Saturday, September 22, 2012

Current LRC Pattern Showing Major Deviations Between Cycles

We are seeing some major deviations in the last Lezak Recurring Cycle (LRC) cycle. Let's take a look at what's happened in the last 40-50 days.

This is the observed 500mb chart on August 7th of this year. Here, we see a moderate ridge stretching from the Southwest into Western Canada, as well as a disturbance pressing south into the Great Lakes. Also being watched is a ridge of high pressure off of Atlantic Canada, and a strong disturbance near the Gulf of Alaska.

This day appeared to feature no major weather events, although some heavy precipitation was observed in the Southeast. The rest of the nation was pretty much dry.

Let's go forward to yesterday, September 21st.

Here, we see a much different, yet somewhat recognizable, pattern across the North American continent. Most notably is a very strong low pressure system being forced south into central Canada, and spreading an autumnal chill through the north central and north east regions of the US. This was not seen in the last cycle. Given, a much weaker version of this did appear on the August 7th chart, but the huge difference in strength is quite surprising.
Additionally, the ridge of high pressure I mentioned in the August 7th chart over western Canada is there, but is stronger. Also note that the same ridge pushed the disturbance previously centered over the Gulf of Alaska further west.
We still are seeing a ridge to the east of Atlantic Canada, signifying the presence of the same pattern, but that ridge is stronger than what was previously seen in early August.

We are entering fall, and this is the season when we begin to see the old LRC pattern die off and the new pattern emerge. Seeing as we just entered fall, these deviations I mentioned should become more intense and common, until the old pattern just disappears and a new pattern emerges.

Deviations are typical in every LRC cycle, but this particular comparison seems unusually anomalous from one date to the other. If I didn't know any better, I would begin to think we are starting to ease into that transition period between the new patterns. As always, time will tell, but this is another interesting development of the Lezak Recurring Cycle.


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