Observations, Models, And Unavailable Data

On TideAhead, an observed weather field comes from the latest National Weather Service observation selected for the page coordinate. Air temperature, humidity, pressure, sustained wind, and gusts may be reported independently. One field can be present while another is absent because sensors, station equipment, and transmitted products differ.

TideAhead rejects weather observations older than three hours. A NOAA CO-OPS water-temperature value is also accepted only from a reporting sensor within 30 miles, with a recent observation time and acceptable quality flags. The sensor name and distance are displayed because the reading does not come from the tide station merely because it appears on the same page.

The National Weather Service hourly forecast and coastal forecast grid describe expected conditions rather than a measurement already made at the page coordinate. TideAhead labels these fields as model guidance. A model can supply temperature, wind, gusts, precipitation chance, and marine fields even when the latest observation omits them.

This explains a pattern that can otherwise look inconsistent: the Air card may lack an observed temperature while the Hourly Forecast lists temperatures for future periods. The first asks, “What did the selected sensor most recently report?” The second asks, “What does the official forecast expect at this grid point?” TideAhead does not relabel the latter as a current sensor reading.

NWS coastal grids can publish wave height without wave direction, or can leave all wave fields empty at a sheltered or unsupported point. TideAhead validates height, direction, and other marine fields separately. A zero modeled wave height with no direction can be shown as calm with no direction; a nonzero wave with no published direction does not receive an invented compass bearing.

A grid's wave height is not the same as breaking surf at a particular beach. Nearshore transformation depends on bathymetry, exposure, refraction, local wind, currents, and shoreline orientation. TideAhead therefore treats its surfing analysis as limited planning context and directs visitors to current NWS safety information.

TideAhead derives a small number of values to make official inputs easier to use. A current tide estimate can be read from an available continuous prediction series. For NOAA subordinate stations, a dashed half-cosine segment may connect two adjacent official high or low events. It remains between those extrema and is never extended outside them.

Fishing, crabbing, and surfing scores are TideAhead planning indices, not agency ratings, catch predictions, access checks, or safety approvals. They are built only when the required current inputs exist, display the factors that changed the score, and keep official rules and warnings outside the score as separate checks.

“Unavailable” can mean the official provider did not publish the field for that point, the source request failed, the response did not pass validation, the value was stale, or the nearest qualified sensor was beyond TideAhead's coverage limit. It does not necessarily mean the physical condition is zero or that no observation exists anywhere in the region.

TideAhead starts a production snapshot with empty layers and adds only validated official responses. It does not use sample conditions, silently retain an expired reading, or substitute an unlabeled “typical” value. This fail-closed approach creates more visible gaps, but it prevents plausible-looking numbers from masquerading as current data.

1. Open the source and freshness details to identify which layer is missing.
2. Check the official NWS forecast page and active alerts for the destination.
3. Compare nearby official NOAA or NWS stations only when the distance and setting are appropriate.
4. Do not interpret missing wave direction, gust, water temperature, or pressure as a favorable condition.
5. If the missing field is important to safety or access, postpone the decision or obtain current local information.

NOAA CO-OPS, NWS forecast grids, NOAA buoys, regional operational forecast systems, satellite analyses, and ocean-wave models have different spatial coverage and meanings. A broad offshore model is not a local harbor sensor; a satellite sea-surface analysis is not a shoreline thermometer; a coastal grid is not a beach-specific surf report. Expanding coverage responsibly requires preserving those distinctions rather than choosing whichever source returns a number.

The complete provider and gap inventory is documented in TideAhead's methodology. For authoritative weather forecasts and warnings, use the National Weather Service; for station water data and predictions, use NOAA Tides & Currents.