Category: EPO

Updated 11.20.23 @ 5:30p

I. The weather pattern will turn progressively colder as we move through the Thanksgiving holiday. This isn’t anything earth-shattering by any stretch, but temperatures running 4° to 8° below normal is pretty stout. There’s also still the potential of an early season arctic “jab” prior to us getting out of the first 3-5 days of December, but that likely comes after this weekend- if at all.

As a whole, it’s a dry pattern that will accompany the chill, but we will want to continue keeping an eye on energy that will eject off the Rockies over the weekend. At times models can underplay these features only to have to correct stronger as we grow closer to the potential event. Will that be the case this time? Impossible to say from this distance- just something we’ll continue to monitor with such a busy travel period. As it is today, modeling wants to “string” the energy out which would essentially be a light or non-event.

II. While the pattern drivers all are aligned for a cold open (first few days) of December, there’s reason to believe a period of milder than normal air will take foot just after- say sometime between 12/5 and 12/8, or so. That said, we’re in a bit of a fork in the road so to speak.

The East Pacific Oscillation (EPO) is going to pop positive at least for a period of time prior to mid-December. This strongly argues for a relaxation of the cold regime that we’ll endure to open the month. Guidance differs on the handling of the MJO, however. Should the American guidance be correct in taking things into Phase 4, when combined with what we see transpiring with the EPO, then we’re off to the races for at least a 7-10 day period of much warmer than normal temperatures. That said, European guidance collapses the MJO into the “null” phase and even hints at things emerging again in the colder phases come mid December. While we still have time to sort through this “mess,” the idea here is that the cold open to the month will moderate to slightly to moderately above normal for a 7-10 day period leading us into mid-month. Thereafter, I’m becoming increasingly bullish for a renewed cold pattern developing towards the Christmas and New Years holidays…