AMARILLO, TX (KFDA) - This week's topic is something that can dramatically impact our weather: La Nina.
We've talked about it a lot lately, but what exactly is La Nina?
La Nina is a cool water anomaly located off the coast of South America. During a La Nina year, the jet stream is shifted to the north due to a semi-permanent ridge of high pressure, and that does lead to some interesting temperature and precipitation trends.
What does it mean for us? Much like the national trends, La Nina typically means a milder winter, but that doesn't mean we won't see harsh Arctic shots.
An interesting trend with La Nina is that it is the time when we typically see some of the coldest Arctic air plunge into the area. Sadly, La Nina tends to mean a lot less rain and snow during the winter months.
We can go on some long dry streaks during La Nina and ultimately will lead to the start of a drought or the intensification of drought conditions.
Now that we know how La Nina affects our area, how does it affect the nation?
It provides some interesting temperature trends across the country. The Pacific Northwest and the Northern Plains tend to be colder than average. Meanwhile the Southern US tends to be warmer than average.
There are also some interesting precipitation trends during La Nina years. Much like the jet stream, most of the precipitation is focused in the Northern U.S., especially the Pacific Northwest and the Northern Plains. The opposite happens in the Southern US where moisture is really lacking.
This year has been the perfect example of how La Nina helps to start a drought.
This year was especially interesting because we had a ton of precipitation, but then it just turned off. Believe it or not, we ended 2017 with a 6-inch surplus but are still in a severe drought. Other years in the past, 1995-96 and 2010-2011 were La Nina years that behaved the same way.
So, this means if we don't get moisture soon, the drought will continue and fire season could be pretty bad.
Check back in towards the end of the month for my next segment on snow!