Category: Forecast Discussion

Snowy At Times For Some; Updated Long Range Thoughts…

Updated 12.29.23 @ 7:09a

Updated with European Weekly thoughts 12/29/23 @ 7:09a

There’s no reason to change any of our thoughts concerning how things play out over the next 24 hours with our upper level low pressure system. That idea from yesterday is available here. In short, it still appears as if parts of west-central Indiana are still greatest at risk of seeing light wet snow accumulation (of course some of our friends in southwest Indiana are already enjoying waking up to snow on the ground this morning).

As we look ahead to the upcoming 3-4 weeks (will add to this post later tonight after having a chance to see the updated Euro Weekly teleconnections), it appears as if we’re heading right towards more of a predominant El Niño regime with an active southern storm track and most persistent cold, relative to average, taking up residence across the southern tier. The updated JMA Weekly model portrays this best over the course of the upcoming 28 days:

Modeling continues to struggle with the MJO evolution over the upcoming 2 week period. While this doesn’t impact the idea of colder times in the short-term period, it does have great implications beyond mid-January. The kind of amplitude shown off the American guidance (image 1 below) would threaten to deliver a much warmer than average period, locally, beyond mid-month. Meanwhile, the European (image 2 below) continues to suggest a collapse into the neutral phase.

The 2 primary other pattern drivers include the PNA and EPO through mid-January. Beyond this point, we’ll start to incorporate the likes of the NAO and AO into our forecast (hence another reason why we’re interested in seeing how the Euro Weeklies show this later today).

Simply based on how the PNA/ EPO combo is forecast, the first week would open with cooler temperatures transitioning into the region and then we would likely see moderation in the week 2 to early week 3 timeframe.

Week 1

Week 2

While we’re certainly transitioning to a cooler and more active pattern over the upcoming couple weeks, compared to where we’ve been to this point in meteorological winter, it’s not yet to a point where anything looks excessively cold or, for that matter, snowy.

That doesn’t mean that there won’t be a couple storms to track that could offer up some meaningful winter weather potential here, but I just don’t see a sustained cold, snowy pattern taking foot through mid-January. Beyond that point, we’ll have to monitor which more extreme solution plays out. Based on everything going on by that point, it’s still likely to be a situation where either more persistent (and significant) cold or warmth develops.

European Weekly update 12/29/23

The new European Weeklies show a warmer option for the 2nd half of January, but contradict their own teleconnections during this time frame. The model goes to a strong negative AO, positive PNA, negative NAO, and a neutral EPO. Of course we’ll have to see what the MJO ultimately ends up doing but that combo strongly argues for the colder option for the 2nd half of January.

Permanent link to this article: https://indywx.com/2023/12/28/snowy-at-times-for-some-updated-long-range-thoughts/

Cut Off Upper Low, Weatherman’s Woe…

Updated 12.27.23 @ 6:55a

A big ole slow moving cut off upper level low pressure system will pinwheel out of the upper Midwest this morning into the TN Valley and Southeast by the weekend.

These features are always known for “surprises” and it’s up to forecasters, including yours truly, to eliminate those surprises over the next couple days. The challenging part with this particular setup is that colder air will be arriving into the region as the more organized bands of precipitation are pivoting south. Precipitation intensity will also be a big player in this event. The heavier, or more intense, precipitation rates will be able to cool the column of air perhaps a bit quicker than most short term model guidance may currently see.

So what does this all mean to me? Today is quiet. After patchy fog burns off, we’re looking at more in the way of sunshine building in. The initial band of precipitation will likely setup tonight across southwestern Indiana. While this will start out as a cold rain, precipitation should switch over to snow prior to sunrise and some localized wet accumulation of snow is likely across Southwest Indiana by daybreak Thursday.

Meanwhile, back up this way, after a dry start to the day, precipitation is expected to become more widespread by early to mid afternoon. As nightfall sets in, rain will likely turn to wet snow showers. Admittedly tricky trying to determine where the steadiest band of precipitation will prevail, the best idea at this point will be across west-central Indiana, including places like Frankfort, Lafayette, Crawfordsville, and Terre Haute. Here, light wet snow accumulation of 1” to 2” seems like a good bet by Friday morning.

Precipitation will diminish from north to south across western Indiana Friday morning. Dry conditions will return until a reinforcing jab of cold air arrives New Year’s Day with scattered snow showers.

Permanent link to this article: https://indywx.com/2023/12/27/cut-off-upper-low-weathermans-woe/

VIDEO: Turning Cooler; Couple Chances Of Light Precipitation…

Updated 12.26.23 @ 6:16a We begin to turn cooler through the day and this sets the tone for a more seasonable close to the year. We’ll continue to watch the…

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Permanent link to this article: https://indywx.com/2023/12/26/video-turning-cooler-couple-chances-of-light-precipitation/

Wishing You A Very Merry Christmas And A Blessed Holiday Season…

Updated 12.25.23 @ 6:58a

From our family to yours, we wish you warmest Christmas blessings and a joyous holiday season!

After a dry start to the day, rain will lift north and overspread central Indiana late morning into the early afternoon. A few moderate showers are likely at times. Rainfall coverage and intensity will diminish significantly as we move through mid and late evening. Though there will be a few exceptions, generally 0.50” to 0.75” will fall south of the I-70 corridor with amounts of 0.25” to 0.50” north of I-70.

1p forecast radar
4p forecast radar
11p forecast radar
Rainfall totals by noon Tuesday.

Strong southeasterly winds and unseasonably mild temperatures can also be expected today. Gusts will approach 40 MPH this afternoon across all of the region.

Our weather will dry out Tuesday and Wednesday but by this time all eyes will be poised to our west as we wait in the cold core upper level low to pivot across the region. While there won’t be a lot of cold air readily available for this system to tap into, we’ll have to see if it can manufacture its own cold air to create some potential localized winter weather “issues” for portions of the southern Ohio Valley and especially the Appalachians prior to the New Year’s weekend. For now, we’ll forecast a mix of rain and snow here Thursday- just know that we’ll likely have to firm that up once the details become clearer regarding the exact track of the upper low. As the ole saying goes, “cold core upper low, weatherman’s woe.” Solutions range from a cold rain to a localized accumulating wet snow event…

Permanent link to this article: https://indywx.com/2023/12/25/wishing-you-a-very-merry-christmas-and-a-blessed-holiday-season/

VIDEO: Fog Lifts And Gives Way To Unseasonably Mild Conditions; Christmas Rain And Colder Transition Later In The Week…

Updated 12.24.23 @ 6:50a Areas of fog and drizzle will dissipate as we progress through the day and we even expect some breaks in the clouds at times. An unseasonably…

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Permanent link to this article: https://indywx.com/2023/12/24/video-fog-lifts-and-gives-way-to-unseasonably-mild-conditions-christmas-rain-and-colder-transition-later-in-the-week/

A Tale Of 2 Potential Extremes For Late January And An Early Lean…

Updated 12.23.23 @ 3:04p

The stage has been set for some time concerning late December and the first week to 10 days of January. There are no changes on our ideas concerning that timeframe. In short, a colder (certainly from where we’ve been as of late, and slightly below the average), and stormy evolution sums up that period.

The timeframe now in question has to do with mid and late January, after what sure looks to be a 5-7 day period of moderation. Unlike what we’ve outlined for late December and early January, the second half of January is likely to feature more in the way of a case of “extreme and nothing in between” type pattern. As outlined in Thursday’s long range post, up to this point, modeling has a couple of different takes on the aforementioned period. The American guidance suggests a repeat of well above normal temperatures and a general lack of winter weather looms with an MJO look poised for the classic warm phases.

You likely don’t need us to remind you of January and February last year. Indianapolis ran a whopping 8.1° above normal through the first couple months of the year.

The reason? An amplified MJO rolling slowly through the Phases 3, 4, and 5 before getting into the colder phases late February and into March.

Back to present day, the American guidance, though slowly backing off from the aggressive idea from a couple days ago, suggests this is once again on the table. Should that come to fruition, mid January would feature well above normal temperatures yet again.

As the great Lee Corso famously coined, “not so fast, my friend.” The European guidance collapses the MJO into the null, or neural phase, before getting into the warm phases. While a period of moderation still will likely follow the chilly open to January, should the Euro idea be correct (and we suspect it is- more on that below), an eventual recycling through the cold phases would likely ensue late January into early February.

By this point, guidance is also beginning to align on other important pattern drivers. Remember, by mid January, we really start to lean in on what the NAO and AO are doing. That’s certainly not to say we don’t pay attention to the PNA and EPO- just that the AO/ NAO can have greater influence on the regime into early spring. Of course, the MJO remains king.

What’s interesting is that each respective “driver” positions itself in a manner that argues cold should rule during the late January and early February period.

Should that MJO circle back into the traditional cold phases, look out. The window will open for a period of true arctic air getting involved with the pattern given the other pattern drivers above. – Target period would be late January (after Jan. 15th) and into early February.

Given what’s out there for the taking, it’s certainly not a pattern for the faint of heart. Buckle up!

Permanent link to this article: https://indywx.com/2023/12/23/a-tale-of-2-potential-extremes-for-late-january-and-an-early-lean/

VIDEO: Wet, Unseasonably Mild Christmas Still On Deck; Colder Shift To Close The Year And Open January…

Updated 12.23.23 @ 7a When we look at our current mild December, I suppose it should really come as no surprise, especially given our research that began early September with…

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Permanent link to this article: https://indywx.com/2023/12/23/video-wet-unseasonably-mild-christmas-still-on-deck-colder-shift-to-close-the-year-and-open-january/

Friday Morning Rambles: Pattern Discussion To Close Out The Year…

Updated 12.22.23 @ 7:15a

We open the period with widespread milder than normal temperatures in the 1-6 day period. Greatest anomalies are centered over the upper Midwest. Note the step down to a pattern, locally, that’s more seasonable if not slightly cooler than normal to close the year and open 2024. That’s the emphasis we want to drive home- though turning colder, we’re not in the camp that our immediate region will have to deal with any sort of arctic air anytime soon.

Days 1-6
Days 6-11
Days 10-15

You know we’ll be keeping close eyes on the Madden Julian Oscillation over the next few days. Should the American guidance come to fruition, then a warmer pattern is certainly alive and kicking after the cooler pattern to open January. Interestingly this morning, early trends are more in favor of the European camp, but it’s still early and we’ll need to monitor closely through the Christmas holiday.

American guidance isn’t as bullish moving into Phase 3 early January with the overnight update.

In the shorter term, morning showers will transition to more of a widespread light rain across the northern half of the state later this afternoon and tonight. Some northern Indiana rain gauges could surpass 0.50″ during this time period from “round 1” of more widespread rain.

Pesky light showers will be around Saturday, but this will be more of a nuisance than anything else. Widespread measurable rain isn’t anticipated. We then flip the calendar to Christmas Eve and the forecast continues to improve. We even anticipate some sunshine to couple with the unseasonably mild air and breezy southerly winds. Highs approaching 60° can be expected as Santa loads up his sleigh.

More widespread rain arrives Christmas Day, especially by late morning and during the afternoon. This is the timeframe when we expect greatest coverage and heaviest rainfall rates of the period. Storm total rainfall of 0.50″ to 1″ still looks like a good bet.

Colder air works in behind the storm and left over “wrap around” precipitation will begin to mix with and change to snow Thursday.

The downhill slide to more seasonable and slightly colder than normal temperatures continues as we close out the year…

Permanent link to this article: https://indywx.com/2023/12/22/friday-morning-rambles-pattern-discussion-to-close-out-the-year/

LR Update: MJO Will Have “The” Say…

Updated 12.21.23 @ 5:15p We’ll transition to a cooler pattern as we close out the year and open January. The MJO (Madden-Julian Oscillation), EPO (East Pacific Oscillation), and PNA (Pacific…

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Permanent link to this article: https://indywx.com/2023/12/21/lr-update-mjo-will-have-the-say/

VIDEO: Timing Out Christmas Rain And Transition To Colder Times…

Updated 12.21.23 @ 7:45a We’ll notice more in the way of cloud cover today but dry times will prevail. Better opportunities for light rain arrive overnight into Friday, especially across…

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Permanent link to this article: https://indywx.com/2023/12/21/video-timing-out-christmas-rain-and-transition-to-colder-times/

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