O'Fishel El Nino Update July 20, 2026

[00:00:01]Hi everybody, I'm Greg Fishell and hello YouTubers. Welcome to the official Weather Channel update on El Nino, which we've been doing every Monday now for maybe about a month, maybe slightly longer than that. And so today, I want to show you some extra graphics that hopefully will give you a better idea as to what sort of circulations are set up by these different patterns of ocean water temperatures and why it has an effect on the globe with weather patterns all over the globe the way it does. So we're going to start off by talking about something called the Walker circulation. Now there are a number of largecale circulations all over the globe. Uh but one of them is called the Walker circulation and it basically encompasses the region in the equatorial Pacific Ocean. So I did my best to indicate an ocean here with waves up and down. And the neutral situation where you don't have an El Nino or a leninia is looking like this where the warmest water is in the western Pacific and then it gradually gets colder and colder until you get over to the coast of Central and South America. Because the water is cold here, the air sinks above it. Sinking motion or basically is against precipitation.

[00:01:09]Rising motion is what leads to clouds and precipitation. So sinking motion is the opposite of that. And then you have strong easterly trade winds or fairly strong easterly trade winds which is typical in the tropics. And then the air rises over this warmest water which heats the air above it and generates thunderstorm activity. And then you have the return flow in the upper atmosphere here. So that's a neutral situation.

[00:01:31]Neither lenino or el nino. Now in an El Nino you actually split that circulation into a couple of halves. Okay? And what happens here is that the warmest water in the Pacific actually shifts from the western Pacific into the central Pacific. And even over here where it's not maybe as warm as this, it's still way above normal. Okay? And so because the warmest water is in the middle of the Pacific, now instead of the vigorous upward motion and thunderstorm activity occurring here, now it is over here.

[00:02:02]Okay? And you have much weaker easterly trade winds. In fact, in some cases, it'll actually reverse and you'll have westerly winds in the tropics, which is very unusual, but it can happen. And then you have the other half of the circulation here, sinking motion here, which means that in areas in the western Pacific like Australia and Malaysia, places like that, they tend to get droughts in in El Ninos because of this fact that the circulation splits into two uh two halves like this, if you will. Okay, so obviously much different impact with all the thunderstorm activity being in the middle of the Pacific as opposed to the western Pacific. And then with a lenia, the warmest water by far is in the far western Pacific. And they get the strong upward motion with thunderstorm activity there. And then you have stronger than normal easterly trade winds which drive that warmest water far into the western Pacific. And then you have sinking motion here which suppresses any thunderstorm activity uh in the eastern Pacific. Okay. So those are the three scenarios and based on where the warmest water is that basically is what controls where the thunderstorm activity is that releases heat into the atmosphere through the process of condensation and that alters the weather patterns all over the globe. Okay. Now let's take a look at these four excuse me four El Nino regions. This is region 1 plus two and the latest anomaly is plus 2.8° C.

[00:03:33]Now the threshold for a strong El Nino is two. So it is already way way above that. But that's only a very small region and that's not really the key one that that we look at. Nino 3 actually went down a tenth of a degree Celsius during the past week. And I was curious about that. did a little bit of digging and it turns out that every once in a while you will get these bursts of westerly winds across the equatorial Pacific and it will drive you know some of the warmer water all the way towards Central and South America and once that wave passes this region there can actually be a little bit of upwelling and also some cooler water. It's it you have to look at large time trends when it comes to these types of things. A oneweek change is not really telling you much. Okay. Now, if this were to continue for the next three or four or five weeks, that would be significant.

[00:04:29]But a oneweek drop of a tenth of a degree in terms of the anomaly is really not any big deal. And then we take a look at Nino 3.4, which is really the key region that we look at, and that went up a tenth, excuse [clears throat] me, tenth of a degree Celsius in the last week. And then over here in the western Pacific at Nino region four, they dropped a tenth. And that's not surprising in an El Nino because again, the warmest water shifts eastward out of the western Pacific. Okay, so these are the sea surface temperature anomalies in all four of those regions going all the way back to June 1st. And [snorts] you can see that the oneplus 2 which is right next to the coast of uh of uh South America and Central America is that that anomaly started off at 1.7 and is now all the way up to 2.8. The region that we look at the closest is Nino 3.4 that was at.5 on June 1st and has steadily increased ever since. And then Nino 4, which is in the Western Pacific, has actually gotten cooler. And again, that is perfectly consistent with a developing El Nino. Okay, so the new methodology and I've changed the wording on this just a little bit uh to try to make it a little bit clearer. Let me get out of the way here so you can read this. So the previous oceanic nino index which was used every year to evaluate El Nino and Linos up until this year compared sea surface temperature anomalies in the Nino 3.4 region to the 30-year average which encompasses the period from 1991 to 2020. Now, however, El Nino and Leninia events are all about sea surface temperature gradients, okay?

[00:06:05]Or lack thereof. And so, with gradually rising sea surface temperatures globally, one has to look at how Nino region 3.4 compares to the rest of the tropical Pacific. Because if the whole tropical Pacific is basically above normal by the same amount, then there's no El Nino. Okay? Okay, the El Nino it has to be concentrated the warming has to be concentrated in most vigorous right along the equator. So if everything's above normal by the same amount doesn't mean anything. Okay, so that's why this new methodology was adapted. So a new index the relative oceanic Nino index or ROI was developed where the sea surface temperature anomalies in region Nino 3.4 are compared to the anomalies in the entire tropical Pacific to see how much the anomalies in that region stand out. And so this is the whole tropical Pacific here and that's Nino 3.4. So this has to stand out compared to all of this for it now to be classified as a legitimate El Nino. These are the thresholds again from 0.5 and and and the the numbers here are anomalies compared to normal in degrees Celsius. Okay. So if you're less than 0.5 above or more than 0.5 below, you're in a neutral state. But as you head up to 0.5 and above, then you've got a weak El Nino 1 to 1.49 moderate.

[00:07:29]Once you get to two, then it is very very strong. And all indications are that's where we are headed. To qualify as an El Nino, you have to have five consecutive overlapping three-month periods with a value of 0 plus.5 or plus 0.5 or more. And what do I mean by an overlapping three-month period? Well, you see these abbreviations here. DG D D D D D D D D D D D D D D D D D D D DJF stands for December, January, February.

[00:07:55]This is January, February, March, February, March, April. So, two of the three months overlap, but you have to have five of those in a row with a 0.5 or higher to officially qualify as an El Nino. And you can see the color coding here indicating all the times when either that threshold was met for an El Nino or a Lin. And these are the probabilistic forecasts for an El Nino.

[00:08:17]And so basically it's up around 100% until you get into the spring of next year. And in terms of comparison of intensities, the darkest colors here indicate the probability of a strong El Nino. And now there is an 81% chance of a very strong El Nino and only a one in five chance that it will end up being weaker than very strong. And this is the latest ensemble forecast. There is the plus two reading right there. And the ensemble mean is at about 2.1 or 2.2.

[00:08:48]And that's gradually been getting higher every week. And there has not been one instance that I can find going all the way back to 1950 where the ROI went from a negative value in the spring to a value of greater than two by the end of the year. So if that does indeed happen, and it looks like it will, then this would be unprecedented in the modern era to have a El Nino develop that quickly.

[00:09:11]And this is a look at the sea surface temperature anomalies under the surface of the ocean. And you can see how strong those anomalies are. And over the past four weeks, some of that warmer water right in there has made it up to the surface. Okay? It started off here. And you can see that by the time we get down here to the most recent period that those colors have darkened. And so that warm water that was subsurface is gradually making its way to the surface and increasing those temperature anomalies. And last but not least, I apologize. I've been like this all day.

[00:09:47]The European ensemble system is really going bonkers with all of this. This was uh on June 1st. are forecast. A lot of the ensemble members had an anomaly of up around plus three. And if we take a look at the most recent one, it got even stronger. Looks like the ensemble mean now is a little bit above plus three.

[00:10:07]We've never had an ROI index that high going all the way back to 1950. Okay.

[00:10:14]So, if the European ensemble system is right, this is going to be really something. And one thing that the a strong El Nino does, it tends to correlate with above normal precipitation in the southeastern part of the United States. And so if we still have a drought situation, this would be a great way to help alleviate that as we head into the spring or head into the winter season. Uh but the other thing you need to take into account is that it can also generate some really really strong storms because it generates a very strong jetream at a low latitude and those storms generally have access to a lot of warmth from the Gulf of Mexico and the South Atlantic and you can get some really really big storms moving across the southern US and up along the east coast. So, uh, that can sometimes be a bit of a drawback, uh, to getting a strong El Nino. And the California coast, Southern California coast can just get raked in these types of situations with flooding and mudslides and all of that. So, it's going to be really interesting to see how strong this gets. And then, of course, uh, even more interesting to see what the impact ends up being in various locations. All right, that's it for now, folks. That is the El Nino update for this Monday, July 20th. Hope you have a great rest of your whatever day you're watching this, and I will see you again on Monday, the 27th. Take care everybody. See you.