It never ends…Storm Dennis follows Storm Clara


Click to enlarge

Storm Dennis, one of the deepest low-pressure centres to have formed in recent years, has brought severe weather to Iceland and many western and central parts of the UK.

Some of the regions now being affected by Dennis were also hit by a preceding storm, Ciara, which brought stronger winds than Dennis but less rain. Nevertheless, rivers were already full and the ground saturated before Dennis’s arrival.

The military has been called in provide assistance in parts of northern England, where rivers have overflowed in recent days.

Click through and check out the photos. The worst waves haven’t hit land [yet?]. They’re up to 100 feet high.

Freezing your butt in North America? Probably not a strong polar vortex!


From Top L, clockwise: Pacific Trough, Arctic High, Alaskan Ridge, Arctic LowSimon Lee

Winter weather patterns in North America are dictated by changes to the polar vortex winds high in the atmosphere, but the most significant cold snaps are more likely influenced by the tropics, scientists have found…

It is already well established that the vortex wind strength influences weather in Europe and Asia, and the study revealed it also has a strong effect on three out of the four main winter weather patterns in North America, giving forecasters an additional tool to understand potentially high-impact weather during winter.

The study, published in Geophysical Research Letters, also revealed that, unlike in Europe, the most extreme cold snaps affecting the whole of North America are not most likely to occur after a weak vortex. Instead, the shape of the vortex and conditions in the tropics were identified as stronger influences of these conditions…

(Researchers) found widespread extreme cold is more common when an area of high pressure extends up to Alaska, and the polar vortex stretches down towards North America – pushing cold Arctic air southward in the lower atmosphere.

The scientists say the influence of the stratosphere on weather patterns, as well as how this interacts with long-term weather patterns in the tropics like El Niño, should be studied further and incorporated into forecasts to improve their accuracy.

Still, awfully complex. Certainly requiring a CPU stronger than my little gray cells. But, my confidence in forecasters incorporating more into their offerings isn’t diminished. Technology keeps on rocking, capabilities continue to grow and expand.

New Mexico – and a wintertime tornado


Click to enlargeAntonio Chiquito/Facebook

❝ Antonio Chiquito was having a relatively normal winter day in Tinian, N.M., on Feb. 17. Temperatures were about 30 degrees, with heavy snow showers, and nothing seemed too out of the ordinary. And then he spotted a tornado — made out of snow.

“I had been at church, and then I came home and took the sheep out,” recalled Chiquito, who lives on the eastern end of the Navajo Nation. “When I was heading inside to warm up, I glanced up and saw the funnel cloud.”

❝ Sure enough, Chiquito’s suspicions were correct: It was a tornado. At first, he was a little frightened, but surprisingly not shocked. He had seen twisters in Tinian before but never following a snow squall.

❝ The National Weather Service in Albuquerque…confirming the funnel as a landspout, which is a tornado that forms from the ground up rather than one that descends from spinning clouds above.

Out-of-the-ordinary weather is now becoming “occasional”. Conservative politicians at a minimum have to acknowledge the existence of real events. Unless they’re president, of course.

Simulation of 2017 Hurricanes and Aerosol Tracking

How can you see the atmosphere? By tracking what is carried on the wind. Tiny aerosol particles such as smoke, dust, and sea salt are transported across the globe, making visible weather patterns and other normally invisible physical processes.

❝ This visualization uses data from NASA satellites, combined with mathematical models in a computer simulation allow scientists to study the physical processes in our atmosphere. By following the sea salt that is evaporated from the ocean, you can see the storms of the 2017 hurricane season.

Examination of Arctic warmth leads straight to the expected cause


Click to enlarge

❝ It normally takes many months to get a paper through peer review and into a journal, but a group of scientists has released their detection and attribution study early, and it’s a stunning indictment. We now know the culprit for the astonishing Arctic warmth of November and December. It seemed very likely that the guilty party was rising greenhouse gasses with Arctic amplification as the accomplice, and that’s JUST what the evidence shows. It’s overwhelming, and the defendants have no choice but to throw themselves upon the mercy of the court.

❝ The analysis shows that even in our present climate that is around a degree warmer than 1900, this heat is unusual, but would happen once every 50-200 years. The odds of it happening in the climate of 1900 are astronomically tiny, however, if we warm another degree, this will be a nearly commonplace event.

The study is here, and for those that do not want to read the whole thing RTFA for the conclusions.

❝ What this study took great pains to do was to show that this warmth is almost certainly not a natural oscillation in the Arctic climate. Such oscillations exist, but when they are subtracted out, this year stands out like a big red sore thumb. Chris Mooney at the Washington Post has a good summary of this study as well.

I’ll leave crayola-sophistry to the climate denial crowd. They have a good couple of years ahead with the government packed by both wings of the Republican Party.

Strangest weather recorded this year — so far


icy imprint left standing in a parking lot in Greenville, North Carolina in FebruaryTrista Stiles

February 2015 wasn’t just the record coldest February in Syracuse, New York. It was also their coldest single month dating to 1903. Their average temperature during the month, taking into account actual highs and lows, was 9 degrees.

By May, the pattern shifted, making record warmth the talk of the Northeast. New Hampshire, Massachusetts, Connecticut and Rhode Island each sweat through their record warmest May. Cities such as Concord, New Hampshire, and Rochester, New York, set record warm Mays. Syracuse just missed out on that lofty pedestal marking their third warmest May.

RTFA for lots more.

It continues, of course. Folks don’t realize that extremes are an expected result of climate change. Even if the defining characteristic is global warming, temperature and humidity changes produce individual weather extremes below as well as above recorded normals. The difference between trends and events.