Category: PNA

VIDEO: Reasons To Believe The Chill To Open October Has Some Staying Power…

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Another Big Shot Of Cool Air Dialed Up, But What About Rain?

“Transient” warmth and continued dry weather will carry us through the short-term period, but don’t get used to it.

Another sharp trough will plunge into the eastern portion of the country next week and offer up the coolest air of the young fall season, along with better chances of at least light rain. The upcoming cool blast is in response to the positive PNA and negative EPO.

The airmass associated with this trough next week will be early November-like for a day or two, and well below late September/ early October norms for the remainder of the period.

Unlike our last trough, this one will feature more upper level energy and this combined with the unseasonably cold air (at the surface and aloft) will generate periods of at least light rain during the early part of the work week.

We’re not talking about a lot of rain, but a badly needed 0.25″ to 0.50″ is better than nothing.

Looking farther out, there’s reason to buy into the cooler than normal pattern having staying power into the first 1/3 of October, and perhaps beyond. More on this in future updates. Make it a great Tuesday!

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VIDEO: Turning Briefly Warmer Before Another Chilly Plunge…

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VIDEO: Soon-To-Be Sally Heads For The North-Central Gulf Coast; Pattern Takes An Active Turn Towards Late Month…

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Long Range Update: Walking Through The Back Half Of September…

We believe the pattern during the 2nd half of the month will be driven by the MJO and PNA. The MJO is forecast into Phase 6 and 7 by the 18th-24th time frame.

Phase 6 is quite warm, but notice how the chilly air begins to push during Phase 7.

Neither phase is overly wet, but there’s hope compared to how dry it’s been over the past 2-3 weeks.

Interestingly enough, after a “neutral” phase with the PNA, both the GFS and European ensemble products predict a strong positive shift just after the 20th. This suggests to me that the week starting around that point should feature more widespread and stronger chill, compared to normal.

Let’s look at the latest model guidance, starting with the European ensemble:

Week 1 is still warmer than normal across our region, but notice the strong cooling by Week 2 (Sept. 18th-25th time frame).

The GFS ensemble is similar during the Week 1 and Week 2 time frame.

Given that strong PNA by late month, it wouldn’t surprise me to see these anomalies grow cooler as time gets closer during that Week 2 period.

Overall, the pattern continues to look dry, although there should be a better shot of rain/ storms as the cold front moves into the region that will ultimately deliver the much cooler air late month.

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