BenW

Okay that's helpful, thank you

Latest UKV available in the model viewer is 21z on 31/03. It's now 14z on 01/01 so we are missing three updates. Any idea what's happening?

Can I make a suggestion to the Netweather team? When you issue a storm forecast or some other publication with a timescale, can you avoid using the time 00:00? So instead of 13/10/23 00:00 - 14/10/23 00:00 use 13/10/23 00:01 - 13/10/23 23:59. It will save a lot of confusion.

But if that were the case wouldn't you expect to see rain close to the radar head increase by more than rain further away? What I'm seeing is rainfall in the sea 150 miles west of the radar head suddenly increasing by exactly the same amount as rain at the radar head.

I made another recording, this time just toggling forwards and backwards either side of the jump. It occurs across a very wide area not just over ground or near the radar head so nothing to do with that. It's almost like the scale changes. Screen_Recording_20231012_235312_Chrome.mp4

Something I have noticed on several occasions in the past is that the intensity of rainfall showing on the radar in a large area off the south west coast of England suddenly changes between 5 minute increments. The jump seems to be more than natural - it's hard to believe that rain actually increases by 4mm/hr simultaneously and uniformly over a 100sqm area. I recorded a video clip which will hopefully work. If you look at the area of heavy rain south west of my location (the triangle) it suddenly increases between the 4th and 5th step. I wondered if there is any technical explanation for this? Recording 2023-10-12 222854.mp4

Brilliant stuff, thanks for letting us know Paul.

Okay, thank you. Not just me then! I'm no good at forecasting these waffly non-descript high pressures over the continent so rely on the UKV to give me a hint at whether it's going to be one of those moist, overcast, claggy sorts of high pressures or wall to wall sunshine!

Hi All, Is it only me or are the UKV long range models not updating? The 03z today and 15z yesterday are not available. It's been impossible to see a forecast beyond 54 hours for the past few days.

Okay thanks. Whilst you're here.... I've always wondered what happens in areas where radar coverage overlaps. Presumably the system is clever enough not to overlay them on to of each other and show rain twice as heavy in the overlap area but then it also needs to work when one of them is out of service. Any ideas how it works?

Is there an outage with the radar covering the South West of the UK? It's rained four times now, once overnight and three times this morning and nothing at all showing on the radar. Admittedly it was light rain but enough to register on my rain gauge. I've seen rain on radar that doesn't reach the ground before but not the other way around!

Well, I look at the models every day (and have done for 20 years) and I would have issued a warning both days if I was in the chair. The high lapse rates, shear and warm unstable moist air over the Atlantic all highly suggestive of line convection. It doesn't always show up on the precipitation graphic that well (though I thought it did a pretty good job of it today). I also noted that a couple of outlets (e.g. Torro and Estofex) thought the conditions were conducive to isolated tornado activity (and indeed there was at least one reported in South Wales) I'd be interested to know what you saw in the UKV that led you to the conclusion the forecast was unremarkable?

Weather is inconsistent! I'm not sure how else I can explain this to you. The warnings are all about probability in the forecast. Looking back after the event and expecting to see consistency in the warnings vs what actually happened is madness. What you don't mention about the previous warning is that as well as saying there will be some typical autumnal weather they also said there was a likelihood of isolated torrential rain and gusts and that was the reason for the warning.

There was a need because the forecast indicated a medium/high likelihood of squalls. The fact that in the event the squall didn't develop in your specific location is irrelevant. This is the nature of weather forecasting - it's a game of probability. Imagine splashing water on the floor. It's impossible to predict exactly where all the drips will land. You'll be able to accurately identify an area that will definitely contain drips. And you'll probably be able to identify areas more likely contain a lot of drips vs areas that will only contain a few. But you couldn't point at a 10mm square and say with certainty that it will be wet or dry. It's the same with forecasting. I can understand people criticising MO for issuing/not issuing a warning when their interpretation of the forecast models suggests one is not needed/needed. That happens constantly in the profession and professional meteorologists are always open to the discussion. But there's absolutely no sense in criticising them after the event. It's like waiting till the end of a horse race and criticising anyone who didn't back the winning horse.

We have a good case in point happening right now. For the past few days days, all of the UKMO model runs have been saying there will be an active front with enough shear to cause a squall running from Northern Ireland to the Bay of Biscay. Squalls are unpredictable and capable of causing flash flooding and taking tiles off roofs etc. so MO issued a yellow warning for a large area covering the whole length of the forecast squall line. Now it is close enough to see on radar it appears the front is quite dispersed towards the southern end so we perhaps won't see an organised squall line in Cornwall/Devon/Somerset. I fully expect that some people, with the benefit of hindsight, will say later today that it was nothing and MO shouldn't have issued the warning in their area. This is really a fundamental misunderstanding of both how the warnings work and how weather forecasting works.