Slight Risk of Thundery Showers Central/ SW UK & Ireland 12Z-18Z
UKMO fax chart shows a develop surface wave feature across the UK and Occlusion for Ireland. Long wave upper trough spreads eastward increasing lapse rates. A relatively moist surface flow looks possible with dew point around 12 deg C. For the UK both GFS and NMM suggest that the wave will be primarily non convective but there looks to be some scope for a narrow prefrontal trough. Models are currently holding the strongest instability for the UK within this zone. Moderate upper jet stream increases vertical shear to a level which should allow some longer lived multi cell clusters to exist for a time with a risk of lightning and small hail. Some restrictions may exist regarding weak PV aloft and winds look fairly straight lined at all levels ATM.
Ireland continues to show the strongest developing CAPE and looks to have the higher risk of sferic activity. Some basic shear in place with multi cell activity the likely result.
The outlook whilst currently looking rather low risk ATM nevertheless has the potential to be upgraded based on the forward projection of the front left exit region of the jet stream and increased PVA aloft. Certainly one to keep an eye on!
This post has been edited by Tony Gilbert: 06 May 2012 - 18:55