Synopsis Situation
A low pressure system over Northern Ireland during the morning will move across the north of the UK. An occlusion associated with the low will sweep across the north of the UK affecting parts of Wales, the northern midlands, and Northern England. In the far north of Scotland a further occlusion drifts into the far north of Scotland.
Northern Scotland
Some heavy showers and an isolated storm seem possible in association with an occlusion moving in. Instability is unlikely to be particularly high and the wind environment is not particularly indicative of severe thunderstorms. Light winds do indicate a possibility of weak funnels created from vertical vorticity sources especially along any convergence zone.
Northern Ireland
Once the occlusion moves away then Northern Ireland should see plenty of showers due to peak daytime heating and steep mid level laspe rates. Models are reluctant to break out much in the way of precipitation, despite having the highest forecast instability for the UK. Taking into account the wind field is fairly weak the risk of severe weather is not thought to be high enough for a slight risk to be issued.
North Wales, North West England, Western Scotland (See Text Area)
An occlusion swings across this region during peak heating hours with models suggesting some moderate rainfall from this in the period after lunch to mid afternoon. Instability from this looks quite low and forecast atmospheric profiles look moist all the way up, so although there may be a few embedded thunderstorms it seems unlikely that these will be severe. Attention is drawn to the fact that wind profiles are conducive to mesocyclone formation with an associated tornado risk; however updraft strengths may not be high enough for this to become a factor. Attention is also drawn to the Edinburgh Glasgow corridor where a low level convergence zone is forecast from mid afternoon onwards giving a slightly higher tornado risk. Instability does increase after the occlusion but wind fields by then are more benign. Taking all factors into account instability is not high enough under the occlusion to warrant issuing a severe thunderstorm risk, but this area should be monitored through the day for developments.
Issued by: Brickfielder - Forecaster for Netweather