December 12, 2019 archive

Through the 11th, December is running 1.6° above normal in Indianapolis. This milder than normal theme is rather widespread so far this month through the Lower 48.

As we look ahead, there are continued reasons to believe the pattern will begin to go through more of a transition towards an ultimately more sustained cold pattern as January evolves. We think that transition really started early this week and will feature plenty of “back and forth” over the the next 2-3 weeks before settling into the more sustained cold regime. There will be storms and “rumors of storms” that we’ll have to track through the transitional period, including smack-dab in the heart of the holiday season this year.

The latest JMA Weeklies (update each Thursday morning) shows this “fight” over the next 1-3 weeks.

Without blocking in place, the way the JMA Weeklies handle the pattern is likely, but the Weeks 2-3 time period does have a chance to offer up a headache or two as the models may begin to adjust to an increasingly “blocky” time of things.

There are at least “hints” that some of the teleconnections that would promote more of a blocky pattern are beginning to align. We caution though that this does take time for these feature to mature and begin to ultimately have a greater impact on our pattern.

As we revisit the latest SST configuration, there’s continued reason to be very excited about this winter if you’re a fan of colder and snowier than normal conditions. We always knew December would be the tough month before the pattern settles into the mean winter pattern late December into March. Now, time to just sit back and watch things unfold. 🙂

Now, back to the short-term. Despite forecast models very much still in (2) separate worlds, we’ve dug into analogs and looked through countless similar patterns from the past. As model consensus develops (hopefully sooner rather than later), let’s see if they (speaking specifically to the GFS and European) converge on this similar solution for best chances of accumulating snow:

We still have many details to sort through and we caution that this system is far from being etched in stone. You’ll want to keep close tabs on latest developments over the next couple of days. With that said, we’re looking for potential wintry impacts here across central Indiana beginning Sunday night and continuing through Monday.

This evening’s video update will focus solely on the Sunday-Monday system, including the latest model developments from 12z. Have a great Thursday!