Our extreme weather: Arctic changes to blame?

By: Dr. Jeff Masters , 9:50 PM GMT on December 16, 2011

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"The question is not whether sea ice loss is affecting the large-scale atmospheric circulation...it's how can it not?" That was the take-home message from Dr. Jennifer Francis of Rutgers University, in her talk "Does Arctic Amplification Fuel Extreme Weather in Mid-Latitudes?", presented at last week's American Geophysical Union meeting in San Francisco. Dr. Francis presented new research in review for publication, which shows that Arctic sea ice loss may significantly affect the upper-level atmospheric circulation, slowing its winds and increasing its tendency to make contorted high-amplitude loops. High-amplitude loops in the upper level wind pattern (and associated jet stream) increases the probability of persistent weather patterns in the Northern Hemisphere, potentially leading to extreme weather due to longer-duration cold spells, snow events, heat waves, flooding events, and drought conditions.


Figure 1. Arctic sea ice in September 2007 reached its lowest extent on record, approximately 40% lower than when satellite records began in 1979. Sea ice loss in 2011 was virtually tied with the ice loss in 2007, despite weather conditions that were not as unusual in the Arctic. Image credit: University of Illinois Cryosphere Today.

Summertime Arctic sea ice loss: 40% since 1980
The Arctic has seen a stunning amount of sea ice loss in recent years, due to melting and unfavorable winds that have pushed large amounts of ice out of the region. Forty percent of the sea ice was missing in September 2007, compared to September of 1980. This is an area equivalent to about 44% of the contiguous U.S., or 71% of the non-Russian portion of Europe. Such a large area of open water is bound to cause significant impacts on weather patterns, due to the huge amount of heat and moisture that escapes from the exposed ocean into the atmosphere over a multi-month period following the summer melt.


Figure 2. The extent of Arctic sea ice loss in the summer July - August - September period in 2007 was about 1.4 million square miles (3.6 million square kilometers) greater than in 1980, according to the University of Illinois Cryosphere Today. For comparison, the lost ice coverage (orange colors) was equal to an area about 44% of the size of the contiguous U.S., or 71% of the non-Russian portion of Europe.

Arctic sea ice loss can slow down jet stream winds
Dr. Francis looked at surface and upper level data from 1948 - 2010, and discovered that the extra heat in the Arctic in fall and winter over the past decade had caused the Arctic atmosphere between the surface and 500 mb (about 18,000 feet or 5,600 meters) to expand. As a result, the difference in temperature between the Arctic (60 - 80°N) and the mid-latitudes (30 - 50°N) fell significantly. It is this difference in temperature that drives the powerful jet stream winds that control much of our weather. The speed of fall and winter west-to-east upper-level winds at 500 mb circling the North Pole decreased by 20% over the past decade, compared to the period 1948 - 2000, in response to the extra warmth in the Arctic. This slow-down of the upper-level winds circling the pole has been linked to a Hot Arctic-Cold Continents pattern that brought cold, snowy winters to the Eastern U.S. and Western Europe during 2009 - 2010 and 2010 - 2011.


Figure 3. West-to-east jet stream wind speeds at 500 mb (approximately 18,000 feet or 5,600 meters) in the mid-latitudes (40 - 60°N) over North America between 1948 and 2010. During fall (October - November - December) and winter (January - February - March), jet stream winds weakened by about 20%, from 13 - 14 m/s to 10.5 - 11 m/s. Spring (AMJ) and summer (JAS) winds changed little during this time period.

Arctic sea ice loss may increase the amplitude of jet stream troughs and ridges
The jet stream generally blows from west to east over the northern mid-latitudes, with an average position over the central U.S. in winter and southern Canada in summer. The jet stream marks the boundary between cold polar air to the north and warm subtropical air to the south, and is the path along which rain and snow-bearing low pressure systems ride. Instead of blowing straight west-to-east, the jet stream often contorts itself into a wave-like pattern. Where the jet stream bulges northwards into a ridge of high pressure, warm air flows far to the north. Where the jet loops to the south into a trough of low pressure, cold air spills southwards. The more extreme these loops to the north and south are--the amplitude of the jet stream--the slower the waves move eastward, and consequently, the more persistent the weather conditions tend to be. A high-amplitude jet stream pattern (more than 1000 miles or 1610 km in distance between the bottom of a trough and the peak of a ridge) is likely to bring abnormally high temperatures to the region under its ridge, and very cold temperatures and heavy precipitation underneath its trough. The mathematics governing atmospheric motions requires that higher-amplitude flow patterns move more slowly. Thus, any change to the atmosphere that increases the amplitude of the wave pattern will make it move more slowly, increasing the length of time extreme weather conditions persist. Dr. Francis discovered that during the early 1960s, a natural pattern in the atmosphere called the Arctic Oscillation increased the amplitude of the winter jet stream pattern over North America and the North Atlantic by more than 100 miles, increasing the potential for long-lasting weather conditions. The amplitude of the winter jet fell over 100 miles (161 km) during the late 1960s, remained roughly constant during the 1970s - 1990s, then increased by over 100 miles again during the 2000s. This latest increase in wave amplitude did not appear to be connected to the Arctic Oscillation, but did appear to be connected to the heating up of the Arctic due to sea ice loss. A warmer Arctic allows ridges of high pressure to build farther to the north. Since temperatures farther to the south near the bases of the troughs are not changing much by comparison, the result is that the amplitude of the jet stream grows as the ridges of high pressure push farther to the north. Thus it is possible that Arctic sea ice loss and the associated increases in jet stream amplitude could be partially responsible for some of the recent unusual extreme weather patterns observed in the Northern Hemisphere. This is preliminary research that has yet to be published, and much more work needs to be done before we can confidently link Arctic sea ice loss with an increase in extreme weather, though.


Figure 4. A high-amplitude jet stream pattern observed over the U.S. on December 13, 2011. Instead of blowing straight west-to-east, the jet was contorted into a southward-bulging trough of low pressure that brought cold temperatures and a snow storm to Southern California, and a northwards-bulging ridge of high pressure that brought record warm temperatures to portions of the eastern 2/3 of the country. The axis of the jet stream is marked by the strongest winds (green and light blue colors) at the top of the lower atmosphere (200 - 300 mb pressure level.)

Earlier snow cover melt on Arctic land also increases the amplitude of jet stream troughs and ridges
As Earth's climate has warmed over the past 30 years, the Northern Hemisphere has seen a dramatic drop in the amount of snow cover in spring (April, May, and June.) Spring is coming earlier by an average of three days per decade, and the earlier arrival of spring has significantly reduced the amount of snow on the ground in May. Less snow on the ground means the land surface can heat up more readily, and May temperatures in Arctic have increased significantly over the past 30 years. Dr. Francis found that the upper-level wave amplitude has increased by over 100 miles (161 km) in summer over the past decade, and this change appears to be connected to the decline in May snow cover. Thus, reduced May snow cover due to global warming may be causing higher-amplitude jet stream patterns, potentially leading to slower-moving weather patterns that favor extreme weather in summer, such as heat waves, drought, and flooding. Note that significant changes to the upper-level atmospheric circulation in spring were not observed, so springtime extreme weather events like the 2011 flooding and tornadoes in the U.S. cannot be connected to changes in the Arctic sea ice or high-latitude snow cover using this research.

Related posts
Florida shivers; Hot Arctic-Cold Continents pattern is back
Jet stream moved northwards 270 miles in 22 years; climate change to blame?

Jeff Masters

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Quoting GeoffreyWPB:


Up late, Geoff?
Member Since: July 17, 2009 Posts: 71 Comments: 26150
Quoting yqt1001:
Typhoon Ketsana (Ondoy) killed 710 people and caused 1bill in damage in the Philippines mostly due to flooding when it hit as a tropical storm.

I almost wonder as to why Megi, who last year made landfall as one of the strongest storms ever recorded, didn't cause enough damage or deaths to warrant retirement, yet these weak rain bearing TS seem to absolutely destroy the Philippines. They may need to change their evacuation policy to anything that bears rain...

Typhoon Ketsana (Ondoy) actually hit Manila as a TS then strengthened once it entered the South China Sea. Manila has a population of 11-15 million, It is one of the most heavily populated city on earth, hence the high death toll, also Manila it only a few feet above sea level, which allowed the flooding to accumulate. The reason why Megi didn't cause enough damage or deaths to warrant retirement cause it hit a relatively lowly populated area of the country and also that part of the Philippines is very much used to being hit by typhoons.
Member Since: September 30, 2007 Posts: 9 Comments: 15935
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Quoting BahaHurican:
I'm not surprised at all about that higher death toll from Cagayan de Oro. The whole city seems to be situated on the flood plain of the river at whose mouth it sits... :o(

I wouldn't be surprised to see the death toll rise to over 500 when all is said and done.

Just sad, I say.


By the looks of it it may rise a substantial amount above 500, there's at least 200 missing and lots of communities that haven't been reached.
Member Since: August 26, 2009 Posts: 0 Comments: 192
I think a lot has to do with track and rain rate there. A storm of a higher wind category may not necessarily be as devastating if the heaviest rains do not have a significant longlasting impact on the islands.

I also have a sneaking suspicion Philipinos are just as human as the rest of us, and assume that "just" a TS is not as bad as a supertyphoon. Thus evacuation signals for the less intense storm, windwise, may be more likely to be ignored...

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I'm not surprised at all about that higher death toll from Cagayan de Oro. The whole city seems to be situated on the flood plain of the river at whose mouth it sits... :o(

I wouldn't be surprised to see the death toll rise to over 500 when all is said and done.

Just sad, I say.
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Typhoon Ketsana (Ondoy) killed 710 people and caused 1bill in damage in the Philippines mostly due to flooding when it hit as a tropical storm.

I almost wonder as to why Megi, who last year made landfall as one of the strongest storms ever recorded, didn't cause enough damage or deaths to warrant retirement, yet these weak rain bearing TS seem to absolutely destroy the Philippines. They may need to change their evacuation policy to anything that bears rain...
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Via the BBC:

Philippine Red Cross Secretary General Gwen Pang told the Associated Press that at least 436 people were dead.

She said that 215 had died in Cagayan de Oro and 144 in nearby Iligan. The rest died in several other southern and central provinces, she added.

Many of the bodies were unclaimed after nearly 24 hours, she said, suggesting that entire families had died.

"The affected area is so wide and huge and I believe they have not really gone to all areas to do a search," she said.

Link
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Quoting sunlinepr:
54 small quakes after last night 5.3....


I hope for your sake they are just aftershocks and not fore-shocks for an even bigger one.
Member Since: September 30, 2007 Posts: 9 Comments: 15935
Quoting Skyepony:
TRMM caught Sendong. Click pic for Quicktime movie..



NASA predicted 'Ondoy-like' rains for 'Sendong'.

Tropical storm Sendong (international name Washi) was expected to bring heavy rains with almost similar amount and intensity as carried by tropical storm Ondoy 2 years ago, according to a prediction made 2 days ago by a joint US-Japanese scientific project. The Tropical Rainfall Measuring Mission (TRMM), a joint project between the US National Aeronautics and Space Administration and the Japan Aerospace Exploration Agency (JAXA), said tropical storm Washi had strengthened when the TRMM satellite passed over December 15. TRRM analysis of data gathered by the satellite's instruments showed that Sendong was already carrying "very heavy rainfall of over 50mm/hr (~2 inches).” In comparison, Ondoy dumped 56.83 mm/hr of rainfall on Metro Manila in September 2009. Around the same day, Philippine state weather bureau PAGASA and the disaster management agency NDRRMC predicted only a 10-25 mm per hour rainfall amount for Sendong. The highest storm warning signal raised over areas affected by Sendong was only signal number 2. The storm devastated southern Philippines Friday night and Saturday morning, causing flash floods that killed at least 180 people and left almost 400 others missing. Sendong is expected to make landfall again early Sunday morning in Palawan. Quoting PAGASA officer-in-charge Graciano Yumul, Presidential Communications Development and Strategic Planning Undersecretary Manuel L. Quezon III said on Twitter Saturday that Cagayan de Oro City received more rainfall in a single day than what the area gets for a month. "For the month of December, normal rainfall for CDO is 113.2mm. The December 16, 2011 volume at 180.9mm in one day in Lumbia is greater than a whole month's rain," he said. Asked regarding the use of rainfall volume in storm warning signals, Quezon said the government is reviewing the system. "There's an ongoing review of that as heavy rains increasingly posing separate peril from old signal system based on winds," he said. President Benigno Aquino also wants to review the country's disaster management plan following the deaths and devastation caused by Sendong. According to the NDRRMC, it properly relayed advisories to local government units, media, the military, police, and emergency response agencies in Mindanao regarding the threat posed by the storm. Around 20,000 soldiers have now been mobilized for rescue and relief operations across the north coast of Mindanao, particularly Cagayan de Oro and Iligan.


_________________________________________________ _____________________________________________
I can not believe they don't use all the resources available. They surely need to change that.
Member Since: September 30, 2007 Posts: 9 Comments: 15935
Quoting PensacolaDoug:


See !!! This proves AGW is a hoax!


lol.

Washi doesnt look as good as (he?) did a day ago
Member Since: August 4, 2011 Posts: 46 Comments: 4485
Quoting BahaHurican:
I also took a quick look at the topography, and I can see why the flooding has been so disastrous; Mindanao is quite mountainous, and a lot of the people live in the narrow river valleys. If they didn't get to high ground before the rain started, it would have been almost impossible to get away from 20 ft of water in time. Think the canyons north of Denver when a flash flood hits. You've all seen the footage on TWC...


This Picture says it all. It's was like a Tsunami.



Video.
Member Since: September 30, 2007 Posts: 9 Comments: 15935
54 small quakes after last night 5.3....

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Quoting flsky:
Currently -37F in South Padre Island, TX

Link


See !!! This proves AGW is a hoax!
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186. Skyepony (Mod)
TRMM caught Sendong. Click pic for Quicktime movie..

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Geoff, those look pretty decent. It's supposed to be 81 again here tomorrow... looking forward to it. However, I also note a front's supposed to come through, so I guess I better get any outdoor stuff done in the a.m......

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For West Palm Beach. Guess we will have to wait till January for the cold weather...

Member Since: September 10, 2007 Posts: 0 Comments: 11158
Quoting AstroHurricane001:
In case you missed it:



Comet C/2011 W3 (Lovejoy) skirting the Sun.


Another graphic of the comet's tail being stripped by the sun. A very interesting thing to see this occur to a comet.



Link
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Sheer devastation in the wake of Washi... who could have imagined that (probably) the last storm in that basin for 2011 would have such devastating effects..

Also, while on topic:

Link

Apparently the center missed Palawan and is now moving north into the China Sea, not south as predicted by earlier models.
Member Since: August 26, 2009 Posts: 0 Comments: 192
iceagenow.com
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Quoting TomTaylor:
mid 60s here in San Diego and I have my sweatshirt on lol


Lol. We still haven't unearthed our sweats this year yet. Denial is a lovely thing. =)
Member Since: August 24, 2010 Posts: 0 Comments: 160
Quoting weatherh98:

yessss
Lolol.
Member Since: August 14, 2010 Posts: 10 Comments: 16976
Quoting washingtonian115:
Are you a snake now??.Lol.J/K.

yessss
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Quoting weatherh98:


noticed thiss too...
Are you a snake now??.Lol.J/K.
Member Since: August 14, 2010 Posts: 10 Comments: 16976
Quoting JNCali:
Ran across this article about the cooling of Antarctic.. Link.. Also the sea ice has been gorwing consistantly here's the link to the whole image.. is there an offset here with the warming in the North?


noticed thiss too...
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Quoting AtHomeInTX:
Quoting Skye from comment 109

It's flannel weather out there right now.. anything less than 76º calls for long sleeves to a true Floridian..




Lol. So we aren't  so different after all. :D

It's 63 here. And I'm freezing!
mid 60s here in San Diego and I have my sweatshirt on lol
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Quoting Skye from comment 109

It's flannel weather out there right now.. anything less than 76º calls for long sleeves to a true Floridian..




Lol. So we aren't  so different after all. :D

It's 63 here. And I'm freezing!
Member Since: August 24, 2010 Posts: 0 Comments: 160
Quoting flsky:
Even worse, they say it feels like -67F!

Feels like -67 in Texas.Oh my it is the end of the world!!!.
Member Since: August 14, 2010 Posts: 10 Comments: 16976
Oh wow, feels like -55C. That's only 1 degree warmer than the coldest temperature ever recorded here (-56C windchill, coldest in Ontario).
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Quoting flsky:
Even worse, they say it feels like -67F!


Its not Weather Underground's fault, the NWS Office temperature says the same thing.

Link
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170. flsky
Even worse, they say it feels like -67F!

Quoting washingtonian115:
That's so like weired.Lol.They need to fix that.
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Quoting flsky:
Currently -37F in South Padre Island, TX

Link
That's so like weired.Lol.They need to fix that.
Member Since: August 14, 2010 Posts: 10 Comments: 16976
Quoting flsky:
Currently -37F in South Padre Island, TX

Link

Lol, with light rain.
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167. flsky
Currently -37F in South Padre Island, TX

Link
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Quoting AstroHurricane001:


The anti-correlation between Arctic warming and Antarctic cooling has been known to appear in paleoclimate records since at least the Younger Dryas...

Had not seen the Youger Dryas information before.. very interesting.. the rapid temperature changes are a bit unnerving.. but it also seems to indicate nature's ability to balance itself through extreme fluctuations.. Thanks Astro!
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Quoting Neapolitan:

First, it's no longer a matter of "if" Arctic ice melts, but when; it's continuing to do so at an increasing rate. Not so long ago, it was thought the earliest the Arctic might be ice-free in summer was three or four decades from now; that prediction has now shrank to just four or five years.

Second, while new Arctic shipping routes will certainly become available, so will new access to petroleum, which development and usage will more than offset any bunker fuels saved by opening the routes.

The negative effects of climate change vastly outnumber and overwhelm the positive effects. Contracting terminal cancer will help an obese person lose weight, but that's a cure far worse than the disease...


Looking for a silver lining... In light of world population growth expecting to reach 8 billion by 2025, and with the increased desertification of arable land I'm faced with the realization bordering on science fiction...
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Quoting JNCali:
Ran across this article about the cooling of Antarctic.. Link.. Also the sea ice has been gorwing consistantly here's the link to the whole image.. is there an offset here with the warming in the North?


The anti-correlation between Arctic warming and Antarctic cooling has been known to appear in paleoclimate records since at least the Younger Dryas. It's likely caused by something associated with the North Atlantic Deep Water - which extends to the continental shelf of Antarctica.



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In case you missed it:



Comet C/2011 W3 (Lovejoy) skirting the Sun.
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Quoting JNCali:
If the arctic ice melts.. new shipping routes will open saving tremendous amounts of fuel as well as reduced CO2 emissions.. New fishing grounds will open up as well as access to petroleum and natural gas resources which can help to free us from dependance on unfriendly countries. Lots of plusses in my book..

First, it's no longer a matter of "if" Arctic ice melts, but when; it's continuing to do so at an increasing rate. Not so long ago, it was thought the earliest the Arctic might be ice-free in summer was three or four decades from now; that prediction has now shrank to just four or five years.

Second, while new Arctic shipping routes will certainly become available, so will new access to petroleum, which development and usage will more than offset any bunker fuels saved by opening the routes.

The negative effects of climate change vastly outnumber and overwhelm the positive effects. Contracting terminal cancer will help an obese person lose weight, but that's a cure far worse than the disease...
Member Since: November 8, 2009 Posts: 4 Comments: 13537
Quoting JNCali:
Ran across this article about the cooling of Antarctic.. Link.. Also the sea ice has been gorwing consistantly here's the link to the whole image.. is there an offset here with the warming in the North?
growing consistently? I disagree.

From what I see it has had periods of growth and shrinkage. Also, if you look from the beginning to the end of the graph the ice levels are fairly similar, with only a little bit of growth. Certainly nothing like the extreme changes we are seeing in the arctic.
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Ran across this article about the cooling of Antarctic.. Link.. Also the sea ice has been gorwing consistantly here's the link to the whole image.. is there an offset here with the warming in the North?
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Wao... I'm just thinking how boring one's life must be to troll the Doc's blog in mid-December, when pretty much blog life is at its nadir... lol
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Washi still looking to bring extensive rains to Southern Vietnam and points southeast...
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Washi
Member Since: August 4, 2011 Posts: 46 Comments: 4485
Quoting JNCali:
If the arctic ice melts.. new shipping routes will open saving tremendous amounts of fuel as well as reduced CO2 emissions.. New fishing grounds will open up as well as access to petroleum and natural gas resources which can help to free us from dependance on unfriendly countries. Lots of plusses in my book..
Bigger problem is with not knowing what's going to happen with the fishing grounds and shipping routes we already have... plus still uncertain impacts on the breadbasket areas of the US, Russia and China. I don't think we can weigh plusses and minuses equally at this point. Plus, your so-called plusses do little to benefit the little places like the Andamans, the Nicobar Islands, and the Bahamas, all of which are too far away from the Arctic to claim any of the benefits you describe, but low enough to suffer from land loss if Artic ice loss gives rise to long-term melting of the snow / ice on the neighbouring landmasses, eg. Greenland.

As I said before, I don't think we can weigh plusses and minuses realistically at this point.
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I also took a quick look at the topography, and I can see why the flooding has been so disastrous; Mindanao is quite mountainous, and a lot of the people live in the narrow river valleys. If they didn't get to high ground before the rain started, it would have been almost impossible to get away from 20 ft of water in time. Think the canyons north of Denver when a flash flood hits. You've all seen the footage on TWC...
Member Since: Posts: Comments:
If the arctic ice melts.. new shipping routes will open saving tremendous amounts of fuel as well as reduced CO2 emissions.. New fishing grounds will open up as well as access to petroleum and natural gas resources which can help to free us from dependance on unfriendly countries. Lots of plusses in my book..
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Quoting WeatherNerdPR:
Washi was a catastrophic storm in the Philippines:
UPDATE 4-Typhoon kills more than 436 in southern Philippines

* Local governments declare state of calamity

* Dozens of bodies washed ashore in nearby towns

* Houses swept into the sea while people slept
Wow... and Washi was only TS at the time? I keep thinking that torrential rains are more and more becoming the deadly factor in these tropical cyclones. The imagery coming out of the Mindanao area is heartbreaking.
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Quoting StallworthSwing:



Reported and ignored...
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Quoting PensacolaDoug:
I see post 111.

The other day some admin removed the "Twelve Days Of Christmas Wunderground version". But about 10 others had already re-posted it. That was a very funny/entertaining post and I don't don't understand how anybody (except for maybe a troll) could have found it offensive. Bizarre.
Oh.... it's back! lol
Never seen that happen before...

I'm going looking for the 12 Days of Wunderground...

Quoting WxGeekVA:
hmmmmmm it's very quiet right now....
Must be snowing somewhere...
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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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