UPDATE 8.30 Weds from Tony Gilbert
Moderate Risk Scattered Gen Tstorms UK & Ireland 12Z-21Z
Slight Risk Weak Tornadoes blue and red boxes
Stronger convection likely late in period yellow box
Outlook rather more broad than earlier predictions with significantly moist low level flow. Convective map is broken down into sub boxes to help locate regions with higher risk potential.
Slow moving occlusion brings rain and showers to much of the UK and Ireland today. Most of the coverage looks to be under a weakly sheared environment. Though, special attention is given to S.Wales later in the day where moderate vertical shear and dry intrusion maybe introduced (red box)and hense the slight risk of tornadoes. Blue box over Ireland signifies a region of convergence within a highly unstable environment. It is within this region that weak convergence zone tornadoes may in fact develop . Though ATM I grade this risk as only slight.
Yellow box highlights significant potential instability as dry air overruns moist primarily after 15Z. We can expect to see a rash of isolated small tstorms as mid level air is rapidly cooled.
The occlusion will typically introduce lots of cloud and rain cooled air throughout the period though the coverage is so broad that small notches of insolation are very likely along the periphery where stronger convection can be generated and should become apparent on radar.