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Dry Monday/Tuesday, Showers and Thunderstorms Wednesday
Plaincast — the National Weather Service forecast, decoded into 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.
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 Grand Rapids, 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.
Discussion
Moisture from Lake Michigan, steep low level laps rates providing around 200 J/kg of storm energy, along with mid level support from the upper level low are sparking off isolated to scattered showers. These will be largely north of a Ludington to Jackson line before the inversion builds in this evening and we lose our surface based instability. Thunderstorms are not expected.
Dry Monday/Tuesday, Showers and Thunderstorms Wednesday
Pressure heights increase Monday into Tuesday as the upper level low over the eastern Great Lakes shifts east. Northwest winds will continue for Monday with gusts to 20 mph. Tuesday winds will be lighter and more variable. High temperatures will be in the 70s Monday and warm to around 80 for Tuesday. Low temperatures will be in the 40s and 50s.
Southerly winds build in ahead of our next shortwave trough that is expected to slowly move through Wednesday. Warm air advection and the low level jet will feed into the area with instability around 1000 J/kg. Shear values only look to be around 25 knots, therefore confidence in storms becoming severe is low. Long range ensemble clusters are in good agreement that most of the rain ends by Thursday morning, although we could see another round of daily showers similar to today Thursday afternoon. The probability of a half inch of rain in 24 hours during this time is less than 20 percent.
Friday ensembles are in good agreement to expect dry conditions but confidence decreases over the weekend as we remain in transitional flow where a few weak shortwaves could bring additional chances for showers and thunderstorms.
This is the plain-text edition, decoded without AI so it loads anywhere. Read the whole Grand Rapids discussion at /o/GRR/, see what changed since the last one, or open The National Desk for where the weather is today.