Category: PNA

Updated 12.29.23 @ 7:09a

Updated with European Weekly thoughts 12/29/23 @ 7:09a

There’s no reason to change any of our thoughts concerning how things play out over the next 24 hours with our upper level low pressure system. That idea from yesterday is available here. In short, it still appears as if parts of west-central Indiana are still greatest at risk of seeing light wet snow accumulation (of course some of our friends in southwest Indiana are already enjoying waking up to snow on the ground this morning).

As we look ahead to the upcoming 3-4 weeks (will add to this post later tonight after having a chance to see the updated Euro Weekly teleconnections), it appears as if we’re heading right towards more of a predominant El Niño regime with an active southern storm track and most persistent cold, relative to average, taking up residence across the southern tier. The updated JMA Weekly model portrays this best over the course of the upcoming 28 days:

Modeling continues to struggle with the MJO evolution over the upcoming 2 week period. While this doesn’t impact the idea of colder times in the short-term period, it does have great implications beyond mid-January. The kind of amplitude shown off the American guidance (image 1 below) would threaten to deliver a much warmer than average period, locally, beyond mid-month. Meanwhile, the European (image 2 below) continues to suggest a collapse into the neutral phase.

The 2 primary other pattern drivers include the PNA and EPO through mid-January. Beyond this point, we’ll start to incorporate the likes of the NAO and AO into our forecast (hence another reason why we’re interested in seeing how the Euro Weeklies show this later today).

Simply based on how the PNA/ EPO combo is forecast, the first week would open with cooler temperatures transitioning into the region and then we would likely see moderation in the week 2 to early week 3 timeframe.

Week 1

Week 2

While we’re certainly transitioning to a cooler and more active pattern over the upcoming couple weeks, compared to where we’ve been to this point in meteorological winter, it’s not yet to a point where anything looks excessively cold or, for that matter, snowy.

That doesn’t mean that there won’t be a couple storms to track that could offer up some meaningful winter weather potential here, but I just don’t see a sustained cold, snowy pattern taking foot through mid-January. Beyond that point, we’ll have to monitor which more extreme solution plays out. Based on everything going on by that point, it’s still likely to be a situation where either more persistent (and significant) cold or warmth develops.

European Weekly update 12/29/23

The new European Weeklies show a warmer option for the 2nd half of January, but contradict their own teleconnections during this time frame. The model goes to a strong negative AO, positive PNA, negative NAO, and a neutral EPO. Of course we’ll have to see what the MJO ultimately ends up doing but that combo strongly argues for the colder option for the 2nd half of January.