PersianPaladin

Trusting GFS past the T192 mark is sort of like trusting Sauron's Ring Of Power. The ring must be destroyed! Meanwhile, tonight temps could get as low as -9C in parts of England. Let's not forget that there is substantial cold not too far away.

I was there, Nick. I was there on that fateful night in the wee small hours when the 00z came out. The Fat Lady was finally untied from her chair thanks to that "poxxing short wave" (in Steve Murr's words) which showed up in exactly the wrong place. Seemingly out of nowhere.

Those of you who have been following the Model Diagnostics Discussions on NOAA for several days and weeks now - will realise that there isn't really a preference for the Euros within the short time-frame of T90. As far as the extended time-frame is concerned, its really too close to call. Though a model blend is usually preferred.

Beast From The East........

We actually have had snow grains falling already up here in parts of the North and North East. Some really interesting local variations produced by a mix of lower level wind flows and regional geomorphology. Its white enough outside to suggest a dusting of snow over here.

06z....

"INTERESTING" is the one word that does sum up the models of late. Certainly not boring, at least from the point of view of those interested in the technical side of weather prediction. There is a lot that can change, and within a surprisingly narrow time-frame.

Yup...the words dogs' + dinner came to mind.

Latest model diagnostics discussions at NOAA seem to prefer the ECM solution for the development of the amplified upper trough out towards NE US/Canada and towards Greenland. Still some difficulty modelling the progression and orientation of that feature, which matters as far as our northerly shot is concerned. http://www.wpc.ncep.noaa.gov/discussions/pmdhmd.html

I think given the rather dynamic and changeable conditions even before T120, it would perhaps be worth easing up on the ramp rollercoaster... Anyhoo, Camelot is quite a while away..... https://www.youtube.com/watch?v=m3dZl3yfGpc

Does one expect massive changes at that time-frame? lol

The positioning of that high involves quite a small margin of error, and given the time-frame - expect quite a few runs before we can even have much in the way of confidence.The northerly is not what interests me at present, its the reloading pattern, the stability of the upper-wave pattern into Greenland, the extent of WAA, and all else besides. The pattern for that is yet to be made clear. The ECM ensembles will be of great interest this evening.

Yes, indeed. I think a toppler northerly is pretty much nailed-on, though its a question as to how quickly the trough ebbs away and is filled in by height rises from the west. 24hrs? 48?hrs I'm going for a slightly more extended toppler than yesterdays GFS charts were showing, as opposed to the previous ECM. What happens after that, with the High directly over the UK or slightly to the North of it; remains very much in the balance. But with significant cold trapped under that high, it could still produce some significant ice-days in some places.

Yes, the 12z GFS really is the cold-pornographer out in FI at the T200+ plus mark. Though what that really suggests in terms of a significant change in upstream signal, remains to be seen.

Yup, but as several others have said - its really what happens into the 2nd week of January that will more likely be of relevance. A little too much mobility hindering suitable jet amplification that can be sustained for more than 48 hours. More likely the ECM remains an outlier in the T120-144 timeframe and will correct itself in the next run.

The signal so far for this winter period has been for an unstable and oft-amplified upper jet, though where that ends up and whether we get that mythical north-african descending arm; waits to be seen.... At T90 lies the first disturbance point where the northern-jet starts to begin to break off and send a little energy southward. At that same time we have a very complicated and dynamic picture of emerging shortwaves, ridges and other features. Changeable certainly, even before T126. But here's hoping...

Latest NOAA long-term forecast discussions indicate the UKMO showing a competitive presence amongst the other models in terms of confidence, however, there is no clear model that is favoured at the moment. So frankly, the GFS could still win out in this scenario. But we don't know that yet...

Yup, like I said before - the T144 time-frame is particularly messy and complex and will take a while to be resolved.

The dreaded "slug", i.e. the Bartlett High is still very much in F.I at present. What happens after T144 is anybody's guess, given the highly complex picture present along with uncertainty as to how much that upper-jet energy increases and to what extent/orientation it bifurcates. For the time-being, expect some cold and settled blocking near or over the UK.

Looks like north-east england, at least my neck of the woods anyway - will be getting sloppy-seconds of heavy rain with the odd rumble if lucky.

Very loud rumble outside here

I only support giving them names on two conditions: 1. That they don't sound like some senile old character from a british soap (Storm Desmond?), and 2. That the names be amusing and memorable (e.g. Storm Wilberforce The Wild, Bertha Bedlam, Horrid Hilda, Rick Astley etc) https://storify.com/weatherchannel/twitter-offers-twc-rejected-names

Yes, and a lot of lightning flashes over there. Really has kicked off. The MetOffice did not forecast "thundery rain" there, so they got it wrong.

Up here in the north-east of England - namely County Durham, there have been at least a couple of occasions this year with some decent storm activity. None of them occuring in my area though, as per usual. There is a storm-shield or force-field around Durham City, keeping overhead lightning away. Doesn't matter how good conditions are regionally, you can guarantee that any cell from the west or the south-west will fizzle as it crosses here, or....INFURIATINGLY....weaken over me whilst strengthening on the western or eastern flank, or entirely weaken and then invigorate again once the drizzle and odd rumble have crossed over. I had a good mind to study the possible micro-climate factors that led to this continual block against storms, but got too depressed to bother. If however, a storm happens to encroach from the south-east (very rare mind), then it's sometimes impressive. But these usually happen outside summer.

I've seen forecasters say this with respect to thunderstorms from France moving northwards and decaying over the Channel, only to sometimes regenerate over the surface of southern England. Yet, this occured at night when surely most of the insolation had gone? Or perhaps there is residual insolation, wind shear, etc? I'd love for the forecasters to stop and give a good explanation as to what exactly was behind that "regeneration". Whether it was a case of clusters of cells with generally weakening updraughts and strengthening downdraughts experiencing a change of dynamics when hitting the coast, acting as "seed" cells for other forms of convection, etc. There should be some case-studies of this.