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Category: EPO
Permanent link to this article: https://indywx.com/video-dry-weekend-looking-ahead-to-the-cool-pattern-that-will-return-early-august/
Jul 24
All-Access Evening Video Update: More Early August Chatter…
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Permanent link to this article: https://indywx.com/all-access-evening-video-update-more-early-august-chatter/
Jul 23
EPO In Control?
As we look ahead to the August pattern, it’s becoming increasingly apparent that the EPO, or East Pacific Oscillation, is trying to take control.
During positive phases of the EPO, warmer anomalies are usually noted across the eastern United States, whereas negative phases tend to promote cooler anomalies through the central into the eastern portion of the country. While the correlation is greatest in the fall and winter, the EPO phase can also have a say in the summer pattern.
As we look ahead at the forecast EPO and upper level pattern, note the similarities:
First, here’s what a negative and positive EPO would typically yield from the perspective of temperature anomalies:
Here’s the forecast EPO into the first week of August.
Note how closely the modeled upper air pattern (and associated surface temperatures) follow suit:
Present (negative EPO)
July 27th – Aug 1st (positive EPO)
Aug 3rd – Aug 8th (negative EPO)
(While we can’t show it here, it’s interesting to see the latest European Weeklies keep the EPO predominantly negative to significantly so through the bulk of August and into September).
So what’s the moral of the story? We believe after a period of transitional heat this weekend into early next week that temperatures will return to seasonal levels in early August, along with an increase in rain/ storm threats as the northwest upper air flow sets up shop. Our official August forecast will be issued early next week.
Permanent link to this article: https://indywx.com/epo-in-control/
Jul 21
Early August Ideas…
The year continues to fly by! We’re now finalizing our forecast for the last month of meteorological summer and will include a look-ahead to our early fall ideas with the official August Outlook that hits the site later next week. With that said, here are some of our early August ideas:
I. Sea surface temperatures remain well above average through the western Atlantic basin as well as the northeastern Pacific. This should promote warmer than normal conditions, overall, along the coastal areas. Additionally, we’ll need to continue to keep a close eye on the potential of additional “home grown” (Gulf of Mexico and off the southeast US coast) tropical development as we move closer to the peak of the hurricane season.
II. The MJO isn’t nearly as hyper as months past. While we’ll continue to keep a close eye on things, we currently don’t anticipate being able to lean on this tool as a good indicator for what may transpire through the month of August (at least early on).
III. We need to keep a very close eye on the EPO over the upcoming week to see if modeling continues to project a significantly negative phase into August. This can “up the ante” for a cooler than normal central US during August if so.
IV. Lack of widespread drought/ dryness. The wet spring and early summer really can help make an impact longer term and that has been seen as early as this week (added humidity with the heat wave), but also helps overall when it comes to late summer and the respect to the staying power, or longevity, of heat waves.
Here’s our early thinking with respect to August temperatures and precipitation. Again, our final, more detailed, outlook will be issued next week!
Permanent link to this article: https://indywx.com/early-august-ideas/
Apr 02
Negative NAO Set To Present Mid-Month Headaches…
In case you missed it, you can find our April Outlook here. We want to ensure we’re very transparent and never shy away from the products we put out there. With that said, as difficult as it can be at times, it’s critically important that adjustments are made when necessary. The fact of the matter is that medium and long range modeling has had a glaring error since late winter and early spring. First, it was the EPO and now the NAO that appear to create all sorts of chaos in the medium to longer range period.
We note the NAO (or North Atlantic Oscillation) is set to drop to as negative of levels since January and some data would suggest we’re going to go even lower.
A negative NAO in April would “normally” lead to this kind of temperature pattern:
The normally reliable European model had this kind of pattern for mid-April only a couple of days ago:
Today, we’re talking about this kind of pattern for the exact same time period:
That’s a “night and day” difference. The reason? The model is beginning to catch on to the significant negative NAO developing. Accordingly, latest data delivers incredible high latitude blocking and subsequent cooler anomalies across a large portion of the Lower 48 for the mid-month period. (Note how close the below temperature pattern in the Day 10-15 time frame is to the analog a few images above. Remarkable stuff).
This time of year won’t result in sustained colder than normal conditions and transient warmth will make itself felt from time to time, but it’s a far cry from the sustained warmth originally expected for mid-April.
As we reflect back to the struggles long range models had with the negative EPO and now flip the page forward to the negative NAO problems, it certainly leads to lower than normal confidence in long range data and leads to a “cause for pause” as we put together monthly/ seasonal data into the upcoming late spring and summer months. Transitional seasons (spring and fall) can always be fickle, but some of the issues with the drivers this spring are in a different league.
Enjoy the “spring fling” that will develop late this week and weekend. The warmest air of the year is still on deck.
Longer term, well sometimes you have to throw ideas that have been made of long hours and hard work in the trash and start over from scratch…
Permanent link to this article: https://indywx.com/negative-nao-set-to-present-mid-month-headaches/