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This content is taken from the University of Reading & The Royal Meteorological Society 's online course, Come Rain or Shine: Understanding the Weather. Join the course to learn more.
1.5

## Come Rain or Shine

Skip to 0 minutes and 6 seconds Hello, I’m Sylvia Knight from the Royal Meteorological Society. Welcome to the course. In the course, we’ll be asking you to have a go at forecasting the weather once each week. Now at the start of the course, you may not have the first idea how to do this. But as the course goes on, hopefully you’ll find yourself applying what you learned, considering what’s going on in the atmosphere, and how that might affect the weather and the forecasts that you’re going to make. So where do you start? Well this is the web page on the Royal Meteorological society website, where you’re going to be inputting your forecast. And as you can see, we’re asking you for four different things.

Skip to 0 minutes and 39 seconds The first is the minimum temperature at the Reading University weather station during the day on the 16th of October. So you might expect the minimum temperature to come at night. And we’re asking you to forecast it to the nearest one decimal place, so you might be putting in a value like, I don’t know, 5.6 or something like that. Similarly, the maximum temperature is the warmest it gets through the 24 hours of the 16th of October. And again, it’s to one decimal place so you’re going to be inputting a value like 10.2 or something like that. Total rainfall is the amount it rains in total through the 24 hours of the 16th of October.

Skip to 1 minute and 18 seconds And then the tricky one is relative humidity at midday, so it’s the actual value of relative humidity that the weather station is recording at midday on the 16th of October. Now relative humidity is just a measure of how much water vapour there is in the air. If it’s 0% it indicates that the air is completely dry. And if it’s 100% that’s the level at which cloud droplets will start forming. And relative humidity changes as the air’s temperature changes, because water vapour condenses more easily in cold air than in warm air. In the UK, the relative humidity is usually above 50%. And if it’s been raining recently, you’d expect it to be over 90%, or maybe closer to 100%.

Skip to 2 minutes and 2 seconds So those are the four values we’ve asked you to forecast. Well, how are you going to– where do you start making a forecast? Well let’s follow this link to the weather forecast on the Met Office site. This is a weather forecast that was made on Thursday the 18th of August for Sunday the 21st, which I’m just using as an example. And on this day, the weather forecast– the temperature was forecast to be between 15 degrees and 20 degrees. And so, for my minimum temperature, well the one it suggests here is 15. For my forecast, maybe I’ll tweak that a bit and enter a value of 14.3. And similarly, the maximum temperature is forecasting as 20.

Skip to 2 minutes and 44 seconds Again, for my forecast, maybe I’ll just tweak that a little bit and enter a value of 20.4. Precipitation is trickier, because the forecast doesn’t actually tell you how much it thinks it’s going to rain. But all through the day the probability of precipitation, the likelihood of rain, is at 10% or less, so it’s fairly unlikely to rain. So I might guess that there’s going to be one light shower during the day and enter a value of 0.4 millimetres for my precipitation forecast. The humidity at midday, if we look, well at 10 o’clock, it’s forecasting a humidity of 73%. At 1 o’clock, it’s falling to 62%.

Skip to 3 minutes and 26 seconds So maybe I’ll guess something in between and put in a value of 65% for my forecast. Now for a little bit of extra information, I’m going to have a look at the forecast chart, also on the Met Office website. If this means nothing to you, don’t worry, it will do you by the end of the course. It will do, in fact, by the end of the first week. So this is a forecast chart issued on Thursday for midnight on Sunday, and it shows a couple of these purple fronts around, occluded fronts. Again, don’t worry if this doesn’t mean anything to you yet, we’re going to cover it very shortly.

Skip to 3 minutes and 59 seconds So these occluded fronts might produce some light rainfall depending on when they come across Reading and how strong they are. So I’m going to revise my rainfall estimate up a bit. I’m going to revised up to 1.4 millimetre. So if I go back to the forecast page, I’m going to enter 14.3 here is my minimum temperature, 20.4 here is my maximum, 65% for my relative humidity, and 1.4 millimetres for my rainfall. So let’s look at what the weather actually did according to the Reading University weather station on this Sunday the 21st of August. These were the values it recorded.

Skip to 4 minutes and 38 seconds And if we look at August 21st, you can see that the rainfall through the day, the accumulated rainfall, went up and the maximum was about 4 millimetres, so that’s quite a lot more than I forecast. Then if we look at the temperature graph, here again is August the 21st. You can see the temperature is this black line. You see the temperature going up in the middle of the day and down again towards the night. The maximum temperature was here just around midday, and that temperature is about 20 degrees, so my forecast wasn’t too bad. And if we look at the minimum temperature, that’s around here at night towards the end of the day.

Skip to 5 minutes and 20 seconds And again, it’s about 15 degrees, so my forecast wasn’t too bad there either. But how about the humidity? And so the humidity is this blue line here. Again, the humidity sank towards the middle of the day just before it started raining. And the minimum value that– so at midday, the humidity was in the high 50s, so maybe slightly lower than my forecast was. So our forecast wasn’t spot on, but it wasn’t terrible. If this is all new to you, don’t panic. Have a go. It really doesn’t matter what you enter.

Skip to 6 minutes and 27 seconds If the course is still running, you can skip forward to the current week and enter a forecast then, and then come back and work through this week’s articles and activities. But I’m afraid that if the course is finished, you won’t be able to have a go at this activity.

# Weather forecast game

Before you start the course, we’d like you to have a go at trying to predict the weather in Reading, in our game hosted on the Royal Meteorological Society website. Don’t worry if you don’t know anything about forecasting the weather yet! We’ve included a link to the official Met Office forecast for Reading in the game, which you may find helpful to look at and tweak a little for your first prediction.

We’ll give you the opportunity to make a forecast at the start of each week of the course, and, hopefully, as your understanding of the processes governing the weather improves, you’ll be able to make a more educated guess and see your score improve.

Your task is to try and predict four elements of the weather in Reading, UK for Sunday 24 June 2018. We’d like you to predict the following:

• The minimum temperature (in degrees C) to the nearest one decimal place

• The maximum temperature (in degrees C) to the nearest one decimal place

• The relative humidity at 12:00 (GMT) to the nearest whole number (%)

• Total rainfall to the nearest decimal place (mm)

What is relative humidity? This is a measure of how much water vapour (gas) is in the air, with 0% indicating that the air is completely dry and 100% being the level at which cloud droplets will start forming (assuming there are cloud condensation nuclei present, for the droplets to condense on to). Water condenses more easily in cold air than in warm air, so the actual amount (or absolute humidity) of water vapour in cold air with a relative humidity of, say, 70%, is less than the actual amount of water vapour in warmer air with a relative humidity of 70%.

In the UK, the relative humidity is usually over 50%. If its been raining recently, you would expect it to be over 90%.

You can find out more about humidity on the Met Office website.

What is UTC? UTC or Coordinated Universal Time is the precisely defined, world standard time. Please note you will see that time is measured as UTC on the Met Office website. For our purposes, it is the same as Greenwich Mean Time (GMT).

Please enter your predictions for this weekend on the link provided at the bottom of this Step and don’t forget to make a note of your predicted forecast so you can refer back to it. Make sure you submit your answers by 24:00 (GMT) on Friday 22 June.

Unfortunately, we have to set this as a cut-off point, to allow us to evaluate the forecasts. If you’ve missed the deadline for this week, you may wish to head to the current week of the course and submit your prediction for that week and then return to Step 1.5 to complete the course.

Please be aware that if you participate in the weather forecasting game:

• We will ask you to provide your FutureLearn user name so that we can record your score for you. You can choose to use an alternative username if you prefer (only identifiable to you). The username that you chose when taking part in the game, together with your score will appear in the report and will be visible to all participants in the course.

• We’ll compile and share the results from the game, each week, to help you evaluate your weather prediction skills.

• The data we gather from the weather forecasting game will only be used for learner feedback within this course and will not be shared outside of this course.

• When we report the results from the game back to learners at the start of each week, we’ll provide a list of everyone’s score, in alphabetical order by username within a PDF document.

• Scores will not be ranked.

Enter your prediction on the Royal Meteorological Society website.

### The results

After the weekend, you can return to this Step to find out how you did. You’ll be able to compare your results with our data, taken from the World Meteorological Organisation’s weather station at the University of Reading.

We’ll be running this forecasting game at the start of each week of the course, so keep tabs on your predictions to see if you improve. Don’t forget you can share your thoughts in the discussion area below, and if you think one of your fellow learners has made a particularly good suggestion/comment, let them know.

We’re looking forward to hearing how you get on and if you like, please use #FLRainorShine to join in with discussions about the course on Twitter, Facebook or Instagram.

## Update: Monday 25 June 2018.

We invited you to predict the weather of Sunday 24 June 2018. Take a look at the Results Table and Sylvia’s Results Summary to find out how you got on in the Weather Forecasting Game in Week 1.

Did you score higher or lower than you expected? We look forward to hearing your thoughts in the discussion area below. And don’t forget, you’ll have another opportunity to see if you can improve on your score when we repeat the game again in Weeks 2 and 3.