CWOP Information for CW8949 (C8949) in San Luis Obispo, CA US

It is possible that this page will report a problem where no problem exists. If you believe that this has happened, then please contact me (address at the bottom of this page) and explain clearly why you think this page is in error. Note that any changes that you make may take a few days to show up here, so please give it a week before commenting.

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Registered Location

If you know what sort of station equipment is in use at this site, then please send email to Philip Gladstone with this information. The email address can be found at the bottom of this page.

The elevation does not correspond with the estimated elevation (61 meters (199 feet) -- source NED Contiguous U. S. 1/3W arc second elevation data) at that point. It seems probable that the elevation was entered as feet rather than as meters. Please use the 'send the updated information' link below to update the location or elevation.

The site location should be at the mark shown -- or very close. Clicking within the map area (or you can drag the 'CW8949' marker) will display the latitude/longitude of that point.

If the displayed location (or elevation) of the weather observing location is incorrect, please drag the marker to the right location (or click in the right location), and then send the updated information. Please note that we are trying to spot either the Stevenson Screen (or equivalent) or the location where the barometric readings are taken.

The best way to get elevation is to consult a topographic map. Make sure that you know whether the contours are marked in feet or meters. Note that handheld GPS receivers do not provide readings of elevation accurate to better than 10-20 meters (technical discussion). If you do not have access to a topographic map, then a GPS receiver is acceptable, but make sure that it is operating in 3D mode and let it average the position for at least five minutes.

For more information on reading maps, please see the Topo Map Reading Guide -- in particular it discusses how to read contours.

NOTE: The Registered Location is the location that the station owner provided when they signed up with CWOP.

There are no photographs of the station. If you are the site operator and have pictures of this location, then please upload them to Flickr (detailed instructions) and add the two tags 'wxtagged' and 'wx:cwop=c8949'. If the picture is of the weather station itself, then please also add the 'wx:station' tag as well.

You can try to find photographs from the area surrounding the site marker by clicking on Find nearby photographs. (There are some) (There are none) (There may be some) (Automatically loaded if any)

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APRS Location

The location reported in the weather reports (via APRS) is significantly different to the registered location above. In particular, the difference is about 9.8 miles. If you have changed your location (or software) since the time above, then this can be a false alarm. Check the location currently being reported at findu.com.

Please check which location is correct. If the registered location is incorrect, then you can correct it by dragging the marker above and using the 'send the updated information link'. If the APRS location is incorrect, then you must enter the correct coordinates into your software which generates the weather report (APRS) messages. Note that the various different types of software take the location in different formats, so be sure to use the correct format when entering the latitude and longitude.

Data Status

All the means and standard deviations shown below are from the last 28 days. Change analysis period to Last 3 days  Last 7 days  Last 14 days  Last 8 weeks  Last 13 weeks  Last 26 weeks  Last 39 weeks  Last 52 weeks  

The inconsistency noted above in your location information means that the analyzed readings for your location may be incorrect. For example, if your location is incorrect, then the analysis values will be for a location other than your station. This will give different analysis results, probably leading to errors being shown below. If the elevation is incorrect, then the comparison of temperature readings will be in error.

Temperature

24 hours   Day time   Night time Average temperature error -14.5 °F -11.8 °F -16.1 °F Error standard deviation 2.6 °F 2.3 °F 1.2 °F Worst average temperature error -15.6 °F -11.9 °F -17.0 °F Worst standard deviation 2.8 °F 3.0 °F 0.8 °F NOTE: If the error above is POSITIVE, then it means that the analysis temperature is HIGHER than the reported temperature. This means that your sensor is reading COLDER than expected.

MADIS rating

Latest daily graph:

The values returned by your sensor indicate a system problem. This can be caused by a 'stuck' sensor that always reports the same value. Please check your station for proper operation.

Neighboring Stations

You can look at those for comparison purposes. The average difference between your station and each station below is listed as well. This may allow you to detect local stations which are erroneous. You can also use these numbers to adjust your instruments -- especially if a number of ASOS stations have similar differences to your station. Also, try increasing the analysis period to more than the default 28 days. The difference is only given if both stations report reasonably often during each day. Some stations only report every 6 hours, and this makes the average of less interest. In this case, the average is not displayed. Since this station has not been reporting continuously during the analysis period (it missed 24 days out of 28), the offsets below may not be accurate.

You can also subscribe to an RSS feed to tell you when new stations come online in this area. Choose either within 100 miles or 250 miles . For stations covered by your Forecast Office: Los Angeles (LOX) .

The sites marked above thus did not report continuously during the analysis period, so the offsets may (probably will) not be accurate.

Quality Control Notes

The 'MADIS rating' reports on the percentage of observations that pass the MADIS checks. You should aim for two thumbs up!

Location Formats

Degrees Minutes Seconds: VWS/VWSAPRS, WeatherLink 5.5, WeatherLink (5.2-5.4), WeatherView (Linux)

Decimal degrees: FreeWX, WeatherView32 (PC application)

LORAN: WeatherDisplay, WUHU, Henriksen WServer

Resources

CWOP Guide (PDF): This is a guide to siting and operating a CWOP station. This is a must-read document.

APRS WX Message format: This describes the actual format of the messages transmitted that carry WX information.

WXQC Mailing List: This is a mailing list where data quality issues are discussed. Assistance with software configuration can often be found here.

Topo Map Reading Guide: How to read USGS topographic maps, with a good section on reading contours.

Geographically nearby web pages: Use Geourl to find web pages that deal with locations geographically close to this site.