Fog, high heat and thunderstorms expected in Cobb County and across the region Sunday August 13

Lightning flashing across a cloudy sky. A Cobb County Courier logo and the words "Hazardous Weather Outlook"

The National Weather Service issued a hazardous weather outlook for  Cobb County and other counties in the region for Sunday Aug 13, 2023.  

Until 9 a.m. patchy fog is forecast, a heat advisory is in effect for the afternoon, and afternoon thunderstorms are expected.

For more information on what a high heat index means, and what it means to expected “scattered thunderstorms,” read to the bottom of this article for explanations.

What is in the statement?

The hazardous weather outlook  gives the following details:

This Hazardous Weather Outlook is for portions of North and

Central Georgia.

.DAY ONE…Today and Tonight…

Patchy fog in portions of far north and northwest Georgia will

restrict visibilities to a quarter of a mile or less until 9 AM

EDT. If driving this morning, slow down, use low-beam headlights

and leave extra distance between you and the vehicle in front of


An Excessive Heat Warning is in effect for portions of central and

east Georgia, roughly along and south of a line from Washington to

Fincherville to Hamilton, from 10 AM to 8 PM EDT. Heat Index

values exceeding 110 degrees will be likely in this area.

A Heat Advisory is also in effect to the north of the Excessive

Heat Warning, roughly along and south of a line from Homer to

Alpharetta to Carrollton, from 10 AM to 8 PM EDT. Heat Index

values between 105-109 degrees will be likely in this area.

Scattered thunderstorms are expected this afternoon and evening,

with the highest chances in west Georgia. Several storms could

become strong, capable of producing gusty winds, frequent

lightning, and locally heavy rain.

.DAYS TWO THROUGH SEVEN…Monday through Saturday…

An Excessive Heat Watch has been issued for central and portions

of north Georgia for Monday, mainly along and south of a line

from Homer to Alpharetta to Franklin. Heat Index values exceeding

110 degrees are possible.

Heat Index values will remain high for portions of central and

south Georgia through early next week. Additional heat-related

advisories and/or warnings may be needed. Take extra precautions

and drink plenty of fluids if you plan to spend time outside today

or early next week.

Periods of thunderstorm activity will continue through next Saturday.

The highest storm chances will occur during the afternoon and evening

hours each day.


Spotter activation will not be needed through tonight.

What counties are affected?

The following counties are included in the hazardous weather outlook:

Baldwin, Banks, Barrow, Bartow, Bibb, Bleckley, Butts, Carroll, Catoosa,  Chattahoochee, Chattooga, Cherokee, Clarke, Clayton, Cobb, Coweta,  Crawford, Crisp, Dade, Dawson, DeKalb, Dodge, Dooly, Douglas, Emanuel,  Fannin, Fayette, Floyd, Forsyth, Gilmer, Glascock, Gordon, Greene,  Gwinnett, Hall, Hancock, Haralson, Harris, Heard, Henry, Houston, Jackson,  Jasper, Jefferson, Johnson, Jones, Lamar, Laurens, Lumpkin, Macon,  Madison, Marion, Meriwether, Monroe, Montgomery, Morgan, Murray,  Muscogee, Newton, North Fulton, Oconee, Oglethorpe, Paulding, Peach,  Pickens, Pike, Polk, Pulaski, Putnam, Rockdale, Schley, South Fulton,  Spalding, Stewart, Sumter, Talbot, Taliaferro, Taylor, Telfair, Toombs,  Towns, Treutlen, Troup, Twiggs, Union, Upson, Walker, Walton, Warren,  Washington, Webster, Wheeler, White, Whitfield, Wilcox, Wilkes,  Wilkinson  

What is the heat index?

The NWS defines the heat index as follows on its website:

The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature. This has important considerations for the human body’s comfort. When the body gets too hot, it begins to perspire or sweat to cool itself off.

Chart from NOAA showing relationship between relative humidity and temperature in heat index

What is the difference between “isolated” and “scattered”?

The NWS defines “isolated” as follows:

A National Weather Service convective precipitation descriptor for a 10 percent chance of measurable precipitation (0.01 inch). Isolated is used interchangeably with few.

“Scattered” has the following definition:

When used to describe precipitation (for example: “scattered showers”) – Area coverage of convective weather affecting 30 percent to 50 percent of a forecast zone (s).

In other words isolated means a few showers, scattered means the showers are likely to cover 30 to 50 percent of the affected region.

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About the National Weather Service

The National Weather Service (NWS) is a part of the National Oceanic and Atmospheric Administration (NOAA).

The NWS describes its role as follows:

“The National Weather Service (NWS) provides weather, water, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy. 

“These services include Forecasts and Observations, Warnings, Impact-based Decision Support Services, and Education in an effort to build a Weather-Ready Nation. The ultimate goal is to have a society that is prepared for and responds to weather, water and climate events.”

>>> Read all the Cobb County Courier climate and weather coverage by following this link.