A large area of high pressure is poised to strengthen across the Southeast, setting the stage for a potentially prolonged stretch of dangerous summer heat from Florida through much of the Southeast. The heat dome is expected to intensify through the weekend and into early next week as sinking air beneath the strong ridge suppresses cloud development and allows temperatures to climb.
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A heat dome develops when a strong area of high pressure becomes established over a region. Air sinks beneath the ridge, warming as it compresses; as a result, the heat builds up. With fewer clouds and less rainfall, the sun has more opportunity to warm the surface during the day. The dome of high pressure acts like a lid, trapping heat near the ground. And since humidity is already high, heat-index values become dangerous.
For South Florida, the story is slightly different but still just as uncomfortable.
South Florida is accustomed to summer heat, but the combination of high temperatures and tropical humidity can make conditions dangerous. As the ridge strengthens, afternoon temperatures across South Florida could push toward the mid-90s, while dew points remain high. That means feels-like temperatures will be the number to watch and will likely trigger heat alerts over the region.
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One thing to note: our rainy season still goes on despite a strong ridge of high pressure. Daily sea-breeze thunderstorms can still develop. Those storms can temporarily cool temperatures, but they can also bring lightning, torrential rainfall and gusty winds. The bigger concern may come during the periods between storms, when sunshine quickly sends temperatures and heat indices soaring again.
Remember to watch the heat index, limit strenuous outdoor activity during the hottest part of the day, stay hydrated, check on vulnerable family members and neighbors, and never leave children or pets inside a parked vehicle.
For South Florida, humidity is already a permanent part of the summer equation, the combination of heat, humidity and persistence will be the story to watch through the weekend and into early next week.
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