September 17, 2019 archive

MJO/ EPO Telling Of Where The Pattern Is Heading To Close September & Open October?

The short-term period will continue to be dominated by unseasonably warm and dry weather. While we’ll notice a drier air mass (lower humidity) in place the next couple of days, temperatures will remain much warmer than where we should be in mid to late September.

As we close out the month and head into early October, there’s opportunity for a cooler change and we can look to the MJO and EPO for these clues.

Let’s start with the EPO. The GEFS has been leading the way on the negative transition late September for some time now. The EPS is now trending more strongly negative as of the past couple of days. This argues for a cooler than normal period of weather as we put a bow on September and open October.

(The strongly positive EPO will promote more well above normal warmth in the short to medium term period).

The MJO is becoming more amplified and the result is that we can add another “tool to the belt” moving forward in determining the overall direction of the longer range pattern.


Phase 8 argues for widespread warmth, but as we transition from Phase 1 into Phase 2 (easy to see that’s where the MJO wants to head), cooler air swings into the East/ South.

That transition may also result in needed moisture. Note the wetter period that develops during the movement from Phase 1-2.

Speaking of moisture, Sunday appears to offer up the best chance of widespread, organized rain/ storms we’ve seen month-to-date. Models are keying in on the potential of 0.50″ to 1″ (fingers crossed) as a cold front moves into the region.

The CFSv2 is following the plan outlined above- transitioning towards a wetter and eventually cooler pattern Weeks 2-3.

Sept. 17th-27th temperature anomalies
Sept. 27th-Oct. 7th temperature anomalies
Sept 17th-27th precipitation anomalies

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