Heat Bursts

I never noticed this rare ‘Heat Burst’ that occurred at Donna Nook in NENE North East Lincolnshire on the 25th of July 2019. I still have the hourly SYNOPs from the AWSAWS Automatic Weather Station at Donna Nook so I can construct a crude thermograph for that evening. As you can see the temperature surged to 32.2°C a rise of 10.2°C between 1950 UTCUTC Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently used prime meridian) and is not adjusted for daylight saving time. It is effectively a successor to Greenwich Mean Time (GMT). and 2050 UTC, at the same time dewpoints fell from 18.3°C to 12.6°C, with the relative humidity falling to just 30%.
This was called by a heat burst, the theory behind heat bursts are that they’re the result of a downdraught of very warm and dry air associated with a decaying thunderstorm. Worldwide they are very elusive, and in the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. extremely very rare mesoscale event indeed. You can read more about them on Wikipedia.
I came across the event after reading about it the book “Very British Weather” from the Met OfficeUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy, who says I never give them credit?

I did a search on Twitter and found that the Met Office did tweet about the heat burst the next day and included their own more detailed thermograph.

Now here’s a mystery, after downloading the archived SFERICs from BlitzortungBlitzortung Blitzortung.org is a lightning detection network for locating electromagnetic discharges in the atmosphere (lightning discharges) with very low frequency receivers based on the time of arrival (TOA) and time of group arrival (TOGA) method. for that day, I found there weren’t any! So what’s going on? Did a visiting holiday maker wild camping on the beach start a barbecue under the Stevenson screen just after 9pm? No, on running another query on Blitzortung I find there wasn’t a single SFERIC detected on the whole planet for that particular day! “Vorsprung Durch Technik” as they say in Germany.

No investigation would be complete without a plotted SYNOPSYNOP SYNOP (surface synoptic observations) is a numerical code (called FM-12 by WMO) used for reporting weather observations made by manned and automated weather stations. SYNOP reports are typically mad hourly and consist of groups of numbers (and slashes where data is not available) describing general weather information, such as the temperature, barometric pressure and visibility at a weather station. chart for the hour in question. As you can see despite what Blitzortung believes there were some heat thunderstorms around, and look to have been medium level affairs, after all this was the day that Cambridge set a new UK record for the warmest July day of 38.1°C.

One final curiosity about this heat burst concerns an AMOUK ship that turn up very regularly in the UK SYNOP reports. I say ship, but because occasionally they do report on land 😲. I still don’t know what they are or who they belong to, I guess they are some sort of mobile AWS which usually turn out very accurate observation for extended periods. I could write software to track them, but that’s another story. The reason I mention them here is that AMOUKo5 reported an even higher temperature at sea of 33.1°C with a dewpoint of 9.6°C, just offshore (53.5N 0.2E) of Donna Nook at 21 UTC. Notice too that the old Humber light vessel (03380) reported a temperature of 29.0°C at that time as well.