Met Office, Severe Weather Warnings
The information below is taken from the official guidance provided on the Met Office website.
MET OFFICE, NATIONAL SEVERE WEATHER WARNING SERVICE
The Met Office provide the UK’s weather warning service. They are a Trading Fund within the Department for Business Innovation and Skills and operate on a commercial basis. The Public Weather Service provides forecasts for the public to help them make informed decisions about their day-to-day activities. The National Severe Weather Warning service is part of this, providing advance notice of weather which could affect public safety. Members of the public can sign up to receive Met Office warnings by email by going to http://www.metoffice.gov.uk/
Understanding warnings
This section introduces the basic concepts of the warning service i.e. when and why warnings are issued; what for; and what they mean.
Timescales
Warnings are available up to five days ahead for the UK.
Types of warnings
There are two types of warnings:
- Warnings – issued up to 24 hours ahead
- Alerts – issued more than 24 hours ahead
Weather types
Warnings and alerts are issued for the following:
- Rain
- Snow
- Wind
- Fog
- Ice
Warning level
Warnings and alerts are based on a combination of:
Likelihood – how likely the event is to occur
Impact – the potential impact the expected conditions may have
Colour of Warnings
A combination of likelihood and impact is measured against a matrix to give each warning or alert a colour:
- Red
- Amber
- Yellow
- Green is used to indicate that no alerts or warnings are in force.
Chief Forecaster’s Assessment
In addition to the warnings, the Chief Forecaster’s Assessment explains why the warning or alert has been given the colour it has, as well as indicating where any uncertainties lie. Further information and advise can be found on their website at http://www.metoffice.gov.uk/ including details of any current weather warnings in force.
HEAT-HEALTH WATCH SYSTEM
A Heat-Health Watch system operates in England and Wales from 1 June to 15 September each year in association with the Department of Health and the Welsh Assembly.
The Heat-Health Watch system comprises four levels of response based upon threshold maximum daytime and minimum night-time temperatures. These thresholds vary by region.
For the West Midlands region the threshold temperature is 30 °C by day and 15 °C overnight.
Green — Summer preparedness and long-term planning
This is the minimum state of vigilance during the summer. During this time social and healthcare services will ensure that all awareness and background preparedness work is ongoing.
Yellow — Alert and readiness
Triggered as soon as the risk is 60% or above for threshold temperatures being reached in one or more regions on at least two consecutive days and the intervening night. This is an important stage for social and healthcare services who will be working to ensure readiness and swift action to reduce harm from a potential heatwave.
Amber — Heatwave action
Triggered when the Met Office confirms threshold temperatures for one or more regions have been reached for one day and the following night, and the forecast for the next day is greater than 90% confidence that the day threshold will be met. This stage requires social and healthcare services to target specific actions at high-risk groups.
Red — Emergency
Reached when a heatwave is so severe and/or prolonged that its effects extend outside the health and social care system. At this level, illness and death may occur among the fit and healthy, and not just in high-risk groups.
Advice: If you want more information about hot weather and your health please visit www.nhs.uk. If you are concerned about your health or somebody you care for, please contact NHS Direct on 0845 4647, www.nhsdirect.nhs.uk or your local pharmacist. Heatwaves can be dangerous, especially for the very young, very old or those with chronic diseases.
More advice on what to do in a heat wave is available on our heat wave advice pages
COLD WEATHER HEALTH WATCH SYSTEM
A Cold Weather Health Watch system operates in England from the 1 November to 31 March every year, in association with the Department of Health.
The cold weather health watch comprises four levels of response based on cold weather thresholds. The thresholds have been developed to trigger an alert when severe cold weather is likely to significantly affect people’s health. The alerts take account of temperature along with other winter weather threats such as ice and snow.
A range of important information can be found at the Staying warm in winter website at www.direct.gov.uk/en/HomeAndCommunity/InYourHome/KeepingSafeAtHome/DG_10027755
Threshold Values
There are three different thresholds for the cold weather health watch. Only one of the three thresholds needs to be breached for a warning to be issued.
The thresholds were developed, working closely with the Department of Health and the Health Protection Agency, to pinpoint when winter weather will affect people’s health.
The thresholds are:
- Mean temperatures below 2 degrees Celsius for 48 hours or longer
- Heavy snow
- Widespread ice
Green – Winter preparedness and long-term planning
This is the minimum state of vigilance during the winter. During this time social and healthcare services will ensure that there is ongoing awareness and preparedness.
Yellow – Alert and readiness
Triggered by the Met Office as soon as the risk is 60% or above for any of the three thresholds to be breached. This is an important stage for social and healthcare services who will be working to ensure readiness and swift action to reduce harm from a potential period of cold weather
Amber — Cold weather action
Triggered by the Met Office when we are experiencing weather which breaches any of the three thresholds. This stage requires social and healthcare services to target specific actions at high-risk groups
Red – Emergency
Reached when a period of cold weather is so severe and/or prolonged that its effects extend outside the health and social care system. A level 4 warning would be issued on advice from, or in collaboration with, our Government partners. At this level, the health effects may occur among the fit and healthy, and not just in high-risk groups.
Advice: If you want more information about how cold weather can affect your health please visit www.nhs.uk. If you are concerned about your health or somebody you care for, please contact NHS Direct on 0845 4647, www.nhsdirect.nhs.uk or your local pharmacist. Prolonged periods of cold weather can be dangerous, especially for the very young, very old or those with chronic diseases.
For more information on how to prepare for cold weather, snow and ice visit our Snow and Low Temperatures advice pages.
