Author: Matthieu

Matt has been a member of the AWM team since January 2012, writing the weekly feature Elsewhere in Weather News which highlights weather news from across the globe. Matt has lived in Winnipeg all his life and has been a weather enthusiast since a very young age. He is currently completing his B.Sc. in Atmospheric Sciences at the University of Manitoba.

Elsewhere in Weather News: September 1st, 2012

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Tropical Depression Isaac: Update

What was once dubbed Hurricane Isaac when it made landfall as a category one hurricane, is now considered a ‘tropical depression’. Isaac continues to pose a threat a week after it made landfall but it has weakened significantly, and will continue to do so, as it penetrates further into the southern half of Continental United States. Although this hurricane was “only” rated a category one when it made landfall, comprising of maximum sustained winds of 135km/h at peak intensity, you would have not guessed the incredible amounts of rain it brought into Louisiana and surrounding Gulf States. Here are a couple of the most impressive rainfall totals recorded throughout the whole event:

-In Gretna, LA, the National Hurricane Center (NHC) unofficially reported 466mm of rainfall.
-In New Orleans, LA, 510mm of rainfall was reported, breaking New Orleans’ old daily rainfall record by 48mm (a record thsat was set by Hurricane Katrina).
-In Kiln, MS (west of Gulfport) 433mm of rainfall was reported.

Not only did Hurricane Isaac bring with it enormous amounts of rain, the storm surge that accompanied it was quite severe. Wind-driven storm surge is mostly caused by the severe winds accompanying a hurricane. These winds push ocean waters towards land similar to a wave but larger in size (in this case with south winds) and in turn, ocean levels are higher than the normal tide. This phenomena makes for serious flooding along the Gulf Coast since the terrain along the Gulf of Mexico is not mountainuous – it is more of a gradual slope. When ocean water then rises, it is easy for it to move inland quickly.

Isaac storm surge

Hurricane Isaac’s wind direction depicted with arrows. Blue boxes along the shoreline show areas where winds were favorable for storm surge. Green arrows (north winds) is where storm surge was less favorable because of the wind direction. Picture was taken just before landfall on the night of August 28th. (Source: NOAA)

In Louisiana, two people lost their lives in the Plaquemines Parish, one of the hardest hit parishes, as the tide rolled in and consumed their house. This now brings the Hurricane Isaac death toll in the United States to four, with damages listed in the hundreds of millions. In Louisiana and Mississippi, power was out to over a million people and it was estimated that 75% of New Orleans was out of power when the eye wall passed closest to the city. For a storm being of weak category one, it did an extensive amount of damage. This was in part caused by it’s broad area of precipitation, large area extending out from the eye of tropical storm force winds, extremely slow movement, and storm surge levels you would expect form a category two or three hurricane.

Flooding

Residents evacuating in Lafitte, LA by boat because of flooding. (Source: Yahoo News)

This week in the tropics there are three other notable storms: Hurricane Kirk out in the middle of the Atlantic which poses no threat to land; Tropical Storm Leslie which does not pose a threat to the United States but as it strengthens, could pose a threat to Bremuda; and lastly, Hurricane Ileana out in the Eastern Pacific poses no threat to land but could cause high surf to the Baja Peninsula.

Elsewhere in Weather News: August 25th, 2012

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Isaac Threatens Southern States

This past week a tropical disturbance in the central Atlantic, east of the Caribbean, has strengthened into a tropical storm – Isaac. As of Friday night, Isaac had sustained winds of 112km/h, a central pressure of 990mb and was eyeing (no pun intended) Haiti. It is especially worrisome that Isaac, a strong tropical storm, is moving towards one of the most impoverished countries in the world, where nearly 400,000 people are still living in tents after the major earthquake back in 2010.

Isaac

Isaac on infrared satellite with centre of circulation identified by arrow. Purple, red represents very cold cloud tops. (Source: WSI)

Isaac will make landfall as a strong tropical storm as it crosses Haiti and then heads toward Cuba. It might have trouble sustaining its strength due to the mountainous terrain of the islands but as it emerges into the Gulf of Mexico, Isaac should organize itself quickly as it takes aim at the Gulf States such as Florida, Alabama, Mississippi and Louisiana. It is expected that Isaac will make landfall on American soil, somewhere on the western part of the Florida Panhandle on Tuesday afternoon. By that time Isaac will have intensified enough to be of hurricane strength, most likely category one. Residents of the Gulf States will have to monitor conditions closely to secure items outside and be ready to evacuate; storm surge along the coast and flooding because of the heavy rains is likely to occur. It will not be uncommon to see rainfall amounts of 100-200mm in the hardest hit areas in the Caribbean and US, however, the more rugged terrain of the islands on the Caribbean could have more devastating effects; landslides and flash flooding.

Isaac track

Isaac’s projected track. (Source: News 13)

In other news around the world, Taiwan has been hit with yet another storm – typhoon Tembin that had sustained winds of 155km/h but struck a less populated area of the country, leaving the large cities like Taipei with only minor flooding and wind damage.

Elsewhere in Weather News: August 18th, 2012

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A Look Worldwide into July, 2012

As reported on Friday, Winnipeg is shaping up to be one of the hottest years since record-keeping began 139 years ago, with July closing out as the 5th hottest month on record for the city. Wondering how the rest of the world faired this past month?

Interestingly, most of the Northern Hemisphere has also experienced extreme temperature anomalies this year. According to the National Climactic Data Center (NCDC), the Northern Hemisphere land surface temperatures this July were 1.19°C above the average, making July 2012 the warmest July in the Northern Hemisphere ever. This year has experienced no shortage of record breaking temps in the Northern Hemisphere – it is now the fourth month in a row that surface land temperature records in this hemisphere have been broken. Canada and the United States have contributed greatly to the record-shattering numbers these past four months but the heat wasn’t confined to North America. South-Eastern Europe has seen conditions almost identical to ours this summer – very dry with record-setting warmth; while Serbia and Bulgaria have been impacted with severe drought this growing season, resulting in severe crop losses. Bulgaria has lost around 10% of its wheat crops due to the sizzling heat, and their maize crops have decimated to the point whereby getting half their average crop will have to suffice. The only countries in the world to have shown significant temperatures below normal this July were Australia, Argentina and parts of the Antarctic.

Temperature anomalies July 2012

July temperature anomalies and circled, areas talked about in EIWN. (Source: NASA Earth Observatory)

Precipitation anomalies July 2012

Precipitation anomalies for July 2012 and circled in red is where severe drought is occurring in South-Eastern Europe. (Source: NCDC)

Arctic Melting

In some areas of the Arctic, July temperatures have exceeded 6°C above average. Arctic ice is continuing to melt at a disturbing rate. The expanse of the Arctic sea’s ice coverage is now at its lowest ever at this time of the year, having dropped even further than measurements from the record-setting year, 2007. In July, almost all of Greenland’s entire ice sheet experienced melting – a “rare event” as described by the National Snow & Ice Data Center (NSIDC). To put things into perspective, sea ice used to reach seven million square kilometers in the 1990s at their minimum, while it has only surpassed five million square kilometers once in the past six years (showing a 29% decrease of minimum sea ice extent in the last few decades). This has lead scientists, like Walt Meier, a scientist at NSIDC, to believe that sea ice could potentially be eliminated by the year 2030 if melting continues at this pace. If this does happen, the ice melt could trigger a domino effect: raising ocean levels, releasing methane from frozen soils, and so on.

Sea ice extent graph

Sea ice extent by year. (Source: NSIDC)

Elsewhere in Weather News: August 11th, 2012

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Barrage of Typhoons Continue to Impact Asia

Haikui, the third typhoon to hit China this month, made landfall on Wednesday affecting over 100,000 people on China’s east coast. Rain, rain and more rain is what the region has experienced these past few weeks as typhoons Saola, Damray and Vincente (reported in previous EIWN posts) have all made landfall. On top of the severe rains brought on by these recent typhoons, Haikui has dumped an additional 200mm in areas where the grounds were already extremely saturated – inland flooding now adding another element of concern for residents.

Haikui track

Haikui’s track as it made landfall on China’s east coast. Forecasted track was as of Wednesday August 8th. (Source: TSR)

Thanks to China’s meteorological authorities who issued a red code warning (most severe) for the city of Shanghai well ahead of the typhoon hitting, many lives were saved as residents had time to vacate the premises. Authorities helped relocate over a million and a half people, mostly from the Shanghai region, before Haikui made landfall, further lessening the risk of casualties in the areas prone to flooding and landslides. Storm surge was also a concern for townships along China’s east coast.

Haikui

Satellite picture of Haikui as it made landfall just south of Shanghai. (Source: Earthweek)

In all, about one million acres of cropland and over six million of China’s residents have been impacted by this major typhoon. Flood damage has been extensive, ranging from roads washed out and stranding tourists and local residents, to homes being washed away by the flash floods. Estimated damage costs from this most recent typhoon are pegged at around the 1.5 billion dollars.

Haikui damage

One of many washed out roads caused by flash flooding in the Zhejiang Province. (Source: Global Times)

Six casualties have been associated with typhoon Haiku to date, however the death toll from the barrage of typhoons since the beginning of July, combined with heavy rains affecting the region, has brought the toll to over 100 people.