Category: MJO

Feb 07

Dissecting Today’s Severe Potential; Winter Returns & Looking More In-depth At The New JMA Weeklies…

The Storm Prediction Center (SPC) has significantly expanded the “slight risk” area to include a large portions of the state.


While a fresh batch of heavy rain will move into central Indiana later this morning (another 1″ to 2″ is a good bet for most communities), the focus shifts to a window where severe thunderstorms will be possible during the early to mid afternoon.

A warm front will lift north through central IN late morning and this will allow relatively warm and moist air to briefly surge as far north as a Logansport to Fort Wayne line.

Note dew points will spike to 60 to 63 degrees over much of central and eastern IN this afternoon.

It’s during the 1p to 5p window when we’re most concerned for the chance of a few severe thunderstorms ahead of the cold front. Damaging winds are of greatest concern, but anytime you have a warm front hanging around central Indiana with these kinds of setups, the potential of a tornado is in the back of your mind. I don’t foresee this being a major tornado outbreak whatsoever, but parameters do suggest the chance of a quick spin-up tornado is present, as well during this timeframe.

The cold front will crash into Indianapolis between 4p and 5p and you’ll certainly know it.

Strong and gusty northwest winds will blow sharply cold air into the region this evening and tonight. In fact, highs in the lower to middle 60s this afternoon will be into the 20s before midnight. Lows Friday morning will fall into the 10s and highs Friday will only top out in the lower 20s with wind chill values in the single digits most of the day.

After a dry open to the weekend, we continue to monitor the potential of a light wintry event Sunday into early Monday. This doesn’t appear to be a big deal, but the chance is there for an inch or two of snow for portions of the central and northern Ohio Valley during this timeframe.

Additional challenges await early and mid next week, but we’ll save those for updates later this afternoon or evening.

JMA Weeklies

The updated JMA Weeklies are in and in short suggest the southeast ridge continues to put up a fight over the next couple of weeks before getting “squashed” in the Weeks 3-4 timeframe.

This is in line with our thinking of the “transitional” period beginning this upcoming week. We think cold will begin to “push,” but isn’t ready to lock-in as of yet. There will be cold readily available to present more of a wintry potential with storms that track through the region when compared to this week, but we think it’s the period from 2/17 through early March that has the capability of featuring more sustained cold.

That’s a strong signal being painted by the JMA Weeklies in the Weeks 3-4 timeframe for widespread cold. Given that the MJO is forecast to swing into Phase 8 by this timeframe, along with the NAO/ AO looking to dip negative, the widespread cold look is a good idea to us during this particular time period.

Permanent link to this article: https://indywx.com/dissecting-todays-severe-potential-winter-returns-looking-more-in-depth-at-the-new-jma-weeklies/

Feb 04

+ AO Supports Current Warmth; Active Pattern Shows No Signs Of Letting Up Into Early March…

After the record-setting cold that gripped the Mid West and Ohio Valley for a few days, the recent “spring fling” has been welcomed with open arms by many! There are multiple reasons behind the warmth, especially with such a strong Arctic Oscillation (AO) in place.

We note the strongly positive AO (image 1) and the respective temperature anomalies that should result (image 2).

To no surprise, model data is bullish on the southeastern ridge holding firm this week.

The resistance put forth by the southeast ridge, combined with the renewed arctic air building across the Northern Rockies/ Northern Plains will continue to yield a very active storm track through the Ohio Valley. We expect precipitation to remain well above normal through month’s end, continuing into early March.

As we look ahead, we note modeling is trending the AO neutral and negative for mid and late month.

As this is taking place, the MJO is forecast to swing into Phase 8.

Phase 8 in mid to late February is a very cold phase.

Should the AO continue to trend negative, that will only raise confidence that cold will return.

Warmth (relative to normal) will continue to rule the day through midweek before we go into more of a transitional period this weekend into next week. Though certainly colder than this week, I’m not quite ready to buy into the idea that the southeast ridge will go quietly into the night. A couple of winter threats loom late weekend into next week, but confidence is low in the specifics. It’s when we get to the last (2) weeks of the month that we think cold will regain control, along with more widespread wintry threats of significance…

Permanent link to this article: https://indywx.com/ao-supports-current-warmth-active-pattern-shows-no-signs-of-letting-up-into-early-march/

Feb 03

Pre Super Bowl Rambles: Stormy Pattern Shifts To A Return Of Significant Cold?

In the short-term, there’s no getting around the very active pattern in place. As we’ve been discussing, we’ll find ourselves “smack dab” in the middle of a battle ground between a stubborn southeast ridge and building cold to our northwest. The fight in between will yield well above normal precipitation over the next couple of weeks.

Over the upcoming (10) days, expect a roller coaster ride in the temperature department as the battle takes place. While the most anomalous warmth is taking place now (IND is on pace to set a new record high temperature before the end of the day), relative warmth will continue to dominate into midweek before colder air presses and wins out.

After Monday’s light rain, we’re targeting (3) opportunities for significant precipitation across the region:

I. Tuesday night-Wednesday (still may include a risk of freezing rain across north-central communities).

II. Wednesday night-Thursday morning

III. Thursday night-Friday morning (ending as light snow)

When all is said and done, model data is in agreement on significant rainfall totals across central Indiana (2″ to 3″ amounts will be common by Friday).

Thereafter, confidence is high on colder air returning as we close the week and head into next weekend.

Guidance suggests that we still need to remain abreast of the potential of a more widespread wintry event late next weekend and this is something we’ll continue to keep close tabs on as we progress through the upcoming week. As of now, this doesn’t appear to be a major event, but stay tuned.

As we look ahead, we’ll have to continue keeping a close eye on the MJO. Today’s update shows the majority of data swinging things into Phase 8 by mid to late month. Should that come to fruition, prospects of another significant cold spell loom large…

Fun times ahead- no matter how you look at it! 🙂

Enjoy the game!

Permanent link to this article: https://indywx.com/pre-super-bowl-rambles-stormy-pattern-shifts-to-a-return-of-significant-cold/

Feb 03

Sunday Morning Video Update: Walking Through The Active Week Ahead; Looking Towards Mid-Feb…

A new week has dawned and with it will come a very busy weather pattern. Thankfully, today we’ll enjoy a “hint of spring,” including temperatures approaching the 60 deg. mark…

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Permanent link to this article: https://indywx.com/sunday-morning-video-update-walking-through-the-active-week-ahead-looking-towards-mid-feb/

Feb 02

Plot Thickens With The MJO…

There’s a lot of interest (no matter the time of year) in the medium to long range weather pattern. With operational modeling updating up to (4) times per day during this time range, there’s always at least some degree of fluctuation between model runs. At times, that fluctuation is more significant than others. It’s at those times when it’s more important than ever to lean on analogs, teleconnections, and other pattern drivers.

Recall that the MJO has been hyper active for the better part of this season- and has played a significant role in the winter pattern through the 1st half of this season. When the MJO features significant amplitude, it’s imperative that we pay close attention.

With that said, we note today that the models handle the current MJO pulse much differently between one another over the next couple of weeks.

For example, let’s go with the GEFS (image 1), curling the MJO into Phase(s) 6 and 7. From a temperature perspective, this is how that would be reflected at the surface

Phase 6
Phase 7

With that said, the European is more bullish heading into Phase 8 by mid-February. If correct, that opens the door for more significant (and widespread) cold.

Phase 8

We’ll continue to keep a very close eye on the MJO over the next week, or so, and hope for better overall agreement between the data. However, given a balance of current teleconnections, SSTs, and MJO, we continue to believe the pattern over the next few weeks will transition from a “battle zone” initially towards one that features cold overwhelming the region by mid-month.

There will likely be rather wild temperature swings through the first 1/3 of the month and that will help power the active pattern. At the end of the day, we expect well above normal precipitation, near-average to slightly colder than normal temperatures, and above average snowfall during the month of February here across central Indiana.

Permanent link to this article: https://indywx.com/plot-thickens-with-the-mjo/