The sea surface temperatures across much of the Pacific Ocean remain unusually warm for this time of year. According to the experts there are two critical pockets of warm water that could influence U.S. winter temperature and precipitation patterns. A good many folks are familiar with the El Niño and La Niña weather events — where warmer or cooler Pacific sea surface temperatures influence weather patterns in the U.S. There is an alternate, and more rare type of El Niño that I had never heard of called a Modoki El Niño!
Whaaat? Modoki is Japanese for “same but different.” Oh, OK, that explains it! Modoki events are a rarer subset of regular El Niños and are marked by warmer water centered in the Central Pacific. With a Modoki El Niño, the core of strongest warming is located within the center of the Pacific. Typically, climatologists monitor El Niño sea surface temperatures a little closer to the U.S. That region of the Pacific is considered inactive. A little further west, however, the story is different. Long-range climate model forecasts above-normal sea surface temperatures to persist across the Central Pacific through the winter months.
So how will this possibly impact our winter? Assuming little change in current sea surface temperatures from what they are now, it’s possible that winter precipitation impacts could align with a Modoki El Niño. OK, get ready for the weatherman’s lingo! Here it goes!
A linkage between warm tropical water and the sub-tropical jet stream, via convection, could steer moisture across Mexico and toward the South-Central U.S. This would result in an unusually dry California and an increase in winter precipitation over the Southeast and the Eastern U.S.
This year’s blob (yes, that’s a weather term) of unusually warm North Pacific sea surface temperatures is the second largest marine heatwave recorded in the Pacific in at least the last 40 years, covering 4 million square miles. The abnormally warm waters extend from Alaska to Canada and as far west as Hawaii. That includes a large swath of water that’s more than 5.4 degrees Fahrenheit hotter than normal for this time of year.
This unusually warm water can have a persistent impact on the position of the jet stream. In the past, the jet stream has been pushed farther north than normal over the western U.S. before dipping south over the Midwest. In other words, a “wavier” jet stream. It’s possible that the jet stream will bow unusually far north around this area of warm water. This would result in a dip in the jet stream and resulting intrusions of cold arctic air into the middle and eastern U.S. This wavy jet stream could also reduce California and West Coast precipitation.
The unusually warm Pacific Ocean is likely to influence the position of the jet stream this winter and shape temperature and precipitation anomalies. However, keep in mind that there is no assurance that these warm pools will persist. Also, in addition to warm Pacific water, there are numerous other factors that will influence winter weather.
OK, here is an old country boy’s interpretation with help from the Farmer’s Almanac — it’s going to be drier than a powder keg and colder than a well digger’s butt in the West. It’s going to snow to beat the band in the East/Northeast and be cold enough to kill a hog. In the Southeast, get ready for warm turd floaters. In the Midwest, get ready for a frog-strangler on ice.
What about Texas, you say? Well in Texas, winter is never that easy to predict, so we will say it is going to be fair to middlin' or maybe pleasant as a peach!
Marty Morgan is Cooke County Ag Agent for the Texas A&M AgriLife Extension Service. Reach him at 940-668-5412 or firstname.lastname@example.org.