Raw model data

Base URL: https://api.wxalerts.org

The model numbers themselves, for building your own products: one model at a point, only the forecast hours you ask for, only the fields you ask for. SI units, nothing derived, no narrative, no blending between models.

GET /v1/forecast/raw?model=nbm&lat=35.22&lon=-97.44&hours=0
GET /v1/forecast/raw?model=hrrr&lat=35.22&lon=-97.44&forecast_hours=0-6&fields=all
GET /v1/forecast/raw?model=rrfs&lat=35.22&lon=-97.44&forecast_hours=0-6&fields=column,surface_pressure

Available by arrangement. This endpoint answers only API keys that WxAlerts has enabled for it; any other key gets 403 with the code admin_key_required. To request access, email support@wxalerts.org or use the contact page and say what you are building. We enable it on a key in your account.

Models

hrrr and rrfs answer in exactly the same shape, so a client written for one reads the other by changing model=. Two differences to know: the column’s top two levels are 75 and 50 hPa in HRRR but 70 and 50 hPa in RRFS (read levels_hpa), and RRFS output arrives about 1 h 50 m after its cycle, later than HRRR’s.

Asking for hours

Use at most one of these. With none, you get every hour available: NBM from the hour in progress onward, HRRR and RRFS the whole newest run.

Hours that do not exist are left out, never padded, so read what came back rather than assuming a length. A run is served once its first two hours are on disk; run.hours_available against run.hours_expected says how much of it has arrived. NBM has no f000, so the hour in progress is usually its forecast hour 1 or 2.

Asking for fields

fields is a comma separated list of names or groups. Default: everything the model offers. An unknown name is a 422 that lists what is on offer.

NBM fields

Group: all.

Accumulation windows. NBM publishes these accumulated fields over windows that grow with lead time, and each comes with a companion telling you which window you got: precip_amount_window_hours, precip_probability_window_hours, thunder_probability_window_hours, snowfall_amount_window_hours, ice_accumulation_window_hours. Precipitation probability, snow and ice are 1-hour in the hourly range and 6-hour past about 100 hours; thunder goes from 1 to 3 to 6 hours; precipitation amount stays 1-hour. Read the window before adding hours together or comparing them.

Each NBM hour carries its own cycle, and it can differ between hours: every valid time comes from the newest NBM run that reached it.

HRRR and RRFS fields

Groups: all, surface (every single-level field), column (every pressure-level field).

Single-level, in each hour’s values:

On every pressure level, in each hour’s levels:

The column is 39 levels, bottom up: 1000 to 100 hPa every 25, then 75 and 50 (HRRR) or 70 and 50 (RRFS). Every hour lists every level, so index k is always the same pressure; a level below the ground at that hour has below_ground: true and every value null.

HRRR publishes omega and RRFS publishes vertical velocity. Both fields are offered for both models: the one the model publishes is passed through, and the other is derived from it (omega = -ρ g w, with ρ from the level’s pressure and virtual temperature). units says which is which.

What a response holds

An RRFS call for f06 with a few fields, levels trimmed to two:

{
  "server_time": "2026-11-12T01:11:35Z",
  "model": "rrfs",
  "location": { "lat": 35.22, "lon": -97.44 },
  "grid_point": { "i": 901, "j": 407, "lat": 35.20763, "lon": -97.43979, "resolution_km": 3.0 },
  "run": { "cycle": "2026-11-11T21:00:00Z", "hours_available": 13, "hours_expected": 19, "complete": false },
  "fields": ["temperature_2m", "mucape", "mslp", "temperature", "omega", "vertical_velocity"],
  "units": {
    "temperature_2m": "K",
    "mucape": "J/kg, 255-0 hPa most unstable parcel",
    "mslp": "hPa, HRRR's MAPS reduction (MSLMA), RRFS's Eta reduction (MSLET)",
    "temperature": "K",
    "omega": "Pa/s, positive downward, derived hydrostatically from RRFS's w and the level's virtual temperature",
    "vertical_velocity": "m/s, positive upward, as RRFS publishes it",
    "pressure": "hPa"
  },
  "levels_hpa": [1000.0, 975.0, 950.0, "...", 100.0, 70.0, 50.0],
  "hours": [
    {
      "valid_time": "2026-11-12T03:00:00Z",
      "forecast_hour": 6,
      "cycle": "2026-11-11T21:00:00Z",
      "values": { "temperature_2m": 287.3, "mucape": 0.0, "mslp": 1018.26 },
      "levels": [
        { "pressure": 1000.0, "below_ground": true, "temperature": null, "omega": null, "vertical_velocity": null },
        "...",
        { "pressure": 500.0, "below_ground": false, "temperature": 258.8, "omega": 0.198, "vertical_velocity": -0.03 },
        "..."
      ]
    }
  ]
}

An NBM response has the same frame without run, levels_hpa or levels, and its grid_point names the NBM cell (cell_id, domain). Only the hours and fields you asked for appear. A field that is present and null means the model has no value there. unavailable_fields lists any you asked for that the model does not publish at that point, such as NBM precipitation type in Hawaii.

Calling it

Send your key in the X-API-Key header (or Authorization: Bearer). A key in the URL is refused with 400 key_in_query, because URLs end up in logs and browser history. Browsers block calls from other websites (CORS allows only wxalerts.org), so call it from a server, script or app.

curl -s -H "X-API-Key: $WXALERTS_KEY" \
  'https://api.wxalerts.org/v1/forecast/raw?model=hrrr&lat=35.22&lon=-97.44&forecast_hours=0-6&fields=all'

Limits

5 calls in any 60 seconds per account, shared by every key on the account and by this endpoint and point soundings together. Every call that passes the key check counts, including one that answers 404 or 503. Responses carry RateLimit-Limit, RateLimit-Remaining and RateLimit-Reset; past the limit you get 429 with a Retry-After. One call can carry a whole run, so ask for the hours and fields you need in one call rather than one call each.

Errors