First Alert Weather In-Depth: La Niña

ROCHESTER, N.Y. (WHEC) — It can be interesting to compare the kind of weather we get a “little ole Rochester” with what we get around the globe. We know that the globe is made up of 71% water. So it stands to reason, that this will have a direct impact on the overall weather.

Let’s focus on the Pacific Ocean right along South America. In a given year, usually, we see what is called the trade winds which pushes that warmer water towards Asia. This year, and last year as well, it has been a little bit of a different set-up with stronger trade winds. This is creating what we call upwelling. There is a lot of cold water that is coming in off the coast of South America that also has a direct impact on the overall weather pattern. The way it is shaping up now, you get a sense of where the warmer sea surface temperature (SST) is located and then where the cooler water is located just to the south. That cooler water is pushing in along the equator. And I should emphasize that we were talking about the water temperature across all of the Pacific Ocean and that has a direct impact on the overall weather pattern around the globe.

Right now we are projecting and the Climate Prediction Center is projecting the jet stream is going to come up through the Gulf of Alaska and then through the northern states and eventually settle in right across the Great Lakes. We know the jet stream is also the steering current for a lot of our storm systems and we are talking about November, December and January. The projection is for colder than normal temperatures through a good portion of North America. A lot of the south is going to be completely dry or nearly dry, But the Great Lakes and the upper Mississippi Valley, including Rochester, could be wetter than normal. In addition, it could also be warmer than normal.

The big question is: Will it be cold enough to support all snow or do we get a lot of that mixed precipitation? This is the kind of analysis that we are going to take a closer look at over the next two weeks. More data will be coming in, so the question is what kind of winter season are we going to find in Rochester?