Matt Makens

Good morning, La Niña is done! Now onto a neutral pattern before El Niño likely
establishes itself. This may come with cheers or jeers depending on your
perspective and how each affects your operations.

Let's walk through some brief details about where we are and where we are
headed.

La Niña is gone in the sea surface conditions – the ENSO region has warmed quite
a lot. Right now, the westernmost region (4) is the coolest and the easternmost
region, (1.2) is warmest.

Moments of La Niña continue in the atmosphere, however, and the atmosphere's
response will be delayed for some time as it takes a while for the atmosphere to
couple with the ocean. One way to measure the atmosphere behavior is with the
Southern Oscillation Index (SOI), which is still in a La Niña phase through
February.

We've already seen the weather pattern across the U.S. act somewhat erratically
– California/West moisture and continuous moisture over the Northern Plains.
Expect more erratic behavior from here on out through this neutral period of
time. Although erratic may not be the most appropriate word to use for the West;
Research shows La Niña and El Niño have little impact on California's
winter-time weather. 

We do know the drought that this La Niña has spread across the country, and
doing away with both will be a good thing.

The latest drought monitor was released Thursday and shows the ongoing drought
footprint across a lot of territory, especially the Central and Southern Plains:

Although I think it is safe to say we are turning the corner and the worst of
the drought is behind us, the Southern Plains still need a lot of water to catch
up. 

I do think conditions through May and perhaps June can give the Southern Plains
some added boosts of precipitation to improve vegetation there, although may
technically stay in a drought for a while. I've attached an image of the past 3
years' moisture deficits to illustrate how far into the hole the La Niña pattern
put us in.

Hard to argue that the recovery for the central U.S. will take time considering
most of it has one to two feet of water deficits in the past three years.

So, where are we going now that La Niña is on the way out? 

The odds increase to more than 50% for El Niño later this year in the ocean
conditions, but there is likely a delay in the weather pattern coupling with
that ocean condition. 

When it comes to those computer modeled odds of El Niño and making sense of the
rapid transition, it is hard to ignore clues like the current precipitation
pattern around India and South America; both indicate El Niño should be in place
later this year. Lightning data in the tropical Pacific can also be used as an
indication that El Niño will arrive. 

There's also support for El Niño's development coming from the atmosphere's
behavior near New Zealand and Alaska. I'd like to see some shifts around Hawaii
to "lock it in" for an El Niño to take over sooner rather than later, though. 

Bottom line: clues in the weather pattern indicate El Niño establishes itself
this year. To illustrate how a weak or strong El Niño impacts summer conditions,
here are precipitation images that illustrate the differences.

And, for the winter:

A lot to be watching for, now that we are turning the corner on the
drought-plagued weather pattern of the past several years.

With La Niña 'officially' over, a look at where we are headed