Stratosphere forecasts

Developments high up in the stratosphere can impact on our weather.

In the winter months a Sudden Stratospheric Warming (SSW) increases the chance of cold weather in mid-latitude locations such as the UK.

The stratosphere temperature and zonal wind forecast charts help show whether an SSW is forecast or is happening.

Stratosphere wind forecast

These charts show a flattened view of the northern hemipshere with the north pole in the centre.

The purple donut shape indicates the Stratosperic Polar Vortex (SPV). If an SSW takes place and the SPV is disrupted or destroyed the chance of cold weather in the UK is increased.

GFS 10hPa wind forecast for t+180 hours. Using GFS 00z run.

GFS 10hPa wind forecast for t+384 hours. Using GFS 00z run.

GFS stratosphere charts

View for all time steps

10hPa wind

• 00z
• 06z
• 12z
• 18z

10hPa temperature

• 00z
• 06z
• 12z
• 18z

1hPa temperature

• 00z
• 06z
• 12z
• 18z

GEFS stratosphere charts

GEFS is an ensemble model which means it is run many times to help account for uncertainty.

Each line on the charts represents the forecast from one of the GEFS runs for the next 16 days.

The GFS run (which the above charts are produced from) is also shown and is labelled "OPERATIONAL"

Zonal winds

If an SSW is forecast the zonal wind speeds will fall sharply and may become negative.

GEFS 10hPa zonal wind forecast at 60° north for the next 16 days.

GEFS 10hPa zonal wind forecast at 60° north for the next 35 days.

GEFS 10hPa zonal wind forecast at 70° north for the next 16 days.

Temperatures

If an SSW is forecast the temperatures will rise rapidly. They can increase by as much as 60C in a few days.

GEFS 10hPa mean temperature forecast at 60° north for the next 16 days.

GEFS 10hPa mean temperature forecast at 60° north for the next 35 days.

GEFS 10hPa mean temperature forecast at 70° north for the next 16 days.