Friday 30 November 2012

SA National Severe Weather Warnings: 30 November 2012 16h00 SAST



Current warning: Eastern Cape Province
Updated: 30/11/2012 15:48:25
Validity: 2012-11-30 to 2012-11-30
Type: Watch. Be prepared
Subject: Heavy rainfall
Detail: 1. Heavy rainfall is expected in the north-east parts of the Eastern Cape.


Current warning: Free State Province
Updated: 30/11/2012 15:48:25
Validity: 2012-11-30 to 2012-11-30
Type: Watch. Be prepared
Subject: Severe Thunderstorms
Detail: 1. Severe thunderstorms are expected over the north-eastern Free State.


Current warning: Kwazulu Natal Provinces
Updated: 30/11/2012 15:48:25
Validity: 2012-11-30 to 2012-11-30
Type: Warning. Take action
Subject: Heavy rainfall, Severe Thunderstorms
Detail: 1. Heavy rainfall is expected in places over KwaZulu-Natal. 2. Severe thunderstorms are expected over the western and central parts of KwaZulu-Natal.


Current warning: Western Cape Province
Updated: 30/11/2012 15:48:26
Validity: 2012-11-30 to 2012-12-01
Type: Watch. Be prepared
Subject: Gale force winds, Extremely uncomfortable
Detail: 1. Gale force south-easterly winds of 35kt or 65km/h can be expected between Cape Columbine and Cape Agulhas till tomorow morning. 2. Extremely uncomfortable, humid conditions will be experienced in places over the West Coast District.


Current warning: All other Provinces
Updated: 30/11/2012 15:48:25
Validity: 2012-11-30 to 2012-11-30
No warnings nor advisories in effect
Subject: No Alerts
Detail: No Alerts

- SAWS

SA Weather Satellite Image: 30 November 2012 15h15 SAST



Images: SAT24 (Click on images for larger view.)

Tornado vs motorist on the N1 highway

Aileen Hutchinson managed to take a photo of the twister funnel forming with her phone.

Aileen Hutchinson, a Tzaneen resident, had a close encounter of a different kind while driving between Pretoria and Polokwane.

http://www.looklocal.co.za/looklocal/content/en/tzaneen-and-surrounds/tzaneen-and-surrounds-news-general?oid=6582046&sn=Detail&pid=4981439&Tornado-vs-motorist-on-the-N1-highway

- Letaba Herald (LookLocal)

Wind wreaks havoc in Cape - Western Cape | IOL News | IOL.co.za

A roof which blew off a house in Oldfield Road, Sea Point, damaged seven cars, a Vespa, power lines, a lamppost and facades of buildings. Picture: Matthew Jordaan/ Cape Argus

 Wind wreaks havoc in Cape - Western Cape | IOL News | IOL.co.za

Photos: SA Weather Observation: South Africa (30 November 2012)


Rhea Morar - Storm about to hit Chatsworth Durban. Rain and thunder right now.



Shaun Matthews - Looks like a big storm on its way to Durban


Rhea Morar - Crazy low cloud activity - Durban.


Rhea Morar - In 2 mins, its a massive downpour. Cannot see for more than a few meters.



Andre Fletcher - Dark clouds, thunder and lightening currently active over Durban CBD.


crisismeddbn Crisis Medical - @TrafficSA @MetroGalZN @jvbtrafficguy: Storm as seen from La Lucia Ridge #durban


Samantha - Storm rolling in over #durban #beachfront


FraserMcH - Storm approaching #Ballito


@gordsreid - Big storm coming, angry skies



Crisis Medical - @TrafficSA @MetroGalZN @jvbtrafficguy: Storm from Umhlanga beach. Dumping a lot of water over Durban North right now.


pillaym - Higgenson Highway Chatsworth..Flooded


Malcolm Duke - near Ballitoville, KwaZulu-Natal
View from ballito looking south.


Dee de Souza - Now cloudy cool with intermittent drizzle. 8.50am. Overlooking Assagay from Hillcrest


Francis Proudfoot Lanham - Pic of this beautiful cloud outside Winterton taken by my daughter.


Zs-one Tp Jakes - Kalk Bay area, 30 November 2012, Cape Doctor (South Easter) still blowing like crazy. Very rough seas! Photo taken facing +- SSW.


SA National Severe Weather Warnings: 30 November 2012 04h00 SAST



Current warning: Limpopo Province
Updated: 30/11/2012 05:45:10
Validity: 2012-11-30 to 2012-11-30
Type: Warning. Take action
Subject: Extremely uncomfortable
Detail: 1. Extremely uncomfortable, humid conditions can be expected over the lowveld.


Current warning: Western Cape Province
Updated: 30/11/2012 05:45:10
Validity: 2012-11-30 to 2012-11-30
Type: Warning. Take action
Subject: Gale force winds, Veldfires
Detail: 1. Gale force south-easterly winds of 35kt or 65km/h can be expected between Cape Columbine and Cape Agulhas today and tomorrow. 2. A high veldfire danger expected over the Cape Winelands tomorrow.


Current warning: All other Provinces
Updated: 30/11/2012 05:45:10
Validity: 2012-11-30 to 2012-11-30
No warnings nor advisories in effect
Subject: No Alerts
Detail: No Alerts

- SAWS

SA Weather Satellite Image: 30 November 2012 06h00 SAST


Image: Eumetsat (Click on image for larger view.)

GFS Medium Range Forecasts of Vertical Velocity and Precipitation: South Africa



Images: U.S. National Center for Environmental Prediction (NCEP)+ 1stweather.com

Ice Sheet Loss at Both Poles Increasing, Study Finds

The midnight sun casts a golden glow on an iceberg and its reflection in Disko Bay, Greenland. Much of Greenland's annual ice mass loss occurs through calving of icebergs such as this. Image credit: Ian Joughin, University of Washington › Full image and caption

PASADENA, Calif. - An international team of experts supported by NASA and the European Space Agency (ESA) has combined data from multiple satellites and aircraft to produce the most comprehensive and accurate assessment to date of ice sheet losses in Greenland and Antarctica and their contributions to sea level rise.

In a landmark study published Thursday in the journal Science, 47 researchers from 26 laboratories report the combined rate of melting for the ice sheets covering Greenland and Antarctica has increased during the last 20 years. Together, these ice sheets are losing more than three times as much ice each year (equivalent to sea level rise of 0.04 inches or 0.95 millimeters) as they were in the 1990s (equivalent to 0.01 inches or 0.27 millimeters). About two-thirds of the loss is coming from Greenland, with the rest from Antarctica.

Monthly changes in Antarctic ice mass, in gigatones, as measured by NASA's Gravity Recovery and Climate Experiment (GRACE) satellites from 2003 to 2011. Image credit: NASA-JPL/Caltech; NASA GSFC; CU-Boulder; Technical University of Munich; Technical University of Denmark; Delft University of Technology, Aerospace Engineering, Netherlands; Durham University, UK; Leeds University, UK

This rate of ice sheet losses falls within the range reported in 2007 by the Intergovernmental Panel on Climate Change (IPCC). The spread of estimates in the 2007 IPCC report was so broad, however, it was not clear whether Antarctica was growing or shrinking. The new estimates, which are more than twice as accurate because of the inclusion of more satellite data, confirm both Antarctica and Greenland are losing ice. Combined, melting of these ice sheets contributed 0.44 inches (11.1 millimeters) to global sea levels since 1992. This accounts for one-fifth of all sea level rise over the 20-year survey period. The remainder is caused by the thermal expansion of the warming ocean, melting of mountain glaciers and small Arctic ice caps, and groundwater mining.

The study was produced by an international collaboration -- the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) -- that combined observations from 10 satellite missions to develop the first consistent measurement of polar ice sheet changes. The researchers reconciled differences among dozens of earlier ice sheet studies by carefully matching observation periods and survey areas. They also combined measurements collected by different types of satellite sensors, such as ESA's radar missions; NASA's Ice, Cloud and land Elevation Satellite (ICESat); and the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (GRACE).

"What is unique about this effort is that it brought together the key scientists and all of the different methods to estimate ice loss," said Tom Wagner, NASA's cryosphere program manager in Washington. "It's a major challenge they undertook, involving cutting-edge, difficult research to produce the most rigorous and detailed estimates of ice loss from Greenland and Antarctica to date. The results of this study will be invaluable in informing the IPCC as it completes the writing of its Fifth Assessment Report over the next year."

Professor Andrew Shepherd of the University of Leeds in the United Kingdom coordinated the study, along with research scientist Erik Ivins of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Shepherd said the venture's success is because of the cooperation of the international scientific community and the precision of various satellite sensors from multiple space agencies.

Over the course of several years, turbulent water overflow from a large melt lake carved this 60-foot-deep (18.3 meter-deep) canyon Image credit: Ian Joughin, University of Washington

"Without these efforts, we would not be in a position to tell people with confidence how Earth's ice sheets have changed, and to end the uncertainty that has existed for many years," Shepherd said.

The study found variations in the pace of ice sheet change in Antarctica and Greenland.

"Both ice sheets appear to be losing more ice now than 20 years ago, but the pace of ice loss from Greenland is extraordinary, with nearly a five-fold increase since the mid-1990s," Ivins said. "In contrast, the overall loss of ice in Antarctica has remained fairly constant, with the data suggesting a 50-percent increase in Antarctic ice loss during the last decade."

For more on ICESat, visit: http://icesat.gsfc.nasa.gov . For more on GRACE, visit: http://www.csr.utexas.edu/grace .

The California Institute of Technology in Pasadena manages JPL for NASA.
Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
alan.buis@jpl.nasa.gov

Steve Cole 202-358-0918
NASA Headquarters, Washington
Stephen.e.cole@nasa.gov

Esther Harward 44 113 343 4196
University of Leeds, United Kingdom
e.harward@leeds.ac.uk

New Evidence for Ice on Mercury

Nov. 29, 2012: New data from NASA's MESSENGER spacecraft suggest that there's enough ice on Mercury to encase the entire US capitol.

"The new data indicate the water ice in Mercury's polar regions, if spread over an area the size of Washington, D.C., would be more than 2 miles thick," said David Lawrence, a MESSENGER participating scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., and lead author of one of three papers describing the findings in the online edition of Science Express.


Mercury's north pole. Red denotes areas that are in shadow in all images acquired by MESSENGER to date. (The mapping of shadows is still incomplete near the pole.) Yellow shows the locations of bright polar deposits imaged by Earth-based radar. Updated from N. L. Chabot et al., Journal of Geophysical Research, 117, doi: 10.1029/2012JE004172 (2012).

Given its proximity to the Sun, Mercury would seem to be an unlikely place to find ice. But the tilt of Mercury's rotational axis is almost zero -- less than one degree -- so there are pockets at the planet's poles that never see sunlight. Scientists suggested decades ago that water ice might be trapped in those shadowed areas at Mercury's poles.

The idea received a boost in 1991, when the Arecibo radio telescope in Puerto Rico detected unusually radar-bright patches at Mercury's poles, spots that reflected radio waves in the way one would expect if there were water ice. Many of these patches corresponded to the location of large impact craters mapped by the Mariner 10 spacecraft in the 1970s. But researchers weren't sure if the radar-bright patches detected by Arecibo corresponded to shadowy places in the craters.

MESSENGER's arrival at Mercury last year changed that. Images from the spacecraft's Mercury Dual Imaging System taken in 2011 and earlier this year show that radar-bright features at Mercury's north and south poles are within shadowed regions on Mercury's surface.

Now, the newest data from MESSENGER confirm that water ice is the major constituent of Mercury's north polar deposits. In the coldest places, the ice is exposed on the surface. In slightly warmer spots, some kind of dark insulating material appears to cover the ice.

MESSENGER uses neutron spectroscopy to measure average hydrogen concentrations within Mercury's radar-bright regions. Ice concentrations are derived, in turn, from the hydrogen measurements. This is possible because water, or H2O, is two parts hydrogen.

"The neutron data indicate that Mercury's radar-bright polar deposits contain, on average, a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer 10 to 20 centimeters thick that is less rich in hydrogen," says Lawrence. "The buried layer has a hydrogen content consistent with nearly pure water ice."

Data from MESSENGER's Mercury Laser Altimeter (MLA) -- which has fired more than 10 million laser pulses at Mercury to make detailed maps of the planet's topography -- corroborate the ice hypothesis, writes Gregory Neumann of the NASA Goddard Flight Center. In a second paper, Neumann and his colleagues report that the first laser measurements of the shadowed north polar regions reveal irregular dark and bright deposits near Mercury's north pole.
"Nobody had seen these dark regions on Mercury before, so they were mysterious at first," Neumann says.

Neumann suggests that both the dark and bright materials were brought to Mercury by comets or asteroids, a finding corroborated in a third paper led by David Paige of the University of California, Los Angeles.
"The dark material is likely a mix of complex organic compounds delivered to Mercury by the impacts of comets and volatile-rich asteroids, the same objects that likely delivered water to the innermost planet," Paige says.

This dark insulating material is a new wrinkle to the story, adds Sean Solomon of the Columbia University's Lamont-Doherty Earth Observatory, principal investigator of the MESSENGER mission. "For more than 20 years the jury has been deliberating on whether the planet closest to the Sun hosts abundant water ice in its permanently shadowed polar regions. MESSENGER has now supplied a unanimous affirmative verdict."

"But the new observations have also raised new questions," adds Solomon. "Do the dark materials in the polar deposits consist mostly of organic compounds? What kind of chemical reactions has that material experienced? Are there any regions on or within Mercury that might have both liquid water and organic compounds? Only with the continued exploration of Mercury can we hope to make progress on these new questions."

Stay tuned to Science@NASA for answers.


Production editor: Dr. Tony Phillips | Credit: Science@NASA

Thursday 29 November 2012

SA National Severe Weather Warnings: 29 November 2012 16h00 SAST



Current warning: Limpopo Province
Updated: 29/11/2012 15:36:39
Validity: 2012-11-30 to 2012-11-30
Type: Warning. Take action
Subject: Extremely uncomfortable
Detail: 1. Extremely uncomfortable, humid conditions can be expected over the lowveld.


Current warning: Western Cape Province
Updated: 29/11/2012 15:36:39
Validity: 2012-11-29 to 2012-11-30
Type: Warning. Take action
Subject: Gale force winds, Veldfires
Detail: 1. Gale force south-easterly winds of 35kt or 65km/h can be expected between Cape Columbine and Cape Agulhas today and tomorrow. 2. A high veldfire danger expected over the Cape Winelands tomorrow.


Current warning: All other Provinces
Updated: 29/11/2012 15:35:47
Validity: 2012-11-29 to 2012-11-29
No warnings nor advisories in effect
Subject: No Alerts
Detail: No Alerts

- SAWS

SA Weather Satellite Image: 29 November 2012 16h00 SAST


Image: Eumetsat (Click on image for larger view.)

Weather History: Riebeeckstad / Welkom Tornado 20 March 1990



Who still remember the Welkom Tornado that occurred on 20 March 1990? Here is a video that was posted on Youtube.

Photos: Weather Observation: South Africa (29 November 2012)


Zs-one Tp Jakes - Fish Hoek this morning, 29 November 2012. Very windy, rough seas! The Cape Doctor is doing his magic!


Pieta Myburg - Bloemfontein @ 12:48


Zs-one Tp Jakes - 29 Nov 2012. It is a windy day down at the waterfront. The flag poles are bending. Temperature I guess is in the low 20's.


Marida Jooste - Kestell op die oomblik wind en reen met tye, kyk uit vir wind.


Ziyaad Warasally - Clouds building up over the Besters area


Francis Proudfoot Lanham - Strange clouds outside Winterton


Sheldon Strydom - Storm structure outside Balgowan, KZN this afternoon. Wasn't the most successful chase.


SA National Severe Weather Warnings: 29 November 2012 04h00 SAST


Current warning: Kwazulu Natal Province
Updated: 29/11/2012 05:12:51
Validity: 2012-11-29 to 2012-11-29
Type: Warning. Take action
Subject: High discomfort and Severe thunderstorms
Detail: 1. extremely uncomfortable, humid conditions can be expected over the north-eastern parts of the KwaZulu-Natal province. 2. (Watch)Severe thunderstorms are possible in the KwaZulu-Natal province.

Current warning: Limpopo Province
Updated: 29/11/2012 05:12:51
Validity: 2012-11-29 to 2012-11-29
Type: Warning. Take action
Subject: High Discomfort
Detail: 1. extremely uncomfortable, humid conditions can be expected over the southern lowveld of the Limpopo province.

Current warning: Mpumalanga Province
Updated: 29/11/2012 05:12:51
Validity: 2012-11-29 to 2012-11-29
Type: Warning. Take action
Subject: High Discomfort
Detail: 1. extremely uncomfortable, humid conditions can be expected over the lowveld of the Mpumalanga province.

Current warning: Western Cape Province
Updated: 29/11/2012 05:12:51
Validity: 2012-11-29 to 2012-11-29
Type: Watch. Be prepared
Subject: Gale force winds
Detail: 1. Gale force south-easterly winds of 35kt or 65km/h can be expected between Cape Columbine and Cape Agulhas.

Current warning: All other Provinces
Updated: 29/11/2012 05:12:51
Validity: 2012-11-29 to 2012-11-29
No warnings nor advisories in effect
Subject: No Alerts
Detail: No Alerts

- SAWS

SA Weather Satellite Image: 29 November 2012 05h30 SAST


Image: SAT24 IR (Click on image for larger view.)

Possible 24 hour rainfall: South Africa (29 November 2012)


Image: 1stweather.com (Click on image for larger view.)

Large, violent tornado caught on video in Italy on November 28


A large and violent tornado struck southern Italy earlier today (November 28, 2012.)

As of now, at least 20 people that were injured from this tornado. There are already unconfirmed reports of at least three deaths from this destructive tornado.

Tornadoes are generally a rare phenomenon, but they do occur in Europe and are not completely unusual. Tornadoes and severe weather are typically common in the fall and spring months of the year as weather transitions from warm air masses to cooler air masses and vice versa.

Check out this amazing video. Pray that everyone that was impacted by this tornado and the other severe storms in this region are safe and sound.



Check out this amazing video of the same tornado that created a fire in the city.



Bottom line: A large, violent tornado struck Taranto, Italy earlier today (November 28, 2012) that has resulted in at least 20 injuries.

- EarthSky

Dust Storm over the Gobi Desert



The Gobi Desert stretches over parts of southern Mongolia and northern China. Home to a variety of landscapes, from grassy plain to bare rock to sand sea, this desert is one of the world’s most prolific dust-producing regions. On November 27, 2012, a dust storm struck the Gobi Desert, and the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured a natural-color image the same day.

Both sand seas and impermanent lakes occur along the China-Mongolia border, and dust plumes arose from multiple locations in this region in late November. Some of the dust on November 27 apparently arose from the fine sediments around Gaxun Nur, an impermanent lake just south of the Mongolia border. Those lakebed sediments were lighter in color than the camel-colored dust to the east. Blowing eastward across China, some of the dust likely came to rest on snow cover south of the Mongolia borer.

The top image provides a wide-area view. Despite the dust plumes and clouds, this image includes areas of clear sky, and skies were clear over the Badain Jaran Desert (Badain Jaran Shamo) of northern China. The bottom image is a close-up of the area outlined in white in the top image. The Badain Jaran Desert boasts some of our planet’s most complex sand dune features, although this desert did not appear to supply much material for the November 27 dust storm.
  1. References

  2. World Wildlife Fund. (2012, August 8) Eastern Gobi desert steppe. Encyclopedia of Earth. Accessed November 27, 2012.
  3. University Corporation for Atmospheric Research. Forecasting Dust Storms. (Registration required).
NASA image courtesy Jeff Schmaltz, LANCE MODIS Rapid Response. Caption by Michon Scott.
Instrument: 
Aqua - MODIS- NASA

Wednesday 28 November 2012

SA National Severe Weather Warnings: 28 November 2012 16h00 SAST



Current warning: Kwazulu Natal Province
Updated: 28/11/2012 15:02:25
Validity: 2012-11-28 to 2012-11-28
Type: Warning. Take action
Subject: High discomfort and Severe thunderstorms
Detail: 1. Extremely uncomfortable, humid conditions can be expected over the north-eastern parts of the KwaZulu-Natal province. 2. (Watch)Severe thunderstorms are possible in the KwaZulu-Natal province.


Current warning: Limpopo Province
Updated: 28/11/2012 15:02:25
Validity: 2012-11-28 to 2012-11-28
Type: Warning. Take action
Subject: High Discomfort
Detail: 1. extremely uncomfortable, humid conditions can be expected over the southern lowveld of the Limpopo province.


Current warning: Mpumalanga Province
Updated: 28/11/2012 15:02:25
Validity: 2012-11-28 to 2012-11-28
Type: Warning. Take action
Subject: High Discomfort
Detail: 1. extremely uncomfortable, humid conditions can be expected over the lowveld of the Mpumalanga province.


Current warning: Western Cape Province
Updated: 28/11/2012 15:02:25
Validity: 2012-11-28 to 2012-11-28
Type: Watch. Be prepared
Subject: Gale force winds
Detail: 1. Gale force south-easterly winds of 35kt or 65km/h can be expected between Cape Columbine and Cape Agulhas.


Current warning: All other Provinces
Updated: 28/11/2012 15:02:25
Validity: 2012-11-28 to 2012-11-28
No warnings nor advisories in effect
Subject: No Alerts
Detail: No Alerts

- SAWS

SA Weather Satellite Image: 28 November 2012 17h00 SAST


Image: Eumetsat (Click on image for larger view.)

SA Weather Observation: South Africa (28 November 2012


Zs-one Tp Jakes - 28 November 2012 - It is a hot day in Cape Town! If you look just to the right of the Ferris Wheel, you can see the puff of smoke from the Noon Gun on Signal Hill. — at V & A Waterfront.


Ziyaad Warasally - Storm clouds moving in over Ladysmith, distant thunder rumbling — at Ladysmith KZN.


Zs-one Tp Jakes - This was sunset last night (27 November 2012) there was a fairly strong breeze (maybe a light wind) from the South East. Photo taken facing in a westerly direction, Noordhoek Area


ka_Gwata Mzukisi - Distant CB possibly over eKurhuleni.



JennzaLynn Jen - Clouds over Pietermaritzburg Thought I'd share.


K2La Ketula - #Boskruin sky. I won't cry if it rains


Eugene Steyn - TS building to the East of Centurion


Kaveer_24 - Look of the clouds in northwold. Slight thunder.


DanielGHolmes - Big thunderstorm approaching Roodepoort.



PC - Bloem sshhhhhhh don't say a word!



Ludwig @7HighFlyer7 - Clouds looking awesome on the Westrand tonight!



Anet Basson - Rainbow in the strange clouds in Wilropark, Roodepoort.



Sam - Looking ominous in Sandton right now.



Stofffel Steyn - Cloudy and look like rain in Glen Marais Kempton Park 18:52



Rossi Marx - Awesome clouds coming down CR Swart,Roodepoort near Roodekrans. 18:40



Carin ♡ - 18:53 Greenstone Hill Edenvale thunder and lightning some serious weather on the way!



Tracey van Heerden - Midstream , Centurion - No thunder , no wind.



Tracey van Heerden - Midstream Centurion



Stofffel Steyn - Pic of lightening



Claudia Voget - Beautiful clouds outside earlier - and the most magnificent blue skies behind this cloud - Happy Wednesday!