Category: PNA

Jan 14

Long Range Update: Colder Than Average Close To January; Looking Ahead To Early February…

Updated 01.14.22 @ 7a

The primary driver (the Madden Julian Oscillation, or MJO) will be in a favorable phase to allow colder than average temperatures to take up residence across the eastern part of the country as we close out January. To no surprise, these particular phases favor positive heights over the high latitudes (blocking) which helps drive more of a persistent colder than normal pattern.

We’ll keep an eye if the MJO gets stuck in the neutral phase, but the “loop” around into Phase 6 this time of year would continue to favor cooler (to colder) than normal conditions across our portion of the country.

That brings us to our teleconnections. The “big 3” (this time of year include the AO, EPO, and PNA) are also all in favorable position to deliver a colder than normal pattern to close January.


One could also build a case that February would at least open colder than normal based off a combo of the above (MJO and teleconnections) and we agree with that idea, but do believe a “flip” in the regime is ahead after the first week, or so, of the month to milder times.

To no surprise, modeling is showing this cold close to the month.

The opportunity is present for Week 2 to be bitterly cold, as the European is hinting above. Sub-zero temperatures are on the table, especially if we can get some snow down.

Speaking of snow, this pattern should produce a couple opportunities for central Indiana to get in on the act before the end of the month, or beginning of February. Despite the incredibly slow start to the season, take any one particular solution with a grain of salt when looking at operational guidance 2 weeks out.

Permanent link to this article: https://indywx.com/2022/01/14/long-range-update-colder-than-average-close-to-january-looking-ahead-to-early-february/

Jan 12

VIDEO: Significant Weekend Questions; Bullish On A Very Cold Close To January…

Updated 01.12.22 @ 7:23a

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2022/01/12/video-significant-weekend-questions-bullish-on-a-very-cold-close-to-january/

Jan 08

Cold, Wintry Pattern Settling In For The 2nd Half Of January…

Updated 01.08.22 @ 4:35p

While we’re dealing with our own wintry precipitation this afternoon, snow lovers continue to wait for the first big event of the season. Watching 2 snow storms blow by to our south over the past week was an added sting.

Patience may very well be rewarded as we navigate the second half of the month as a classic wintry pattern carves itself out over the eastern portion of the country.

The GFS was first to key in on this pattern evolution, and now, today, the European is finally seeing the light (shown below). What makes this pattern different is the likelihood of high latitude blocking (courtesy of a negative arctic oscillation) which will help the regime sustain itself. On that note, it’s been my experience that the GFS does better handling AO transitions from positive to negative and was the primary reason we leaned on the GEFS earlier this week. Run to run consistency was also another player.

November and December failed to produce teleconnections that were aligned for cold, but that should change as we push towards mid month. This is ultimately a byproduct of the primary driver- the MJO rumbling into Phase 8 (finally). As the AO goes negative, the EPO should follow suit. Unlike in December, the PNA should also be in a much more favorable state for persistent eastern cold.

The idea here is that the majority (if not all) of the second half of January will feature below to well below average temperatures and multiple opportunities for “more meaningful” snow- whether it be from a series of Clippers, a more classic panhandle cross-country winter storm (example pictured below), or a combination of both.

At the very least, it’s certainly not a boring pattern, and for the first time this season, it appears as if we’ll be able to lock this cold in.

Permanent link to this article: https://indywx.com/2022/01/08/cold-wintry-pattern-settling-in-for-the-2nd-half-of-january/

Jan 06

VIDEO: Double Shot Of Arctic Love Heading Our Way; Long Range Update Into Late January…

Updated 01.06.22 @ 7:20a

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2022/01/06/video-double-shot-of-arctic-love-heading-our-way-long-range-update-into-late-january/

Dec 30

VIDEO: More Significant Storm As We Usher In The New Year; Long Range Update…

Updated 12.30.21 @ 8a

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2021/12/30/video-more-significant-storm-as-we-usher-in-the-new-year-long-range-update/

Dec 28

Time To Put Up Or Shut Up…

Updated 12.28.21 @ 7:52p

We’ve laid out our ideas and there’s certainly a lot on the table, but we’re now at the point to see whether or not the ground work that’s been laid will come to fruition. The active pattern has arrived and it’s this 10-day period of transition that we continue to believe will ultimately usher in a more persistent and prolonged cold stretch in the January 10th through 31st period.

The MJO is the kicker here and looks like we’re heading into Phase 8 (a notorious phase for eastern cold in January).

Do we stall in 8 or loop back into 7 for another late month tour through this cold phase? Time will tell.

Meanwhile, the PNA continues to look like it’s heading neutral to maybe even positive down the road.

More on this and other teleconnections early in the morning as our hectic Christmas schedule transitions back to normal!

Permanent link to this article: https://indywx.com/2021/12/28/time-to-put-up-or-shut-up/

Dec 26

For Now, It’s A Tale Of The MJO And PNA…

Updated 12.26.21 @ 7:38a

Over the past couple of weeks, several of the teleconnections (EPO, AO, and NAO) have been in favorable phases for cold air to take up residence in our neck of the woods. However the combination of Phase 6 of the MJO (image 1 below) and a deeply negative PNA (image 2 below) have fought off any sustained or significant cold.

As we look ahead, there are changes in both of these critical pattern drivers. First, the MJO looks to continue progressing deeper into Phase 7. This is significant as today, though while officially in 7, we’re really still feeling the effects of 6. There’s a lean from guidance that Phase 8 is also within reach as we get towards mid-January, but we won’t get greedy. 🙂 If we can at least get deeper into 7, that will greatly lessen the influence of the warmth that continues to linger with Phase 6.

Note how the trough likes to settle into the eastern portion of the country during these phases.

That then brings us to the PNA. Guidance is trending things closer to neutral towards Day 10. This is significant as it would allow the southeastern ridge to at least get beaten down (not totally squashed as long as we remain negative), but certainly enough to allow the cold currently bottled up out west to bleed east.

This can be illustrated best by looking at the 500mb pattern evolution over the next couple weeks per the latest GFS ensemble below.

To summarize, while we still have warm days ahead of us, there does at least appear to be a couple trends heading in the right direction for all of those longing for colder and potentially more wintry times as we get past the new year.

Hang in there you snow lovers. It’s far too early to jump off the ship…

Permanent link to this article: https://indywx.com/2021/12/26/for-now-its-a-tale-of-the-mjo-and-pna/

Dec 24

VIDEO: Busy Short-Term Pattern; Drivers Behind The Regime Into Mid-January…

Updated 12.24.21 @ 7:35a

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2021/12/24/video-busy-short-term-pattern-drivers-behind-the-regime-into-mid-january/

Dec 22

The Beat Goes On And On And On…

Updated 12.22.21 @ 7:45a

Average temperatures on the 22nd of December include a high of 38.6° and a low of 24.7°. We’ll be slightly under those levels today in what can be termed an “island” of cold in a “sea” of warmth. In fact, the month is running close to 7° above normal thus far.

Highs today will top out in the lower to middle 30s for most of central Indiana.
December 2021 has featured widespread above normal temperatures, centered across the s-central Plains into the TN and OH Valleys.

As we look towards the all-important Christmas forecast, quiet weather will carry us into Christmas Eve. That’s when we’ll tighten the pressure gradient and build in southwest gusts of 30 to 40 MPH.

Those southwesterly winds will transport a few scattered light showers into the region Christmas Eve evening into Christmas Day, but these won’t be a big deal. “Scattered” and “light” are the key words.

What will be a big deal are the temperatures. In fact, latest guidance is pointing towards a new record high on Christmas Day. Should we see any sunshine get into the mix, this will be easily achievable.

Modeled high temperatures on Christmas afternoon.
A look at Christmas Day records in Indianapolis, IN

Thereafter, the same general pattern remains intact, locally (- PNA ridge), but notice the cold bleeding into the West between Christmas and New Year’s. Does this eventually make progress east? We think so as we get into January…

Permanent link to this article: https://indywx.com/2021/12/22/the-beat-goes-on-and-on-and-on/

Dec 19

VIDEO: Detailed Look At The Pattern To Close Out The Year And As We Head Into January; Shift to Cold Still On The Table?

Updated 12.19.21 @ 11a

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2021/12/19/video-detailed-look-at-the-pattern-to-close-out-the-year-and-as-we-head-into-january-shift-to-cold-still-on-the-table/

IndyWx.com