NOAA Tropical Cyclone Best-Track Records - HURDAT2

NOAA's HURDAT2 tropical-cyclone best-track database - the National Hurricane Center's official post-storm reanalysis - as clean, per-fix records. One row per best-track fix (a cyclone's position and intensity at a synoptic or special time), carrying its storm id, storm name and basin, across the North Atlantic and NE/Central Pacific basin files.

What one record represents

The source is NOAA NHC HURDAT2, published as two basin text files. Each file lists storms as a header line - storm id, name and number of fixes - followed by that many track-fix lines. This Actor parses the header/child structure and emits one record per track fix, stamping each fix with its storm's id, name (UNNAMED where none was assigned), basin and season year. Each record carries the fix date and UTC time, a record identifier (e.g. L for landfall), the system status (HU, TS, TD, EX, SD, SS, LO, WV, DB), latitude and longitude (verbatim and as signed decimal degrees), maximum sustained wind, minimum central pressure, the 34/50/64-knot wind radii in all four quadrants, and the radius of maximum wind.

Sample output

Real rows from a live run of this actor (first 5 rows, selected columns).

One full record from the same run, exactly as delivered:

{
  "storm_id": "AL011851",
  "storm_name": "UNNAMED",
  "basin": "AL",
  "basin_name": "North Atlantic",
  "storm_year": 1851,
  "fix_date": "18510625",
  "fix_time_utc": "0000",
  "record_identifier": null,
  "status": "HU",
  "latitude": "28.0N",
  "longitude": "94.8W",
  "latitude_deg": 28,
  "longitude_deg": -94.8,
  "max_wind_kt": 80,
  "min_pressure_mb": null,
  "r34_ne": null,
  "r34_se": null,
  "r34_sw": null,
  "r34_nw": null,
  "r50_ne": null,
  "r50_se": null,
  "r50_sw": null,
  "r50_nw": null,
  "r64_ne": null,
  "r64_se": null,
  "r64_sw": null,
  "r64_nw": null,
  "radius_max_wind_nm": null,
  "record_id": "AL011851:18510625:0000:0",
  "source": "NOAA NHC - HURDAT2 best track",
  "source_dataset": "AL",
  "licence": "U.S. Government work - NOAA National Hurricane Center HURDAT2 best-track database. Public domain (17 U.S.C. 105); no copyright. NWS/NOAA disclaimer: provided 'as is' with no warranty; not for use as the sole basis for safety-of-life decisions. Attribution to NOAA/NHC requested.",
  "attribution": "NOAA National Hurricane Center - HURDAT2 best-track database",
  "caveat": "One record per best-track fix (position/intensity at a synoptic or special time) across the North Atlantic (AL) and NE/Central Pacific (EP) basin files, each in its 2025-season edition (revised 27 Feb 2026). Every fix carries its storm id, name (UNNAMED where none was assigned; never a person) and basin. Wind radii and pressure use null where the source records -999/-99 (missing). Radius of maximum wind exists only from the 2021 season onward.",
  "observed_at": "2026-09-25T17:24:42Z"
}

Coverage and volume

The two basin files, in their 2025-season editions (revised 27 February 2026), together carry 87,631 track fixes - 55,605 in the North Atlantic file (hurdat2-1851-2025-02272026.txt, seasons 1851-2025) and 32,026 in the NE/Central Pacific file (hurdat2-nepac-1949-2025-02272026.txt, seasons 1949-2025). Those counts were measured live from the files fetched at build time.

Sol's Wave-3 index put this door at about 87,631 track-fix rows; measured live at build time the two basin files carry exactly 87,631 fixes (55,605 Atlantic + 32,026 NE/Central Pacific).

Both editions were confirmed as the newest published files in the NHC HURDAT directory at build time. The Actor delivers the fixes in file order (storm by storm, fix by fix) and stops as soon as your Maximum records cap is met.

Format and parsing

The record layout is quoted from the NHC HURDAT2 format document (https://www.nhc.noaa.gov/data/hurdat/hurdat2-format-atl-1851-2021.pdf). A header line reads, verbatim from that document:

AL (Spaces 1 and 2) - Basin - Atlantic; 09 - ATCF cyclone number for that year; 2021 - Year; IDA - Name, if available, or else "UNNAMED"; 40 - Number of best track entries - rows - to follow

and each data line carries date (YYYYMMDD), time (HHMM UTC), record identifier, status, latitude, longitude, maximum sustained wind (knots), minimum pressure (mb), the 34/50/64-knot wind radii (NE, SE, SW, NW), and the radius of maximum wind. Where the source records -999/-99 (missing), the Actor delivers null. The radius of maximum wind exists only from the 2021 season onward and is null before then.

Licence and attribution

HURDAT2 is a U.S. Government work in the public domain (17 U.S.C. 105) - no copyright. The full notice, including the NWS/NOAA disclaimer, travels on every record:

U.S. Government work - NOAA National Hurricane Center HURDAT2 best-track database. Public domain (17 U.S.C. 105); no copyright. NWS/NOAA disclaimer: provided 'as is' with no warranty; not for use as the sole basis for safety-of-life decisions. Attribution to NOAA/NHC requested.

Attribution to NOAA/NHC is requested and stamped on every record. The data is provided "as is"; it is a historical reanalysis, not a real-time or safety-of-life product.

Person-data policy

HURDAT2 carries no personal data. Storm names are tropical-cyclone names (or UNNAMED, or a number such as "TEN"), never persons; a per-record assertion rejects any forecaster/analyst/person field (verified with a planted-field test). No natural-person data is processed.

Interpretation caveat

One record per best-track fix across the North Atlantic (AL) and NE/Central Pacific (EP) basin files, each in its 2025-season edition (revised 27 Feb 2026). Every fix carries its storm id, name (UNNAMED where none assigned; never a person) and basin. Wind radii and pressure use null where the source records -999/-99 (missing). Radius of maximum wind exists only from the 2021 season onward.

Values are reproduced verbatim from the best-track files; the Actor never rewrites a field. Latitude and longitude are delivered both as the source's verbatim strings (e.g. 28.0N, 94.8W) and as signed decimal degrees for direct numeric use. A fix's record_identifier is blank for ordinary synoptic times and set (for example L) at landfalls and intensity maxima.

Data quality and freshness

Wind, pressure, the twelve wind-radii fields and the radius of maximum wind are delivered as real numbers (null where missing); latitude/longitude have both string and numeric forms. The record_id composes storm id, date, time and a per-storm sequence, so every fix is uniquely keyed and the dataset is safe to diff, deduplicate or upsert. HURDAT2 is republished on NHC's post-season reanalysis cycle; re-running the Actor picks up new seasons and any reanalysis revisions, and each record's observed_at stamp dates the snapshot. The run's RUN_RECEIPT records the source URLs, how many records were delivered and charged, and confirms charge_equals_delivered.

Provenance and compliance

Every run reads www.nhc.noaa.gov/robots.txt at runtime; the gate result (URL, status, byte length, SHA-256 of the policy) is written to the run's RUN_RECEIPT, and both basin file paths are confirmed crawlable before any fetch. The Actor never bypasses a block or fetches through a mirror.

Inputs

• Maximum records (maxRecords) - hard cap on track-fix records delivered and billed. You are billed only for records actually delivered. The two files together carry ~87,600 fixes.

Output

Records land in the Actor's default dataset and export as JSON, CSV, Excel or via the Apify API. A tabular overview view surfaces storm id, storm name, basin, fix date/time, status, latitude, longitude, maximum wind and minimum pressure.

Fields in detail

The record leads with record_id, storm_id, storm_name, basin, basin_name and storm_year, then the fix: fix_date, fix_time_utc, record_identifier, status, latitude/longitude (verbatim) and latitude_deg/longitude_deg (signed decimals), max_wind_kt, min_pressure_mb, the twelve wind-radii columns (r34_ne ... r64_nw) and radius_max_wind_nm. The provenance block closes every record. Because each record carries its storm id and basin, you can regroup the fixes into storm tracks or aggregate to per-storm intensity with a single group-by.

Scaling and limits

Set Maximum records low to sample cheaply or high to pull the full best-track history. The Actor streams the two files and delivers incrementally, so memory stays flat, and you are billed only for what is delivered. Because HURDAT2 is a fixed historical reanalysis republished each post-season, re-running keeps a downstream climatology current with new seasons and revisions, and each record's observed_at stamp dates the snapshot. To build a per-storm panel, group the fixes on storm_id; to compare basins, filter on basin.

Typical uses

Insurance, catastrophe-modelling and climatology teams use this cell as the authoritative track history for Atlantic and eastern-Pacific cyclones - one flat table of every reanalysed fix, with intensity and wind structure, that regroups into storm tracks on storm_id or aggregates to per-storm peak intensity with a single group-by. Because latitude and longitude come as signed decimals, the fixes drop straight into a GIS or a spatial join against exposure data, and the landfall record identifier isolates the fixes that matter for coastal impact. Researchers use the full 1851-onward Atlantic record for long-period trend work, with the caveat that pre-satellite seasons carry more missing wind-radii and pressure values (delivered as null, never as a guessed number). A scheduled run keeps a downstream climatology current as NHC publishes each post-season reanalysis.

Sibling Actors

It sits beside the fleet's NOAA Storm Events database records and natural-hazard event records, which are distinct datasets (event catalogues, not best-track fixes). It shares its text-file engineering - the runtime robots gate, verbatim-value discipline and push-then-charge billing - with the fleet's other NOAA records Actors, from which it stays distinct as a best-track fix feed (position/intensity every few hours) rather than an event catalogue.