🌧️Forecast Receiptsv0.4click a Tennessee county · see how often the federal forecast guidance was right
🌧️ Forecast Receipts v0.4
Federal forecast guidance, graded in public.
Forecast Receipts asks one question: how often was the weather forecast right for your county? Each county is matched to the nearest airport weather station that has forecast records. For each day, the forecast made the day before is checked against what that station measured for the high and the low, and against the county’s own CoCoRaHS volunteer rain gauges for whether it rained. The report card in the Temp tab shows how often it was within 3°F, the average miss, whether it leans warm or cold, and how its rain calls held up. So far it grades Tennessee: 91 of 95 counties for temperature and 81 for rain.
Two forecasts get graded: the National Blend of Models (NOAA: “The goal of the NBM is to create a highly accurate, skillful and consistent starting point for the gridded forecast.”) and the older GFS MOS guidance. The report card will be rebuilt once a week. No login, and no trackers of our own.
Does a 30% chance rain 30% of the time?
The Blend gives a day chance and a night chance of rain, not one 24-hour number. Together they pin the 24-hour chance between two values: at least the bigger of the two, at most the two added up. If the forecast is honest, the share of days that actually rained should land between those values. Every graded county-day in the current build:
(loading)
Built on the same posture as SnapBasin and the Cumberland Discrepancy FEMA audit: federal data, one click from the source, let the engineer (or the schoolkid) argue.
What's in v0.4
📐 Forecast report card (Temp tab) — trailing 30 days, graded per county: right within ±3°F, average miss, warm/cold lean, rain calls checked against county volunteer gauges, and a side-by-side of the two forecasts on the same days
🌧️ Rain tab — NWS chance of rain, the nearest ASOS station's recent totals, and a link out to CoCoRaHS volunteer reports
🌡️ Temp tab — NWS forecast next to the latest ASOS observation, plus the report card (no citizen layer — temperature isn't what CoCoRaHS tracks)
⚡ Severe tab — active NWS alerts at the point, plus links to SPC convective outlooks and storm reports
Three basemaps: OSM standard, satellite, topographic (the contour map is for the kids learning to read terrain)
County boundaries default-on (plotly’s public US-counties GeoJSON)
Pinned-counties cache in localStorage with CSV export
Search by county+state or street address (via OSM Nominatim)
What's NOT in v0.4 (honest list)
Every county gets its own station — they don't. Grading needs an airport station with forecast records; rural counties borrow the nearest one (up to ~25 miles) and the card says so. Counties with nothing close enough are left ungraded rather than faked.
Official NWS point-forecast grades — the NWS API serves only the current forecast. NCEI keeps the forecast as national grids; the simpler route for this page is to save the API’s point forecast every morning. That isn’t running yet.
Live CoCoRaHS layer in the rain tab — browser requests to CoCoRaHS didn’t work in our testing, so the live tab links out to their reports. (The report card’s rain grade does use CoCoRaHS, pulled by the build from the Iowa Environmental Mesonet archive.)
Rain grades for every county — the rain grade needs at least one volunteer gauge report in the county. Counties with none are left ungraded for rain.
Eclipse layer — hidden in v0.4 until its dates and paths are checked against NASA’s eclipse catalog.
Local TV meteorologist accuracy — we haven’t found structured data; it would take manual entry. Out of scope.
Data sources
National Weather Service: api.weather.gov (forecast + observations, no key required)
Built by Travis Jenkins / User Zero 🦄 · started February 2026 · built September 2026
Architecture: static HTML, public data only, no backend. This page keeps nothing about you except pinned counties in your own browser’s localStorage. To work, it sends searches to OpenStreetMap’s Nominatim and clicked map points to the NWS and FCC APIs, and it loads map tiles, Google Fonts and the Leaflet map library from unpkg. Educational/observational use. Not affiliated with NOAA, NWS, or any federal agency. The deltas are not a critique of meteorology — they're a record of how hard the atmosphere is to predict.