Issued 2024-05-20 09:47:51
Valid: 20/05/2024 1000 - 21/05/2024 0600
Quite a complex upper and surface pattern over the next 24 hours, with an upper low over western France slowly drifting north while an upper level high over Scandinavia strengthens – this will serve to strength the cyclonic flow across central Europe into Tuesday. But for Monday, a generally slack pressure pattern prevails – which will encourage breeze convergence zones to set up – particularly across western Rep of Ireland along with western coastal areas of mainland UK. Surface airmass will be most moist across the island of Ireland, where dew points are forecast to reach 15-16C, this will yield around 500-1000 j/kg CAPE this afternoon with surface heating. This instability and the trigger of lift created by breeze convergence will support the development of heavy showers and some thunderstorms over the Rep. of Ireland and perhaps into western N. Ireland. There is a risk of localised flash-flooding along with hail where storms pass.
Elsewhere, airmass of mainland UK won’t be so moist as across Ireland, nevertheless, surface breeze convergence just inland across western and southern coastal areas could trigger some isolated heavy showers and perhaps a thunderstorm or too. Tonight, an area of mid-level instability is forecast to cross the North Sea from Netherlands / N Germany and spread across E England on the nose of an elevated warm moist plume pulled northwest and lifted through differential thermal advection, as upper flow strengthens – bringing some elevated heavy showers and perhaps isolated thunderstorms overnight.
Issued by: Nick Finnis
Issued by the Netweather forecast team whenever there is a risk of storms or severe convective weather, these discussion based and in depth forecasts will highlight the areas at risk and give an in depth description of the risk and the factors surrounding it.
