It’s midwinter in the northern hemisphere and midsummer in the southern, and the weather is a lot of what you’d expect: Dangerously icy conditions in the US; tropical downpours in Africa; two new reports showing that 2014 featured unabated global warming, especially in the arctic.
Let’s go Around The World.
Slippin’ And a-Slidin’: Massive Car And Truck Pileup On Icy Roads In Philly On Sunday
Dangerous Weather Event Fennel caused a smashup of 50-plus vehicles in Philadelphia on Sunday, as temperatures hovered just below freezing at the surface, while warmer, saturated air surged in from the Atlantic just above the ground. This is the recipe for freezing rain, and roads were covered with a slick glaze.
Fennel is an ongoing event, as arctic air plunges south into the eastern United States on the western side of a lobe of the polar vortex, then holds its position near the surface due to its high density as warm air from nearby bodies of water overruns it periodically. New cold fronts are expected this week, and another round of freezing rain is possible next weekend. Slippin’ and Slidin’ could occur anywhere from Texas through the Mississippi Valley to the mid- or north Atlantic coast.
Flooding In Malawi
At least 176 people have been killed, with many more still unaccounted for, in flooding in the southern part of Malawi and adjacent Mozambique. Heavy rain is common during the African summer; 90% of Malawi’s 40 inches of annual precipitation falls from November to April, with a peak in January.
The affected region is between 15 and 20 degrees south latitude. In the southern hemisphere’s winter (May to October), tropical moisture moves north and high pressure from the sub-tropics settles over the area. Little or no rain falls in most winter seasons.
An entirely different weather regime brings heavy rain in the summer half of the year, especially the months December through March. Tropical easterly trade winds deliver moisture from the Indian Ocean; instability associated with the intertropical convergence zone wrings out the moisture.
This year’s massive floods threaten to eclipse the historic deluge of March, 1991, which killed nearly 500. Another round of heavy rain is possible later this week, as additional moisture from the remnants of tropical cyclone Chedza reaches the area.
Tropical Cyclone Mekkhala Swerves Away From Manila As Pope Commemorates Haiyan Victims
A visit by Pope Francis to the Philippines to commemorate the 7,000 victims of 2013’s Super-Typhoon Haiyan was threatened by a tropical cyclone, but the 50-mile-per-hour storm veered north at the last moment, allowing the Pope, attired in a plastic raincoat, to hold a service in Manila.
Divine intervention? You decide. Meteorologists only know the atmospheric flow changed slightly to push Mekkhala farther north than they had initially anticipated.
December, 2014 And Full-Year 2014 Are Warmest Ever
NOAA and NASA have both issued their final accounting of temperature for December and full-year 2014. It was a foregone conclusion that temperatures would set new records. December was the sixth month of the year to establish a new record for warmth; 2014 is the hottest on record and the first to break the old record in a year in which there was no official El Niño.
Decoded Science will have a full review of the data on Wednesday.
In a separate report, NOAA finds that the arctic is warming at twice the rate of the rest of the world.
Measurements of the albedo over Greenland confirm the feedback mechanism that is suspected to be at work: The reduction in ice cover is lowering the albedo, the reflective power of the surface of the earth.
As result, the ground is absorbing more of the sun’s radiation and in turn heating the arctic atmosphere.
Winter’s Not Over In Northern Europe, But Extreme Weather Event Courgette Has Ended
The unusually cold and windy weather that northern Europe has experienced the last month, named Extreme Weather Event Courgette by Decoded Science, is officially over.
The weather in that region will return to normal, which is to say merely awful rather than abominable. Temperatures will moderate and winds will calm down to simply strong as opposed to hurricane-force.
Who’s Winning The WAR?
The acronym for Weather Around the World (WAR) is a fitting description of what goes on in the atmosphere. Decoded Science has pointed out that one of the flashpoints in this ongoing battle is between the nascent El Niño and the unusually warm water in the eastern North Pacific. El Niño had the upper hand for a while and brought heavy rain to southern California. But recently the omega block of high pressure in the jet stream has returned to the west coast.
Long term forecasts suggest that a continuation of this pattern will keep El Niño at bay — and keep the eastern part of the United States in a deep freeze.
On the other side of the Atlantic, the jet stream flow has eased, Courgette is over, and a new pattern is emerging, with a southern branch of the jet stream bringing storms to northern Africa.
Another Year. Another New Record For Warmth?
The average global air and sea temperature in 2014 was 58.24 degrees Fahrenheit. If Las Vegas was setting odds, the over/under for 2015 would probably be 58.31, an increase of the same amount by which 2014 broke the old record.
As the global air and sea temperatures set new monthly and yearly records, flora and fauna are changing their ranges and habits. How is global warming affecting things where you live?
Decoding Science. One article at a time.