This winter is expected to bring a number of strong storms that will impact the West Coast and southern half of the country, according to the National Oceanic and Atmospheric Administration’s official winter outlook released Thursday. The outlook depends on the effects of near-record strong El Niño weather.
El Niño, characterized by above-average ocean temperatures in the tropical Pacific Ocean, is causing a domino effect of changing weather patterns around the world, and while its strength will likely peak in December, it could leave its mark in the Lower 48 all winter long.
Many parts of the country are expected to be warmer and wetter than usual this winter due to the effects of El Niño, but that doesn’t necessarily mean there will be less snow than usual, NOAA forecasters said.
Given the current near-record strength of El Niño and continued record-warm ocean temperatures around the world, the winter storm has the potential to bring unusually heavy rain and mountain snow to areas in its path.
Warmer water increases evaporation, and warmer air can carry more moisture, providing additional moisture to storms as they reach land and move across the country.
Although no two strong El Niño winters are alike, most winters have common temperature and precipitation trends. That’s because El Niño typically directs the jet stream, a cross-country river of air that flows from west to east that guides storms, toward the southern tier of the United States.
As a result, the southern part of the country experiences more storms, wetter and cooler weather, while northern states tend to be drier and milder than average, NOAA said. (Yes, snow-loving Northeasterners. This usually means strong El Niño winters, especially inland, where there is less snow on average.)
But National Oceanic and Atmospheric Administration meteorologist John Gottschalk said some of the storms along the southern tier could turn northeast along the East Coast, bringing heavy rain and snow to the mid-Atlantic coast and major cities in the Northeast, depending on the availability of cold air. “These storms can be very powerful,” Gottschalk said.
⛅ Get CNN Weather in your inbox
The forecast is just beginning. We bring you expert coverage and the stories behind the weather. So you always know more than just the numbers. Sign up for newsletter
In addition to above-average precipitation expected across the West Coast and southern states, above-average precipitation is also expected along the East Coast.
El Niño’s cooling trend and increased precipitation will bring snow, sleet, and freezing rain to parts of the Southeast and southern Plains. Exactly how much precipitation will decrease in these regions will depend on how cold it gets and whether the cold air coincides with storms.
Although El Niño is likely the main factor influencing winter weather, it is not the only phenomenon in this town. Other factors, such as the polar vortex, will also affect the amount of cold air and snow, especially along the northern side of the country.
California could be hit hard by this El Niño, as reliable seasonal computer models predict that the state’s winter precipitation could be well above average.
Democratic Gov. Gavin Newsom has already declared a state of emergency for the El Niño winter, considering the potential for massive inland flooding, strong winds, heavy snow and coastal flooding from waves riding on abnormally high tides in the event of a major storm.
While there is no guarantee that a strong El Niño will result in an unusually wet California winter, history shows that it tilts the odds in favor of such an outcome. And El Niño events can be particularly damaging there. The 1997-1998 Super El Niño set seasonal rainfall records across the Golden State, causing widespread flooding and landslides.
“An increased chance of rain and snow may provide relief to drought-stricken areas, but too much precipitation on dry soils can cause devastating flash floods and mudslides. Now is the time for communities and individuals to plan for the upcoming winter,” National Weather Service Director Ken Graham said in a statement.
El Niño also causes severe thunderstorms. Thunderstorms typically peak in the spring and then pick up again near and along the Gulf Coast in late fall and early winter.
El Niño makes Florida especially at risk during the winter months. Michael Tippett, a climate scientist at Columbia University, said this scenario is reversed because other parts of the Gulf Coast are experiencing less activity than usual.
In particular, temperatures may be higher than normal at more than half of the 48 degrees altitude. El Nino isn’t the cause of everything. Global warming due to fossil fuel pollution is a constant influence. Winter is the warmest season in most parts of the United States, according to an analysis by the nonprofit research group Climate Central.
The region that is expected to be drier than normal is not completely consistent with the El Niño phenomenon, but it is limited to the northern layer, and the El Niño phenomenon is also expected to be milder than normal. And being unusually warm and dry is not a combination that will result in snow.
Similar to winter temperatures, research shows that climate warming has also affected snowfall over the decades. Since 1970, annual snowfall has decreased in nearly two-thirds of the United States, according to Climate Central.
Only time will tell how cold this winter will be, but there is little doubt that El Niño will play a leading role alongside the warming climate.
