Another peak at winter

Could be a roller coaster IF analog years are right

In this peak I am adding additional factors such as matches to this years active hurricane season, and the Ouasi-Biennial Oscillation QBO (high stratosphere wind cycle) currently expected to be +West. The final winter outlook issued by early November will factor in many other signals.

Since much of this is still leaning heavily on the El Nino Southern Oscillation (ENSO) signal it is worth noting that in the past decade or so what we think of as typical ENSO climate behavior has not shown up, in other words El Nino and La Nina seasons recently are no longer behaving like they usually did in the past.

The modern trend has been for an El Nino winter to be warm with little or no snow/ice and for a La Nina winter to be highly variable on both temperature and precipitation ending up about 50/50 as to how it averages out over the course of a whole winter.

Last winter the ENSO condition and the atmosphere rarely seemed to be in-sync. If anything they were largely at odds.

Having said that, here is the latest analog list and what they show.

For those new to following my blog or who are used to getting entertainment weather instead of meteorology let me repeat what analog years are. You can search the web for more on ENSO, El Nino, La Nina on your own if you like.

Analogs are examples from the past which come CLOSE to matching current or expected conditions in the oceans, atmosphere, stratosphere and solar cycle. You then composite all of those close matches from history to see what they suggest MAY happen in the future.

[Analog: A person or thing seen as comparable to another]

When meteorologists assemble a long-term weather forecast, such as a winter or summer forecast, they will examine current atmospheric conditions and look for previous years with similar conditions. This is considered an analog forecast. Think of the word analogous.

Forecasters take these years with the most similar global weather pattern, then map the temperature and precipitation outcome for the United States. The maps shown represent a compilation or composite of the years listed to come up with an aggregate impact for the December through February time frame.

But remember just like they say in financial circles: “Past performance does not guarantee future results."

CURRENT ANALOG RESULTS FOR WINTER 2020-21:

In terms of SNOWFALL, the average of the analog years was 1.11 inches. (The long-term average snow for Atlanta is officially 2 inches at Hartsfield Airport). The range was a low of zero and a high of 4.7 inches.

Out of the 13 analog years 8 (62%) had at least a coating of snow while 5 had none, 4/13 (31%) had an inch or more snow.

The analog years from the historical data showed a cold November, a warm December, a near-normal to cooler January, and a slightly milder than normal February:

For precipitation the analog years showed a slightly wet December, a near-normal January, and a dry February:

And what about those Farmers Almanac’s? Here is what they show in their somewhat vague maps, for details you’ll have to buy and read them:

For daily updates follow me on Twitter @MellishMeterWSB.

Kirk Mellish

Meteorologist

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