Mesonet Ticker for September 17, 2026

                
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September 17, 2026 September 17, 2026 September 17, 2026 September 17, 2026


Ohhhhh yeahhhhh




Buckle up, because this Ticker is pure unadulterated climatological geek-mode.

Some people get excited for concert tickets, some for their favorite TV show, and
some for their favorite food (Wolf Brand Chili and Pop-Tarts, anyone?).

Me? I wait for the CPC 3-month outlooks. Call me boring, call me lame, but at
least call me for dinner, but with a possible "historic" (strongest since 1950)
El Nino in the house, I have been waiting with bated breath (look it up...it
ain't "baited") for the new CPC October-December outlooks, just to see if they
went there.

They went there.

And as awesome as the precipitation outlook appears, what with the increased odds
of above normal precipitation, I might be even more excited for the TEMPERATURE
outlook. Even though climatologically speaking, CPC punted and gave the "Equal
Chances" tag to the Southern Plains--meaning equal chances of above-, below- and
near-normal temperatures--it doesn't show a clear above-normal signal like it has
for basically the past year!

But still, this El Niño is becoming a monster. CPC now gives a greater than
90% chance of a very strong El Niño this fall/winter and a 75% chance that Oct-
Dec reaches a RONI (the index used to classify the strength of ENSO, WITH long-
term oceanic warming taken into account) of +2.5°C or greater, which would
exceed previous events in the record back to 1950 by that metric. That's why
CPC is leaning so heavily on ENSO composites in these outlooks.

The one caveat they mention, and I also mentioned it previously this month,
the PDO is currently fairly strongly negative (-1.11 in August). The famous
1982–83, 1997–98 and 2015–16 El Niños all occurred with a positive PDO, so CPC
specifically notes that the negative PDO could dampen the classic El Niño
response in some areas.

Better not be our area, for crying out loud!

Okay, the precipitation outlook IS the big story. After the brutal summer/early-
fall flash drought, CPC is now showing the large-scale pattern becoming
increasingly favorable for more frequent precipitation across Oklahoma from
mid-fall into winter. And importantly, this isn't merely one model throwing out
a wet Oklahoma. CPC says the Oct-Dec wet signal is supported by El Niño
composites plus a broad collection of dynamical and statistical guidance. By
winter, the expected subtropical jet becomes the dominant precipitation signal
across the southern tier.

Yeah. This is the first outlook in quite awhile where I'd circle Oklahoma and
say, "Now THAT is what we wanted to see."

And there may be an even better part: Oct-Dec appears to be the beginning of
the El Niño wet signal rather than its peak. CPC maintains that southern
Plains wet tilt right through the heart of winter.

Now, does that mean more snow? Possibly, simply for the fact that there will be
more CHANCES for snow because of more storm systems. Obviously, each storm
system will be different, and the availability of cold air will be the key
there, but keep in mind that even if we end up below-normal in temperature
during these periods, that doesn't mean the cold air perfectly coincides with
the storms to provide frozen precipitation.

Remember our last "Super" (very strong) El Nino from 2015-16, November and
December were both extremely wet. In fact, It was our 2nd-wettest November on
record at that point, and remains out wettest December of all time, and it was
mostly rain. We did have a big winter storm right after Christmas, however,
when the cold air and storms lined up perfectly.







But overall, this is excellent news, and the first good climatological news
(worst newspaper EVER) we've had in awhile. And the best part (part 2, after
the temps)? CPC expects major drought relief in Oklahoma through the next
three months.



And that would be significant, because we saw more drought intensification this
week across western and southern Oklahoma, even as eastern parts of the state
saw some diminishment.



Now just looking at the October outlooks, we see the beginnings of El Nino's
influence on our precipitation chances, but temperatures are still favored
to be elevated, mostly because of our current lack of soil moisture still
indicates some warming impacts due to increased sensible heat/decreased latent
heat exchanges.



So El Niño is already showing up in the October precipitation outlook, but its
temperature influence hasn't really taken command yet. The wet southern-tier s
torm-track signal is beginning to emerge, while antecedent drought and soil-
moisture conditions are still fighting against the cooler side of the classic
El Niño pattern.

The CPC October outlook discussion contained a remarkable sentence, too (to a
climatologist, at least). Bear with me as I geed out (and we all know just how
painful that can be):

“Due to the strong and dominant El Nino, the Madden-Julian Oscillation (MJO) was
not a factor in the October forecast.”

That's a pretty remarkable sentence for September 17.

Why?

Because that sentence is basically CPC saying: the background tropical state is
so strongly dominated by El Niño that the MJO is becoming a secondary player.
Normally, especially in the fall, CPC pays close attention to the MJO because
its eastward-moving tropical convective envelope can temporarily alter the jet
stream, storm tracks and U.S. temperature/precipitation patterns on the 2–6
week timescale. But right now, the tropical Pacific is already strongly
reorganized by El Niño: enhanced convection is entrenched over the central/
eastern equatorial Pacific, convection is suppressed near Indonesia, and the
low- and upper-level wind patterns are strongly coupled to that oceanic
warming. CPC explicitly says the El Niño response is the primary driver of
anomalous tropical convection and winds.

So when CPC says the MJO “was not a factor,” they’re essentially saying:

“We don't need a transient MJO pulse to explain the tropical forcing we're
seeing. El Niño itself is overwhelming the signal.”

This is a result of the SST anomalies being strongly coupled with the
atmosphere.

Okay, geek-mode off. At least I THINK it's off...geeks cant' self-diagnose,
you know.

Even nearer-term, our rain chances go up quite a bit this weekend, and then
into next week. Yeah, we'll still be close to record heat for the next few
days, but the heat dome's days are numbered.





Still above normal to some degree(s), but it ain't 100s, amirite??? And
the rainfall amounts are greater across north and western Oklahoma over the
next seven days, but things are looking up at least.



I fully expect folks to be disappointed after a week or two, thinking..."Where's
the kaboom? I thought El Nino was going to make us all start building an ark?"

Well, a couple more caveats...El Nino's influence is just getting started, and
it certainly doesn't peak in October. It will strengthen more and more as we
go through late-fall into winter.

And the most important caveat of all...none of this is guaranteed. It's a tilting
of the odds. Granted, those odds are increased due to the strength of the El
Nino, but not 100% by any stretch of the imagination. But things are definitely
looking up.

Gary McManus
State Climatologist
Oklahoma Mesonet
Oklahoma Climate Survey
gmcmanus@ou.edu
                

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