From Tony Gilbert
11.30am Sat
Slight Risk of Severe Thunderstorms Ireland through to Northern UK & SW Scotland 12Z Sat 9th Aug-03Z Sun 10th Aug
Moderate Risk of Tornado Development same period. Transitional as per convective map below.
Recent and quite dramatic changes in the models highlight a period of risk for severe thunderstorms and tornado development within the post frontal trough. UK & Ireland will likely see prolonged periods of rain within the range of the cold front. UKMO forecast synopsis suggest the development of a strong surface trough in the wake of the cold front bringing further thundery showers to highlighted regions afternoon and overnight. Sharp upper troughing encourage lift and increases lapse rates through period. Polar maritime feed from the west sustains a good consistant flow of moisture at surface within a highly unstable environment. Strong upper and low level jet increase vertical shear numerically and steadily with height giving perfect balance of updraft to downdraft exchange. Weak surface winds allow for notable veer and strong speed shear in the lowest layer and is plotted within the red boxes. Current models push lift marginally into the warm sector so outlook requires constant monitoring for any changes. ATM I am very encouraged by vertical moisture distribution allowing for the best possible scenario for potential instability.
Prime risk today is based on the serious risk of tornado development and hense attributation the risk of categorized severe thunderstorms. Moderate CAPE and medium level freezing levels will suggest moderate hail possible. Dry air mid levels allow for strongest levels of gust possible. Based on mean average gust calculations between 800mb and 600mb this suggest up to around 40kts possible ATM.