UKC

Weird weather feature

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 Phil Lyon 14 Jan 2022

On windy.com at the moment there's a particularly intense feature in the middle of the atlantic. 

Can anyone shed more light on the mechanics of the sharp line north/south that is visible on temperature, windspeed and most views.

https://www.windy.com/-Show---add-more-layers/overlays?54.392,-14.619,4

thanks

 martianb 14 Jan 2022
In reply to Phil Lyon:

Interesting. On the metoffice surface pressure charts it appears to be a rather elongated centre of a low pressure system

https://www.metoffice.gov.uk/weather/maps-and-charts/surface-pressure

Why it's like that i'm not too sure. Possibly due to the position of the cold/warm/occluded fronts

 MikeR 14 Jan 2022
In reply to Phil Lyon:

It's basically a fairly active low pressure system, you can see it marked on the midnight chart here

https://www.metoffice.gov.uk/weather/maps-and-charts/surface-pressure

When you have a very sharp wind veer like you are seeing here, it's generally indicative of a fairly active front, which basically means to expect more intense precipitation and a spell of strong gusty winds as the front moves over you.

The reason it's so marked in this case is partly do to the temperature contrast. If you look at the chart and follow the isobars back to see where the air is coming from, you can trace the warm sector air (i.e. the air following behind the red warm front) back to the tropical Atlantic/Sahara, while the cold air on the other side of the low has come from northern Canada (that's a bit trickier to tell, but you can trace it back by looking at previous charts here  https://www.wetterzentrale.de/reanalysis.php?map=1&model=bra&var=45&jaar=2022&maand=01&dag=14&uur=0000&h=0&tr=1440&nmaps=24#mapref )

The other reason is that there is a deep trough in the pressure pattern up at the jet stream level extending south from Greenland. This is engaging with the low pressure at the surface, enhancing the uplift of air in the low and deepening the low pressure system. You can kind of see it if you move the level slider from surface to 300 hPa.

 MikeR 14 Jan 2022
In reply to martianb:

The reason it's elongated is due to the SW-NE alignment of the front that it grew from (see the second link in my post above to watch it develop), and also because of the orientation of the tough that's driving it in the upper part of the atmosphere.

In fact if you look at the forecast chart for 1200 Saturday on the Met Office, you can see the trailing cold front extending south from the low has developed a number of lows on it, which may then form their own low centers. This is because this upper trough is elongating with sections breaking off it. These sort of events are quiet complex and always introduce increased uncertainty into the forecast.

 Flinticus 14 Jan 2022
In reply to Phil Lyon:

An ancient evil has awaken due to melting ice and is on the move. God help us all.

 martianb 14 Jan 2022
In reply to MikeR:

Thanks MikeR. Everyday is a school day.

 Phil Lyon 14 Jan 2022
In reply to martianb:

Really interesting insight, thanks.

 freeflyer 14 Jan 2022
In reply to Phil Lyon:

What MikeR said. Netweather is my favourite site for looking at the jet stream:

https://www.netweather.tv/charts-and-data/jetstream

ff

 wintertree 14 Jan 2022
In reply to freeflyer:

This is a great link for looking at different layers of wind etc.

https://earth.nullschool.net. I love the way the geography of the planet fades from the circulation patterns as you go up through the altitude layers.  At times, the doldrums are really visible as well at the surface layer.  The particles layers are fascinating as well.  Also the SST layer.  Well, all the layers really.


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