What exactly is a heat dome?

File photo of hazy sunshine. The heat in the region is courtesy of a heat dome that's on the move. (Photo by Spencer Platt/Getty Images) (Spencer Platt, 2023 Getty Images)

JACKSONVILLE, Fla. – The heat has been on the past several days, and more warmth is on the way.

It’s all courtesy of an expanding heat dome lifting north and east.

But, what exactly is a heat dome?

Defining the dome

Heat domes develop normally in the summer months when large areas of high pressure develop.

The atmosphere behaves like a fluid, and the ridge is actually a large dome-like structure in the atmosphere.

The heat "dome" is a vertical ridge of high pressure that keeps fronts and storm systems away.

This dome continues to build and does not allow cold fronts and storm systems to push into it.

This particular heat dome got started last week over Texas.

Temperatures across much of the Lone Star state soared into the triple digits, with some cities breaking their all-time record highs.

The dome on the move

After a week of extreme heat in Texas, the heat dome has begun to expand north and eastward.

Much of the Southern US and the southern Midwest are now under Heat Advisories and Excessive Heat Warnings.

Heat alerts stretch from the Midwest through much of the Southeast.

Highs temps in parts of this area will soar into the upper 90s and low 100s, with feel-like temps pushing above 105°.

The local impacts

The heat dome is not impacting the weather in Southeast Georgia and Northeast Florida, and this warmth will remain in place for the next several days.

Highs in the mid to upper 90s are expected for the remainder of the week, and the stretch of heat will likely continue into parts of the holiday weekend.

High temps in Jacksonville the next 7 days.

There is some uncertainty about how long the warm spell will last, but it is looking somewhat likely the heat dome will begin to break down late next week.

This will allow a return to a more typical summertime weather pattern, with highs in the low 90s.

The high heat across the region is going nowhere over the next several days, and it’s all courtesy of a heat dome that will be slow to break apart over the next week.