NAME
MetAlerts - Weather alerts from the Norwegian Meteorological Institute
DESCRIPTION
This service provides meteorological warnings in CAP format, as well as a listing of current warnings in an RSS 2.0 feed. Both are in XML format, but there is an experimental GeoJSON version in beta.
Alerts are issued on three levels:
- Red - Extreme weather with over 50 % probability.
These will normally have an issued name,
look for
incidentName
in the CAP file - Orange - Severe weather, or extreme weather with less than 50 % probability
- Yellow - Less severe weather, or severe with less than 50 % probabilty
Each CAP message is one of the following types,
as indicated in the msgType
value:
- Alert - warning about a new phenomenon
- Update - modifies a previous Alert/Update (which is no longer valid)
- Cancel - invalidates a previous Alert/Update
For more information on the CAP format and meanings, see the "other resources" tab.
USAGE
/current
Use the RSS feed to get a list of CAP warnings, optionally filtered by query parameters.
https://api.met.no/weatherapi/metalerts/2.0/current.rss
(CURRENTLY NOT IMPLEMENTED FIXME)
Do not download each CAP file more than once, and certainly not every time you download the RSS feed! (this is liable to getting you throttled). Once issued the CAP file never changes, so it should be downloaded only once and stored locally.
Output format
Unless the cap
parameter is given,
we return an RSS 2.0 feed of alerts.
Tip: Many browsers have removed RSS support and insist on downloading RSS feeds to disk despite being perfectly able to display XML.
To avoid this,
you can indicate .xml
as output format,
which will return the corresponding MIME type so it can be displayed in the browser.
Experimental GeoJSON format
Due to user feedback we are working on a supplemental GeoJSON format, where all relevant information is included without the need to open separate CAP files.
https://api.met.no/weatherapi/metalerts/2.0/current.json
This also works for other methods,
like all
,
test
,
archive
and so on.
Note: This is currently open for testing, but is rather slow and not optimized for full scale use. Do not use this in production environments! If you start sending lots of continous traffic to this service you are liable to get throttled or blocked.
/all (CURRENTLY NOT IMPLEMENTED FIXME)
Normally only currect alerts are listed,
with expired alerts filtered out.
Using /all
will list all alerts issued during the last 30 days.
Since updates only refer to the previous alert, you may potentially miss some events if you don't poll the feed regularly. Example:
[A] <---updated by--- [B] <---cancelled by--- [C]
If you download alert A, but fail to fetch B before it is cancelled by [C], you will have no way of knowing that alert A is no longer valid (unless the time period has elapsed). Therefore you should either delete all previously downloaded alerts when fetching the feed, or use /all
to ensure you get all published updates and cancellations.
Parameters
cap
Retrieve CAP XML message with given guid
lang
Output language, currently "no" or "en" for Norwegian and English, respectively
event
Filter by CAP eventType, legal values are: blowingSnow, forestFire, gale, ice, icing, lightning, polarLow, rain, rainFlood, snow, stormSurge, wind
You can find matching icons (SVG and PNG) for all events on the Yr warning icons repo.
incidentName
Filter by incident
geographicDomain
Filter by land or marine
county (fylke)
Filter by Norwegian county number where available (only land areas, not gale warnings etc). The county number is defined as always having 2 digits, so the counties Østfold to Aust-Agder must be zero prefixed. Currently one single county allowed per request.
Note that the list of counties is undergoing several changes in the period 2018-2020. For an updated list, please see this dataset from SSB.
lat, lon
Coordinates for geographical search (returns all alerts covered by the search location)
Note: This feature is experimental, and may be changed without prior notice!
period
Only used with the /archive
method. Use ISO format for months, on the form YYYY-MM. Periods outside the archive timespan will return error. Legal values are: 2019-01, 2019-02, 2019-03, 2019-04, 2019-05, 2019-06, 2019-07, 2019-08, 2019-09, 2019-10, 2019-11, 2019-12, 2020-01, 2020-02, 2020-03, 2020-04, 2020-05, 2020-06, 2020-07, 2020-08, 2020-09, 2020-10, 2020-11, 2020-12, 2021-01, 2021-02, 2021-03, 2021-04, 2021-05, 2021-06, 2021-07, 2021-08, 2021-09, 2021-10, 2021-11, 2021-12, 2022-01, 2022-02, 2022-03, 2022-04, 2022-05, 2022-06, 2022-07, 2022-08, 2022-09, 2022-10, 2022-11, 2022-12.
sort
Sort RSS items on field (in ascending order). The following fields are available:
- area
- event
- incidentName
- t_onset
- t_published
- type
Example requests (CURRENTLY NOT IMPLEMENTED FIXME)
https://api.met.no/weatherapi/metalerts/2.0/current.rss
(RSS feed)https://api.met.no/weatherapi/metalerts/2.0/current.xml
(same output as above, but displayed in browser as XML)https://api.met.no/weatherapi/metalerts/2.0/current.json
(GeoJSON FeatureCollection BETA)https://api.met.no/weatherapi/metalerts/2.0/current?lang=en
https://api.met.no/weatherapi/metalerts/2.0/all
# don't filter out expired alertshttps://api.met.no/weatherapi/metalerts/2.0/current?county=42
(show alerts for Agder county)https://api.met.no/weatherapi/metalerts/2.0/current?cap=...
(check RSS feed above for working URLs)
/Archive/archive
This is used to get historical alerts from the archive, which is segmented by monthly intervals. Currently it only contains data for the period Jan 2019 to Dec 2022, but this updated yearly.
Note: This feature is experimental, and may be changed without prior notice!
Test warnings
Meteorologists sometimes want to test fictional CAP warnings to check that they work upstream. These can be accessed via RSS at the /test
endpoint:
https://api.met.no/weatherapi/metalerts/2.0/test.rss
https://api.met.no/weatherapi/metalerts/2.0/test.json
https://api.met.no/weatherapi/metalerts/2.0/test?cap=...
Available (CURRENTLY NOT IMPLEMENTED FIXME)
Available is implemented, but shows only CAP files, not RSS feeds. To view historical alerts, use the period
parameter. Test warnings are not supported.
https://api.met.no/weatherapi/metalerts/2.0/available.json
https://api.met.no/weatherapi/metalerts/2.0/available.xml?period=2021-01
(reading from archive)
Icons
You can download alerting icons in SVG format (which can be converted to PNG) from the Yr GitHub page:
In the future this icon set will be migrated to the Weathericons GitHub repo as currently used with Locationforecast.
Healthcheck
To check if any files that should be available are missing, please use https://api.met.no/weatherapi/metalerts/2.0/healthcheck
. This is only available on servers on the internal MET network.
Changelog
2023-08-06
New version 2.0 beta, using new CAP profile for testing
2021-02-10
Added lightning
event type.
2021-02-10
Experimental alert archive implemented. Use the period
parameter to enable. The RSS feed link has been removed from available, now only lists CAP files.
2019-11-01
The eventCode drivingConditions
has now been replaced by the eventCodes ice
and blowingSnow
to better reflect actual causes instead of consequences
2018-06-19
Support for filter on incidentName
2018-03-08
Support for search by county number (for warnings issued after 2018-03-15)
2017-07-22
Experimental support for search by coordinates
1.1, 2017-05-20
New version of CAP format (1.0). MetAlerts 1.0 will expire 2017-12-01
1.0, 2016-09-01
More search parameters, improved stability. The cap
parameter now requires an ID, not a date.
0.2, 2016-04-20
Format officially changed to RSS 2.0
RSS now validates, using RFC-822 date format and no duplicate items
0.1, 2016-03-02
Renamed to MetAlerts. Format claimed to be Atom, but is in fact RSS 2.0 (invalid)
0.1, 2016-01-19
New product for testing
Changelog
Other versions
Supplemental documentation
Alerting colour criteria
Other documents (in Norwegian)
- Hva er ekstremvær?
- Farevarselplan - describes the criteria for issuing alerts
- Samordning av farevarsler ved MET og NVE (20-2017) - describes our application of the CAP format