Convective Outlook: Sun 04 Jun 2017
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Sun 04 Jun 2017 - 05:59 UTC Mon 05 Jun 2017

ISSUED 23:13 UTC Sat 03 Jun 2017

ISSUED BY: Dan

... DAYTIME ...
Broad upper trough over northern Britain on Sunday will slowly exit to the NE as transient upper ridging develops ahead of more pronounced trough overnight and into Monday. Cool mid-levels atop SSTs/diurnal heating inland will produce another day of widespread showers across northern areas in particular, but also more showers are likely across southern Britain compared with Saturday as an instant-occlusion type feature migrates eastwards. Instability will be sufficient for occasional / sporadic lightning virtually anywhere, but the best environment (where lapse rates are steepest, CAPE highest combined with some late-day increase in DLS) will be found across northern and eastern Scotland - hence a SLGT issued here. Hail 1.5-2.0cm will be possible with this activity, perhaps also a funnel or weak tornado.

... OVERNIGHT ...
Overnight a deepening surface low will approach from the Atlantic, its associated fronts bringing rain to Ireland then western Britain. In a strongly sheared environment, the cold front will likely exhibit elements of line convection, particularly over southern Ireland. The depth of convection will be limited somewhat, and given marginal instability it is questionable as to how much lightning activity there will be (if any) - but this region will be monitored for a potential upgrade to SLGT. Conditions will be favourable for squally winds / rain and perhaps a tornado with any bowing segments. Some concern also over rainfall totals given likely training over similar areas as cold front becomes parallel to flow - but exact positioning is subject to some error, and may well be offshore where the greatest rainfall totals occur.