chionomaniac

Mike, if you compare today’s ECM runs looking at southern Greenland, you will see a massive swing towards greater heights in this area. If that’s the trend.........

ECM certainly not zonal tonight. Been waiting for this type of change earlier in the run for a while. The next Atlantic low ‘should’ head in the same direction as the first but with better cut off ridging to its north.

I know, I must be. The two area were increased amplification off the eastern USA and evidence of the Atlantic low becoming cut off with better heights into eastern Greenland. Hence the better negative inclination at T+96. Small changes at the start of a run can have bigger implications down the line

I’m waiting for the next frame to run for the ECM. Now I know that there is a 12 hr disparity for direct comparison with the previous run, but I see two areas of improvement already by T+72....

Anyone who wants to learn more about the mechanisms of heat flux associated with trop wave activity interacting with the strat would do well to read these series of tweets by Amy. Brilliant explanation.

No, as BA has suggested we then need to look at the tropospheric precursors to wave 2 activity and these are looking promising. I would be looking at initially week 3 ( end of) and thereafter for potential, subject to wave 2 activity creating a significant strat event. Without this keep watching because I see a Scandi ridge being a theme this winter.

That was going to be my next point, because it is exactly what we want to see.......

I would say that it is the other way around. Wave 1 displacements are perfect primers for weakening the vortex followed by a wave 2 chop. The wave 1 SSW's as you said are poor for NW Europe and that will still probably be the case without another wave 2 following on behind, and this is where I would be looking for strat PV destruction.

That just shows the extent of warming and not the vortex profile. And it is indicative of a displacement type warming from wave 1, not a wave 2 type split event. And it would still be a bit short. When looking back previously at wave 1 type SSW's there are two types. One, where the vortex loses power, dis[places off the pole but quickly regains strength and recovers the pole position in a relatively short time. The other is rarer and occurs when the warming is so significant that rather than just getting displaced, it is completely destroyed and it takes it a long time to rebuild. It is the latter type of displacement that will have the greater chance of a significant tropospheric response.

If you hadn’t looked at any previous output this autumn (especially FI) and this was the first run you had looked at, then you would say that in the first half of the run the building blocks are in place and it wouldn’t take much for a notable cold spell to develop. That doesn’t change by looking at the second half of the run. It won’t take much to change from retrogressive nothingness to something far better. When the Scandinavian block is in place, then we need to look upstream and get the right split flow from the tip of Greenland to reinforce the block. Small margins that can change in the coming runs. And nice to get rid of the mild drizmable weather of today.

We need to be looking West in these scenarios. At T+168 the potential is still there

Just had a look at the video I took prior to the one above and have screenshot some lightning photos. Can anyone see the possible tornado a full five minutes before we turned the corner and saw it on our right? Photos 3,6&7 Last photo shows nado on the ground

Here is a video yesterday of the lead up and of the tornado which dropped next to us whilst we were under the meso. sorry about the upside down bit - I was holding 2 devices recording at the time whilst trying to ensure that the tornado didn’t cross our path. On another note, when we noticed that the stream had dropped out the computer needed to be reloaded and then chose to reupdate itself at that critical moment with the signal dropping out. We were in an extremely dangerous position where everyone needed all there wits about them as the radar grab shows.

Getting a bit excited now. I leave early tomorrow. I’m cautiously liking the trend in the models with a surface trough building towards the west of the central plains by the weekend. This should allow enough moisture to be sucked up from the GOM. interestingly there is a gfs tornado signature for the first three days happy with that so far

I can’t wait. Do you have a list of preferred model sites and essential chasing sites? I probably know most of them but may have lost a few - such as those giving out real time dew points Cheers.