The National Weather Service issued an Extreme Cold Warning for Cobb County and other parts of north and central Georgia beginning at noon on Monday, January 20. Counties from metro Atlanta northward were singled out (see the list further down the article).

In this article, you will learn:

1. What is in today’s National Weather Service alert
2. What counties are included in the alert
3. What is meant by the terms “isolated” and “scattered”
4. About the National Weather Service and what it does

What is in the statement?

The statement gives the following details:

This Hazardous Weather Outlook is for north and central Georgia.

.DAY ONE…Today and Tonight…

Isolated showers are possible across central Georgia through mid-

morning.

.DAYS TWO THROUGH SEVEN…Monday through Saturday…

Confidence in an Arctic air mass impacting the Eastern U.S.

beginning early Monday morning is high. Wind chills from as much

as 5-10 degrees below zero to the teens are forecast to develop

in north and central Georgia Monday through Thursday. An Excessive

Cold Warning has been issued for north Georgia Monday morning,

with a Cold Weather Advisory in effect for the remainder of the

forecast area.

It is becoming increasingly likely that a winter storm will

impact north and central Georgia Tuesday through early Wednesday.

Uncertainty remains regarding exact accumulation, but snow is

likely to be the dominant precipitation type. A Winter Storm Watch

has been issued for areas along and south of the I-20/I-85

interchange for the potential for as much as 2-3″ of snow

accumulation. Please continue to monitor for future updates.

What counties are affected?

The following counties are included in the hazardous weather outlook:

Bartow, Carroll, Cherokee, Cobb, Dawson, DeKalb, Douglas, Fannin, Forsyth, Gilmer, Gwinnett, Hall, Haralson, Lumpkin, North Fulton, Paulding, Pickens, Polk, South Fulton, Towns, Union, White.

Including the following cities:

Atlanta, Blairsville, Bremen, Carrollton, Cartersville, Cedartown, Cleveland, Cumming, Dahlonega, Dallas, Dawsonville, Decatur, Douglasville, East Point, Ellijay, Gainesville, Hiawassee, Jasper, Lawrenceville, Marietta, Woodstock

What is meant by “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).

Isolated thunderstorms and scattered thunderstorms are two terms used to describe different distributions of thunderstorm activity within a particular area. The main difference lies in the extent of coverage and how the thunderstorms are spatially distributed:

1. Isolated Thunderstorms:
   • Isolated thunderstorms are relatively rare occurrences that happen sporadically and are generally confined to a limited area.
   • These thunderstorms are often characterized by being few and far between, with significant gaps between individual storm cells.
   • Typically, isolated thunderstorms cover less than 20% of the forecast area.
   • Despite their isolated nature, these storms can still be intense and may produce heavy rain, lightning, gusty winds, and possibly hail.
2. Scattered Thunderstorms:
   • Scattered thunderstorms are more widespread than isolated thunderstorms and cover a larger portion of the forecast area.
   • In a scattered thunderstorm scenario, numerous individual thunderstorms develop, but they are not continuous or widespread enough to be classified as a “line” or “cluster” of storms.
   • Scattered thunderstorms generally cover between 30% to 50% of the forecast area.
   • Although scattered thunderstorms are more widespread, they still leave considerable gaps between storm cells, and not everyone within the forecast area will necessarily experience a thunderstorm.

In summary, isolated thunderstorms are fewer in number and more localized, covering a smaller area with significant gaps between storms, while scattered thunderstorms are more widespread, covering a larger area with numerous individual storms occurring somewhat randomly across the forecast area.

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.”