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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95. kmanislander
3:02 PM GMT on August 24, 2007
The quikscat pass this morning does not show anything at the surface so what we are seeing must be in the mid levels only
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93. icepilot
8:41 AM CST on August 24, 2007
While the north pacific current is classified a warm on your chart by the time it hits the NA shore it is relitively cool 40 deg or so as to morph into the cold Calif Current.

I screwed up on the N. Atlantic and Gulf stream, both of which are classifed warm currents, but again I say that as they impact the northern Europe land mass they are relitively cool. 40 degs or so

The main point I was trying to make was the Moderation of weather to land masses to their east.

Well, we will see whats whats this winter and coming spring - grin
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92. kmanislander
2:58 PM GMT on August 24, 2007
Posted By: stoormfury at 2:53 PM GMT on August 24, 2007.

i am happy that my colleagues have seen the area


Good find my friend. This time of year even a little swirl bears watching. Lets hope it runs into SA before anything develops out of it.
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90. stoormfury
2:55 PM GMT on August 24, 2007
i quite agree that systems have developed in this ares have developed rather quickly and have become major hurricanes. although not too impressive st the moment. the potential is there for development
Member Since: August 22, 2006 Posts: 0 Comments: 2600
87. fldoughboy
2:53 PM GMT on August 24, 2007
Not sure if anyone has mentioned it, but this is the 15th anniversary of the landfall of Hurricane Andrew. I remember evacuating from Miami and sitting in some of that traffic. I had to get back anyways because it was my first day of school at my local college.
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85. stoormfury
2:52 PM GMT on August 24, 2007
i am happy that my colleagues have seen the area
Member Since: August 22, 2006 Posts: 0 Comments: 2600
83. kmanislander
2:51 PM GMT on August 24, 2007
Here is a wider shot showing Barbados to the WNW of it

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81. yippeekaiyea
2:48 PM GMT on August 24, 2007
How is this site funded? Who pays Dr. Masters? I just like to know background on sites.
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80. kmanislander
2:48 PM GMT on August 24, 2007
TCC

9N 48W

Just SE of the Leewards
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76. kmanislander
2:44 PM GMT on August 24, 2007
Something else to watch carefully



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73. windsurfer68
2:39 PM GMT on August 24, 2007
I recently saw an article about another 1930s article by the Washington Post that stated in the 1930s, the Artic Caps and glaciers were melting exposing huge amounts of land mass. Also it said that the seals were vanishing. Also in Greenland recently, didn't they find missing planes from WW II under 280 feet of ice?
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72. stoormfury
2:40 PM GMT on August 24, 2007
this is the loop


Link
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70. stoormfury
2:33 PM GMT on August 24, 2007
look at 9N 48W convection is building in what appears to be a deveolping LLC




Link
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69. sullivanweather
2:32 PM GMT on August 24, 2007
ocean current

I don't know which cold current you're talking about???
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64. sullivanweather
2:25 PM GMT on August 24, 2007
Icepilot, again it is a theory, but I do believe that it does hold water.

There was much above normal snowpack in the spring across northern New England and I believe this helped to contribute to some late-season snowfalls in the area.

While it is not uncommon to have late-season snowfall in the Northeast the severity of the snow that had fallen and number of snow events were certainly something to take note of.
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63. mississippiwx23
2:29 PM GMT on August 24, 2007
I am more interested in a possible storm off of the Mexican coast in the Pacific in about a week. It seems every model is forecasting it to form and the European wants to make it a major storm. Will have to keep an eye out for it in 4-5 days or so.

The NOGAPS does bring that system the Dr. was talking about into the gulf. At least it is something to watch right now. Lets hope its just a rainstorm for Central America, and thats it (which I think it will be).
Member Since: August 20, 2007 Posts: 3 Comments: 683
62. icepilot
8:24 AM CST on August 24, 2007
sullivanweather at 8:16 AM CST on August 24, 2007.

Icepilot.

You're kidding about England having "weather dominated by cold ocean currents to their west...." right?

No, The North Atlantic and the Japanese Currents are considered "Cold" currents. But their effect on the land masses to their east is one of "Moderation" of the land masses weather
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60. icepilot
8:23 AM CST on August 24, 2007
sullivanweather
I just did not understand what you were saying with the phrase:
average to below average late fall/early winter.

As for increased increased snow pack in the arctic - I don't agree with your theory - but who knows - we can talk about it next spring.... grin
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59. funeeeg
2:21 PM GMT on August 24, 2007
I find it strange that some people are saying that the antarctic ice sheet is expanding.I believe that was a prediction, the actual reality is completely different. It seems that it is actually losing ~ 150 cubic Km per year. It is the great thinning of the ice that is a concern.
have a read of this link:Link and: Link
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58. stoormfury
2:17 PM GMT on August 24, 2007
good morning
The atlantic is relatively quiet this morning. there is some rotation at 9N 48W. Although it may be a little south, we have seen cyclogenis in this vicinity in the past. we just have to wait for a few more frames to see if there is a chance of something trying to form
Member Since: August 22, 2006 Posts: 0 Comments: 2600
56. sullivanweather
2:14 PM GMT on August 24, 2007
Icepilot.

You're kidding about England having "weather dominated by cold ocean currents to their west...." right?
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55. sullivanweather
2:02 PM GMT on August 24, 2007
Posted By: icepilot at 1:58 PM GMT on August 24, 2007.

sullivanweather

two things:
what does the following mean?

contribute to an average to below average late fall/early winter across North American

2. The increased area of open water at the pole will retard the number of freezing degree days AND could effect/reduce the amount of snow fall along the land borders of the Arctic Ocean. While the amount of moisture in the air will increase (when frozen, the arctic has desert like precip amounts) the overall temperature range will be higher due to the liquid water heating the Atmospere. Resulting in many mor rain events and "mild" winters. As evidenced by the weather experienced in the NW US and England, both who have weather dominated by cold ocean currents to their west....


1. Normally, during La nina years the pattern features a large trough to develop over the northwestern/north-central part of North America. With large areas of open water north of Alaska/Siberia (extra heat) this should cause this trough to range further towards the east and closer to where the largest concentration of sea-ice is during the autumn months.

Other factors lead me to believe this will happen (persistant/almost semi-permanent ridging across the western US/ trough in the eastern US.


2. A 'mild' winter in Siberia is still well below freezing and the same goes for Alaska/Canada. If there's more moisture available for this cold air there will be increased snowfall amounts. One only has to look as far as the Great Lakes, which is at a much lower latitude than the arctic, to see that snow can and does occur downwind of large areas of open water.
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54. tillou
2:08 PM GMT on August 24, 2007
48 degrees x 10 degrees is the only area in the Atlantic basin that has any type of cyclonic spin. Too bad its a little to far south.

I bet $20 the wave over Africa also disapates.
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53. 0ldman
2:02 PM GMT on August 24, 2007
Actually July in Atlanta was slightly below normal (by 1.6F), but I guess being slightly below normal during the hottest time of the year is still broiling.
That was the case here in Alabama as well, however I don't think its July he's speaking of. June and July were actually below the average, very comfortable. The end of July to date is just this side of absolutely miserable.
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51. FlaRob
1:54 PM GMT on August 24, 2007
Does anyone have an idea what the steering pattern and BH are forecast to do in the next few weeks? The same as now, or possibly back to a June-July pattern.
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49. LuvsStorms
1:58 PM GMT on August 24, 2007
once again, hot here in swla, but virtually no humidity...TWC said 41% again this morning. That is unreal for us...we're usually at 90% or higher. I'm LOVING it!!!!!!!
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47. tillou
1:59 PM GMT on August 24, 2007
No tropical activity anywhere. Its a little too quite for me.

Good news today, but will it be good news tomorrow?

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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.