I thought that I might take a quick look at some of the more significant larger-scale “signals” that might drive our weather patterns as we round out February and enter March.

Keep in mind that “weather” signals tend to be short-term, often lasting a week or two before changing. A mild winter can quickly change to a cold snap, as we recently experienced. Likely, while we have been in a predominant dry pattern for quite some time, there is still plenty of time for more significant winter or early spring water resources recharge.

Here is a “weather” signal that I often refer to, especially during the colder months — the Arctic Oscillation (AO). In a general sense, the AO is an indicator of pooling (or not) of cold arctic air. Note that after a 20-day stretch of a negative AO, this signal recently returned to a neutral or just slightly positive (red circle) reading. While the AO is very difficult to accurately predict out past the next two weeks, you can note a tendancy towards a cyclic pattern. This, in a very general sense, supports my forecast rule of thumb that winter patterns tend to realign about every two weeks or so.

Now, let’s look at the larger-scale climate pattern. La Niña conditions have been holding steady around -1.0 (degrees C) for several months now. The following image shows an ensemble of climate models. The majority indicate that ENSO readings will moderate back to neutral (-0.5 – 1.0) somewhere in the March, April, May (MAM) time frame (blue star).

While all of this might be interesting, what does it mean for water resources? I suspect that we will see at least a “moderate” amount of weather systems over the next few weeks during this transition period. The next AO pattern, the one that sets up for March, will be critical as to potential winter water resources recharge. While the La Niña has generally tended to keep most of the Southeast U.S. on the dry side, and likely will continue to do so for the rest of winter, it is possible that it will play less of a role as we head into spring and summer.