Developments to the southwest

[xmetman]

Developments to the southwest

[Smartie]

Cloud top striations indicative of explosive deepening, there was a cluster of sferics ~ 15 UTC as the nose of the dry intrusion started to dig in.

[xmetman]

Dave, are developments going to plan with this feature?

[Smartie]

Looks like the GFS is too shallow by at least 4 hPa but that's not unusual. The GFS T+3 did not quite match the WV imagery at 15 UTC. Haven't looked at the ECMWF. The GFS handled the Zeus storm, coming out of the same area, earlier this year quite well at short  range, but not a similar one in 2015(?). One area where small errors (ie at the mesoscale) might impact is on any snow forecast for the SE tomorrow.

19 UTC- cloud hook formed, likely sting jet in the next few hours but only over the sea. Cold conveyor belt  will produce the strongest winds over land.,

[Smartie]

GFS T+6 pressure of 2 PVU surface overall is a good fit to the WV field at 18Z  (better than 15Z. 18Z UKMO analysis has a 976 hPa closed contour.

[Richard Dixon]

Fascinated with some of the structure in the Arome model - esp the high-velocity "streaks" over Biscay ahead of the main wind "hook".

Richard

[Smartie]

Should be a METOP pass about now, hopefully we'll be lucky and get some scatterometer winds.

D

[Smartie]

GFS has too shallow a centre and thus this is  displaced to the SE in the model. SLP centre should be in the dry slot  near the bent back warm front and tear drop shaped.

WV IR blend 21 UTC GFST+9 MSLP and surface ob.

[Smartie]

METOP B scatterometer pass timed at 2040 shows a strong CCB jet developed early, the patch of less strong winds (red barbs) between the hook and the cold front is likely the SJ.

[Trevor Harley]

I apologise for posting a lot but I've decided the only way I'm going to learn is by asking about things I don't know - and that's a lot!

 

Cloud top striations indicative of explosive deepening, there was a cluster of sferics ~ 15 UTC as the nose of the dry intrusion started to dig in

Cloud striations I think I get - just the visible appearance

explosive deepening - a low forms very rapidly

What though is a cluster of sferics - lightning?

A dry intrusion - a body of low-humidity air?

Trevor 

[Freddie]

Correct on all counts!

--
Freddie
Fishpool Farm
Hyssington
Powys
296m AMSL
http://www.fishpoolfarmweather.co.uk/
https://twitter.com/FishpoolFarmWx for hourly reports

[Smartie]

For explanation of some of the terminology see eg-

http://onlinelibrary.wiley.com/doi/10.1017/S1350482797000613/pdf

http://onlinelibrary.wiley.com/doi/10.1002/wea.2795/full

[Trevor Harley]

Thanks, I'll look.