop something hitting nicaragua. i believe those are the cmc, nogaps, and the ecmwf
Member Since: August 2, 2007 Posts: 19 Comments: 19234
357. Tazmanian
7:56 PM GMT on August 24, 2007
ok 456
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356. extreme236
7:56 PM GMT on August 24, 2007
TWC was talking about some non tropical low in the atlantic somewhere. they said they are watching it to see if it can get tropical characteristics. im still trying to figure out where this low pressure is lol. there are a few low pressures so im trying to figure out which one there talking about
Member Since: August 2, 2007 Posts: 19 Comments: 19234
354. Weather456
7:54 PM GMT on August 24, 2007
Taz, its a non tropical low, forecast to move to the northeast into the North Atlantic
Member Since: July 24, 2005 Posts: 407 Comments: 19076
353. Chicklit
7:49 PM GMT on August 24, 2007
AinFLA, if you are admitting humans have caused global warming, then your argument is flawed for obvious reasons.
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352. Dakster
7:50 PM GMT on August 24, 2007
AinFLA,

And my point is "we" weren't around during most of your post. In fact if you condensed the time the Earth was formed to the present into a one year period, where Jan 1 was the day the earth was created and Dec 31 at midnight is current day and time. Man arrived about 30 seconds ago...
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351. Tazmanian
7:51 PM GMT on August 24, 2007
what do you all think about this 1003mb low on this map?

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350. Weather456
7:44 PM GMT on August 24, 2007
Posted By: CCTXangel at 7:32 PM GMT on August 24, 2007.

Good afternoon everyone!! anything new going on in the tropics??


we have a low pressure swirl associated with a tropical wave near 9.65N/47.75W.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
348. Dakster
7:39 PM GMT on August 24, 2007
Problem with South Florida is that the building code was relaxed in the 70's thru the 80's. A lot of wood frame houses were built (my current one included) and it really wasn't until after Hurricane Andrew that the codes were tightened down. This was a time when construction was very brisk and "cookie" cutter homes were built ala Coutry Walk to name one infamous development.

The current 2005 building code is very strict and in fact houses built in the 70's and 80's couldn't be economically "retro-fitted" or fixed to meet current codes. In other words if they received 25% or more structural damage they would have to be bull-dozed... Again, mine included. I am not just talking out of my you-know-what. I had alot of damage in 2005 and several structural engineers (Rimkus to name one group) have advised me of the above.

BTW, my previous house which was built in 1949 went thru Andrew without a hitch. Even the interior walls were solid conrete or poured CBS block. I bet the island homes are built like this too and that is why there wasn't as much damage. The design and construction practices of these homes has been around for over 50 years! Just look at any home in the old (east) section of Hialeah with the flat concrete roofs. After you replace the jalousie (spelled that way on purpose) windows with impact windows they are not going anywhere...

Hopefully we don't have to find out just how well FPL replaced those aging poles!
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347. AinFLA
7:47 PM GMT on August 24, 2007
dakster'

In the begginning..........

The earth was a molten blob of stuff. It was warm.

Then it cooled...

Then it warmed...

Then it cooled...

Then it warmed...

Then it cooled...

Then it warmed...

Then it.... Well you get the point.
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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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