Met4Cast

Completely agree. Having spoke to the deputy chief the thinking behind the amber thunderstorm warning was to avoid confusion with having multiple “weather type” warnings over the same area, i.e a rain & a separate thunderstorm warning. Personally, I don’t think it would have been too confusing to have the amber be a rain warning but, that was the internal thinking anyway, I’m sure they have the research data for it.

I’m somewhat surprised by the surprise by many on here that there wasn’t more activity during the early hours of this morning. The “event” went practically as forecast from where I’m sitting, the main risk was always from the initial area of rain / elevated storms that moved northwards and indeed did produce across parts of Sussex & Kent before fading. As per the above quote, the second area of more prominent rainfall that arrived 3-4AM was always likely to be limited in terms of lightning due to saturated profiles and very weak instability. The Met Office amber thunderstorm warning certainly confused things but it was primarily a rain warning with no mention of frequent lightning in the forecast text, unlike previous amber thunderstorm warnings which often highlight this. Certainly not a “bust” as far as I’m concerned, I’m not sure it could have gone more to plan.

Agreed! It seems by the time the second area of more intense rainfall develops the vast majority of the instability has cleared northwards. Main risk for thunderstorms in the southeast is almost certainly late this evening / 1-2am ahead of the rain event. Some sporadic strikes possible in the amber warning timing zone but rain is the biggest hazard, rather than thundery activity!

Agreed. The thinking is that having a separate “rain” warning within a broader yellow thunderstorm warning could be potentially confusing. I can see the logic, but perception of it isn’t great when there’s an amber thunderstorm warning and all most see is heavy rain. Difficult line to walk I suppose.

Yeah I wouldn't get too caught up over it being an "Amber Thunderstorm" warning. The text makes it clear that it's primarily for the rainfall with no mention of frequent lightning etc. An "Amber Rain" warning would probably be a better warning type vs thunderstorm, despite the possibility of a few sporadic strikes / embedded areas of convection within the broader rain band. Most will see "amber thunderstorm warning" and assume very active thunderstorms are on the way but that's not the case here.

Mitch the motorbike storm No - Doesn't look nearly active enough to be worth while honestly.

Atlantic breakdown The second round will likely be just heavy rain, the first batch of storms / rain that moves through uses up pretty much all of the energy. That said - It's only really the UKV going for it now with AROME & HARMONIE for example backing off significantly. Not personally expecting an overly impressive light show but certainly the risk of heavy rain & a few flashes!

Addicks Fan 1981 Given our rapidly changing climate it's increasingly difficult to forecast longer term, as Tamara used to say the GSDM / AAM isn't a magic bullet to forecasting. Personally, I'm finding increasingly that localised conditions are over-riding broader teleconnective forcing, we've seen this happen in the last few winters & potentially unfolding here too. Given how insane global SST patterns are at the moment it's impossible to say what impact these are having on weather patterns. The baseline is shifting. Rising AAM should, in theory lead to a settled/warm or even hot NW Europe yet NWP modelling continues to favour unsettled / westerly regimes. Interesting to see how this plays out. Original post: https://community.netweather.tv/topic/101615-summer-2025-forecast-and-model-commentary/?do=findComment&comment=5314632

Addicks Fan 1981 Given our rapidly changing climate it's increasingly difficult to forecast longer term, as Tamara used to say the GSDM / AAM isn't a magic bullet to forecasting. Personally, I'm finding increasingly that localised conditions are over-riding broader teleconnective forcing, we've seen this happen in the last few winters & potentially unfolding here too. Given how insane global SST patterns are at the moment it's impossible to say what impact these are having on weather patterns. The baseline is shifting. Rising AAM should, in theory lead to a settled/warm or even hot NW Europe yet NWP modelling continues to favour unsettled / westerly regimes. Interesting to see how this plays out.

Yes - You’d typically expect a 10-14 day lag phase between rising AAM & pattern changes downstream across Europe, hence end of July / early August the key period for the next potential hot spell, for example You’re quite right in that it’s too simplistic to say rising AAM = heatwave and high pressure, it is far more complicated than that but broadly that’s what we’ve seen. High AAM regimes favour warmer / drier summers, low AAM regimes favour cooler / wetter summers. Summer last year was a great example of a low AAM summer. This year has been quite odd in terms of the heat, we’ve been broadly in low AAM / Nina configurations which would typically favour cooler & unsettled patterns across NW Europe but we’ve seen the opposite. Part of this seems to be down to the anomalously warm SST’s across the Mediterranean & around the UK, but also persistent heat domes across N Africa, I think we’re fortunately not to have seen a classic heatwave plume thus far, personally SST’s globally are rather.. wacky at the moment, who knows what feedback mechanisms that’s generating or what impact this is having on the more typical teleconnections. Not sure I agree re: the later part of your post though, all three heatwaves across the UK have been a result of sinking air compressing & warming. The latest Met Office deep dive went into this with far more detail.

Off the charts.. Expect models to begin shifting increasingly towards an Azores high extension in the next 2-3 days. The bullet has been fired. Original post: https://community.netweather.tv/topic/101615-summer-2025-forecast-and-model-commentary/?do=findComment&comment=5313607

We can actually match the three heatwaves so far this year to increases in momentum. Note how the increases in AAM tendency occur just before heatwave conditions arrived across the UK. Despite this, total AAM has remained consistency in a negative regime which explains the broader westerly flow and the lack of sustained hot weather patterns, this is the reason we're yet to have a true Spanish plume type heatwave, the heat we have seen in the UK has largely been homegrown as a result of high pressure subsidence, pretty impressive that we've seen temperatures as high as we have, really. The biggest & likely most sustained increase in momentum of the summer is now underway. Modelling will likely begin latching onto this so I wouldn't be overly surprised to see more output similar to the AIFS beginning to appear. Late July / early August remains the broader landing zone. Original post: https://community.netweather.tv/topic/101615-summer-2025-forecast-and-model-commentary/?do=findComment&comment=5313730

We can actually match the three heatwaves so far this year to increases in momentum. Note how the increases in AAM tendency occur just before heatwave conditions arrived across the UK. Despite this, total AAM has remained consistency in a negative regime which explains the broader westerly flow and the lack of sustained hot weather patterns, this is the reason we're yet to have a true Spanish plume type heatwave, the heat we have seen in the UK has largely been homegrown as a result of high pressure subsidence, pretty impressive that we've seen temperatures as high as we have, really. The biggest & likely most sustained increase in momentum of the summer is now underway. Modelling will likely begin latching onto this so I wouldn't be overly surprised to see more output similar to the AIFS beginning to appear. Late July / early August remains the broader landing zone.

Very poor to the point that I don't use them. It's far better, I find, to anticipate rises / falls on the back of MJO activity & looking at hovmollers etc than it is to look at an AAM model forecast specifically. It also helps that MT events follow FT, i.e positive FT will lead to positive MT as the increase or decrease in momentum transfers eastwards. AAM tendency today is now through the roof thanks to +MT events. FT will soon be turning positive thanks to the MJO gaining some strength and transferring east, boosting westerly momentum at long last,. Knowing +FT is followed by +MT we can be fairly certain that we will be seeing a substantial rise in AAM now, this has been anticipated for a while (as per previous posts) but it's always important to see it occurring in real time as these charts show. Note the steady rise on total AAM, would expect this to continue with the low AAM regime now likely coming to an end. This surge in momentum should heavily favour an extension to the Azores ridge and the potential for something more sustained in terms of settled weather & potential heatwaves compared to the generally shorter lived hot spells so far this summer. This is perhaps a perfect example of teleconnections leading the models, i.e models have been consistent on going for unsettled weather in the mid-extended, I would expect now this real-time +ve AAM is being fed in that we'll begin to see a shift away from the unsettled regimes being presented within NWP modelling. Late July / early August a broad timeframe for this more substantial pattern change. Timing is one of the most difficult aspects when it comes to all of this stuff. Original post: https://community.netweather.tv/topic/101615-summer-2025-forecast-and-model-commentary/?do=findComment&comment=5313610

Very poor to the point that I don't use them. It's far better, I find, to anticipate rises / falls on the back of MJO activity & looking at hovmollers etc than it is to look at an AAM model forecast specifically. It also helps that MT events follow FT, i.e positive FT will lead to positive MT as the increase or decrease in momentum transfers eastwards. AAM tendency today is now through the roof thanks to +MT events. FT will soon be turning positive thanks to the MJO gaining some strength and transferring east, boosting westerly momentum at long last,. Knowing +FT is followed by +MT we can be fairly certain that we will be seeing a substantial rise in AAM now, this has been anticipated for a while (as per previous posts) but it's always important to see it occurring in real time as these charts show. Note the steady rise on total AAM, would expect this to continue with the low AAM regime now likely coming to an end. This surge in momentum should heavily favour an extension to the Azores ridge and the potential for something more sustained in terms of settled weather & potential heatwaves compared to the generally shorter lived hot spells so far this summer. This is perhaps a perfect example of teleconnections leading the models, i.e models have been consistent on going for unsettled weather in the mid-extended, I would expect now this real-time +ve AAM is being fed in that we'll begin to see a shift away from the unsettled regimes being presented within NWP modelling. Late July / early August a broad timeframe for this more substantial pattern change. Timing is one of the most difficult aspects when it comes to all of this stuff.