With a little over a week left in April, thoughts continue to focus more and more on May. While our official monthly outlook will come out later next week, we did want to present our early thoughts on the first week of the month.
In short, a rather persistent upper trough is expected to dominate the eastern 1/3 of the country into the 1st week of the month. This should keep things cooler than normal, overall.
This also lines up perfectly with Phase 2 of the MJO in early May. (After a week of disagreement, model data now agrees that the MJO should “flirt” with Phase 3 before cycling back into Phase 2 early May). We note this favors cooler than normal temperatures across our portion of the country.
From a precipitation perspective, there aren’t particularly strong signals for wetter/ drier than average conditions with Phase 2 in May- at least for the Ohio Valley.
The positive PNA, however, can support a bit more of an active storm track through our region and that’s what model data is showing from this distance.
The positive PNA, of course, also supports cooler than normal temperatures across our portion of the country…
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Permanent link to this article: https://indywx.com/2020/04/17/late-season-wet-snow-storm-for-northern-portions-of-the-ohio-valley-fresh-long-range-thoughts-into-may/
Seemingly all winter, we’ve been unable to get the NAO, AO, EPO, PNA, and MJO to cooperate and align. The end result is an overall pattern that has been unable to produce widespread, sustained cold. As we progress through the remainder of the month, the contradicting signals will continue.
Despite the negative NAO (a signal notorious for drawn out cold patterns this time of year), the deeply negative PNA and developing strongly positive EPO will hold off any significant cold. Even in the immediate term, notice how the signals are’t matching up (i.e. strongly positive NAO with a negative EPO).
The MJO is forecast to rumble into Phase 4 to close the month and this is also a phase that favors eastern ridging.
Given the above, to no surprise, the consensus of model data is for a warm, wet close to the month.
Does this pattern change in April and we actually see some alignment with our teleconnections? What about the MJO? Does the current movement continue and do we get into the colder Phase 1 as currently shown? Interesting times ahead as we sort through the data. Our official April Outlook will be online late week.
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Permanent link to this article: https://indywx.com/2020/03/07/video-gorgeous-weekend-discussing-timing-of-systems-next-week-and-longer-range-impacts-of-the-mjo-epo/
January is flying by! With only 10 days left in the month, Indianapolis is running a whopping 8.2° above normal along with more than 3″ above normal in the precipitation department (unfortunately for snow lovers, this excess moisture has fallen primarily as rain, as IND is running a deficit of 5.2″ in the snowfall department).
January month-to-date temperature anomalies, courtesy of the Midwestern Regional Climate Center
January month-to-date precipitation anomalies, courtesy of the Midwestern Regional Climate Center
On a broader scale, here’s a look at the current month-to-date temperature anomalies for the Lower 48 as a whole:
January Lower 48 month-to-date ‘mean’ temperature anomalies, courtesy of weathermodels.com
As a refresher, our January forecast looked like this:
The baseline of this thinking had to do with the idea we had that the MJO would roll out of the warm phases (5 and 6) and strongly into the colder phases after mid-month. Secondly, the other driver was the thought that the current SST configuration in the north Pacific would “force” a negative EPO as the winter season matured.
While the MJO did, indeed, rumble out of the warmer phases just after mid-month, the EPO has not cooperated. Furthermore, instead of the MJO tracking into Phases 8, 1, and 2, it appears it wants to go into the “null” phase to figure out its ultimate destination for the 2nd half of winter (this will be key with Feb. and March). While this doesn’t necessarily support warmth, it doesn’t offer enough ammo to fight the warm signal from the strongly positive EPO.
Now that we’re beginning to turn the page to the 2nd half of winter, there are other items to begin paying closer attention to. In addition to the EPO and MJO, some of these features include the AO, NAO, and PNA. With that said, to drive more of a consistent colder than normal theme, we need to get the EPO at least into the neutral range as some of the other ingredients noted above transition into more favorable colder phases. With a strongly positive EPO, it’ll be tough to sustain well below average temperatures.
With all of that said, all hope is not lost for winter lovers. Climatology speaking, we’re in the coldest time of the year. Even in “marginally” cold patterns, or even “warm” patterns this time of year, wintry issues can create headaches. Secondly, it’s worth paying close attention to the MJO over the next couple of weeks as some of the data wants to take things out of the null phase and transition towards the traditionally colder phases of 8, 1, 2, and 3.
As it is, the next couple of weeks should present a fairly active storm track across the region. In the face of what should truly be a “torch” pattern, the saving grace (at least for fans of winter weather) has to do with the strong Hudson Bay ridge and tendency this kind of pattern has to force stormy times underneath. While far from a “slam dunk,” these kind of patterns can produce- even in the face of a strong positive EPO.
If you had to choose, would you rather have a bitterly cold and dry regime or seasonably mild with at least being on the playing field for wintry mischief over the next couple of weeks?
More in the AM, friends. Make it a relaxing evening! 🙂
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As another year comes to a close and the winter pattern begins to “mature,” we thought we’d do a little rambling…
This evening’s rambles have to do with the variety of “drivers” that at times like to take control of our weather pattern. You hear us use terms like the MJO, EPO, AO, PNA, and NAO (amongst others) often, but at times, these various pattern drivers can have more impact than others, and at varied times of the year.
Traditionally, if the MJO (Madden Julian Oscillation) is highly amplified, that’s going to serve as the basis of our medium or longer range forecasts. However, if the MJO is in the null phase, other teleconnections can take control of the wheel. Sea-surface temperature configuration can give hints to the way these elements may behave during the season(s) ahead, but we caution each respective season takes on a flavor unique to it’s own. That’s what makes this business so fun, challenging, and, at times, frustrating. 🙂
It’s also important to understand when the ingredients noted above have the greatest impact on our immediate weather. We love to lean more heavily towards the NAO and AO mid-to-late winter into the spring, for instance. Case in point, a negative EPO and positive PNA can quickly trump a positive AO/ NAO this time of year, and vice-versa.
In the event you didn’t have a chance to see it Sunday, we released our January Outlook. We have a very stormy month outlined that includes cold “overwhelming” things as the month progresses. A lot of this has to do with the fact we think we see a “shake-up” with the MJO out of the warm phases and into the traditional cold phases of 8,1, and 2 taking shape during the 2nd half of the month. Additionally, we continue to believe the favorable north Pacific sea surface temperature configuration (for a cold Great Lakes and OHV) will begin to force the negative EPO/ positive PNA.
The NEW European Weeklies show the transitional time of things through the 1st half of the month, but note the building more persistent NW NA ridge during the 2nd half of the month and corresponding reflection of an eastern trough. Should the MJO be heading into Phase 8 around this time frame (and we think it will), this trough will likely correct stronger in future updates for late month.
The model sees the stormy time of things through the month and into February. (Important to note that even “warm” months this time of year can also feature above normal snow. Just see this December- nearly an inch above normal for the month). As things stand now, we see multiple opportunities for snow as January gets underway, including Saturday PM, and again Tuesday night into Wednesday.
Make it a great evening! We’ll be back early in the morning with a fresh video update.
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For those that may not have had an opportunity to review our December Outlook over the busy Thanksgiving weekend, you can do so here.
This morning, we wanted to again review our forecast and provide further context behind our overall active, warmer than normal call for the month as a whole.
Before digging in to those additional details, here’s our 2019 December Forecast:
The “baseline” of this slightly-moderately milder than normal December is due to what appears to be the tendency of the MJO to run into the warmer phases (remember, Phases 3-5 this time of year argue for warmer than normal conditions across the East). The most updated MJO forecast continues to stay the course here.
At least through mid-December, the PNA and EPO are also forecast to be in phases that would support warmer than normal conditions across our portion of the country in the overall sense.
This isn’t to say that we won’t have cold and snow to deal with at times this month. We just believe the colder, wintry conditions that may present themselves will be transitional and that warmth will win out at the end of the day.
As we look ahead, there’s reason to believe other factors will come into play that will begin to change the pattern towards one that’s more suited for prolonged cold around, or just before, Christmas. Furthermore, despite the relative warmth forecast for the month of December, we remain firm on the idea of a colder, snowier than normal winter season.
