THU 22 OCT 2026 - mesocast.uk/forecast/?date=2… - valid until FRI 23 OCT 06Z Storm Austin peaks in intensity with storm force winds and damaging wind gusts in excess of 90mph approx. 400 miles offshore of Cornwall at 13Z on Thu 22 Oct. The strong cyclonic circulation approaching in association with Austin facilitates robust warm air advection and very warm moist air characterised by dew points 12-14 C, heights aloft are forecast to readily decrease with the cold pool sharpening toward evening. Approx 17Z in the evening a developmental left exit jet-streak at 200hPa moves close to or over Cornwall encouraging increasing upper level divergence and further height falls. A complex combination of strong vorticity associated with a robust cyclonic regime, increasing moisture advection from the S, unseasonably warm SSTs and rapidly cooling air aloft helps facilitate rapidly steepening mid-level lapse rates and increasingly unstable profiles. Given very high wind-shear associated with robust mid to upper flow and instability below organised convective activity is likely to pursue. The largely saturated profiles are likely to be some-what challenging in lightning production and so there remains some question marks over lightning coverage, but given the strong kinematic flow and enhanced instability (especially over the warm SSTs) offshore, some embedded elements could achieve sufficient convective depth for the development of torrential downpours to become thundery. Should sufficient convective depth be achieved, most likely initially offshore and across Cornwall from 18Z through the late evening period, then isolated marginal severe thunderstorms are plausible with main threats being stretched vorticity induced water spouts, funnel clouds or brief tornadoes, hail, and damaging wind gusts in excess of 55mph, perhaps as high as 70mph offshore or around immediate coastal areas of the extreme SW of Cornwall for example. Additional hazards will be extremely heavy rainfall and localised flash flooding and pockets of lightning. This marginally severe convective threat migrates E into Devon and along S Devon coasts toward the IOW areas up until midnight. Again it is probably worth emphasising that the highest likelihood of lightning should be across the Channel and slightly offshore under those higher SSTs, however given flow state any development that occurs will easily move ashore - especially across Devon and Cornwall. It is also worth noting that optimal mid to upper level flow phasing with optimal moisture and lift occurs across the English Channel likely post peak of Austin, despite the unlikelihood of sting jet induced surface winds Jersey and Guernsey in particular should be alert to the enhanced threat of isolated supercells capable of producing extremely damaging winds, strong tornadoes, hail and torrential rain through approx. 02-06Z Fri AM. It would require unlucky phasing for this to occur given the relatively small island sizes of the Channel Islands, but the risk should still be highlighted given recent history in similar events.

FR| 09 OCT 2026 - mesocast.uk/forecast/?date=2… Heavy showers and a few isolated thunderstorms are possible across the far N of Scotland and parts of NW England on Friday. Secondly, there is the low chance of isolated lightning occurring along a SE surging cold front for other parts of England through the morning/afternoon. Main threats, scattered heavy showers, some torrential with isolated pockets of lightning, gusty winds (especially along the cold front), and perhaps an isolated weak spin up should the linear convection become better est.