The current position and intensity of any active storm does not come from the latest advisory from the National Hurricane Center (NHC) for the Atlantic and East Pacific basins or the Central Pacific Hurricane Center (CPHC) for the Central Pacific basin. For this important data you must refer to the agency responsible for issuing forecasts in the particular basin you are looking at. The current position and intensity is provided to show what data the early cycle models initialized with.

This system updates in real time by accessing the Automated Tropical Cyclone Forecasting System (ATCF). Our site downloads the latest best track data, model data and center fix data from here, which is a National Oceanic and Atmospheric Administration (NOAA) FTP server, and processes the data to be visually displayed on our site. That system and the processing system our site uses may contain errors at times. Please consult the agency responsible for issuing forecasts in your basin, as this information, in addition to possibly containing errors from time to time, is only updated every 6 hours by the NHC. Updates made through regular and special forecast advisories may not be reflected here for three hours or more since ATCF data is usually offset from NHC advisory data by 3 hours. Normal ATCF update times are 0Z, 6Z, 12Z, and 18Z. Since the positions are valid at the time noted, it may take an hour for them to be posted to the ATCF system and then be downloaded by our site. Under most normal circumstances, best track data and NHC model data come in starting around 0:30Z, 6:30Z, 12:30Z, and 18:30Z on our site. (And it may be a half hour after that for late posted data.) Sometimes 6Z best track data may not be available for weaker storms. Normal NHC advisory update times are 3Z, 9Z, 15Z, and 21Z, with special advisories possible at any time, and these do not appear here.

An invest area, noted with a number from 90 to 99, represents an area that is being watched for possible development. Refer to the tropical outlooks at the NHC and the CPHC for guidance on the possibility of development from these areas and look for the latest official advisory data if the storm is a tropical depression or higher.

Older storms in our best track and model archive that have been processed by our system came from the "archive" folder in the ATCF system. While live storms are updated in real time as the storm progresses, older storms that are no longer active are never updated automatically. At times best track data for older storms is adjusted by the NHC and this system will not automatically update the best track data on our site. If you become aware of a storm that has had its best track data adjusted please let us know and we will reprocess the data.

Sometimes our system uses the file "storm.table" in the "archive" folder for storm names when that file has information for an older storm. Our system uses the storm name from there rather than the storm name in the best track file. When the storm name in the "storm.table" file differs from the best track file a note will be displayed on the storm pages for that storm. We also use the "storm.table" file to compare the development noted in that file to the development noted in the best track file. Unlike how our system does storm names, if the development does not match our system will use the data from the best track file instead. The "storm.table" file is more often incorrect when it comes to development while it is more often correct when it comes to storm names. Again, when the development does not match a note will be displayed on the storm pages for that storm about it.

Through the end of 2021, over a quarter of a million files and counting are used to run this system. (over eight gigabytes of data) In part due to that reason, it is impractical to manually verify all the data in this system. If you see any problems, please contact us.