NWS: Record-like heat prompts advisory for Naples, Collier County

A heat advisory is in place this week for Collier County as record-like temperatures continue to scorch the landscape.

The National Weather Service in Miami issued a heat advisory for Collier through Wednesday. Advisories are posted when heat index temperatures are expected to be 105 degrees or higher.

"Over the past week we've seen heat indexes of 105 to 110 degrees across South Florida," said Cameron Pine, a meteorologist with the NWS in Miami, which covers the Naples-Collier area. "And there's a combination of factors as to why that's happening."

The heat index in Naples Wednesday is forecast to be 109 degrees.

Naples typically measures just slightly cooler than Fort Myers during the summer, mostly because the Naples Airport (where measurements are taken) is closer to the coast than Fort Myers' Page Field (where the weather station is for Lee County).

But this week Naples will be a few degrees warmer than Fort Myers.

"We're dealing with a plume of Saharan dust and it's covering the very tip of South Florida," Pine said as to why Naples would measure hotter than Fort Myers during the summer. "In Collier County, there is a thin layer of dust over Naples where it's not over Fort Myers. With the dust the rain chances drop and then the sunny conditions prevail."

Pine said temperatures in Naples have been running 5 to 7 degrees higher than average.

The heat is being caused by several factors: it's summer, rain chances have been slim on some days ― meaning cloud cover is typically sparse ― and Saharan dust is lingering over extreme South Florida.

Also, a ridge of high pressure has been sitting over the region, keeping cloud cover and rain away. Rain chances go up this weekend, according to NWS.

Pine said warmer-than-average sea temperatures are also contributing to the excess heat.

Fort Myers hot as well

Conditions will be hot in Fort Myers as well, even though it's only by a couple of degrees. The "feels like" temperature will be close in both towns.

"We've got a stalled frontal boundary giving rain across the north part of the state, but we've had high pressure aloft, giving us a very stagnant air mass to stick around," said Rodney Wynn, an NWS meteorologist out of Ruskin, which covers the Fort Myers-Lee area. "It seems like it's really been super-hot, the hottest ever but in reality, it's not a record. It's a couple of degrees off."

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Heat index is calculated by using the high temperature for the day with the humidity measured during the hottest point in the day.

A high of 90 degrees, for example, and a humidity mark of 60% equals a 100-degree heat index, Wynn said.

Heat-related illnesses can be more common

"Heat related illnesses are a major issue; so we also say if you have to go outside, don't go outside for prolonged periods of time," Pine said. "But if you do, take frequent water breaks and wear lighter colored cloths so you're not absorbing as much UV rays. A prolonged heat wave only increases that threat."

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This article originally appeared on Fort Myers News-Press: Naples under heat advisory; Saharan dust part of heat wave equation