This site is being migrated from my previous wiki at http://ke3vin.org/pmwiki.php/Main/Weather
For the Eclipse on August 21, 2017 please see Eclipse 2017
I am a trained Skywarn spotter. See What is Skywarn for more information.
Here is a script I use to alert me on days that spotter activation may be required based on the NWS HWO product for my forecast office (WFO or WSFO).
The HWO or Hazardous Weather Outlook is created daily by your local forecast office. In it is always a mention of Skywarn Spotter activation.
Even if you are not a trained spotter it is still good to know the outlook of the area where you will be that day. I travel fairly enough and visit relatives across several geographical areas. I can modify my script on a given day to include additional forecasts by the local WFO when I am traveling. Or I can put in the URL below (modify the "issuedby=" in the URL) and change the WFO or simply visit the top site at http://www.weather.gov/ and put in the zip code or city name for your current location and click down to Hazardous Weather.
Since I spend 90% of my time in Deltona, FL and 10% in Greeneville, TN (I own property in each) I monitor both offices statements.
The text only HWO for MLB is at http://forecast.weather.gov/product.php?site=NWS&issuedby=MLB&product=HWO&format=txt&version=1&glossary=0.
The text only HWO for MRX is at http://forecast.weather.gov/product.php?site=NWS&issuedby=MRX&product=HWO&format=txt&version=1&glossary=0
There is also a RAW text source for MLB but I am not sure how long it will last:
Notice the "issuedby=" in the URL. That is where you would put in the code for your local forecast office. Forecast offices nearest you and their codes can be found at http://www.srh.noaa.gov/jetstream/nws/wfos.html.
The output of the script is sent to via email daily at 7:30am via cron (in Linux)
30 7 * * * /home/kinscoe/bin/nws_spotter_activation.sh | mailx -s "Daily Hazardous Weather Outlook" -r email@example.com firstname.lastname@example.org 2>&1
This script runs in Linux Bash shell (https://www.gnu.org/software/bash/) however it can also run in Mac (which already has Bash installed) or Windows using the Cygwin install. For Cygwin see https://www.cygwin.com/. For the Mac (and Linux as well if you do have these dependencies installed) the script should work fine but you will also need to install curl and html2text. Curl is likely already installed on both Mac and Linux by default. It has been on the Mac since 10.8 I believe. For Linux consult your distribution for the proper way to install Curl or visit the source code download at https://curl.haxx.se/. html2text may be slightly harder to obtain. You can visit the source code page at http://www.mbayer.de/html2text/. In Mac you can obtain a port using Macports or Homebrew. I recommend Homebrew. In Homebrew I used the command
brew install html2text
The Bash shell script:
The script is now at Github.
The output which I will see in email similar to (actual email received 2017-07-20):
HWO statement for MLB... .SPOTTER INFORMATION STATEMENT... Spotters are requested to monitor the weather and self activate if needed. In addition, please report any rainfall amounts greater than 3 inches to the National Weather Service. For full outlook click on http://forecast.weather.gov/product.php?site=NWS&issuedby=MLB&product=HWO&format=txt&version=1&glossary=0 HWO statement for MRX... .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. For full outlook click on http://forecast.weather.gov/product.php?site=NWS&issuedby=MRX&product=HWO&format=txt&version=1&glossary=0
This could also be sent to Twitter or other such alerting media.
"NEXRAD or Nexrad (Next-Generation Radar) is a network of 158 high-resolution Doppler weather radars operated by the National Weather Service, an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce. Its technical name is WSR-88D, which stands for Weather Surveillance Radar, 1988, Doppler. NEXRAD detects precipitation and atmospheric movement or wind. It returns data which when processed can be displayed in a mosaic map which shows patterns of precipitation and its movement. The radar system operates in two basic modes, selectable by the operator: a slow-scanning clear-air mode for analyzing air movements when there is little or no activity in the area, and a precipitation mode with a faster scan time for tracking active weather. NEXRAD has an increased emphasis on automation, including the use of algorithms and automated volume scans. Second generation NEXRAD radar systems will have the capability to optically detect hailstone size down to the square mile." - Intellicast
Details on the NEXRAD system are available in Federal Meteorological Handbook No. 11.
There are additional handbooks (publications) available for download from the Office of the Federal Coordinator for Meteorology (http://www.ofcm.gov/publications/fmh/allfmh2.htm).
Four volumes are available:
- A - System Concepts, Responsibilities, and Procedures
- B - Doppler Radar Theory and Meteorology
- C - Products and Algorithms
- D - Unit Description and Operational Analysis
The official Interface Control Documents (ICDs) contain detailed information on the binary data formats and product specifications.
Public - https://radar.weather.gov/
Weather Radar Applications - http://www.ou.edu/radar/z_r_relationships.pdf
The netCDF data format (https://www.unidata.ucar.edu/software/netcdf/) is a set of software libraries and machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The Java NEXRAD Viewer allows users to export Level II or Level III radar data into netCDF format for later manipulation using programs such as MATLAB.
My code (to be migrated from SVN) is at https://github.com/KevinPInscoe/WXTools.