South Florida heat hits record; cool air on way

Overnight lows have been higher than usual for quite some time.

A two-week streak of abnormally warm temperatures is challenging South Florida records and pushing heat indexes to “concerning” levels into the weekend.

On Thursday, official weather service gauges in West Palm Beach cooled to only 82 degrees, breaking the 1991/1995 record of 81.

Official weather service gauges in West Palm Beach and Fort Lauderdale cooled Wednesday morning to only 81 and 82 degrees, respectively, tying overnight heat records set in both cities in 1998.

The unofficial low Friday morning in West Palm Beach was 80 degrees, which would tie a 1999 record if it holds true.

Blame a stubborn Bermuda high, which has had a hold on the state through much of the month, for the unusual warmth. Fifteen days have seen the mercury rise to 90 degrees or warmer at Palm Beach International Airport, including hitting a whopping 93 degrees on Sept. 19 and 20.

The normal daytime high for late September is 87 or 88 with the normal overnight low typically dropping to 75.

Derrick Weitlich, a meteorologist with the National Weather Service in Melbourne, said the extra daytime heat has been aided by an easterly sea breeze pushing farther inland and causing showers and thunderstorms to bypass the coast.

“The storms increase cloud cover and rainfall to really cool things off, but we’ve been drier than normal for most of the month and had higher temperatures,” Weitlich said.

An average of 4.6 inches of rain has fallen over coastal Palm Beach County this month, which is more than 2 inches below normal, according to South Florida Water Management District records.

Miami meteorologists warned Thursday of “feels like,” or heat index, temperatures in the triple digits into the weekend. West Palm Beach hit a high of 91 degrees Thursday with a heat index of 105. Although warm, it’s not enough to trigger a heat advisory, which is issued when the index is forecast to reach 108 degrees for at least two hours.

“Heat indices are a concern the next few days as temperatures could feel 100 to 107 in some locations in Hendry, Glades, Collier, Palm Beach and Miami-Dade counties,” meteorologists at the Miami NWS wrote in their forecast.

Through Monday, daytime highs in West Palm Beach are expected to reach near 90 degrees with overnights dipping into the upper 70s.

This weekend, the Bermuda high will move farther west with its center over the Peninsula. Its clockwise flow is forecast to whip winds up to 15 mph with higher gusts. By Monday, east winds could increase to 16 mph with higher gusts.

That means higher chances of rough seas and rip currents through the weekend.

On Tuesday, a stronger high pressure system moves across the northern part of the United States, which could push a “backdoor” cold front “possibly through South Florida,” Miami meteorologists said.

Weitlich said a backdoor front is one that comes from the northeast. He’s skeptical one would make it to South Florida this early in the season.

“In terms of temperatures, we certainly won’t see much of a change,” he said.