It's almost over by now but then it was always going to be over one day, wasn't it?
I will add the pictures at another date, my time is running out on here today. …
The small Low off Newfoundland on the MetOffice’s North Atlantic chart as of Sunday, 27 April, slips between two large Anticyclones (Highs) in the west of the North Atlantic by late Monday the 28th.
On Tuesday everything changes.
The large cyclone (Low) over Iceland moves ashore at Norway. There is a lot of occluded frontage on the charts for T+72; which, along with the making and breaking of set-ups portends seismic activity.
The North American EFS shows a set of Lows spread across Canada on the 27th April chart for the 28th. There is an almost unfailing connection with a line of Lows there and large seismic event elsewhere. The set up on the 28th however, is not a straight line on the chart. And there is a noteworthy relationship between earthquakes and tornado cells, where one seems to displace the other from time to time.
The following day the same model run shows there are just two Lows on the continent. This generally means that there will be a medium sized quake, something like a 6 to 6.5 Magnitude one. But again, there is a caveat. Out in the Pacific just off the chart, there appears to be another Low and this one makes it three in a line.
I am not familiar enough with the chart source to be more definite about the behaviour of the things yet.
The southern hemisphere pictured by the computers at BOM, Australia shows a not very convincing forecast for tropical storms. The cartouche is when a streamline around Antarctica forms with the 1016 millibar line running most of the way around the continent more or less following the outline of the place.
What throws it out is that the isobars hold two or three large weather systems that cause elongation. In fact I don’t think it ever really gets going, thanks to a mid Indian Ocean storm from T+36 on and another storm to the east of Australia over Santa Cruz.
This “nearly” storm (shown as a Medium threat in the Joint Typhoon Warning Centre’s image: ABPWSAIR (27/060 0Z)) follows a similar pattern (through the anticyclone in the Pacific Ocean) quite clearly seen from T+120 on.
After that, things go quite pear shaped with the rotation of storms around the Antarctic continent resembling the coils on the stator plate of an electricity generator (from T+150 on.) It will be interesting to see if this state of things is from where the development of tropical storms in the Northern Hemisphere can be said to occur. I have a feeling it is a semi annual condition. I can’t remember how long it lasts though.