Convective/Thunderstorm Discussion Spring/Summer 2018

Could be some locally heavy downpours tomorrow with the risk of thunder overland.

Messy sky today but enough clear skies letting convection form to produce some lightning/hail after the occluded front went through .



NASSA Pic sometime around mid day. Nice looking convection forming around Portlaois / Carlow.

Some small chance of thunderstorms tomorrow evening perhaps as cold uppers are drawn in after the fronts go through ( perhaps up along the Atlantic seaboard ?) .More of a chance on Sat with better diurnal heating under cold air aloft with convection bubbling up from late morning. Lapse rates look good with the possible addition of decent DLS more so on the Eastern side of the country perhaps. Should be good sunny spells to produce some big heavy slow moving showers.

http://www.convectiveweather.co.uk/forecast.php?date=2018-04-07





Day 1 Convective Outlook
VALID 06:00 UTC Sat 07 Apr 2018 - 05:59 UTC Sun 08 Apr 2018

ISSUED 20:22 UTC Fri 06 Apr 2018

ISSUED BY: Dan

... ENGLAND / WALES ...

On the forward side of a sharp upper trough, which will continue to dig across Iberia, a frontal wave will drift northwards across England and Wales - bringing an area of rain across Wales and W England eventually into S Scotland. On the eastern flank, and points east, elements of medium-level instability will exist which may be sporadically destabilised in association with the passage of a shortwave, moving northeast through the morning/early afternoon. Some high-based showers will be possible, capable of producing lightning - though given rather marginal instability, confidence on lightning coverage is too low to upgrade to SLGT.

... REPUBLIC OF IRELAND / NORTHERN IRELAND ...
Under the upper trough, cold air aloft will produce some reasonably steep mid-level lapse rates. Diurnal heating will allow 400-800 J/kg CAPE to build, with topography and low-level convergence aiding the development of numerous heavy showers and a few thunderstorms for the afternoon and early evening hours.

Limiting factors will be a lack of shear, resulting in messy pulse-type convection in the main, and perhaps also a hang back of cloud associated with the frontal wave over England/Wales, which may serve to dilute insolation somewhat. Nonetheless, the strongest cells could produce hail up to 1.5cm in diameter, while low-level convergence could produce a couple of funnel clouds.

Just a couple of light showers here near Tralee, can see bigger convection inland.