Summerstorm

Sleety here with quite a few snowflakes mixed in now.

It would help us if you gave a little more detail on your location such as your elevation as NW Wales is a big area

Great chart would be even better if the high was slightly Futher north and tilted NW-SE instead to allow the Arctic air out over Siberia to sink into Scandinavia and over to us. As otherwise it drags milder air into eastern Europe from Georgia and the Black Sea. Although it is unlikely to come off like that at that time frame so this is all academic at this stage.

Think the GFS OP is having an exerstential crisis. Scandi High or Greenland High which do I prefer?

GFS not quite as good as the UKMO, looks good at 120 like the UKMO but then blows the low up and elongates the low in the mid Atlantic. Although it does have that similar little low over Italy which may become helpful if that strengthens to keep the AH out of Southern Europe. It does drop the cooler air around +144 but the AH ridging back into S Europe stops the low from sinking and introduces milder air. One thing to notice is can we eek out any extra amplification at +120 as seen on both runs to help us especially without blowing up that low pressure to the east of us and whether we can get a favourable angle from the low exiting the US to get some WAA to assist the Atlantic Ridge. Secondly the GFS P looks better doesn't blow that low up and in turn keeps some of the cooler -6 air in and brings in a nice slider around Day 7 although feels academic at that stage. In my opinion follow the OP GFS up to 120/144 hrs then follow the Parallel from there.

We aren't focused on that part of the run what we are focused on is the 120/144hr time mark what we are looking for is for the two lows not to phase and to avoid any shortwaves from the Eastern US and Scandi Low's. Therefore we maintain a better Atlantic Ridge this means that the Greenland high is stronger and thus hopefully pushes the pattern further south allowing cooler northerly air to drop down behind it. Otherwise if we don't maintain that high or it doesn't get reinforced by the artic high then the jet stream gets forced further north again and we end up in a SW air stream as a consequence as the Azores High starts ridging into Iberia again.

Looks the Para is interested in throwing up another ridge around D11 which would be helpful to drain heights out of Iberia and Italy Although it's all a bit academic at that range unfortunately the LP on the eastern seaboard is too strong and the ridge collapses. But I am merely speculating at this point. Also looks like @Battleground Snow beat me to it

The GEM at +144 looks pretty similar to the GFS except for the better ridge on the latter from the AH in the Atlantic keeping the two lows separated and creating some nice WAA up the eastern side of the low. Overall the GFS looks better imo as can be seen from the charts being posted around Days 9-11 with some cooler air around -6/-8 in the mix. The other thing of note is the possible link of heights across eastern europe to the Arctic high on the GFS also wonder if that is something to keep an eye out for?

Hopefully the Aleutian Ridge out in the Pacific will help and reinforce the Arctic/Greenland high if we can get sufficient WAA up the W of USA and push some of the colder air our way.

Yep that'll be a big factor plus they have a more continental climate than us and it is hundreds of miles in land so less mixing of the air from the milder sea from the Med or Atlantic also this is unlike what we have from the Irish and North sea as the farthest you can get from the sea here is only 70 miles.

Yeah can we have some more snowfall there's not a single flake on the ground here.

Well hardly anything stuck last night and it's all melted now so a bit of a let down here especially seeing videos of some many areas within 10 miles or so with a covering.

Snowing here now turned to flakes about 10 mins ago

Snowing here now as well turned from sleet to flakes.

Bit highlighted in red just a quick grab from Google Maps. A bit like Hants for Hampshire or Notts for Nottinghamshire to add a couple more examples. Anyway moving back to the topic still awaiting to see where this Wales cell heads seems to be moving at the speed of a snail.

Oxfordshire Shortened version of the county a bit like Hants for Hampshire

Had constant flashes here for the last 2 hours what a show. Had some torrential hail about 45 mins ago and some lovely overhead bolts. Now watching it move away and seeing the flashes lighting up the clouds.

Got a lovely view of the lightning flashing inbetween the clouds as it moves away.

Literally constant lightning and occasional thunder overhead. I could be stupid but I swear I can see a funnel cloud or some crud trying to descend as the sky lights up with flashes. Here is a phone video from a few mins ago. VID_20200810_234354.mp4

Most of the precipitation has gone now but we still have constant T&L overhead seen a few bolts nearby. Quick video showing the strobe lightning show. VID_20200810_233831.mp4

Really heavy hail now really load rumble of thunder just and some lovely bolts of lightning across the sky.

Seeing some lovely bolts overhead now and hearing some thunder just started hailing as well.

Yep and a lovely round of verbal abuse going on down the road ruining the silence

Seen a couple of bolts overhead just and had a rumble of thunder.

Quick video of some of the lightning here. Taken with my phone so not sure how good it will look. VID_20200810_225851.mp4