What is an Area Forecast Discussion (AFD)?

An Area Forecast Discussion is a detailed narrative forecast written 3-4 times daily by National Weather Service meteorologists. Unlike weather apps that show icons and numbers, AFDs explain the reasoning behind the forecast - why models disagree, what forecasters are watching, and where uncertainty exists.

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Plaincast uses Anthropic's Claude AI to summarize each forecast section into natural, readable prose. It also annotates the original text with a 230+ term jargon glossary, converts Zulu (UTC) times to local time zones, and highlights key information for quick scanning.

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How often are forecasts updated?

NWS meteorologists issue new Area Forecast Discussions 3-4 times per day, typically around 4 AM, 10 AM, 4 PM, and 10 PM local time. Plaincast automatically fetches the latest discussion when you load the page.

Flagstaff NWS Forecast in Plain English

Area Forecast Discussion · National Weather Service Flagstaff (FGZ) · issued Monday, July 27 at 4:08 PM MST.

Synopsis

Monsoon moisture remains in place, but high pressure remains centered over New Mexico. This is keeping the potential for showers and thunderstorm mostly contained to the higher terrain during the afternoon and evening hours today. Chances for afternoon and evening showers and thunderstorms will continue Wednesday, mainly for the higher terrain, before temperatures start rising Thursday and remaining elevated this weekend.

Discussion

Visible satellite imagery shows a developing cumulus field over the higher terrain, but the development into showers and thunderstorms appears to be suppressed by the high over New Mexico, despite the presence of the monsoonal moisture. Still expecting isolated to scattered showers and thunderstorms to develop over the higher terrain later this afternoon, with storm motion pushing convection toward the north-northeast today. Convection south of the Mogollon Rim is expected to be limited, mostly associated with any outflows that push activity southward.

Forecast guidance continues to support the high pressure weakening slightly Tuesday and Wednesday, before strengthening again as it moves westward later this week. This may allow a slight increase in showers and thunderstorms Tueday and Wednesday, thought the greatest chance remains over and near the higher terrain. As the high strengthens and shifts westward later this week, temperatures will begin to climb Thursday and continuing into the weekend. Based on the consistency of guidance supporting increasing temperatures, and drier air for later this week and weekend, an Extreme Heat Warning was issued for the Grand Canyon, below 4000 feet, starting 10 AM MST Thursday, and then extending to Yavapai County valleys and basins below 4000 feet and to Marble and Glen Canyons, and Oak Creek and Sycamore Canyons, including Sedona, starting 10 AM MST/11 AM MDT Friday. These hazards are expected to continue trough 8 PM MST/9PM MDT Sunday.

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