December 2017 archive

Dec 17

Mild And Relatively Quiet Week Before Cold Changes For Christmas…

Highlights:

  • Light showers later today
  • Mostly quiet weather week awaits
  • Much colder as Christmas nears

Sunday Showers…A weak weather system is approaching the state as we type this forecast update.  That system will deliver light showers through the afternoon hours, but this won’t be a major weather event by any stretch of the imagination- more of a nuisance than anything.

Our next “event” will come Tuesday night in the form of a dry frontal passage.  This will trend us cooler Wednesday, but still above seasonal norms.  Quiet times will persist with sunshine through midweek, allowing last minute shoppers (no finger pointing here :-)) to at least not have any weather worries as they finish checking off the list!

A more significant cold front will approach as we close the work week.  This will provide showers and gusty winds, followed by a colder feel late in the day.

Looking ahead towards Christmas Eve and Christmas Day, confidence continues to remain high on a much colder pattern taking hold.  However, it’s purely speculative at this point whether we’ll be enjoying “white” for the big day.  Stay tuned.

Upcoming 7-Day Precipitation Forecast:

  • Snowfall: 0.00″
  • Rainfall: 0.20″ – 0.40″

 

Permanent link to this article: https://indywx.com/mild-and-relatively-quiet-week-before-cold-changes-for-christmas/

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 15

Unseasonably Pleasant Open To The Weekend…

Highlights:

  • “Can’t beat it” weather for mid-December
  • Raw second half of the weekend
  • Changes loom

Great Open To The Weekend…High pressure and a relatively mild southwest flow will help boost temperatures to near 50° Saturday afternoon, complete with plentiful sunshine.  We will note an increasingly gusty southwest breeze late in the day.

The second half of the weekend will feature an increasingly wet period, along with a “raw” feel.  Rainfall amounts won’t be particularly impressive, but rain gear will be required on the way out to church Sunday morning.

High pressure will quickly build back in thereafter and remain in control of our work week weather.  A nice stretch of pleasant conditions (by mid-December standards) will prevail, including plentiful sunshine.  Enjoy it as big changes loom.

The all-important Christmas-New Years period is growing ever closer and data continues to suggest we should gear up for busy times in the forecast office.  An active pattern looms, including one that will trend progressively colder.

Upcoming 7-Day Precipitation Forecast:

  • Snowfall: 0.00″
  • Rainfall: 0.10″ – 0.25″

Permanent link to this article: https://indywx.com/unseasonably-pleasant-open-to-the-weekend/

Dec 14

VIDEO: Latest Thoughts Around The Pattern As Christmas Nears…

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Permanent link to this article: https://indywx.com/video-latest-thoughts-around-the-pattern-as-christmas-nears/

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/