Dec 04
Quiet weather continues for now. We look ahead to our next storm system as well as the longer range pattern drivers in this morning’s video update…
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Permanent link to this article: https://indywx.com/2020/12/04/video-timing-out-the-arrival-of-our-next-storm-reviewing-the-pattern-drivers-into-mid-late-month/
Dec 03
December certainly has opened on a cold note. Through the 1st few days of the month, IND is running more than 6° below normal. Our short-term products will continue to handle the quiet times through the upcoming week. As is typical on Thursday, we’ll look ahead to some longer range items of interest in this evening’s post.
To start, let’s dig in to the pattern drivers. Initially, the PNA and AO are aligned in a manner that supports the chill. As we go into mid-month, we lose the positive PNA (in my opinion, it was this feature that’s responsible for the cold start to Dec and subsequent OHV snow event). The EPO remains unfavorable for durable cold.
The latest European Monthly MJO plot keeps things in the “null” phase. To me, this says we need to continue to lean more heavily on the teleconnections in the shorter to medium range period. We’ll continue to monitor for the MJO to become more amplified down the road. Once this takes place, the MJO should drive things for the majority of the winter.
Seeing as how 2/3 major teleconnection drivers trend warmer by mid-month and the MJO remains a relative non-factor, it’s no surprise to see the longer range modeling warming things up mid and late month.
Today, the 3 primary long range models we look at all show warmth carrying the day to wrap up the month. Additionally, they continue the drier than normal theme into early parts of January.
JMA Weeklies:
CFSv2 Weeklies:
European Weeklies:
While shots of chill will continue to impact the region (after the more sustained chilly regime in the immediate term), there’s little reason to buy into any chance of durable, sustained cold to wrap up the month and head into the early parts of January.
Permanent link to this article: https://indywx.com/2020/12/03/long-range-update-christmas-to-new-years-period-on-the-horizon/
Dec 03
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Permanent link to this article: https://indywx.com/2020/12/03/video-all-is-quiet/
Dec 02
While we’ll continue to monitor an upper level low ejecting out of the Plains and tracking east late week, it continues to look like this particular storm system will miss…
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Permanent link to this article: https://indywx.com/2020/12/02/video-generally-quiet-chilly-weather-takes-us-into-next-week/
Dec 01
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Permanent link to this article: https://indywx.com/2020/12/01/video-cold-open-to-meteorological-winter-big-weekend-differences-on-the-models/
Dec 01
The way modeling has been “forced” to correct colder over the past week to 10 days to open December has been staggering. Without question, the initial driver of this change has to do with the strongly positive PNA. Note how this is forecast to remain strongly positive over the upcoming week before trending neutral by mid-month.
This favors a trough over our part of the country and into the Deep South through the better part of the upcoming couple of weeks. We’ve been posting about how the strongly positive PNA could lead to other teleconnections aligning in a manner that could lead to the possibility of more “meaningful” or longer lasting cold beyond mid-month. The trends of the AO, EPO, and NAO have been towards this colder direction over the past few days and it’ll be interesting to see if these trends continue.
Perhaps more importantly has to do with the MJO. While the majority of guidance keeps the MJO in the “null” phase (meaning we’ll lean heavier into the teleconnections above) into and through mid-month, it’ll be worth keeping a close eye on this. The one outlier is the Canadian taking a highly amplified MJO towards the cold phases (after blasting through the warm phases quickly) by mid-month. Again, we’re not throwing our eggs into the MJO basket right now and prefer to lean heavier on the tele. trends.
The latest CFSv2 has been trending colder for December with each model update- especially over the Southeast and TN Valley:
The latest European Weeklies are somewhat similar, but colder across the West.
The JMA Weeklies want to put the ‘mean’ trough (and associated cooler pattern) over the Southeast for December:
Consensus of longer range, monthly products places an area of widespread drier than normal weather across a good chunk of the country:
While there are obvious reasons for a lower confidence forecast around mid-month, thinking here is that we’ll maintain a seasonal to slightly colder than normal regime for our immediate region into the Southeast this month. This is quite different than the recent December torches we’ve been dealt and may seem much cooler than normal as a result. I believe the strongly positive PNA will “force” those other pattern drivers towards a manner that will drive the cooler pattern for the better part of the month before potentially trending milder around Christmas and New Years.
Permanent link to this article: https://indywx.com/2020/12/01/december-2020-outlook/