Plaincast — the National Weather Service forecast, decoded into plain English

Plaincast decodes the National Weather Service's Area Forecast Discussion — the real forecast, written 3 to 4 times a day by the meteorologist on shift — into plain English. The discussion is where a forecaster explains their reasoning: which models disagree, what they are watching, and how confident they are. Below is the current edition for San Francisco, with its shorthand expanded. The full experience — an AI plain-English summary beside the annotated original — loads with JavaScript, and every one of the 68 forecast offices has its own edition.

Area Forecast Discussion · National Weather Service San Francisco (MTR) · issued Friday, September 11 at 4:51 AM PDT.

Messages

Temperatures near seasonal averages through the next week

Short Term

What a difference a day makes. The continuing development of a cutoff low off the coast of British Columbia has led to a remarkable cooling through the evening and overnight hours, the return of a marine layer of around 500-1000 feet, and a stratus deck over the coastal regions and through the Petaluma Gap and the Golden Gate. As of midnight, temperatures across the Bay Area and Central Coast are running around 5 to 25 degrees below what they were 24 hours prior. Through the day, the aforementioned cutoff low will strengthen as it parallels the coast of the Pacific Northwest. Morning lows will range from the middle 50s to lower 60s in the lower elevations, and the middle 60s to the middle 70s in the higher elevations, while afternoon highs will top out in the middle 80s to the lower 90s in the inland valleys, the upper 90s to the triple digits in the warmest spots of southern Monterey County, the upper 60s to the lower 80s close to the Bays, and the lower to middle 60s along the Pacific coast.

This is the plain-text edition, decoded without AI so it loads anywhere. Read the whole San Francisco discussion at /o/MTR/, see what changed since the last one, or open The National Desk for where the weather is today.