La Nina Update - things are moving SLOW

It's been a little while since we touched on some of the details of El Nino and La Nina. Remember, they are contributors to our longer-term weather patterns that can unlock clues for the months ahead. El Nino is when the water along the equator in the Pacific is warmer than average - La Nina is just the opposite. See the examples below:

The top image is La Nina with the bottom one showing the El Nino example:

We have just emerged from a short-term El Nino (lasted only about a year). Prior to that, we had a 3 year La Nina that ended in early 2023.

Notice the colder water that is just below the surface - upwelling continues and there is a better than 70% chance that by late fall, we will be in a La Nina. As that colder water surfaces, easterly winds will push some of it toward the central Pacific Ocean.

What has changed recently is that the onset of La Nina is taking longer than earlier thought. And there's even some question as to how strong it will get before it starts dissipating again in early 2025. Take a look at the series of images below, starting with October and ending in February. You'll see the gradual progression of the colder water (blue colors) migrating from east to west. We should reach La Nina status by the end of the year, but when you look at February, already the blue is fading off the map. That would indicate a warming of the water in that region.

October:

November:

December:

February:

What generally happens in a La Nina winter for Kansas? Generally, they tend to favor slightly colder weather overall, but of course there are exceptions. The winter of 1999/2000 had a strong La Nina and ended up warmer than average. The winter of 2011/12 was warmer than average, and it was a moderate La Nina. There is a tendency for the northern jet to be stronger (ushering in the colder blasts), while most of the better moisture gets shunted off to the east of Kansas. It doesn't mean the entire winter is dry and snow-free, but I think it's a very, very low chance of much drought easing this winter given the oncoming La Nina setup.

Thanks for reading

Have we had our last widespread 100s

It is certainly looking that way based on trends we are seeing for the next week and beyond. It's not 100% set in stone yet, but with each passing day that we don't hit the century mark, the odds go up that we are done with 100s (on a widespread scale). And recent rains can help lower chances of hitting 100 too.

Here's where the latest count stands as of Friday, August 15. Most of the state has had an "average" number of 100s this summer:

Here's why we think our days with triple digits may be behind us now. Take a look at where the heat ridge is focused into our third week of August. 

If we are NOT hitting 100° with the high right in our backyard, once it begins to shift away from Kansas in early September, we should be cooling even more:

I've even seen some information lately suggesting we go into a cool period just in time for this year's Kansas State Fair. Wouldn't it be nice if we had a stretch of 70s and 80s for the fair? It sure seems like we always have a "chilly" couple of days and then at least a few really warm afternoons. Stay tuned for more about that.

I do have this for you - an early look at September (the month as a whole) - might be near or slightly cooler than average. Again, it's early, but just some of the stuff that we are looking at behind the scenes. Most models are terrible at picking up on cool weather, so the fact that we have something that looks like this gives me reason to think next month might be pretty nice and fall-like.

Downbursts:

We had some incredible photos come in on the night of August 14th (Wednesday) of some downbursts that hit near Bennington. Perhaps you've heard them referred to as microbursts. They are one in the same and often do damage that is comparable to a week tornado. First of all, we can usually forecast the environment in which they form. We can detect them on radar, but in many cases, the damage is already done by the time they are detected. Take a look at the two photos - same storm, but from slightly different angles. (photos courtesy Amanda Raccagno and Tara Nisbeth)

I can't recall photos that showcase a downburst as good as the ones shown here. Usually, the photos are from much farther away and even more blurry. However, you can clearly see the descending ball of wind, and something has to give when they hit, and it's never the ground. That wind spreads out in all different directions.

Downbursts are more common in summer (and in the desert Southwest) when the lowest 5,000-7,000 feet of the atmosphere are relatively dry. That can favor downbursts with some of the precipitation evaporating as the air descends quickly below the base of the storm. As for how widespread the damage can be underneath of the downburst, it varies. I've seen some that are only a city block wide, and others that can be a mile or better. 

Have a great day!