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Category: MJO
Permanent link to this article: https://indywx.com/evening-video-update-snow-storms-and-a-major-pattern-shift-on-the-horizon/
Feb 17
Sunday Morning Video Update…
A wintry mix this morning sets the stage for another active week of weather across central Indiana. We also look forward to late Feb and early March…
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Feb 16
All-Access Saturday Evening Video Update…
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Feb 14
Reviewing The Latest European Weeklies And Updated Long Range Thoughts…
We’re growing closer and closer towards the period we’ve been thinking would present one last round of cold, wintry weather (relative to normal) for the ’18-’19 season.
While the stormy idea will likely end up being correct, the significant cold that we thought would “spread out” (as opposed to being confined to the NW and northern Plains) is in jeopardy.
The overall upper air pattern over the upcoming few weeks will likely continue to be dominated by a mean trough position across the central and west, along with the persistent southeast ridge.
This will continue to result in above normal precipitation into the first week to 10 days of March, with a very active storm track.
From a temperature perspective, the baseline of our ideas being centered on the MJO appears to be the error in our forecast. It’s not that the MJO isn’t heading into Phase 8 (it’s officially there now, as noted below), but it appears other teleconnections are “trumping” this cold ingredient.
The combination of the positive Arctic Oscillation (AO) and negative Pacific North America pattern (PNA) are the drivers and are showing no signs of wanting to let go of the wheel.
The AO is forecast to remain strongly positive into early March.
The PNA is forecast to remain negative into early March.
Note how both of the above support that southeast ridge and associated relative warmth.
At one time, it appeared as if the North Atlantic Oscillation (NAO) would dip negative, however, that’s no longer the case.
While the active idea will come to fruition, the cold (at least to the magnitude we thought) will have a difficult time. That isn’t to say that enough cold air won’t get involved with a couple of these storms to result in wintry precipitation of significance, but rather that sustained cold will be tough to come by. Snowfall (of the heavy, wet variety) very well still could end up above normal with these moisture-laden systems over the next few weeks.
European Weekly Update
The new European Weeklies are in and follow the idea above nicely. They forecast a very stormy pattern to persist over the next few weeks with a battle ground between cold to our northwest and warmth to our southeast. We’ll have to be watchful for a couple of storm systems capable of delivering heavy amounts of precipitation. Given the teleconnection states over the next 6 weeks, it continues to look like any sort of significant wintry weather will need to take place before mid-March. Thereafter, warmer than normal times are expected, including true spring-like weather emerging. I know most can’t wait…
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Feb 12
We Have The Storms; Time To Add The Cold…
Over the past month, a widespread portion of the Ohio Valley, including central Indiana, is running close to 200% of average in the precipitation department. There’s no wonder flooding issues have resulted in spots- especially across the lower OHV region.
As we look ahead, the active storm track will persist, but there will be one key missing ingredient from the better part of the past couple of weeks and that’s more in the way of sustained cold. After reviewing some of the latest data, there’s no reason to change our ongoing idea of the transitional period (in the midst of that now) giving way towards one that will feature more in the way of “lock and load” cold in that 2.18 through 3.10 time period. We expect this period will run well below average in the temperature department and above average in the snowfall category. Snow removal clients, we recommend gearing up for a busy time of things over the upcoming few weeks.
The basis of this idea initially focused squarely on the MJO and the fact that modeling was keying in on things swinging into the favorable cold phases of 8, 1, and 2.
Taken at face value, this would be the corresponding upper air look in those respective phases:
Phase 8 (coldest)
Phase 1
Phase 2
Phase 3 (cold begins to “back into the west and there’s at least a hint of the SE ridge returning)
As most longtime followers know, we put more stock into the NAO state during the latter winter and spring months, as this teleconnection can “trump” others during this time frame. We notice the NAO is forecast to trend negative as we progress through the back half of February.
A negative NAO will result in widespread cold this time of year:
After remaining strongly positive for the past couple of weeks, the AO is forecast to plunge negative as we progress through the remainder of February. Again, this increases confidence on a return of more sustained and significant cold potential.
It should also be pointed out that the active pattern should continue, especially considering the southeast ridge should put up some resistance over the upcoming couple of weeks. The latest ensemble products would agree in the mean upper air pattern:
With colder air overwhelming the pattern, more of these storms will be capable of producing impactful wintry precipitation over the upcoming few weeks. After storms grab the headline, attention will shift to the possibility of another significant arctic blast before the end of the month.
In the more immediate term, we continue to keep close tabs on the following dates for the potential of snow and/ or ice:
I. Friday night, 2/15 and Saturday, 2/16- southern half of Indiana
II. Sunday, 2/17
III. Tuesday night, 2/19 and Wednesday, 2/20
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