December 2019 archive

Dec 15

Time For The Heavy Equipment: Localized Storm Totals Approach One Foot By The Time All Is Said And Done…

High resolution guidance started to show the snowier solutions earlier this evening and that trend has continued this evening. The consistency is great to see, but we also notice a couple of interesting elements “upstream” that will likely ultimately end up producing a memorable mid-December snow storm across central Indiana by the time all is said and done.

Before we talk specifics, here’s our updated snowfall forecast. Please note, this is expected total snowfall by daybreak Tuesday morning. We wouldn’t be shocked to hear of localized one foot amounts along the I-70 corridor.

Periods of heavy snow will come to an end during the overnight. We think by 3a to 4a, most of the snow from “round 1″ will be to our east and we’ll be left with clean up duties before a Monday morning rush that will likely still be heavily impacted. By the time the 1st round is finished, most of the I-70 corridor will be shoveling and plowing away 4″ to 6” of wet snow.

We’ll then get into the expected lull in the action through a good chunk of the daytime Monday. That said, curious eyes will be focused in on south-central MO mid-to-late morning as precipitation blossoms in response to a strengthening surface wave that will move northeast out of the Ark-la-tex and into the TN Valley tomorrow night.

Precipitation will expand in coverage and intensity yet again tomorrow morning to our southwest.

This will promote an expanding shield of moderate to heavy precipitation moving northeast and overspreading central Indiana by mid afternoon Monday. For us here across central Indiana, this will fall as snow.

Heavy snow will return to the I-70 corridor Monday afternoon.

If you don’t have to travel tomorrow, we’d recommend staying home and off the roads. While conditions will improve late morning into early afternoon, travel conditions will go downhill in significant fashion by 3p to 4p Monday across central Indiana- including the metro.

Periods of snow, heavy at times, will continue into the overnight before pushing off to the east before sunrise Tuesday. By that time, the heart of central Indiana will be cleaning up from a double digit and most memorable mid-December snow storm.

Periods of snow will continue into the overnight Monday.

We’ll be left with colder, but generally dry conditions Tuesday. Temperatures will remain below freezing through the day, but the majority of the region won’t be dealing with any additional snowfall after sunrise…

Gas up that snowblower! Next update will come early in the AM.

Permanent link to this article: https://indywx.com/2019/12/15/time-for-the-heavy-equipment-localized-storm-totals-approach-one-foot-by-the-time-all-is-said-and-done/

Dec 15

Heavy Snow Tonight: Timing Out “Part 2” Monday And Looking Closer At The Late Month Pattern…

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Permanent link to this article: https://indywx.com/2019/12/15/heavy-snow-tonight-timing-out-part-2-monday-and-looking-closer-at-the-late-month-pattern/

Dec 15

Client Brief: Updated Snowfall Forecast; Conditions Go Downhill Quickly This Evening…

Type: Impactful Wintry Weather

Forecast radar 9p Sunday

What: Accumulating snow; mixed wintry precipitation

When: This evening and Monday afternoon – Tuesday morning

Temperatures: Lower to middle 30s, falling into the middle 20s Tuesday morning

Wind: East northeast 10 to 15 MPH, shifting to the northwest Monday night with gusts to 25 MPH

Blowing/ Drifting: Minimal

Pavement Impacts: Plowing and salting will be required.

Right out of the gate, let’s talk accumulation: While we don’t need to make significant changes to the snowfall forecast, we did “tighten” the 3″ to 6″ band up a bit and scaled the 1″ to 3″ zones closer into central Indiana on both the north and south sides. This continues to be a central Indiana event- at least as far as heaviest snowfall totals go.

This event will still come in 2 waves, but it now appears as if the initial surge of moisture this evening and tonight will feature the heaviest snowfall rates. Snow will overspread the region this evening (arriving into Indianapolis, itself, between 6p and 7p) and come down heavily at times through the overnight hours. Part 1 will end before daybreak, but the damage will have been done by that point and the morning commute will be significantly impacted as central Indiana digs out from 3″ to 5″ of wet snow.

We’ll get a break through the bulk of the daytime Monday, but precipitation will once again overspread the region from southwest to northeast Monday evening, continuing into the predawn hours Tuesday. This will take the form of snow across central Indiana with a wintry mix and/ or a cold rain across southern and southeastern Indiana. An additional coating to 1″ of snow is possible with this 2nd wave of moisture.

Finally, winds will shift to the northwest and drive colder air into the state Monday night behind the departing storm. Everyone (including southeastern Indiana) will be below freezing Tuesday morning with additional travel impacts likely.

Confidence: High

Next Update: This evening

Permanent link to this article: https://indywx.com/2019/12/15/client-brief-updated-snowfall-forecast-conditions-go-downhill-quickly-this-evening/

Dec 14

VIDEO: 2-Part Storm Sunday Evening-Tuesday Morning; Active Times Through The Holiday Season…

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Permanent link to this article: https://indywx.com/2019/12/14/video-2-part-storm-sunday-evening-tuesday-morning-active-times-through-the-holiday-season/

Dec 14

Client Brief: Snow Storm Inbound Sunday Evening – Monday…

Type: Impactful Wintry Weather

What: Accumulating snow; mixed wintry precipitation

When: Sunday evening through Monday

Temperatures: Lower to middle 30s, falling into the lower to middle 20s Monday night

Wind: East 10 to 15 MPH, shifting to the north Monday night with gusts to 25 MPH

Blowing/ Drifting: Minimal

Pavement Impacts: Plowing and salting will be required.

Sunday will feature a thickening and lowering cloud deck through the afternoon hours and this foretells what’s to come by evening. An expanding area of snow will overspread southern Indiana early evening and push into central/ north-central Indiana by mid-to-late evening, continuing into Sunday night. This will be the 1st of 2 rounds of wintry precipitation that will likely result in “plowable” accumulations for a good chunk of central Indiana come Monday evening. There will likely be a “lull” in the wintry precipitation Monday morning, but we anticipate widespread wintry precipitation to return late morning through the afternoon and into the evening hours Monday. In and around Indianapolis and points north, this 2nd round of precipitation should also primarily take the form of snow, but we think southern Indiana will have a period of sleet and potentially a cold rain across far southern Indiana before transitioning back to snow before ending. Because of this, we think southern Indiana will fall into the 1″ to 3″ range for storm totals. Much colder air will pour into the state Monday evening as winds shift to the north/ northwest and gust up to 25 MPH. Snow will pull out of the state from west to east late Monday night. Due to the timing of this storm, big impacts are expected to the morning and evening rush hours Monday.

Confidence: High

Next Update: 2:30p Saturday

Permanent link to this article: https://indywx.com/2019/12/14/client-brief-snow-storm-inbound-sunday-evening-monday/

Dec 13

Snow Arrives Sunday Evening; Latest Thoughts On Monday And Beyond…

After a dry and cold Saturday, weather will begin to deteriorate Sunday evening. We think snow will overspread central Indiana Sunday evening into Sunday night before transitioning to a wintry…

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Permanent link to this article: https://indywx.com/2019/12/13/snow-arrives-sunday-evening-latest-thoughts-on-monday-and-beyond/

Dec 13

Client Brief: Impactful Winter Weather Event Sunday Evening Through Monday…

Type: Impactful Winter Weather

What: Accumulating snow; mixed wintry precipitation

When: Sunday evening through Monday

Temperatures: Lower to middle 30s

Wind: East 10 to 15 MPH, shifting to the north Monday night with gusts to 25 MPH

Blowing/ Drifting: Minimal

We continue to closely monitor the potential of an impactful winter weather maker Sunday evening through Monday. Initially, we think “overrunning” precipitation will overspread central Indiana Sunday afternoon and evening. This should fall in the form of snow for most. As the surface low draws closer, precipitation will increase in intensity Sunday night into the day Monday. The all-important track of the surface low appears to take a path from western Arkansas Sunday night, along the Ohio River Monday morning and into western Pennsylvania by Monday night. This is a favorable track for accumulating snow across portions of the state. The map above features our “ridiculously” early idea on best chances where the heavier snowfall will occur (shoveable totals seem like a good bet for places in and around Indianapolis and points north). Downstate, enough warmer air should get pulled into the system for a time Sunday night into Monday morning that a wintry mix of precipitation (sleet, snow, and rain) is expected to cut down snowfall totals. As the storm pulls up to our northeast, gusty northerly winds will develop with lingering snow showers in Monday night, along with colder conditions.

We’ll have an updated video post later this evening and will keep close eyes on data not only today, but straight through the weekend.

Confidence: Medium-High

Next Update: This evening (Video)

Permanent link to this article: https://indywx.com/2019/12/13/client-brief-impactful-winter-weather-event-sunday-evening-through-monday/

Dec 12

VIDEO: Ready For Wintry “Fun And Games?”

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Dec 12

Latest Thoughts On Early Next Week; Long Range Update Into Early Jan…

Through the 11th, December is running 1.6° above normal in Indianapolis. This milder than normal theme is rather widespread so far this month through the Lower 48.

As we look ahead, there are continued reasons to believe the pattern will begin to go through more of a transition towards an ultimately more sustained cold pattern as January evolves. We think that transition really started early this week and will feature plenty of “back and forth” over the the next 2-3 weeks before settling into the more sustained cold regime. There will be storms and “rumors of storms” that we’ll have to track through the transitional period, including smack-dab in the heart of the holiday season this year.

The latest JMA Weeklies (update each Thursday morning) shows this “fight” over the next 1-3 weeks.

JMA Weeklies Day 3-9 shows the cold returning to our portion of the country.
The pattern warms significantly across the Plains in the 10-16 day time frame and some of this milder air will try and eject east into the Ohio Valley.

Without blocking in place, the way the JMA Weeklies handle the pattern is likely, but the Weeks 2-3 time period does have a chance to offer up a headache or two as the models may begin to adjust to an increasingly “blocky” time of things.

There are at least “hints” that some of the teleconnections that would promote more of a blocky pattern are beginning to align. We caution though that this does take time for these feature to mature and begin to ultimately have a greater impact on our pattern.

The latest GEFS insists on a developing negative EPO in the medium to longer range. We know this favors eastern cold. Eventually, this should, indeed, take place, especially due to the northeast Pacific SST configuration and help drive more long-lasting cold, locally.
Interestingly, the GEFS also depicts a developing negative NAO mid and late December. This can help result in more sustained cold across our portion of the country into the northeast.

As we revisit the latest SST configuration, there’s continued reason to be very excited about this winter if you’re a fan of colder and snowier than normal conditions. We always knew December would be the tough month before the pattern settles into the mean winter pattern late December into March. Now, time to just sit back and watch things unfold. 🙂

Now, back to the short-term. Despite forecast models very much still in (2) separate worlds, we’ve dug into analogs and looked through countless similar patterns from the past. As model consensus develops (hopefully sooner rather than later), let’s see if they (speaking specifically to the GFS and European) converge on this similar solution for best chances of accumulating snow:

We still have many details to sort through and we caution that this system is far from being etched in stone. You’ll want to keep close tabs on latest developments over the next couple of days. With that said, we’re looking for potential wintry impacts here across central Indiana beginning Sunday night and continuing through Monday.

This evening’s video update will focus solely on the Sunday-Monday system, including the latest model developments from 12z. Have a great Thursday!

Permanent link to this article: https://indywx.com/2019/12/12/latest-thoughts-on-early-next-week-long-range-update-into-early-jan/

Dec 11

Several Opportunities For Wintry Weather Over The Next Couple Of Weeks, But Many Details To Sort Through…

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