Moderate Risk of Scattered Thundery Showers central and central Southern UK 12Z-19Z
Slight Risk of Funnel Cloud Development as per region above
Almost stationary low central UK acts as fulcrum to wrapped occlusion allowing for another round of thundery showers to develop through Weds afternoon within a cyclonic circulation. GFS and NMM are currently bolstering CAPE above 500 j/kg by mid day based primarily on almost 100% humidity at surface. Surface temps and dew point almost run parallel within the the marked zone by early afternoon suggesting very low cloud bases possible. This combined with strong vorticity at all levels would suggest a defined risk of FC's possible.
Opinion; concerns are raised as to whether the 500mb upward CAPE values will actually be achieved based on cloud cover reducing heating somewhat and a saturated atmosphere in place up to the tropopause slowing the cooling of cloud tops? Based on the current model output it is quite possible that due to a rapid increase in cold pooling at surface once the first lot of showers occur that instability could rapidly diminish by mid afternoon. We can nevertheless expect to see some photogenic hard mid level inversions spread to many parts during this process.
There is a small risk of thundery showers for central Ireland and Scotland. This will need to be addressed using the morings model ouput.
This post has been edited by Tony Gilbert: 17 April 2012 - 19:22