Numbers first. AI explains. You can verify everything.

Every briefing moves through the same stages: data ingestion from official NOAA, NWS, AWC, FAA and Canadian sources; route decomposition along every filed waypoint; route- and altitude-aware product selection; deterministic precomputation of the flight's measurable facts; multi-model forecast consensus where it applies; AI synthesis under restate-exactly rules; and semantic validation of the finished text against the deterministic facts before anything is published. Over 1,500 guardrails and automated checks stand behind that chain.

Beyond the roughly 30-hour window of official aviation forecast products, and on non-US route legs, FlightWeatherCheck adds a four-model numerical consensus from ECMWF, GFS, ICON and GEM: per-field medians and ranges for cloud, visibility, wind, gusts, precipitation and winds aloft, each carrying an explicit HIGH, MEDIUM or LOW model-agreement level. Disagreement between models is presented to you as uncertainty — with re-briefing guidance — rather than hidden behind a single confident number.

Before any AI is involved, the facts of your flight are computed directly: route distance and estimated block time along the full planned path, wind components at your cruise altitude from the published winds-aloft data, corridor terrain clearance versus your planned altitude, TFR and advisory timing against your departure and arrival window, observation ages, and how forecast conditions compare to your personal minimums. These values are calculated from official source data — never estimated by a model.

AI synthesizes: it reads the computed facts, the raw weather products, and the forecast discussions, and writes the operational narrative a pilot actually wants — what matters, what to watch, what would change the call. It is instructed to restate the computed values and source data exactly, and not to invent numbers, altitudes, times, frequencies, or airport facilities that are not in the data. Automated cross-checks compare the finished text against the source data before a briefing is published, and a briefing that fails its completeness checks is not delivered.

Every briefing retains its underlying source products — the raw METARs, TAFs, winds-aloft tables, advisories, TFR listings, and forecast discussions ride at the bottom of the report. If a sentence in the analysis says the ceiling is trending down, the observation it came from is on the same page. We think a supplemental briefing you cannot verify is not worth having.

Each briefing ends in one of four advisory reads: GO, MARGINAL GO, CONDITIONAL GO, or NO-GO — always with the reasoning, the hard stops, and the conditions that would change the call stated explicitly. A verdict is an analysis of the weather against your route and your stated minimums. It is not authorization, and it is not a substitute for an official briefing, NOTAM review, or pilot-in-command judgment.

The fastest way to judge the methodology is to read real output: two complete sample briefings are public, including a NO-GO with its full reasoning. The data behind every briefing is listed on the weather data sources page.