A global configuration provides the large-scale weather forecast and also supports the nested higher resolution regional models with boundary data. More detailed short-range forecasts are provided by these high-resolution models which are able to represent certain atmospheric processes more accurately, as well as having a more detailed representation of surface features such as coastlines and orography.

This dataset contains UK atmospheric high resolution data from the UK Met Office operational NWP (Numerical Weather Prediction) Unified Model (UM).

A post-processed regional downscaled configuration of the Unified Model, covering the UK and Ireland, is used with hourly forecast data covering the period T+0 to T+120 hours is used. With a resolution of approximately 0.018 degrees are able to produce hourly data at surface level and at standard pressure levels up to eight times a day.

The model’s initial state is kept close to the real atmosphere using incremental 3D-Var data assimilation.

This archive currently holds data from April 2016 onwards.

An issue has been identified with the representation of the Transverse Mercator projection in the GRIB files in which some of the projection metadata values were set incorrectly. This error has been corrected in all data since 15th Jan 2020. The values that were corrected are as follows:

Up to 15/01/2020:

Source of Grid Definition: 12

Latitude of True Origin: 49

Longitude of True Origin: -2

From 15/01/2020:

Source of Grid Definition: 0

Latitude of True Origin: 49.0e06

Longitude of True Origin: -2.0e06