In recent weeks, sea-surface temperatures near the west coast of South America have warmed to normal levels, putting us in La Nada, between the warmer El Niño and cooler La Niña sea-surface temperatures.
Scientists at the National Weather Service’s Climate Prediction Center say that we’ll likely stay in this pattern through the summer season.
However, other climate scientists point to a weak El Niño, the warmer-than-normal sea-surface temperature event. This is based on the much warmer sea-surface temperatures in the Gulf of Alaska and east of New Zealand, along the international dateline. Many computer models project that we’ll be in a weak El Niño pattern later in the spring as ocean temperatures are expected to warm along the equator.
The above-normal water temperatures in the Gulf of Alaska may be the cause of some of the extreme weather patterns we’ve seen across the country. Low pressure systems will often form near regions of warmer waters. High pressure ridges will sometimes be enhanced to the east of the strong low pressure systems, like the one in the Gulf of Alaska, giving the western U.S. drier-than-normal weather and colder and snowier conditions east of the Rockies.
Thanks to that strong high pressure ridge, California and the Southwest are going through one of the driest periods on record. California Gov. Jerry Brown has declared a drought emergency for the state. Major cutbacks of water supplies are expected, especially if weather patterns stay drier than average.
If we stay in a La Nada or a weak El Niño sea-surface temperature cycle, there is still a good chance for more colder and snowy weather across the northern U.S., especially east of the Rockies.
Conditions in the Inland Northwest should start turning toward the wetter side as we get close to the new moon on Jan. 30. I expect to see occasional snow and rain as the high pressure system breaks down. There is also the chance that the next six weeks will be a bit wetter than normal in our region, but California and the Southwest should remain drier than normal for the rest of the winter.