Extra tropical Ophelia has now weakened and is currently moving across Scandinavia. The next weather system being monitored is currently a tropical disturbance south of the sub tropical ridge in the tropics which is expected to become absorbed into the Atlantic flow and interact with the jet stream in the next few days.
There will be two areas of low pressure, the first a typical Atlantic depression forecast to bring spells of heavy rain and strong gusty winds during Thursday evening into Friday morning affecting many parts of England and Wales. However, it is the second system following on behind which has tropical remnants that will bring a period of more severe weather later on Friday peaking through Saturday.
An area of low pressure is forecast to rapidly intensify as a tropical disturbance invigorates the jet stream on Wednesday evening. The tropical disturbance is currently forecast to become a strong Atlantic Storm sub 970mb a few hundred miles West/South West of Ireland during late Thursday into the early hours of Friday morning.
The current thinking is that the storm will undergo maximum strengthening out in the Atlantic and will begin to weaken as it moves toward the United Kingdom and Ireland during Friday Evening into Saturday. There is some uncertainty on the intensity phasing of the low and as a result it is still possible that the low could be a weak Atlantic storm on approach as it makes landfall.
On current information we have issued an advanced weather watch for an Atlantic Storm to weaken into a strong depression on landfall across S Ireland, SW England and Wales on Friday Night/Saturday AM, but the risk of storm conditions is not being ruled out entirely.
Regardless of the slight uncertainty on intensity severe gales are expected on Saturday for the far South West of England, Cornwall and Devon including exposed parts of South and West Wales with the risk of gusts of 55-65mph, potentially up-to 70mph.
Elsewhere a spell of very windy weather is expected with 40-50mph gusts quite widely.
Accompanied by the strong depression will be heavy rainfall and there is a concern that the fronts associated with the low could become slow moving and stall increasing the risk of persistent rainfall in places, and the risk of localised pluvial flooding or more serious fluvial river flooding.
Some disruption is possible with wind issues most likely in the South West of England and for Wales with the possibility isolated power outages, tree damage and some minor structural damage – local transport may also be affected. Further North there is a chance of disruption due to flooding but there does remain some uncertainties on this and further updates will be provided.
It should be noted that there remains a chance that this low or depression could still be named Storm Brian by the Met Office in the coming days and could be a little stronger than this early guidance suggests, as a result this forecast will be reviewed in the next 24-36 hours.
Be aware of the risk for adverse weather on Thursday, Friday and especially Saturday with the potential for a few locations to experience locally severe conditions for a time. Disruption at the end of the week and to start the weekend will be possible.