Cumulus development galore - Timelapse - Herne Bay, Kent - 5th May 2023
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- čas přidán 5. 09. 2024
- A day with a lack of storms for my corner in Kent but a lot of developing cumulus was observed which made for brilliant cloudscapes and brilliant timelapsing conditions. UKV did have showers developing overhead and nearby (Canterbury, etc) but these never came to fruition although you can see anvils from storms to my west over London developing and bubbling away during the course of the day. I'll leave the Convective Weather outlook so you can get a general outlook for the day.
Convective Outlook
VALID 06:00 UTC Fri 05 May 2023 - 05:59 UTC Sat 06 May 2023
ISSUED 07:05 UTC Fri 05 May 2023
ISSUED BY: Dan
An upper ridge will transit slowly across Scandinavia, while a longwave upper trough extends from the Atlantic across the British Isles. Fairly extensive cloud and showery outbreaks of rain, most persistent in E/SE Scotland, should gradually clear to the north and/or break up through the day with increasing insolation leading to heating of a moist low-level airmass (T 15-17C / Td 10-13C), especially from late morning onwards. This, in conjunction with a mid-level cold pool drifting northeastwards, will yield 500-1,000 J/kg MLCAPE across portions of England and east Wales. Numerous heavy showers and thunderstorms are likely to develop, particularly aided by areas of low-level convergence such as from southwest England across the south Midlands to East Anglia. Forecast soundings suggest ELTs around -50C, with cloud tops potentially around 30,000ft.
For the most part, limited mid/upper flow will result in weak wind shear, with pulse-type mode most favoured. That said, some backing of the low-level winds over East Anglia and eastern Lincolnshire could bolster 0-6km DLS to greater than 20kts, perhaps aiding somewhat with storm longevity in these areas. Cells will mature as they drift gradually northeastwards, therefore the greatest lightning risk will tend to be favoured more towards eastern England, not least because some areas may have several thunderstorms pass in the vicinity through the afternoon. It is worth noting that the mid-level cold pool will begin to move out to the North Sea from 12z, and so gradual warming aloft from the southwest through the afternoon may result in shower/thunderstorm activity reducing across southwestern areas a little earlier than the typical diurnal cycle would dictate. The strongest cells may produce wind gusts up to 40mph and hail perhaps a little over 1cm in diameter, but the lack of any substantial shear will preclude the risk of any severe convective weather (aside from any localised flooding).
Scattered heavy showers are also likely across central and northern portions of Ireland/Northern Ireland in response to diurnal heating and low-level convergence, although here shallower convection will tend to limit the coverage of lightning (especially compared with England). It is possible there may not be much in the way of lightning activity here.
Overnight, most lightning activity will cease as showers slowly decay, but there may be a small risk of a few isolated lightning strikes in the vicinity of the surface low that approaches SW England towards the end of the night.