October 14

NOAA: 85% Chance of La Nina Winter – No Correlation Between October Cold Snaps and Winters To Follow

Graphic credit: Minnesota DNR.

Does Snow in October Mean We’re In For a Rough Winter? The short answer is no. And The Minnesota DNR has the data to back that up: “…So, do early snows tell us anything about the coming winter? In short, no. It appears that an October snow is just an October snow, and has no bearing on the remainder of winter. From 1884 through 2019, 45 out of 136 Octobers in the Twin Cities have seen at least one day with measurable snow. The winters that followed those instances of snowfall have spanned nearly the entire spectrum of possibilities: dry, wet, snowy, cold, warm, and of course, average. In northern Minnesota, where October snows occur most years, the range of winter conditions after those snows is even wider. Even a persistently snowy autumn cannot promise us a brutal remainder of winter…”

85% Chance La Nina Lingers Through Winter. NOAA’s Climate.gov has an update; here’s an excerpt: “…The altered atmospheric circulation of ENSO affects global weather (here’s how that works in general and La Niña in specific). Since ENSO can be predicted months ahead of time, a lot of research has gone into understanding the patterns of ENSO’s global weather impacts. The idea is that if we can predict ENSO, we can get an early picture of what global weather could look like months into the future. A recent study by some of our colleagues at the International Research Institute for Climate and Society (IRI), led by Nathan Lenssen, carefully re-assessed global precipitation (rain, snow, etc.) patterns during ENSO events. They looked at La Niña and El Niño impacts separately, because the impacts are not always opposite. Meaning, although El Niño may be related to a wet winter in one location, La Niña doesn’t necessarily mean a dry winter in that location…”

Halloween Thaw? The last few runs of NOAA’s GFS model looking out nearly 2 weeks hint at a milder, zonal, west-to-east flow aloft by late October, which could be good for a shot at 60F by Halloween. Lower your expectations.

No More Snow Days After Covid-19? These Schools Used Online Learning to Cancel Them. USA TODAY has the post; here’s an excerpt: “…Since students could work online, snow days at Bancroft-Rosalie were already a thing of the past when the pandemic struck. Other districts, including New York City schools, have canceled snow days or are looking into doing away with them because of the prevalence of online schooling. New York leaders said abolishing snow days will help the district fit in as many instructional days as possible.  “When we first started doing it, people weren’t interested in having remote learning during snow days. They thought that was a day kids should have off. People are going to rethink how you can use remote learning now in schools,” Cerny said...”

Graphic credit: Minnesota DNR and State Climate Office.

Tropical Storms Can Sometimes “Supercharge” the Hurricanes That Follow. Here’s an excerpt from a new study highlighted at National Geographic: “…But new science shows that Gordon’s effects, in conjunction with a heat wave over the region in its wake, helped Michael intensify into the strongest storm ever to make landfall in the Florida Panhandle. The scenario “supercharged the ocean battery” that powered the very intense hurricane, says Dzwonkowski. Tropical cyclones feed on hot ocean waters. Warm water acts as storehouse of energy that storms can draw on, like a battery: the hotter the water, or the more of it there is, the more energy can be transferred into the air above. Cold water, in contrast, can drain energy from a storm…”

October 9, 2018 file image of Hurricane Michael: AerisWeather.

Wildfire Smoke Travels Far But Never Really Disappears. Popular Science has an interesting post with data I wasn’t aware of – here’s an excerpt: “…Just as local weather impacts smoke movement, so too can smoke change local weather patterns, says Clements. When smoke shades the incoming rays of light, the temperature differential between the shaded and unshaded portions of air can create a “density current” in which air flows from areas of high to low pressure, often in the opposite direction of the prevailing wind. These currents can carry smoke particles far from the origin of the fire. This “smoke shading” can also suppress ambient wind. A warm and sunny day spurs convection currents, Clements explains. “Eddies and thermals form, which makes the atmosphere more turbulent at the surface,” he says...”

Image credit: “A massive cloud of smoke on September 9, 2020.” NASA Earth Observatory.

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