Weather for December in South Florida expected to be wetter than normal with El Niño

There won’t be a white Christmas for South Florida, but it may be a soggy one as a brawny El Niño digs in, encouraging showers and storminess in the long-range forecast.

The Climate Prediction Center is calling for an up to 70% chance of above-normal rainfall for the Sunshine State in the days between Dec. 16 to Dec. 29, which would follow a pattern for the southeast coast of plentiful rain this dry season. The dry season runs Oct. 15 to May 15.

West Palm Beach ended November with nearly 5 inches of rain for the month, more than an inch above normal. Fort Lauderdale received 11.2 inches, which was a whopping 7.5 inches more than average.  Miami saw 9.35 inches, which was 5.8 inches above normal.

But while there is confidence that a damp December lies ahead, there’s less certainty in the temperature forecast. The Climate Prediction Center is giving equal chances to it being warmer than average and cooler than average for the month.

Climate Prediction Center's forecast for Dec. 16 through Dec. 29.
Climate Prediction Center's forecast for Dec. 16 through Dec. 29.

AccuWeather long range meteorologist Alex DaSilva said his team is forecasting December to be 2 to 3 degrees warmer in South Florida, which is unusual for an El Niño year.

“Typically, you would be cooler and wetter but this El Niño has been tricky and is behaving a little funky,” said DaSilva, noting the active hurricane season with 20 named storms. El Niño, which officially arrived in June, normally works to cut down tropical cyclones with wind shear, leading to fewer storms.

More: El Niño battled warm ocean temperatures during the above average 2023 hurricane season

DaSilva said the cool spell in late November that dropped temperatures in West Palm Beach to 55 degrees on Nov. 29, was caused, in part, by a blocking high-pressure area over Greenland that funneled cool air down the east coast.

That block is expected to be weak or non-existent at the end of this month.

“It’s going to be one of the players,” DaSilva said about the block. “We still have three weeks but indications are it won’t be around during the middle to latter portions of the month.”

Climate Prediction Center's forecast for Dec. 16 through Dec. 29.
Climate Prediction Center's forecast for Dec. 16 through Dec. 29.

The normal high temperature in West Palm Beach on Dec. 25 is 76 degrees, as measured at Palm Beach International Airport. The normal low is 60.

During El Niño years, the Pacific warms and trade winds weaken. That shifts the position of deep tropical thunderstorms in the Pacific, which disrupts upper air patterns. The jet stream gets shoved south over the Gulf of Mexico, where the rushing river of air incites tumult in South Florida skies.

The Pacific must warm to 1.5 degrees Celsius (2.7 Fahrenheit) above the three-month average normal for an El Niño event to be considered strong.

Emily Becker, an associate scientist with the University of Miami, said last month the threshold for a strong El Niño was officially met.

More: El Niño in Florida can mean rainy, cool dry season, but climate change may blunt the chill

The Climate Prediction Center said there is a 35% chance this El Niño will become “historically strong," which means a temperature of 2 degrees Celsius (3.6 Fahrenheit) above average. That’s only happened four times before in records that date back 73 years — 1972-73, 1982-83, 1997-98 and 2015-16.

“The strength of an El Niño event matters because the stronger the event, the more likely that we’ll see the characteristic changes in temperature, rain and snow, and other impacts,” Becker said in a monthly climate blog. “Of course, where the weather is concerned, there are no guarantees. However, a stronger El Niño makes it a safer bet that we’ll see the expected patterns.”

West Palm Beach has felt warmer-than-normal winters since at least 2012, even during the robust El Niño event of 2015-2016.

Rainfall amounts have better matched up with the reputation of El Niño. During the winter of 2015-2016, 19.9 inches of rain fell at PBIA. The average for the winter months of December, January and February is 9.58 inches.

While the southeast coast of Florida has been flush with rain this dry season, parts of the west coast and Panhandle are already in moderate to extreme drought.

Last month, the South Florida Water Management District issued a water shortage warning for Lee and Collier counties as underground aquifers begin to dry up.

More: Heat wave has Florida split with drought on the west coast and bountiful rain on the east coast

The warning just encourages adherence to landscape irrigation guidelines and conservation of water. On Nov. 28, the district issued a water shortage order for northeastern Cape Coral, which triggers mandatory irrigation restrictions.

Robert Garcia, a meteorologist with the National Weather Service in Miami, wasn’t optimistic that two cool fronts expected this week would bring much rain with them.

There is a 20% chance of rain with a mild cool front Monday. That will be followed by a stronger push of cold air on Wednesday that will dip temperatures into the 40s and 50s in Palm Beach County. Thursday morning is forecast to be the chilliest.

“It will be a reminder that we are in December,” Garcia said.

Kimberly Miller is a veteran journalist for The Palm Beach Post, part of the USA Today Network of Florida. She covers real estate and how growth affects South Florida's environment. Subscribe to The Dirt for a weekly real estate roundup. If you have news tips, please send them to kmiller@pbpost.com. Help support our local journalism, subscribe today. 

This article originally appeared on Palm Beach Post: El Niño may mean wet and stormy Christmas for South Florida