Nowcast

NAME

Nowcast - Immediate weather forecast for specified locations in the Nordic area

DESCRIPTION

This service delivers two-hour weather forecasts in JSON or XML for locations in Norway, Sweden, Finland and Denmark. Forecasts are updated every 5 minutes. It is our best estimate of the current weather conditions.

Coverage

This forecast is dependent on functional radar coverage of the requested locations. In some places this is not accessible due to topography or range. Radars might also be temporarily out of production due to technical issues; in such cases no precipitation forecast can be issued.

Due to changes in radar coverage we currently do not support downloading of shapefiles describing the area of radar coverage. Only the MEPS area shapefile is available for download.

complete.json

The JSON version will delived temperature forecasts for the whole MEPS area irrespective of whether radar coverage.

Please check the RadarCoverage parameter in the JSON output for one of the following conditions:

ok

Location is in radar coverage and the forecast is produced as normal

temporarily unavailable

The radar is on the blink, no forecast can be issued

no coverage

The location is outside radar range or blocked by geographical features

Note that this is different from Nowcast version 0.9, which returned a 422 Unprocessable Entity HTTP status code for locations outside radar range.

classic.xml

For requests outside operational radar coverage, the classic version will deliver an "empty XML" document, i.e. one containing only the top level element (as in 0.9). For locations outside MEPS (Nordic area), a 404 will be returned.

JSON format and variables

Version 2.0 defaults to JSON format for data. For an explanation of the various variables, see the Datamodel documentation. The JSON format is described in the General Forecast Format documentation.

Weather icons

Along with the new JSON format we also have a new set of weather icons, in PNG, SVG and PDF formats. They can be downloaded from GitHub.

The filename (minus extension) corresponds to the symbol_code in the JSON format, including variations for day, night and polar day. This means there is no need for calculations or fetching data from the Sunrise service in order to present the correct weather icons.

Note: There is a typing error in lightssleetshowersandthunder and lightssnowshowersandthunder (extra "s" after "light"). Unfortunately, correcting this would mean breaking existing applications, so it has been postponed to the next version of weathericon/locationforecast.

Wind symbols

Wind direction denote where the wind is coming from, where 0° is north, 90° east, etc. For GUI applications use we suggest using arrows, like these:

⬇

0° (north)

⬅

90° (east)

⬆

180° (south)

➡

270° (west)

USAGE

Parameters

lat

latitude in decimal degrees, mandatory

lon

longtitude in decimal degrees, mandatory

altitude

whole meters above sea level (integers), optional but recommended for precise values.

Sample request URLs:

Oslo

https://api.met.no./weatherapi/nowcast/2.0/complete?lat=59.9333&lon=10.7166

Bergen (XML)

https://api.met.no./weatherapi/nowcast/2.0/classic?lat=60.3894&lon=5.33

Trondheim

https://api.met.no./weatherapi/nowcast/2.0/complete?lat=63.4308&lon=10.4034

Tromsø

https://api.met.no./weatherapi/nowcast/2.0/complete?lat=69.6827&lon=18.9427

Vardø

https://api.met.no./weatherapi/nowcast/2.0/complete?lat=70.3705&lon=31.0241

Coverage

A shapefile of the area covered can be downloaded as a ZIP archive at https://api.met.no./weatherapi/nowcast/2.0/coverage .

Status

Operational status for this product can be checked at https://api.met.no./weatherapi/nowcast/2.0/status .

Schema

XML Schema for classic XML can be found here:

    https://api.met.no./weatherapi/nowcast/2.0/schema

The JSON schema is included in the OpenAPI (Swagger) feed:

    https://api.met.no./weatherapi/nowcast/2.0/swagger

AUTHENTICATION

Due to poor adherence to the identification requirements in the Terms of Service, we have implemented more stringent checks on sending a unique identifier in the User-Agent header. Any requests with a prohibited or missing User-Agent will receive a 403 Forbidden error.

Examples of banned User-Agents include:

  • okhttp
  • Dalvik
  • fhttp
  • Java

CHANGELOG

version 2.0 launched, 2020-12-13

2.0 out of beta, added classic.xml output. Version 0.9 will be removed 1 March 2021

Changes to current version 0.9, 2020-11-09

We have replaced the old production backend for version 0.9 with the new one as used by beta version 2.0. This will incur some trivial changes, but is not expected to cause any compatibility problems for well-behaved clients:

  • The @xsi:noNamespaceSchemaLocation and Model@name attributes will be updated to reflect the new production
  • An @altitude attribute will be added to the location element (same as for Locationforecast)
  • The number of decimals in latitude/longitude is no longer fixed

version 2.0 beta, 2020-09-11

New version using JSON and FORTI in development.

2017-09-11

Added coverage method

2017-06-21

New schema, now returns empty XML when no radar data available

version 0.9, 2016-05-01

Initial version

 

Changelog