Medical evacuation helicopter and crewmen at airport.

HeliBrief® HEMS

Welcome to HeliBrief® HEMS, our mobile and tablet accessible weather briefing product for Helicopter Emergency Medical Service. This product is regulated by the CAA.

We have developed this product to be accessible from all mobile devices (optimised for an iPad mini), as well as on a desk top in the control room setting.

Below, you will find some content which we hope will provide you with guidance around some of the features in the product. We have created a User Guide and a PDF version can be provided to each base, along with access credentials.

There is a feedback button in the product for specific product feedback, but you can also provide feedback by email at

For 24/7 product support, please ring 0370 900 0100 or email

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Colour States
Triggered Lightning
UK Low-Level Significant Weather Charts
Aerodrome Actual Weather - METAR Decode
Aerodrome Forecast - TAF Decode

Colour states

Colour states are a good way of quickly ascertaining the conditions over an area without viewing the full observation. A colour state provides a convenient way to assess the observed visibility, cloud base, and amount of cloud at a location, as reported in the locations METAR. Poorer conditions are highlighted by red or yellow symbols; good conditions are highlighted by blue symbols.

The table below lists the conditions that determine the colour state to show.

Colour State Visibility Range1 Cloud Base Range2, 5/8 or more BKN/OVC
Blue 10km or more 1500ft or more
White 5000m to 9km 1200ft to 1400ft
Green 4000m to 4900m 600ft to 1100ft
Amber 500m to 3900m 200ft to 500ft
Red Less than 500m Less than 200ft

No METAR currently available: Either there is no METAR available, the METAR could not be decoded automatically, or the latest METAR is more than 2 hours old.

1 Visibility is reported to the nearest 50m up to 500m, 100m between 500m and 4900m, and the nearest 1 km for 5000m or greater.

2 Cloud base is reported to the nearest 100 feet.

The colour states are regularly updated to reflect the latest METARs available to Helibrief®.

Poorer flying conditions are prevalent at those locations highlighted by red and amber colours, whilst good conditions are highlighted by blue colours. Grey symbols indicate that the latest METAR is unavailable or cannot be decoded.

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Triggered lightning

The triggered lightning layer shows areas where there is high, medium, or low risk of triggered lightning. Forecasts are provided in 1 hour time steps out to 6 hours ahead. If there is no forecast risk of lightning strike, then there will be no colour visible for this layer.

Triggered lightning risk is forecast using an algorithm based on total surface precipitation rate (rain and snow); the average temperature of the model levels between 2000ft and 3000ft; and the height of the freezing level above 750 feet.

Visible images

The structure of clouds in satellite images can inform pilots a lot about the weather, and animated sequences can tell pilots about the movement of these weather systems.

Bands of cloud often indicate the presence of weather fronts, whilst individual clouds are likely to provide detail on the location of convective clouds. Both frontal and convective cloud information is useful to pilots because each are often accompanied by potential weather hazards such as icing, turbulence, hail, and lightning. Gaps in the cloud cover can also reveal the location of snow fields.

Infrared imagery

Satellites also measure the temperature of the clouds and the surface with an infrared sensor. This results in infrared satellite imagery.

The thermal contrast between land and cloud tops allows the position of clouds to be revealed during the hours of darkness. The brightest clouds are those with the greatest thermal contrast, i.e. those with the highest tops such as CBs. Those with little contrast with the land have similar thermal differences so are most likely low cloud like stratus, or fog.

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UK Low-Level Significant Weather Charts

UK Low-Level Significant Weather Charts

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Aerodrome Actual Weather - METAR Decode

Aerodrome Actual Weather - METAR Decode

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Aerodrome Forecast - TAF Decode

Aerodrome Forecast - TAF Decode

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HeliBrief® HEMS Overview

The following information summarises the features present in the current release (February 2016) and known issues.

Current features

HeliBrief® HEMS is iPad enabled.

Application configurable to the one of 36 locations selected on the home page.

Home page displays an overview of:

  • Colour states
  • Precipitation rate
  • Surface visibility
  • Wind FL020
  • Lightning
  • Cloud, fog and surface pressure
  • Weather shown on interactive map:
    • Colour states - similar METAR colour state categories to OHWeb (note: these are different to military colour states). Colour states older than 2 hours no longer displayed. Specials for military airfields no longer displayed.
    • Aerodrome warnings
    • Cloud and visibility
      • Surface visibility
      • Cloud, fog, and surface pressure
      • Visible satellite
      • Infrared satellite
    • Lightning
      • Triggered lightning.
      • Lightning  (this weather layer includes both observations and forecast)
    • Wind
      • Wind surface
      • Wind FL020
    • Precipitation
      • Precipitation rate (this weather layer includes both radar observation and forecast)
      • Precipitation type
    • Ground state
      • Visible satellite
      • Snow false colour satellite
    • Sea conditions
      • Significant wave height
      • Sea surface temperature
      • Surface current
    • Map Overlays
      • Lat/Long Grid
  • Text content of TAFs, METARs, and aerodrome warnings, where available, can be displayed in a dynamic list alongside the map, with contents based on locations displayed on the map.
  • TAF, METAR, and aerodrome warnings lists.
    • North England, Scotland, and Ireland
    • SE England, E Anglia, Midlands, and Wales
    • S England, S Wales and Channel Islands
  • Charts
    • Regional pressure settings
    • Surface pressure
    • F215 low level significant weather
    • F214 spot winds
    • Lee wave and rotors
    • British Isles analysis chart
  • Advisories
    • Volcanic ash advisories
    • SIGMETs
  • Notices - system notices are accessible from the page header.
  • PDF User Guide.
  • Feedback email via menu link.

Known Issues

The following items are known to exist and may be addressed in future releases of Helibrief® HEMS. There is no need to contact the Met Office if you encounter any of the issues listed here. All other issues identified should be reported to the Met Office at

  • HeliBrief® maps and charts are not optimised for printing. Most pages are printable, however some printer settings may need to be adjusted.
  • The map weather layer picker does not work for a specific version of Internet Explorer (IE 11.0.9600.16672). Updating to the current version from Microsoft will correct this.
  • The logout button in the menu will not log out the user, but will return the user to the Met Office My Services page, from where the user can log out.
  • Where a METAR is greater than 2 hours old, the map METAR colour can differ to that shown in the METAR list for up to 5 minutes.

Supported Devices

Desktop Platforms

  • Windows 7 with the latest versions of Chrome, IE11, or Firefox.

Mobile Platforms

  • iOS9 or later, using Safari, with a minimum screen size of 320×568dp (this is equivalent to the 4" screen of the iPhone5)
  • Android 4.4 or later, using Chrome, with a minimum screen size of 320×568dp.

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