TUESDAY’S HAILSTORM A CLASH OF TWO FRONTS
Ripe clouds piled up east of Lake Okeechobee on Tuesday, growing tall at the edge of a southwest wind and fated for an afternoon collision with an approaching cold front.
The clash of boundaries suspended raindrops atop powerful updrafts high in the atmosphere, where they clung to each other in subfreezing temperatures, gathering an icy mass until layer by layer they grew too heavy, and fell as hail.
While unusual in South Florida, brawny hail showers can fall from thunderstorms where late-season cold fronts have chilled temperatures aloft to below freezing. Tuesday’s upper-level temps were about 14 degrees, according to one measurement taken by the National Weather Service in Miami.
Melbourne NWS meteorologist Matt Bragaw said the combination of the deep southwest flow over the lake and the cool front created an atmosphere that gave the storms longer lifespans.
“There was no single mechanism that was the key factor,” said Bragaw, who noted the bulk of the hail was focused in a confined area in St. Lucie County and on the Martin and Palm Beach County line. “There may have been storminess without the front, but no hail. The two played off each other.”
According to preliminary storm
reports, pea-sized hail was seen in Fort Pierce, with quarter-size hail falling in Hobe Sound. A third report had up to golf ball-size hail in the River Ridge community in Tequesta, just north of County Line Road. There was also a video showing peasized hail bouncing off a balcony near the Jupiter Inlet, and a NWS-trained weather spotter reported similarly-sized hail in Atlantis.
“I’ve been living in this town 50 years, and I’ve seen hail before, but I’ve never seen as much hail as I did Tuesday,” said Tom Knapp, who lives in River Ridge and saw what he described as marble-sized hail. “You could have gotten a sled and slid down my front lawn because it was literally a sheet of ice because of the accumula- tion of hail.”
Knapp said he saw no damage in his neighborhood, but the length of the hail shower and the quantity that fell was impressive.
“My pool, it was amazing, it looked like it was boiling,” he said.
Tuesday’s storms didn’t just conjure hail. Waterspouts were spotted off Palm Beach Shores and farther south in Marathon, where one image posted by the NWS in Key West shows three spouts at once.
Also, more rain fell in parts of Palm Beach County in 24 hours than did all of March.
Lake Worth received the highest amount of rain at 3.16 inches, with Boynton Beach as runner-up with 2.7 inches. Delray Beach recorded 1.54 inches, with Royal Palm Beach measuring 1.4 inches, based on South Florida Water Management District gauges.
Most of coastal Palm Beach County got just 0.53 inches of rain in March, which was 3.03 inches less than what’s normal for the month.
While it’s getting late in the season for cold fronts to push through Florida, the National Weather Service is calling for a weak front to reach South Florida on Friday, when rain chances jump up to 30 percent during the day.
Strong thunderstorms capable of hail are not forecast, and the weekend should be mostly clear with high temperatures in the low 80s.
The federal storm events database shows hail has fallen in Palm Beach County on 58 days dating back to April 2000. Large hail of 1.5-inch diameter or bigger, has only happened on eight days. The most recent event that created large hail was on April 15, 2016, when a 2-inch diameter hailstones were reported in Hypoluxo.
“It’s not unheard of in Florida, but it’s certainly not common,” Bragaw said.
It’s much less common in summer, when cold fronts don’t make it through Florida to reduce temperatures aloft.