Posts

Doug Simonian

From Strong El Nino to Strong La Nina?

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Over the past few months, we have had an El Nino. In fact, it has been one of the strongest El Ninos on record, and is one of the reasons why this past winter was generally quite warm, and why the Pacific Jet stream was so fast and active. It also helped to trigger the historic blizzard we had on January 22nd-23rd. Currently, while we still have an El Nino at the surface, conditions are rapidly flipping towards La Nina when one takes a deeper look at the oceans, as well as the trends in the climate models.

Under “normal” conditions, where there is no El Nino nor a La Nina, the trade winds are persistent in the Equatorial Pacific, which generally blow from east to west. This “pushes” the warmest Equatorial waters further west towards Australia and Indonesia, leaving cooler waters in their wake with more upwelling of subsurface cool water as well. Over the past year or so, these trade winds rapidly weakened and even reversed in some areas, allowing warm water to flow back eastward (instead of getting forced westward) towards the entire Equatorial Pacific, spreading eastward towards Peru. As warmer water builds, Oceanic Kelvin waves, which move from west to east — but also move up (upwelling) and down (downwelling) to transport warm or cool water vertically — are able to push warm water to strong depths and generate “pools” of warm water. This allows an El Nino to sustain itself, as even when a brief period of trade wind acceleration takes place and more upwelling happens, the water upwelled is still warm. It can take months to fully reserve a new El Nino equilibrium.

But finally, the proverbial rubber band is snapping.

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Miguel Pierre

Increasing signals for a January pattern change

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Meteorological winter began about three weeks ago. Over the next 10 days, it appears the pattern will be un-supportive of winter weather — and may further support record breaking warmth. But some changes maybe underway for the New Year. Our long range outlook will discuss the meteorological pattern for the upcoming 30 to 45 days. With an in depth look into meteorological patterns and the developing global circulations, we’ll explain the processes occurring that will drive our weather pattern for late this month and January.

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Miguel Pierre

Here’s Why the Warmth This December Has Been Historic

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With the release of our Winter Forecast came the news that December was likely to average above normal in terms of temperature. Historically, almost all Strong El Nino events featured warmer than normal December’s in the Eastern US. The warmth this December, however, has been far more exceptional than anticipated. Temperatures have been well above average for almost all of the month. Multiple record highs have been broken in New Jersey and New York’s climate reporting stations. And, even still, a more anomalous warm surge is expected during the period of time near Christmas through New Years.

Currently, temperatures are running around 10 degrees above average. At this rate, extrapolating forward, December could average more than 5 degrees above normal. The meteorological reasoning behind this exceptional event features a juxtaposition of some very anomalous features:

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John Homenuk

Record breaking warmth will return Christmas week

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I’m dreaming of a…Green Christmas? While there will certainly be no shortage of “White Christmas” puns in the weather headlines over the next week, the real story will be in the meteorological pattern evolving. The warmth we experienced over the past few days was impressive, and the warmth being advertised on medium range forecast models for the period around Christmas is arguably more impressive. Owing to a large trough in the West and Southwest United States, a large ridge is expected to build over the East Coast, pumping in much warmer than normal air once again next week.

Without any cold air source, or high latitude blocking, mild Pacific air can enter the region unabated. This is the same reason that record high temperatures were broken during the tail end of last week and this past weekend — southerly winds brought in mid and low level atmospheric temperatures that were highly anomalous. And it is likely the same reason that records will be broken in the period of time around Christmas.

Here’s how the pattern will shake down, and why:

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