The powerful El Niño that dominated Florida’s hurricane season is making itself known this winter with a “parade of systems” rolling through the U.S. and bringing another cool front to the state early next week.
As if timed for the new year, a pattern of Pacific-born storms has battered the west with torrential rain and whiteout snow. Depending on hardiness and path, those systems typically make their way east, showing up in some form in Florida.
“Generally the conditions are a bit more resembling the El Niño winter pattern,” said Robert Molleda, the warning coordination meteorologist at the National Weather Service office in Miami. “How much of that will persist, we’ll have to see, but it looks like the pattern is locked in for now.”
Floridians are familiar with the tropical systems that form in hurricane season off Africa’s coast and thunder across the Atlantic. A similar storm template can set up in the Pacific during El Niño years, although the systems do not become hurricanes.
A weak front carrying some rain is expected to move into South Florida today, but a stronger system should greet the Sunshine State late Saturday into Sunday. While Saturday’s high temperature should hit 80 degrees, Monday will be in the low 70s with overnight temperatures dipping into the low 60s.
By mid-month, overnight lows are forecast to plunge into the low 50s, according to the Pennsylvania-based AccuWeather.
“We’re going to have a teeter-totter effect,” said AccuWeather senior meteorologist Dan Kottlowski about the impact of El Niño. “The storm comes into Southern California; a high builds over the West Coast; and the subtropical jet dips.”
Winds in the upper atmosphere are like waves rolling across the U.S. west to east. The strongest is the jet stream — a swift current of air that can travel as fast as 125 mph in winter. The recent weather pattern includes a split jet stream — a polar jet to the north and subtropical jet to the south.
Areas of low pressure spinning counterclockwise form in the Pacific Ocean, embedding themselves along the subtropical stream.
The spin sucks moist air into the upper atmosphere where it cools and becomes precipitation. That means rain in Florida, but sometimes snow, freezing rain and sleet up north.
On Thursday, NWS forecasters in Miami wrote “the parade of systems” continues as the subtropical jet remains established across the southern U.S.
“As long as you have the steady southern stream that extends from the east Pacific all the way across the country, the low pressure systems will eventually make it across,” Molleda said. “We are talking about a jet stream with over 100 mph winds. These systems move pretty fast.”
Long-term forecasts for South Florida called for a cooler, wetter winter as the strongest side of El Niño took hold. While that prediction seemed a fantasy as December boiled with summerlike weather, temperatures are still expected to dip below normal in the coming weeks.
“Bottom line here, when El Niño is coming, it’s a huge effect on Florida,” said James J. O’Brien, professor emeritus of meteorology and oceanography at Florida State University. “In summer, it kills hurricanes, and in winter, it can increase storminess.”
WEATHER ONLINE: Follow Kimberly Miller’s updates on Twitter @kmillerweather and at The Post’s WeatherPlus blog at palmbeachpost.com/weatherplus