NOAA’s Secret Weather Sites


HADS Home page showing over 16,000 NOAA weather sites

Most sailors in the Seattle area are familiar with the West Point and Seattle NOAA weather sites on the internet. But did you know that those sites are only the tip of the iceberg so to speak of the over 16,000 NOAA weather observation sites. There is one at the Alki Lighthouse in West Seattle for example.

Finding the station closest to your location from the over 16,000 weather observation stations in the United States and Canada can be a bit of a challenge even if you have the secret handshake on where to start.  But lets give it a whirl.

Visit the Hydrometeorological Automated Data System home page HADS Home Page, you will find a map of the United States, Mexico and Canada with a lot of dots on it.

Click on the map and you will be taken to another page with links to each US state, Canada and Mexico.  Click on the state you want to find a weather observation station for.  Now the fun begins, the sites are listed in alphabetical order, but many times a small river or creek might be named and the city or town placed at the end of the description or lake name is first along with some “Emergency Install” stations, I sometimes found it difficult to locate the station I was looking for and at times resorted to paging down the whole list or using the Search Web Page function to try and find the town.

If you click on Washington State, the second station listed will be


Clicking on the “91s” will take you to the Alki Point Weather station, the station is located about 40 yards east of the Alki Point Lighthouse (open for free tours most summer weekends).

There is a map showing where the station is located and a spread sheet with all sorts of numbers, data from the station is uploaded once an hour at about 12 minutes, 15 seconds past the hour.  The Latitude and Longitude are given with other information.  Just below the boxes of data and just above the map there is a drop down box for the amount of data to display, the default is “Today” next to the amount of data to display drop down is a “Decoded Data” box, click on it to see the data displayed in tabular form.  The time is UTC or GMT (London, England) so the appropriate offset will need to be added or subtracted for local time.

At the top of the tabulated data is a graph data option to display the data in a graphical form.

Abbreviations for the data:

Julian Date: Julian Date (integer)
Hour: Hour of the day HH:MM
HG: Height, river stage
HP: Elevation, pool
PC: Participation, Accumulator
PP: Precipitation, actual incremental
TW: Temperature, water
TA: Temperature of air
TX: One Hour MAX Temperature
TN: One Hour MIN Temperature
US: Wind Speed Miles per hour
UD: Wind Direction Degrees
UP: Peak Wind Speed MPH
XR:Humidity, relative
VB: Voltage Battery

NOTE: Not every station has every sensor.

Many of the stations are remote located and stand alone, they have a solar panel that charges a small battery, this makes installing the station much easier since power lines don’t need to be ran to the station.  The battery voltage data lets the technicians monitor the health of the battery and the charging system and service the system before problems that cause the station to shut down.

NOAA owns very few of the over 16,000 stations listed.  Many of those stations are owned by other agencies such as the Water Resources Division of the U.S. Geologic Survey, the U.S. Army Corps of Engineers, the Tennessee Valley Authority, the Bureau of Land Management, the U.S. Forest Service, the Bureau of Reclamation, and departments of natural resources from numerous state and local agencies throughout the country.  In total, HADS receives data from nearly 200 different agencies.  NOAA receives the data, processes it, and then disseminate it.

A special note about the data:

Data values presented on HADS web pages are PROVISIONAL and HAVE NOT been reviewed nor evaluated through quality control tests.

This means you are seeing the raw data with no quality control checks on it, if an instrument goes out of calibration for some reason the data displayed may be in error and not reflect the actual conditions at the weather site.  So a bit of checking is in order, if the wind speed is showing 95 MPH and a hurricane or other storm is not happening , maybe the wind instruments are not functioning correctly.  So please use caution when using these sites.

What exactly is HADS and what is it intended for?  From the NOAA web site:

HADS is a real-time and near real-time data acquisition, processing, and distribution system operated by the National Weather Service Office of Hydrologic Development. The system exists in support of National Weather Service (NWS) activities of national scope, specifically the Flood and Flash Flood Warning programs administered by the Weather Service Forecast Offices and the operations performed at River Forecast Centers throughout the United States. Additionally HADS created data products bolster several other NWS program areas including fire weather support services, local and national analysis of precipitation events, hydrologic modeling, and the verification of NEXRAD precipitation estimates.

A special thanks to Charles the NOAA Electronics Technician for sending me the link and explaining what the different abbreviations are.  He was servicing the Alki Point weather station one of the days I was helping with Alki Point Lighthouse Tours and gave me a short explanation of how the Alki Point Lighthouse weather station operated and explained the functions of the different parts of the station and the way the data is collected and sent back to NOAA.

Thanks also to Paul from the HADS team that pointed out that NOAA owns very few of the over 16,000 instrument stations.

Thanks for your interest in and support of boating safety.

 – c / m –

This entry was posted in Boating Safety, Sailing and Boating Skills and tagged , , . Bookmark the permalink.

2 Responses to NOAA’s Secret Weather Sites

  1. Another site is mesowest. It is easier to navigate. But, just USA sites.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.