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.

How does Plaincast translate NWS forecasts?

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.

Which NWS offices does Plaincast support?

Plaincast supports 68 NWS forecast offices across all US regions including Los Angeles (LOX), New York (OKX), Chicago (LOT), Houston (HGX), Phoenix (PSR), San Francisco (MTR), Miami (MFL), Seattle (SEW), Denver (BOU), and many more.

Yes, Plaincast is completely free and open source. It uses the NWS public API for forecast data and Anthropic's Claude for AI summaries. No account or API key required.

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.

Honolulu NWS Forecast in Plain English

What is an Area Forecast Discussion?

Area Forecast Discussions are the real forecasts, written 3 to 4 times daily by NWS meteorologists reading the models and interpreting what they mean for your area. They offer far deeper insight than any weather app, but they're written in dense meteorological shorthand. Plaincast uses Anthropic's Claude to summarize them into plain English, side by side with the annotated original.

Area Forecast Discussion · National Weather Service Honolulu (HFO) · issued Thursday, July 16 at 3:02 PM HST.

Revised in 10 passages since the 9:08 AM discussion. See every revision.

Synopsis

Locally breezy trade winds will remain through most of the weekend before easing a bit early next week. Fairly typical summertime weather is expected through the week, with showers favoring windward and mauka areas.

Discussion

Dominant high pressure far north of the area will maintain locally breezy east-northeast trade winds through Saturday. By Sunday into early next week the high looks to get disrupted just a little by a front passing far north of the area. This will allow trade winds to weaken a little bit during the beginning of next week. Long range guidance then shows the high re-strengthening and allowing trades to become breezy again during the second half of next week. A ridge aloft will maintain stable conditions that will limit shower intensity and keep windward rainfall totals on most islands less than a quarter of an inch today. Aside from scattered afternoon showers on the Kona slopes, leeward areas will experience little rainfall.

A typical summertime shower distribution can be expected through the week and into next week, with mainly windward and mountain showers with afternoon showers for the Kona slopes. Windward and mountain showers will also have a slight boost during the overnight/early morning hours, with all showers remaining mostly light.

This is the plain-text edition, decoded without AI so it loads anywhere. The full Plaincast experience — plain-English summaries beside the annotated original, with the forecast changelog — loads automatically with JavaScript, or open the interactive edition.