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The Leeroy Jenkins Factor

Andrew Freedman @ 9:46 AM

In weather as in life, teamwork is essential. A storm, be it a severe thunderstorm, a noreaster or a hurricane, is never the result of any single actor, but rather the product of a combination of ingredients working together as an interlocking system.

Jason Samenow's Forecast

Forecast Confidence: Medium-HighToday: Cloudy with occasional late rain especially this afternoon. Any morning rain may mix with sleet. Highs in the mid 40s.
Tonight: Cloudy with rain, lows 35-40
Monday: Clearing skies, very windy (gusts over 40mph possible) and cool. Highs in the upper 40s.

Such teamwork might result in raindrops on your head one spring afternoon, a gentle rain that nudges delicate cherry blossoms off the trees one by one, as if each drop was destined to serve that purpose. Or it could cause snow in early December, the kind of snow that reaches into your childhood as it coats the ground.

Forecasting the evolution of such systems requires anticipating exactly how each player is going to enter into and then play the game. Is the cold high bluffing and it really intends to retreat to the north, thereby allowing warm air into a coastal storm that will change snow to rain? Or does it have a full house to back itself up?

Forecasting demands trust that the different moving parts of the atmosphere are going to come together to form the kind of team you think they will, and will then play the game very close to how you anticipate. A single factor can throw the game into disarray, and turn a good forecast into a bust.

The history of forecasting blunders is replete with examples of bad bets, and of
"Leeroy Jenkins" situations in which the atmosphere refuses to cooperate with the best laid plans (see also this wikipedia reference). These are scenarios in which one player, such as the wimpy High, destroys the overall game plan with one unanticipated, unilateral move.

The individual components of a storm are not at all interesting to the typical weather consumer who is concerned primarily with the end product of the atmosphere, such as rain, snow or wind, rather than the process that went into creating such phenomena. (Although it would remove a major source of loneliness for me if it turned out that normal people care about things like where the mid level low is going to be located). Correctly analyzing and anticipating the evolution of each element is essential to making an accurate forecast.

As I write this, for example, a storm is sauntering across the Midwest, preparing to lunge eastward into New England. The atmospheric elements are starting to come together for a nasty (i.e. fun) spell of weather in the northeast, as a deep fetch of warm air at the low and mid levels gets dragged north, up and over a dome of dense, cold air.

Computer models and meteorological intuition suggest that a low pressure center will redevelop along the east coast and morph into a strong coastal storm in the Gulf of Maine in the near future, plastering that state in snow by Monday night while bringing the dreaded "wintry mix" of freezing rain, sleet and boring old rain to the rest of New England.

I, along with other snow lovers in the Boston area, am hoping for a Leeroy Jenkins in this situation, because I need one element to come out of line that in turn causes changes that ripple down the snow supply chain until enough cold air wraps into the storm for a rain/sleet mix in Boston to change back to snow and accumulate.

Such an outcome, however, requires a change to occur within the team dynamic in a very precise way. A Leeroy Jenkins could easily tip the balance further towards rain, or prohibit the storm from intensifying in the first place.

Some weather forecasters would probably prefer that they always be right, since it is, after all, their job to be accurate. However, unexpected moments in weather, as in life, are a big part of what I live for. I'm obsessed with the weather precisely because it can't be predicted 100 percent. What is predictable is boring and to be shunned like a bad sitcom. Give me an atmospheric Leeroy Jenkins any day over continuous forecasting successes.

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