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

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

Share this Blog
4
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1097 - 1047

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27Blog Index

1094. GRDRATNAVARRE
9:42 PM GMT on August 25, 2007
For those that like cool imagery and bouy sites here's a couple good ones for national radar and buoys. Once in just click your way to what you want to see.
http://radar.weather.gov/Conus/full_loop.php
http://www.ndbc.noaa.gov/
Member Since: Posts: Comments:
1093. extreme236
9:40 PM GMT on August 25, 2007
I am sticking with my 14-16 storms prediction. Dont know it will be right or not but its only august so I guess we have to wait till december to know for sure if anyone's prediction is right
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1092. Skyepony (Mod)
9:24 PM GMT on August 25, 2007
cirrocumulus~ Can you show us any scientific papers backing the increased number of storms??




check it out

Number of storm days goes down world wide as well. But the overall ACE (Acumulated Cyclonic Energy) goes way up looking at this world wide. Gray & others research says the increase in the # of more intense worldwide storms isn't happening but they look at as an increase in Cat 3,4 &5 compared to 1 & 2s. Where that messes up the results since the # of cat 3s are less.
Member Since: August 10, 2005 Posts: 179 Comments: 38333
1091. Drakoen
9:36 PM GMT on August 25, 2007
Posted By: extreme236 at 9:37 PM GMT on August 25, 2007.

....A watched pot never boils lol


lol. 90L was well wacthed even when it was of Africa. I guess the model agreement made up for that.
Member Since: Posts: Comments:
1090. BahaHurican
5:30 PM EDT on August 25, 2007
Whether or not we have an above average season at the end of the season is not prorated on the basis of what we have at the end of August. Above average now does not translate into above average at the end of the year. Below average at the end of August does not translate into below average in December.

In other words, everybody who wanted to make a forecast, including Amy, has done so. Can we now just watch the storms so we can see who's right? This horse is so dead people have been wearing its skin as shoe leather and cowboy chaps for about 3 years. . .
Member Since: Posts: Comments:
1088. JupiterFL
9:37 PM GMT on August 25, 2007
Has anyone talked to Lefty lately?
Member Since: Posts: Comments:
1087. extreme236
9:36 PM GMT on August 25, 2007
well StormW, looks like another one of those, wait and see things. kinda like a go to bed and wake up and see if anything has changed. A watched pot never boils lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1084. JupiterFL
9:31 PM GMT on August 25, 2007
Thank god for the regulars who are back to discussing tropical weather. Thank you StormW,Drak etc... Its good to know that we didn't go a whole day talking about Global Warming on a tropical blog.
Member Since: Posts: Comments:
1083. extreme236
9:31 PM GMT on August 25, 2007
hey StormW that wave offshore seems to have cyclonic turning, well evident turning
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1079. extreme236
9:29 PM GMT on August 25, 2007
Amy, season have late starts. Cyclones dont have a rule on when to form. I will believe your predictions when were at October. Right now, I just dont feel we can make predictions when were not even at the peak yet. Lets just sit back and watch. Its not the number that matters, its the strength. It only takes one storm to kill
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1078. Drakoen
9:29 PM GMT on August 25, 2007
Posted By: Amystery at 9:29 PM GMT on August 25, 2007.

it will be interesting to see what happens come the peak of the season, will yall start thinking we might not have a above average season if we dont have a named system by then, or if we have just one?


Is that the way to submissively agree with you...
Member Since: Posts: Comments:
1076. BahaHurican
5:26 PM EDT on August 25, 2007
Skypony, I was thinking about this earlier today. I can't see the US trying to claim on the Canadian side. Aren't we friends??? LOL

The Canadians may have to upgrade the Mounties . . .
Member Since: Posts: Comments:
1075. boobless
9:19 PM GMT on August 25, 2007
Posted By: hosweather at 8:34 PM GMT on August 25, 2007.
Interestingly, the GFS also develops this wave initially but then has it lose structure as it races west at breathtaking speed. The CMC moves the system west at a more normal speed. It may be on to something here--definitely worth watching.

Looks like both have movement correct-SSW, staying tucked up under the ridge. GFS has the breathtaking speed in hand, based on vis frames available. Catl would be the place for slow down in forward speed.
Way too early to call (for me), but if this develops in the Catl, future track may not be as straight forward as Dean (no pun intended).
1072. extreme236
9:27 PM GMT on August 25, 2007
noaa only dropped it from 13-17 to 13-16. not that significant
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1071. Drakoen
9:26 PM GMT on August 25, 2007
Posted By: Amystery at 9:25 PM GMT on August 25, 2007.

I am referring to the healthier looking wave over africa that is already about 15N


Just because it looks like that doesn't mean its better of than the wave at 10N 10W. It doesn't have any type of circulation. Could easily get broken into stratocumulus clouds when it exists Africa.
Member Since: Posts: Comments:
1069. extreme236
9:26 PM GMT on August 25, 2007
They might be right. But NOAA also gave a 85% chance for a above average season
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1068. Drakoen
9:25 PM GMT on August 25, 2007
Member Since: Posts: Comments:
1067. BahaHurican
5:17 PM EDT on August 25, 2007
Drak,

Also no patience and an inability to live without constant entertainment . . . LOL

I always view the low periods as a time to review the history and see what is possible, as well as read up on phenomena I haven't fully understood. YMMV . . .
Member Since: Posts: Comments:
1065. Drakoen
9:24 PM GMT on August 25, 2007
If you look here you can see the circulation in eastern guinea.
Link
Member Since: Posts: Comments:
1064. Skyepony (Mod)
9:05 PM GMT on August 25, 2007
Here is something from the weather news today dealing with the sea ice topic. The scramble for which countries claim where of the North pole seabed & who owns what of the Northwest Passage. Canada is arming icebreaking boats, begining some military bases up there. Russia put a flag on the ocean floor. USA isn't respecting Canada's claims. Greenland wants in on this & it goes on. My 2 points, settling who gets to drill there could get real messy in many different ways. Many money hungry people salavate at the thought of this sea ice melting. & I know our reliable records with the exact amount of ice only go back to 1979 but had there been a melt of the Northwest passage even for some months on a yearly bases anytime in the last few 1000 years or so some country would have claim too it.
Member Since: August 10, 2005 Posts: 179 Comments: 38333
1063. extreme236
9:21 PM GMT on August 25, 2007
the SAL is continueing to weaken
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1062. Weather456
9:11 PM GMT on August 25, 2007
East Atlantic Update

As of 1800 UTC (2PM EDT), a tropical wave is analysed near 28-29W south of 20N moving west near 10 knots. The wave axis is located just to west of the cape Verde Islands. No surface feature is associated with the wav and most of the convection is along the African Monsoon trough/ITCZ but enviromental conditions appears favorable for development as the wave is capped by an upper anticylone. Another interesting area is a broad area of low pressure currently over West Africa near 10-11N/12-15W. I'm a little unsure the fate of this feature as the same upper anticyclone is porducing easterly shear south of 10NN from the African Coast to near 40W but this is forecast to lessen a bit. Two areas to watch and I give both 20% chance of dveloping within the next 48 hrs.

by W456
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1061. boiredfish
9:21 PM GMT on August 25, 2007
texascanecaster1.......go to tropics chat....lol
Member Since: Posts: Comments:
1060. cirrocumulus
9:17 PM GMT on August 25, 2007
Miss Bennet: Get back to the basics. The global warming is also increasing the quantity not just the intensity. Warmer water equals more storms.
Member Since: Posts: Comments:
1059. extreme236
9:21 PM GMT on August 25, 2007
systems can form off africa at 12-13N, they dont have to be at 10N to develop
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1056. extreme236
9:20 PM GMT on August 25, 2007
Drak, Amy isnt looking at wehre the circulation is. she is just trying to say something to downcast it
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1055. runningfromthestorms
9:15 PM GMT on August 25, 2007
So then will all of us that use oil, coal and chemicals in our daily lives to stay warm, go to work and light our houses would be as guilty as the people who bring us the life altering energy - take us back to the stone ages - this is stupid litigation!! Sorry Miss Bennet but it is - shut down the life support equipment in the hospitals etc, we need the energy and after all, the knowledge of GW came many years after the advent of the use of fossil fuels, long after they were a part of our daily lives
Member Since: Posts: Comments:
1054. Drakoen
9:19 PM GMT on August 25, 2007
Posted By: Amystery at 9:19 PM GMT on August 25, 2007.

the wave that will be coming off africa in a couple days is too far N.


What are you looking at? 10N 10W is where the low to mid level circulation is.
Member Since: Posts: Comments:
1052. extreme236
9:18 PM GMT on August 25, 2007
Amy, we have had 4 pure tropical systems. we have gotten in double digits for the past decade. I dont understand why you think it will be so inactive
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1050. Drakoen
9:15 PM GMT on August 25, 2007
It seems that as soon as Dean left everyone is already ruling out the season...
Oh well i guess thats just a lack of educational knowledge.
Member Since: Posts: Comments:
1049. extreme236
9:14 PM GMT on August 25, 2007
Amy, you forget we are in a la nina pattern. la nina's give more active late seasons as well. just because things arent timed out like they should doesnt mean it will be below average. storms dont have rules on when to form and when not to form. 2001 had 4 storms in october, and they only had 4 by this time
Member Since: August 2, 2007 Posts: 19 Comments: 19234

Viewing: 1097 - 1047

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.