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Category: Arctic Cold
Permanent link to this article: https://indywx.com/video-gloomy-monday-colder-pattern-awaits/
Dec 16
EPO-PNA Battle
One of the many ingredients we like to throw into the mixing bowl when developing our medium range forecast is the teleconnection breakdown. Many times, the various teleconnections play into themselves and agree, but, at times, conflicting signals lead to a fight. At any given time, one or the other “big boy” teleconnections can take control of the pattern and simply overwhelm. As things stand now, it appears as if the two teleconnections trying to control are the EPO (Eastern Pacific Oscillation) and PNA (Pacific North America pattern), highlighted below.
As we’d expect, as these two fight it out, a battle will ensue across the central and eventually eastern portion of the country. The negative EPO is a widespread cold pattern, while a negative PNA favors south-central and southeastern ridging (a warmer pattern).
When we look at the latest ensemble data, we see this battle playing out within the modeling.
Eventually, we expect the deeply negative EPO to take control and overwhelm the pattern with cold. However, as this transition of power takes place, the negative PNA won’t go down without a fight and will likely play a role in the weather leading up to Christmas.
The negative PNA suggests we need to remain on guard for the potential of an interior snow/ ice event around Christmas. As we’ve been mentioning, from this distance there’s no way to say whether this is an impactful wintry event for our region, or just to our north or south. We should be able to become more detailed within the next few days…
Permanent link to this article: https://indywx.com/epo-pna-battle/
Dec 14
VIDEO: Latest Thoughts Around The Pattern As Christmas Nears…
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Dec 13
Wednesday Evening Rambles…Cold Reinforcements Tonight; Weekend Moderation…
I. A look at the current snowpack shows the northwest flow nicely, and another storm is just missing central Indiana to the north and northeast this evening (not included in this morning’s snowpack update). The southern Appalachians have also been capitalizing in this northwest flow pattern, not to mention the southern stream event that dumped hefty snows on the Deep South.
II. While the sticking snows will miss us this go around, scattered snow showers will impact central IN overnight into early Thursday morning. There’s also still the potential of a skinny lake effect snow band to impact a narrow portion of western and north-central IN early Thursday.
III. Reinforcing cold air will plunge south Thursday. Highs will remain below freezing along with wind chill values in the 10s most of the day.
IV: A milder southwesterly air flow will result in slightly “warmer” temperatures this weekend (mid 40s for highs Saturday) before showers arrive to close the weekend. Despite the slight relaxation of the cold, this will come with a gusty breeze over the weekend.
Permanent link to this article: https://indywx.com/wednesday-evening-rambles-cold-reinforcements-tonight-weekend-moderation/
Dec 12
Tuesday Evening Rambles: Wintry Weather And More Christmas Week Chatter…
I.) The pattern we’re currently dealing with is one that presents multiple challenges in the near term. East-central and northeastern portions of the state have gotten in on the snow act today, but, so far, most of central Indiana has missed out on the snowy goods. With such a fast-paced northwest flow, we have to remain on guard for potential “surprises” in this pattern. Perhaps the HRRR is beginning to pick up on this. Latest runs want to deliver a “pop” of snow Wednesday morning, associated with “warm” air advection (WAA). We’ll monitor tonight.
9a forecast radar Wednesday
II. The northwest flow will continue to provide disturbances plenty capable of producing periods of snow again Wednesday evening through the end of the week. Are these monster storms? Hardly, but they can “suddenly” become sufficient enough to create travel problems given the pattern. For those who live across the northern half of the state, plan to keep close tabs to local forecasts if you have travel plans through the end of the week.
III. A period of brief moderation will come in this pattern early Christmas week, but all eyes continue to focus on the period between December 22nd through December 26th for the potential of impactful weather across our region. For model “worshipers” out there, we suggest paying more attention to overall trends, and a blend of ensemble data, as opposed to specifics associated with operational runs. It’s a “jailbreak” pattern of sorts as true arctic air will be pouring down the Plains while the southeastern ridge tries to fight for a time. The resistance from the southeastern ridge and associated tight thermal gradient should promote a very stormy regime for the interior (Ohio Valley into the interior northeast) as we head into the true holiday/ Christmas stretch. As of now, we favor the idea of multiple waves along the pressing arctic boundary, as opposed to one big storm. Looking back through the records shows some of the heaviest snows at IND have come from similar set-ups. Understanding each set-up is unique, the overall pattern does have to raise an eye brow for potential of wintry weather in, or around, our region as Christmas approaches…
Permanent link to this article: https://indywx.com/tuesday-evening-rambles-wintry-weather-and-more-christmas-week-chatter/