Saturday will be another feels-like-over-100-degrees day.
The unrelenting heat across South Florida broke records in recent days, and while the heat indexes were slightly lower Friday and are expected to remain there Saturday, there’s still not much of a change ahead.
Heat index values were up to 111 degrees Friday, prompting a heat advisory for all of South Florida. The National Weather Service Miami has extended the advisory until at least 7 p.m. Saturday, which will again be a sunny, humid day with highs in the mid 90s and heat index values up to 108 degrees.
To meet the criteria for an excessive heat warning in Broward and Palm Beach counties, the feels-like temperature has to reach at least 113 degrees for at least two hours, while in Miami-Dade, it has to exceed 110 degrees. Feels-like temperatures under a heat advisory are below that, at 105 degrees or higher for at least two hours.
Wednesday was the first day that the National Weather Service Miami had to issue an excessive heat warning for its entire coverage area, which extends from Key Largo up to Lake Okeechobee.
Tuesday had previously broken another record, with nearly all of the coverage under a heat warning, a first for Palm Beach, Glades and Hendry counties. The warnings on Thursday extended into mainland Monroe County for the first time this week.
Nightfall has provided little relief. The coolest evening temperatures in the forecast over the next several days are in the upper 70s and low 80s.
“Really there hasn’t been much break at all from this heat,” said said George Rizzuto, a meteorologist for the National Weather Service Miami. “Usually you cool off overnight and ramp up again during day.”
The stifling heat is due to a combination of high sea surface temperatures and low-level moisture largely brought by the Bermuda High, a “semi-permanent high pressure feature” over the Atlantic that has remained stationary for a prolonged period of time, Rizzuto said.
Forecasters are predicting an increasing chance for showers and thunderstorms over the weekend and early next week, with the potential for some street flooding. There’s a 50% chance on Saturday afternoon and evening while Sunday and Monday are likely to be rainier.
Feels-like temperatures are still expected to be over 100 degrees early next week, according to the forecast.
