Polar Lows

[carinthian]

There have been some recent posts regarding timings of Polar Lows. Primarily a winter feature that is notorious to predict. However, some have occurred as early as October in the Norwegian Sea. Of all my time in the UK , I can only recollect viewing the development of one noticeable as it developed and that was way back in 1969. On February 7 th a severe blizzard developed across the Northern Isles with gusts of 118 mph recorded at sea Level. As the Polar Low slipped SE across Central Britain , a severe blizzard developed with much drifting.  I can recollect that in Cheshire on the morning of the 7 th after a very cold night the sky turned milky grey very fast and snow set in mid-morning with temp around -2c and by late afternoon nearly 20 inches of level snow had settled . The wind turned strong as it veered northerly and blew the snow into deep drifts and the temp fell to -7c by 5pm . The Polar Low moved out by early evening leaving a still star lite night.

The synoptics at the time showed a deep cold Arctic air mass plunge over the British Isles. Prior to the Polar Low development over the open sea close to the Northern Isles, the soundings up stream recorded a very cold air mass establish over Jan Mayern ( -20c at 850mb ) and( -45c at 500mb) So, certainly very cold air aloft is the catalyst for its formation but I would think for models to predict would be almost impossible more than 24 hours out. Trough lines or developments yes, but closed Polar Low with in the cyclonic family remains a bit of a scientific enigma  but a fascinating one. Having experienced the one as described is certainly a wonderful atmospheric phenomena. Good luck if you find one !

 

Edited August 24, 2022 by carinthian

[carinthian]

21 hours ago, carinthian said:

There have been some recent posts regarding timings of Polar Lows. Primarily a winter feature that is notorious to predict. However, some have occurred as early as October in the Norwegian Sea. Of all my time in the UK , I can only recollect viewing the development of one noticeable as it developed and that was way back in 1969. On February 7 th a severe blizzard developed across the Northern Isles with gusts of 118 mph recorded at sea Level. As the Polar Low slipped SE across Central Britain , a severe blizzard developed with much drifting.  I can recollect that in Cheshire on the morning of the 7 th after a very cold night the sky turned milky grey very fast and snow set in mid-morning with temp around -2c and by late afternoon nearly 20 inches of level snow had settled . The wind turned strong as it veered northerly and blew the snow into deep drifts and the temp fell to -7c by 5pm . The Polar Low moved out by early evening leaving a still star lite night.

The synoptics at the time showed a deep cold Arctic air mass plunge over the British Isles. Prior to the Polar Low development over the open sea close to the Northern Isles, the soundings up stream recorded a very cold air mass establish over Jan Mayern ( -20c at 850mb ) and( -45c at 500mb) So, certainly very cold air aloft is the catalyst for its formation but I would think for models to predict would be almost impossible more than 24 hours out. Trough lines or developments yes, but closed Polar Low with in the cyclonic family remains a bit of a scientific enigma  but a fascinating one. Having experienced the one as described is certainly a wonderful atmospheric phenomena. Good luck if you find one !

 

Here is a Reanalysis chart which preludes 24 hours of the above mentioined Polar Low development across The Northern Isles. It clearly shows the ingredients needed for formation :

a) Open sea surface.

b) Very cold 500-hpa dam up-stream as shown around Jan Mayern.

c) At least 528 dam 500-1000mb values established ahead of its track.

Easy as that !

 

Edited August 25, 2022 by carinthian
duplicated

[damianslaw]

I think the christmas eve 95 blizzard in the N Isles and far NE Scotland came courtesy of a polar low. That one tracked SE into the N Sea and grazed NE mainland Scotland only.