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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!
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Our weekend will wrap up on a pleasant note. Though clouds will be on the increase, temperatures will rise to much warmer than normal levels by early-December standards. Highs today will top out in the lower to middle 50s with increasing cloudiness.
Those clouds will eventually give way to rain during the overnight hours. A few sprinkles are possible this evening, but it’s not until midnight and into the predawn hours that the more concentrated rain will arrive.
Most of central Indiana can expect rainfall totals between 0.50″ and 1.00″ Monday. The steady rain Monday morning will taper to showers during the afternoon hours.
Colder air will pour into the state Monday night and gusty northwest winds. This cold air mass will eventually “catch up” with the moisture to our southeast and lead to a flip to snow for places from central and eastern KY into the Appalachians Tuesday. Meanwhile, lake effect snow showers will develop across northeast Indiana. For the most part, despite some light snow showers Tuesday morning, central Indiana shouldn’t expect anything “exciting” in the winter weather department.
High pressure will settle overhead through the midweek stretch with sunshine returning along with seasonably cold conditions.
Thereafter, a developing storm system in the Gulf of Mexico will lead to an active close to the week. Low pressure will form in the central Gulf Friday afternoon before tracking up along the Appalachian chain into the weekend. With a lack of cold air and retreating high (orientation of the cold air supply/ high pressure system is critical this time of year), this should be another mostly wet and not white weather maker.
Cold air will eventually wrap into the system from the west late in the weekend and could lead to precipitation ending as wet snow, but this idea is far from being “etched in stone.”
Video update will come a bit later with fresh 12z thoughts, along with a look-ahead to Christmas. Make it a great Sunday, friends!