The stage is set for winter’s return. With that said, the upcoming week will likely feature a “transitional” time of things before winter returns with more authority during the 2/18 through 3/10 time period.
While the positive AO will continue to be heard from in the more immediate term (forcing the active storm track into the Ohio Valley and Great Lakes), this should eventually give way to a negative AO by mid and late month. Factor in a Phase 8 of the MJO and developing negative NAO and winter weather lovers will likely have a 2-3 week period of “fun and games,” including the potential of a couple significant events, along with well below normal cold late February and early March.
That said, this isn’t last year. Recall it was around this time that we were initially “faked out” by a wintry February when in all actuality it was a case of delayed, but not denied, with the worst of winter (relative to average, and in the means from a snow perspective) occurring in March and April. There are growing indications that we should actually have a spring this year, but more on that at a later time. 🙂
Let’s take a look at some of the latest long range modeling, starting with teleconnections first (always the basis of a long range forecast).
Simply put, the GEFS teleconnections line up for a return of colder than normal conditions during the middle to latter part of February. We love to see the agreement in the teleconnection states (trending negative AO (image 1) and NAO (image 3) and trending positive PNA (image 2)).
The latest European Weeklies would also agree. Note the strongly positive AO (image 1 below) at present dips negative during the 2nd half of February.
The European Weeklies like the idea of the PNA at least getting to neutral late month into early March.
- Also of importance is what the Weeklies do with both teleconnections by mid-March (this would support a warmer pattern, overall).
- Since we’re talking about the European Weeklies, while we can’t show the model output itself, it should be noted the model does deliver cold back into the region in rather widespread fashion during the last couple of weeks of February and into the first week of March.
Other model data paints a similar picture as noted below between the GEFS and CFSv2 Weeklies:
But, like other data would suggest, the CFSv2 is also in agreement that as early March gives way to the middle of the month, warmer times loom…
(In the event you missed it this morning, we reviewed the updated JMA Weeklies earlier here).
The latest MJO update continues to back up the idea of colder times returning mid and late February, continuing into early March, as noted below. Remember, this time of year, Phases 8 and 1 are colder phases for our neck of the woods.
To summarize, we expect this upcoming week to begin the transition back towards an overall colder and increasingly busy time of things from a wintry perspective. Those will snow removal interests should anticipate above average snowfall during the 2/18 through 3/10 time frame. The aforementioned period also should run colder than average, as well. However, those tired of winter, hang in there- hope is on the horizon once to mid-March and we should actually enjoy a pleasant spring this year after missing out in ’18!
The basis of our late-December forecast is built from the MJO, or Madden-Julian Oscillation. We note the MJO is expected to rumble through Phase 4 before heading into Phase 5 around Christmas. Phase 4 (image 2 below) is a warm phase and correlates well to what the week ahead will provide. However, Phase 5 (image 3 below) is a colder phase and could “up the ante” for the potential of wintry weather around Christmas.
If the MJO amplitude remains, it’ll roll into Phase 6 to close the month and open January. Here’s how that would correlate in the temperature department:
The upcoming week will run milder than normal- lining up perfectly with MJO Phase 4.
The first of our targeted holiday storm systems will come at the tail end of the warm Phase 4 and will likely deliver a wind-whipped rain in here as early as Wednesday night and Thursday morning. However, as the storm pulls northeast along the Ohio River, it’ll deepen on its journey into the eastern Great Lakes region. This will help pull colder air into the region, likely resulting in rain transitioning to snow Friday. Given the path of the storm, this doesn’t favor some sort of prolonged backlash snow event, but it could be enough to result in accumulating snow across eastern Ohio Valley sections and downwind of the snow belt regions of northern IN, OH, and MI.
The pattern, as a whole, appears to be one of transition to close the month and open January and it’s not really until we get to mid-January where we think all of the drivers “align” to create more of a lock and hold cold pattern. With that said, a stormy late December pattern can present problems, even in the midst of relatively mild times. We’ll be here to dissect the storms as they come throughout the holiday season…
More specific to Indianapolis, here’s the monthly temperature breakdown so far for 2018:
While we have conflicting temperature ideas, both suggest a drier than average month emerging:
At the end of the day, our call on May’s forecast from mid-April would be for an early cooler than average start before flipping towards more of a seasonable to slightly warmer than normal regime. Our idea all along this spring has been that when this pattern flips, the potential is present to jump right to a summery feel. In the face of the new European Weeklies, we still feel this warmer idea mid and late May is on the table. We’re in agreement with the data of a drier than average month.