Convective/Thunderstorm Discussion Autumn/ Winter 2023
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The Cold front looks a bit active during it's passage tomorrow night, might get a few storms, highlighted on weather forecast after the 21.00 news too.
Munster might have the best chance but could get some around the coasts also.
Weds has the upper Low and associated cold pool in over Ireland aiding instability which could see thunderstorms during the day with some big heavy convective showers, perhaps could see hail also.
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Any lightning reported around Galway this morning? Just spotted something large burning and falling from the sky in multiple pieces near Carnmore. Thought first it might be a pylon as there are some around there. I have some dashcam footage, not great but you can clearly see the bright orange glow from 2 objects. In person I could see a smoke trail behind them, they were falling/floating down slowly.
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Below is just a copy and paste from netweather. Sounds interning
Longwave upper trough extends south over the N Atlantic from Greenland and Iceland to the west of UK and Ireland on Tuesday. A surface low will be slow-moving to the south of Iceland, a cold front will move eastward across Ireland and UK through the day, lying across W Scotland, Wales and SW England at noon then N Sea and Low Countries at midnight.
Ahead of the cold front, the nose of 14-16C theta-w plume will push in across SE England / E Anglia through the morning. An area of elevatedinstability looks to develop on the northern extent of the plume across S England and E Anglia during the morning, as a shortwave trough moving infrom the Atlantic moves NE creating lift of the northern edge of the plume and steepening lapse rates. This will support the development of heavy showers and perhaps some elevatedthunderstorms moving NE over these areas through the morning and into the early afternoon.
Cold front across the west of mainland Britain at noon before moving east across the UK through the afternoon will also produce some convection, thanks to forced ascent of warm moist conveyor ahead of front, with a risk of isolated thunderstorms embedded in band of showery rain along front. Heavy showers and a few thunderstorms may also develop across Ireland, Irish Sea coastal areas and SW Scotland in post-frontal airmass characterised by colder upper air / steep lapse rates.
Convective Outlook ⚡ (meant to say brief, isolated tornadoes on map)
Along a cold front, a squall line looks fairly likely to set up Approaching Ireland and Scotland by around mid morning with widespread 90 KM/H+ winds along the cold front bringing squally winds and rain. Strong winds and heavy rainfall look to be the main severe threats.
As the morning gets on, the lift will increase along the south of England and along the squall line. So showers form and move through the central south and southeast of England in areas with 75+ J/KG of 3CAPE for some sunrise showers to form and move north east into the early afternoon potentially. This occurring along a shortwave trough, may bring the risk of some weak flooding with it.
The Irish risk continues on into S/SW Scotland with 150+ J/KG of 3CAPE along the squall line and 35+ knots of LLS. Large amounts of that momentum is shifted downwards and that may transfer into stretching the surface streeamwise vorticity. This may transfer into a local increase of the LLJ in certain areas, for some rotation along spots of increased vorticity. So some brief spin up tornadoes are possible.
Most energy looks to be transferred downward so the spin up tornadoes and strong wind gusts are fairly potential risks along the squall line. Mainly in the slight risk areas where squall line intensity and potentially lightning frequency looks to be increased. Eventually, the cold front weakens as it moves through Northern England and Scotland mid afternoon and lifts north, significantly weakening to essentially nothing by the evening.
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