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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It aint an act.....:)
Is there any possibility of the polar ice cap suddenly breaking up like has happened with a couple of the antarctic ice shelves?
Not under the same types of stresses - the top surface of an antarctic ice shelve can be several hundred feet above sea level and while it is floating on water , it is still attached to land or aground on the bottom or both. Basicly it is a glacier that has flowed out and onto the sea. The sea ice has formed, floating, on the water and, except for "fast" ice, is not attached in any significant way to anything. It also does not rise above the sea level to any great height
We had a nice rain here yesterday, but a few miles down the raod it was bone dry still.
10N 51W seems to be trying to organize
Yesterday this feature was below 10 but it has now risen above 10 and this means it will now track into the Caribbean. The increase in Lat may also aid in development by allowing it to escape from the ITCZ
They can develop in the ITCZ but the further S the harder it is for them to develop
The disturbance near 51W is at about 10.5 N IMO
Hi Extreme
They can develop in the ITCZ but the further S the harder it is for them to develop
Thanks for the answer. I figured they could but I knew it is hard for systems to develop the farther south they are
"Tropical cyclone formation is not expected during the next 48 hours.".....
97 days left in the Atlantic season.
StormW, something new for you to follow now LOL
Something else perhaps to keep an eye on ?
The pressure now is relatively low at 1010.8 approx.
The other interesting thing is you can see how the pressure bottomed out from Dean and at the same time the winds were up significantly.
Maybe they WERE true. Before the explorers came.
Well I see there is still a little interest in the 50w area. Any models showing anything for it?
What about the shear?
Any rain in SC to beat the heat? FL got pounded last night 3 inches of rain at Disney and great lightning show.
current - less than 10 knots
12 hrs forecast - less than 10 knots
24 hrs forecast - less than 10 knots
36 hrs forecast - less than 20 knots
These forecast correspond to the enviroment the wave is expected to be...not just for the central atlantic.
things are unusually quiet in the tropics..... see we are back to "blob" watchin at 50W.....
Hey SJ..... you ready for the Rajun Cajuns next week? If we can get some improved O-line play, we may have a nice year! :)
I thought it was the SC State Bulldogs?
Just spotty rain sg03!
Morning SW, thanks for the update!
The poles experience full light and full dark each year.
Reasons why one side melts faster?
Based on 1200 UTC Surface Observation
Based on 1315 UTC Satellite Imagery
An upper low in the North-Central Gulf of Mexico continues to interact with a broad area of low pressure (estimated 1010 millibars) and a tropical wave near 92-93W to produce scattred showers and thunderstorms over the Bay of Campeche. The area lies in a favourable enviroment for futher development but none of the computer models develops this system into anything. Based on forecast rainfall patterns and enviromental steering flow this system is forecast to move slowly to the west-northwest to northwest deepening to about 1008 millibars then spreading rain over Northern Mexico/Southern Texas in 48-66 hrs time.
by W456
so less than 40yrs in geological terms is a "blip", and I don't see how anything can be extrapolated from 40yrs of data.....
SJ...... SCstate is the third game! :)
http://gamecocksonline.cstv.com/sports/m-footbl/sched/scar-m-footbl-sched.html
This is my first posting. What is with La Nina? Is she still active or dormant? I recall last year El Nino took over, which resulted in quiet tropics? Thanks.
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