The National Weather Service forecasts mostly cloudy skies here in Cobb County on Thursday, September 12, 2024, with a high near 74 degrees.

The National Weather Service has issued a hazardous weather outlook for Cobb County and other parts of the region due to a Flood Watch that will be in effect today through Friday evening for portions of west Georgia. 

A Wind Advisory is in effect today through early Friday morning for portions of north Georgia. An isolated, brief tornado threat will also be in place this afternoon into tonight, mainly for areas west of the I-75 corridor.

What you will read in this article

1. The extended forecast for Cobb County
2. Last month’s climate summary for the metro Atlanta region
3. The climate almanac for metro Atlanta
4. What the National Weather Service is, and what it does

What does the extended forecast have in store?

This forecast is centered on Dobbins Air Reserve Base in Marietta.

Today

Showers likely, mainly before 2pm. Mostly cloudy, with a high near 74. East wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 70%.

Tonight

Showers and thunderstorms likely before 1 a.m, then showers likely and possibly a thunderstorm between 1 a.m and 2 a.m, then a chance of showers and thunderstorms after 2 a.m. Mostly cloudy, with a low around 66. East wind 15 to 20 mph, with gusts as high as 30 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.

Friday

A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 7 a.m. Some of the storms could produce heavy rainfall. High near 75. East wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%.

Friday Night

Showers and possibly a thunderstorm. Low around 66. East wind 10 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 80%.

Saturday

Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 76. Chance of precipitation is 70%.

Saturday Night

Showers likely and possibly a thunderstorm before 2 a.m, then a chance of showers and thunderstorms after 2 a.m. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.

Sunday

A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 76.

Sunday Night

A 30 percent chance of showers and thunderstorms before 2 a.m. Mostly cloudy, with a low around 63.

Monday

A slight chance of showers between 8 a.m and 2pm, then a chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 78. Chance of precipitation is 30%.

Monday Night

A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 62.

Tuesday

A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 80.

Tuesday Night

A 10 percent chance of showers and thunderstorms. Partly cloudy, with a low around 62.

Wednesday

A 20 percent chance of showers. Mostly sunny, with a high near 82.

What was the climate like in the latest reporting period?

The NWS climate summary for metro Atlanta has now been updated with August 2024 figures.

In an article entitled What is the Difference between Climate and Weather?, the National Ocean Service describes the difference as follows:

“Weather is what you see outside on any particular day. So, for example, it may be 75° degrees and sunny or it could be 20° degrees with heavy snow. That’s the weather.

“Climate is the average of that weather. For example, you can expect snow in the Northeast in January or for it to be hot and humid in the Southeast in July. This is climate. The climate record also includes extreme values such as record high temperatures or record amounts of rainfall. If you’ve ever heard your local weather person say “today we hit a record high for this day,” she is talking about climate records.

“So when we are talking about climate change, we are talking about changes in long-term averages of daily weather. In most places, weather can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season. Climate, however, is the average of weather over time and space.”

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The climate report for the Atlanta area for the previous month shows how much departure from the average temperatures that month represents. The average temperature for a date is the average over a 30-year period.

Date	Max	Min	Average	Departure from norm	Precipitation
2024-08-01	94	74	84	2.8	0
2024-08-02	93	77	85	3.9	0.04
2024-08-03	91	74	82.5	1.4	0
2024-08-04	91	74	82.5	1.4	T
2024-08-05	92	75	83.5	2.5	T
2024-08-06	93	77	85	4	0
2024-08-07	96	74	85	4.1	0
2024-08-08	96	77	86.5	5.6	0
2024-08-09	95	76	85.5	4.7	0
2024-08-10	93	73	83	2.2	0
2024-08-11	92	69	80.5	-0.2	0
2024-08-12	92	70	81	0.4	0
2024-08-13	93	71	82	1.4	0
2024-08-14	92	76	84	3.5	0
2024-08-15	90	74	82	1.6	0
2024-08-16	91	72	81.5	1.2	0.39
2024-08-17	95	71	83	2.8	0.11
2024-08-18	91	72	81.5	1.3	0.23
2024-08-19	89	70	79.5	-0.6	0
2024-08-20	89	70	79.5	-0.5	0
2024-08-21	85	67	76	-3.8	0
2024-08-22	85	69	77	-2.7	0
2024-08-23	85	65	75	-4.6	0
2024-08-24	88	66	77	-2.5	0
2024-08-25	90	69	79.5	0.1	0
2024-08-26	92	70	81	1.8	0
2024-08-27	94	71	82.5	3.4	0
2024-08-28	97	74	85.5	6.5	0
2024-08-29	98	76	87	8.2	0
2024-08-30	96	75	85.5	6.8	0.03
2024-08-31	M	M	M	M	M

Climate Almanac for metro Atlanta

This almanac provides information on past climate conditions for September 12, allowing comparisons to current weather. 

Simply put, it helps you see what the weather would typically be like on this day, according to historical data.

Daily Data	Observed	Normal	Record Highest	Record Lowest
Max Temperature	M	85	99 in 2019	64 in 2017
Min Temperature	M	67	75 in 1925	47 in 1940
Avg Temperature	M	76.0	86.5 in 2019	59.5 in 1940
Precipitation	M	0.13	0.88 in 1964	0.00 in 2021
Snowfall	M	0.0	0.0 in 2023	0.0 in 2023
Snow Depth	M	–	0 in 2023	0 in 2023
HDD (base 65)	M	0	5 in 1940	0 in 2023
CDD (base 65)	M	11	22 in 2019	0 in 2017
Month-to-Date Summary	Observed	Normal	Record Highest	Record Lowest
Avg Max Temperature	85.8	86.1	97.8 in 1925	75.1 in 1967
Avg Min Temperature	68.4	68.4	75.3 in 1925	60.3 in 1968
Avg Temperature	77.1	77.2	86.5 in 1925	68.1 in 1967
Total Precipitation	0.82	1.51	7.37 in 1888	0.00 in 2002
Total Snowfall	0.0	0.0	0.0 in 2024	0.0 in 2024
Max Snow Depth	0	–	0 in 2024	0 in 2024
Total HDD (base 65)	0	0	8 in 1940	0 in 2024
Total CDD (base 65)	135	147	261 in 1925	44 in 1967
Year-to-Date Summary	Observed	Normal	Record Highest	Record Lowest
Avg Max Temperature	77.7	75.5	78.3 in 2012	69.8 in 1885
Avg Min Temperature	58.7	56.4	59.2 in 2023	50.7 in 1940
Avg Temperature	68.2	66.0	68.6 in 2012	61.0 in 1940
Total Precipitation	44.36	36.29	55.58 in 1920	21.08 in 2007
Total Snowfall (since July 1)	0.0	0.0	T in 2001	0.0 in 2024
Max Snow Depth (since July 1)	0	–	T in 1942	0 in 2024
Total HDD (since July 1)	0	0	11 in 1986	0 in 2024
Total CDD (since Jan 1)	2127	1795	2185 in 2019	1090 in 1967

Period of Record:

• Max Temperature : 1878-10-04 to 2024-09-11
• Min Temperature : 1878-10-04 to 2024-09-11
• Precipitation : 1878-10-01 to 2024-09-11
• Snowfall : 1928-12-25 to 2024-09-10
• Snow Depth : 1928-12-25 to 2024-09-09

For much more information on the climate in our area, visit the NWS Climate FAQ for the Atlanta area.

What does the National Weather Service do?

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.”