PEMBROKE PARK, Fla. – The heat over the past week has been not only unpleasant but also unprecedented. Miami just recorded its hottest average temperature for any week on record. That’s out of all the weeks, from any month, since 1895.
88.1 degrees: That’s the number that stands above all else. It is the high and low temperatures from the past seven days averaged out. This means that, on average, any point in the day it’s about 5 degrees hotter than normal. That’s a lot.
The afternoons have been baking. Miami has been in the 90s for nearly two weeks straight. Two afternoons have set record highs so far, but more are likely to come before the heatwave subsides. The heat index has spiked to 105 degrees.
But was has been really impressive is the heat at night. The past six consecutive nights have been records. Miami has tied its all-time record-warm low temperature three times in just the past week.
So what gives? What is the reason for the punishing heat? The answer is a mixture of atmospheric setup, tied in with a bit of mystery.
Reason 1: High pressure at around 18,000 feet causes air to sink, and sinking air warms.
Reason 2: Saharan dust has invaded the area. This limits our typically stormy afternoons, which act as an air conditioner as they circulate cooler from higher up in the atmosphere.
Reason 3: Warm ocean temperatures, along with the dust and lack of air-circulating storms, have kept our humidity very high. Humid air can’t cool off as well at night, which is why our nights have been so very warm.
But these three elements still may not fully explain the issue. None are especially impressive features on their own. So it remains to be seen if we just had the misfortune of the three pieces combining at just the right time, or if some additional force is aiding in Miami’s hottest week on record.
The heatwave will continue through mid-week. By Thursday, the impacts of the dust and high pressure look to diminish just enough to move away from record-levels. Even then, expect hotter-than-normal weather into the July 4 weekend.
For the latest forecast, go to the Weather Authority by clicking here.