ATLANTA — After a stretch that mixed storms and slightly less oppressive air, the official discussion is back on heat and a narrow storm window.
The National Weather Service Peachtree City Area Forecast Discussion issued at 3:28 a.m. EDT Thursday, Aug. 20, leads with two key messages:
- A few storms on Thursday and Friday could be strong to severe, capable of gusty to damaging winds, frequent lightning, and locally heavy rainfall.
- Warm and humid conditions return Thursday and Friday, with heat index values climbing back into the triple digits each afternoon.
At issuance, the product listed no watches, warnings, or advisories for the forecast office — heat indexes were described as close to Heat Advisory criteria, but not quite there.
Thursday heat numbers
The short-term section (issued 3:14 a.m. EDT) said forecast highs are in the upper 90s to lower triple digits outside elevated terrain. Where air is a bit drier, temperatures could approach or hit 100°F, with mid-90s elsewhere and apparent temperatures in the triple digits pretty much everywhere.
Preliminary point guidance in the same AFD put Atlanta at about 98°F Thursday with a 20% daytime storm chance and a 75°F overnight low, then roughly 93°F Friday with higher storm odds.
NWS language is plain on outdoor risk even without an advisory: use caution if exerting yourself outdoors during peak afternoon heating.
Storm timing uncertainty
Forecasters were monitoring morning convection along a frontal boundary northwest of the area and put only about a 20% chance of anything progressing into Georgia near sunrise because of a dry layer aloft.
For the rest of Thursday:
- Isolated thunderstorms are possible across north and west Georgia in the afternoon where moisture returns; those were not expected to be especially strong.
- A better organized chance may arrive late evening or overnight, possibly after sunset into midnight or later, as a shortwave helps fire storms along a stalled front/moisture boundary — more likely originating over north Mississippi/Alabama and/or west Tennessee before pushing into Georgia.
- SPC Marginal Risk coverage was noted for that overnight threat, with isolated damaging wind gusts possible.
Friday’s setup shifts the moisture gradient roughly along the I-85 corridor, favoring more diurnally driven afternoon and evening storms.
Aviation guidance (06Z TAFs) flagged afternoon air-mass storm chances and a more organized line that may approach from the northwest shortly after 00Z to as late as 06Z, with medium confidence on timing.
Weekend pattern, still hot
The longer-range discussion keeps highs in the 90s for most of north and central Georgia through the extended period — a couple of degrees above average — with a possible multi-day reprieve from the most expansive afternoon convection after frontal influence, then isolated to scattered storms and triple-digit heat indexes returning as the airmass moderates early next week.
How to use this
This package is a forecast discussion, not a storm survey and not a heat-advisory declaration. Treat the triple-digit heat-index language as the day-to-day outdoor planning signal, and treat Thursday night into Friday as the higher-attention window for stronger storms until a later NWS update narrows timing.
Primary source: NWS Peachtree City Area Forecast Discussion — issued 3:28 a.m. EDT Aug. 20, 2026.