A heat wave coming?
If you follow social media or read the tabloids, you won’t have missed the headlines over the past few days that a tropical heatwave is looming for the UK next week.
Is this true and how hot will it get?
What are the rumours?
Some publications report a UK high of 40ºC around 16 July.
That’s because one of our supercomputer models on Saturday 2 July – for the first time ever – produced a scenario where parts of the UK could experience high temperatures of 41ºC later next week.
If that happens – unlikely – it will be unprecedented.
The fact that a computer model is even predicting a temperature of over 40ºC in the UK is the first and alarming sign that climate change predictions are becoming reality.
Hottest UK forecast on record – GFS Computer Model Forecast for 16 July as of Saturday 2 July 2022 Credit: Data: GFS. Website: www.wetterzentrale.de
What is computer modeling?
To predict the weather in advance, meteorologists use mathematical predictions made by supercomputers called computer modeling.
There are several of them around the world, each using historical data and ground observations to give a possible scenario for the coming weather – based on probability.
In the UK we have a Met Office supercomputer. This takes about half a million observations per day. When there is no data, the computer will fill in the gaps.
The closer we get to the forecast day (or event), the more accurate the model becomes – because there is more information.
Sometimes models differ. Sometimes everyone agrees.
Currently, the majority of models highlight a “warming trend” starting late this week and continuing into next week. But the 40ºC scenario – thankfully – seems unlikely.
More likely scenario (as of today) – GFS computer model forecast for July 16 as of Monday, July 4. Credit: Data: GFS. Website: www.wetterzentrale.de
What is the reality?
Remember that the model’s forecast was nearly two weeks ahead. Today, Monday 4 July, after only 48 hours, the temperature forecast for 16 has already dropped by more than 10 degrees.
But a drop of 10 degrees could still see parts of the UK heat up to around 30ºC later next week.
This is higher than the UK Met Office’s threshold for a heatwave and higher than the July average.
UK heat wave threshold (3 consecutive days or more) Credit: Met Office
So at this stage we are looking at things warming up from the end of this week, with heat wave criteria likely to be met later next week.
It’s July. Heat waves are becoming more frequent. 30ºC is not as unusual as it was a decade ago.
And as we get closer, day after day, the computer models will adjust their predictions using the latest information.
Follow the predictions, not the gossip!
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