Another last minute warning

Courtesy of UKMO

I can’t understand why the Met Office left it until the last minute again to issue a yellow warning for wind and heavy rain for the southeast after watching a series of line convection squalls embedded in the cold front as it moved eastward crossed the country, the first of which affecting eastern Scotland as early as 07 UTC yesterday. These late warnings seem to becoming quite the norm these days and do an injustice to the word warning which in reality they are not. The Met Office had already ignored gusts to storm force ten from eighteen sites earlier in the day and not issued a yellow warning, they occurred mainly but not exclusively at coastal sites in the west, accompanied by large rainfall totals (~80 mm) from the cold front across the high ground of western Scotland.

Wouldn’t it have been much easier to have just issued a blanket warning for the whole country
for squally winds and heavy rain on this cold front ?

But it seems that as soon as any extreme weather is likely to affect the southeast they can’t help themselves but spring into action, never mind that other parts of the country has been putting up with these kind of conditions for a good part of the day. That said it does look like yesterday evening they were just plain caught out by the heavy rain across the southeast. Looking at the warning area itself it barely covers the area to the northwest of London where the highest accumulations of 30-40mm fell, but to be fair this warning was for intense rain of 10 to 15 mm in half an hour. Which in itself is a strange kind of warning because some very heavy showers can produce these kind of totals in convective situations – so where the hell do you draw the line?

Estimated accumulations from weather radar

What’s interesting is that within 25 minutes of issuing the warning the Met Office tweeted with an animation of their mesoscale output showing the forecast intense rainfall. So why didn’t they think to act on it? Model problems again? It looks that the NWP model they did show didn’t have a good grasp of the actual situation at 20 UTC when compared to the weather radar at the same time.

The possible gusts of 50 to 55 mph on the coast mentioned in the warning were in fact on the low side, with a gust of 67 mph at Langdon Bay at 23 UTC, but then again similar gusts had been occurring as this cold front passed through places further north and west, and those gusts and heavy rain hadn’t attracted a yellow warning.

In conclusion

The Met Office warning system is in need of a complete rethink and overhaul. In my opinion they should scrap their impact based warnings system and reintroduce an automated threshold based system that’s directly linked to monitor the latest mesoscale NWP to generate warnings. They should introduce a web interface that uses a postcode based GIS to display the latest warning state in much the same way as the German DWD do now. At least then severe weather warnings will be issued promptly and impartially, hopefully the automated system will be also more proactive and issue warnings well ahead of time rather than the reactive forecaster based system we have at the moment, and just as importantly apply the same rules everywhere. It’s almost fifty years since I issued my first warning regarding “The snow now falling…” to the Duty Sergeant at some RAF station and it’s about time we accepted that we are now living in the age of the computer.

Courtesy of the DWD
Scroll to Top
%d bloggers like this: