How a split in the polar vortex helped turn up the heat in Florida

The wintertime spell of record heat continued in Florida this week with a seasonal oddity in Earth’s northern latitudes partly to blame.

A split in the polar vortex, a pinwheel of stratospheric arctic air that circles the North Pole, helped force frigid winds into the western U.S., and triggered a chain reaction that allowed tropical warmth in the east to drift as far as Lake Ontario.

For Florida, it’s meant a record mercury reading of 89 in Tampa on Tuesday — 16 degrees above normal — and mostly sunny skies in Palm Beach County where an April-like daytime high crept to 83 Tuesday. On the southern banks of Lake Ontario, Rochester, N.Y. reached 70 degrees Tuesday — a staggering 35 degrees above normal. Boston also hit 70 degrees, which is 30 degrees above normal.

SEE: Check The Palm Beach Post radar map

“There will be lots of records smashed east of the Mississippi,” said Bob Henson, a meteorologist and blogger for Weather Underground. “The whole northern hemisphere is going through an adjustment after the polar vortex split.”

According to the National Weather Service in Miami, little will change for South Florida through the weekend with partly sunny skies, a 20 percent chance of rain and temperatures in the low to mid 80s. Overnight temperatures this week will hover near 70.

In Palm Beach Gardens, where the Honda Classic is scheduled through Sunday at the PGA National Resort & Spa, spectators may want hats to guard from the sun, while players may be more wary of the winds.

“It should be fairly breezy Thursday and Friday, then the winds come down a little Saturday and Sunday,” said Larry Kelly, a meteorologist with the NWS in Miami. “Thursday looks to be the breeziest with gusts up to 21 mph.”

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Jane Broderick, the director of golf for the PGA National Resort and Spa, said the forecast winds aren’t out of the ordinary for the tournament. In 2016, peak wind speeds as measured at Palm Beach International Airport hit up to 35 mph during the week of the Honda Classic.

But a strong easterly flow is more apt to send balls into the water in the Bear Trap, Broderick said.

“The prevailing winds have always made the champion golf course a little more difficult,” Broderick said. “If the winds are blowing strong, the players may have to change their target.”

Forecasters are not expecting a repeat of the disastrous 2015 tournament when 5 to 7 inches of rain fell in areas of northern Palm Beach County, flooding PGA National and sending hundred of spectators scurrying for cover. The deluge was the result of a stalled cold front that sparked thunderstorms and winds swift enough to topple the floating scoreboard near the 18th green.

“They will suspend play if there is dangerous weather, but that’s not likely without a front,” Broderick said.

And there is no front in the forecast for South Florida, Kelly said.

While the northeast will cool down in the coming days, the high pressure and warm temperatures will continue for the Sunshine State.

Tiger Woods at the Honda Classic Pro-Am at PGA National in Palm Beach Gardens on Feb. 21.

Already this month, 18 heat records have been set or tied at stations monitored by the Miami NWS in West Palm Beach, Fort Lauderdale, Miami and Naples.

The Southeast Regional Climate Center shows 11 cities in Florida are having their warmest February on record, including Tampa, Sarasota, Melbourne, Fort Myers and Miami.

West Palm Beach’s average temperature so far this month is 74.7, making if the third warmest February on record as of Tuesday, according to the climate center.

“It’s definitely one of the warmest Februaries,” Henson said. “It will be a photo finish for record warmest.”

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The polar vortex is rocking, so why such warm weather in the east?

As the northeast was mired in frigid temperatures last winter, the term polar vortex was regular dinnertime chatter as it got blamed for burying Boston in more than 100 inches of snow.

But this year the polar vortex is quite strong, yet there’s nary a peep about it’s influence on the weather, noted J. Marshall Shepherd, director of the atmospheric sciences program at the University of Georgia.

Shepherd is also host of the Weather Channel’s “Weather Geeks” show.

It’s turns out this year’s  brawny polar vortex – a swirling mass of cold air over the arctic – can actually be linked to the crazy-warm temperatures throughout the eastern U.S.

Palm Beach County heat record could be tied today. Read why here. 

A stronger, or more stable, vortex is less likely to release frigid polar air, which then cascades south through Canada and into the U.S. The jet stream, which wraps around the globe in a circular pattern, also plays a role. When it weakens, it becomes wavy, again allowing cold air to punch south.


“When the polar vortex is strong, Arctic air cannot escape the ‘fence’ and ooze its way down into the United States,” Shepherd wrote on his Forbes science blog. “I say ‘ooze’ because cold air is dense relative to warm air. If the Polar Vortex weakens, the cold air can more easily penetrate into the lower 48 states.”

In a YouTube explanation posted on a White House blog last year,  John Holdren, director of  the White House Office of Science and Technology, explains in about two minutes what the polar vortex is and how it relates to climate change.

AccuWeather senior meteorologist Alex Sosnowski writes that El Nino’s strong westerly winds may be helping keep the polar vortex contained up north. When El Nino dissipates, which it’s not supposed to do until spring at least, fluctuating steering winds “may allow the polar vortex to weaken, shift position and send frigid air well to the south.”


NASA image of polar vortex in January 2014.
NASA image of polar vortex in January 2014.