Category: PNA

Running the Gamut; Looking Ahead to April…

We’ll apologize in advance for the long-winded post tonight, but there’s a lot to cover. Not only do we have the accumulating snow on deck, a couple of strong storm systems this weekend into the middle of next week, but the long range pattern is set to turn cold (again) after a mid-month respite. We also want to look ahead to our early thoughts towards April…

Let’s take things one at a time:

Thursday-Friday Snow

While we don’t have major changes to our ongoing snowfall forecast, we have “sagged” the swath of 1″ to 3″ snow south just a hair given the latest computer model guidance. Steadiest snow should fall Thursday night into the predawn hours Friday. We’d anticipate a slick Friday morning commute through the heart of central Indiana.

Snow should exit off to the southeast around, or just before, lunchtime Friday. As always, your ground-truth reports are welcome (feel free to send to us on Twitter or via e-mail).

Warmer Side Of Things

The ‘mean’ trough position will shift to the west (temporarily) and lead to an overall milder time of things for the mid-month stretch. Unfortunately, the milder air will come with a wetter pattern.

This milder, wetter pattern will be highlighted by (2) storms:

I. Saturday, 3/10

II. Tuesday-Wednesday, 3/12-3/13

Both storm systems will be capable of producing locally heavy downpours and embedded thunder. Greatest chances of severe will remain south of central IN with this weekend’s storm, but may be further north next week. We’ll keep a close eye on things and issue Client Briefs if need be as we get closer.

A combination of the GFS and European computer models print-out rainfall totals between 1″ and 2″ over the upcoming 10-days and this seems reasonable given the fact both storm systems will be able to tap into Gulf of Mexico moisture.

From a temperature perspective, the brutal cold will come to an end behind our late week snowmaker. While “transient” chill will follow both of the upcoming storm systems, we’re heading into a much milder pattern, overall, through the mid-March stretch. Mildest air will come directly in front of the storm systems, highlighted by a couple of 60 deg. + days the middle of next week.

Positive PNA takes over

Unfortunately (for lovers of spring), the mid-month warm-up will be only a “tease” as we’re set to trend cooler, relative to normal, for the last 10 days of the month. The reason? A developing positive PNA.

To no surprise, we see the cooler pattern returning on the computer models:

Not only will we turn colder to close the month, but Thursday likely won’t be our last accumulating snow of the season…

Looking Towards April

Despite the late-March “set back” to a chilly time of things, we continue to think a more sustained “stick and hold” spring pattern looms around the corner. In fact, we agree with the latest CFSv2 delivering a warmer than normal pattern for April, as a whole, to the eastern portion of the country.

Note that as we go, the model is getting warmer for April with each passing day. As things stand now, we think the trough will pull back to the west with a more sustained ridge in place across the eastern portion of the country in April. With this, a wetter than average regime likely awaits, including an uptick in severe chances further north into the region.

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“Hectic” March Pattern Rumbles Along…

After tomorrow’s accumulating snow event, we’re tracking 2 storm systems and a temporary warm-up over the weekend into next week. Don’t get used to the warmer air, as a positive…

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VIDEO: All-Access Long Range Update…

This evening’s long range video update discusses the pattern drivers behind the late-March weather pattern…

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All-Access Video Update On The Longer Range, And Honing In On Short-Term Systems…

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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…


Permanent link to this article: https://indywx.com/reviewing-the-latest-european-weeklies-and-updated-long-range-thoughts/