wxobslog

Regularly logs weather observations from selected stations using the NWS API.

Database Configuration

Postgres with the PostGIS extention is required to run wxobslog. Most cloud providers offer Postgres with the PostGIS extention already installed. You must enable it with the query:

CREATE EXTENSION postgis;

The environemt variable WXOBSLOG_DB_CONNECTION_STRING needs to be set for your desired database connection configuration. For example:

$ WXOBSLOG_DB_CONNECTION_STRING=postgresql://wxobslog:[email protected]:5432/wxobslog?sslmode=require python3 -m wxobslog

SQLAlchemy documentation for database connection strings can be found here.

Station IDs

Station IDs are four letter codes which represent a specific NWS observation station. A list of all stations can be retrieved with:

$ curl -X GET "https://api.weather.gov/stations" -H  "accept: application/geo+json"

A list of stations for a specific state can be retrieved by providing a two-letter abbreviated state parameter value:

$ curl -X GET "https://api.weather.gov/stations?state=IL" -H  "accept: application/geo+json"

Additionaly, station ids are shown at the top of the regular NWS forecast page, in parenthesis:

Commands

The prompt wxobslog> will show after wxobslog is started. The prompt accepts these commands:

• track <station id>
  • Starts tracking observations from the given station id.
• untrack <station id>
  • Stops tracking observations from the given station id.
• list
  • Lists all station id's currently being tracked.
• update
  • Forces an update of all tracked station ids.
• interval
  • Sets the update interval to check for new observations.
• quit
  • Exits wxobslog.

Schema

Here is an example of a couple log entries:

wxobslog=# \x on
Expanded display is on.
wxobslog=# select * from observations;
-[ RECORD 1 ]-----------------+-----------------------------
station_id                    | KORD
timestamp                     | 2019-05-08 18:51:00
barometric_pressure           | 101420
dewpoint                      | 5.60000000000002
heat_index                    | 
max_temperature_last_24_hours | 
min_temperature_last_24_hours | 
precipitation_last_hour       | 
precipitation_last_3_hours    | 
precipitation_last_6_hours    | 
raw_message                   | KORD 081851Z 09013KT 10SM BKN055 BKN080 OVC250 13/06 A2995 RMK AO2 SLP145 T01330056
relative_humidity             | 59.6008796741699
sea_level_pressure            | 101450
temperature                   | 13.3
text_description              | Cloudy
visibility                    | 16090
wind_chill                    | 
wind_direction                | 90
wind_gust                     | 
wind_speed                    | 7
-[ RECORD 2 ]-----------------+-----------------------------
station_id                    | KJFK
timestamp                     | 2019-05-08 19:51:00
barometric_pressure           | 102340
dewpoint                      | 9.40000000000003
heat_index                    | 
max_temperature_last_24_hours | 
min_temperature_last_24_hours | 
precipitation_last_hour       | 
precipitation_last_3_hours    | 
precipitation_last_6_hours    | 
raw_message                   | KJFK 081951Z 14011KT 10SM FEW050 FEW100 SCT250 17/09 A3022 RMK AO2 SLP232 T01720094
relative_humidity             | 60.1341856232283
sea_level_pressure            | 102320
temperature                   | 17.2
text_description              | Partly Cloudy
visibility                    | 16090
wind_chill                    | 
wind_direction                | 140
wind_gust                     | 
wind_speed                    | 6

Not all observations will contain every column field. Fields like max_temperature_last_24_hours are only updated periodically. Fields like wind_chill will only be updated when relevant.

All units are SI; that is: pascal, celsius, meters, meters-per-second, etc. Azimuths are measured in degrees.

Timestamps are normalized to UTC.