Storm & Convective Forecast
Issued 2017-05-28 22:08:52
Valid: 29/05/2017 06Z to 30/05/2017 06Z
CONVECTIVE/ STORM OUTLOOK- 29TH MAY 2017
Upper trough axis approaches western Britain from the west, as upper ridge extending north from the Mediterranean across Central Europe begins to relax. A plume of warm, moist and unstable air will be present across central, southern and eastern England on Monday, ahead of cold front moving in from the west, which will clear eastern England Monday night, diurnal heating of this warm humid air combined with breeze convergence could trigger some isolated thunderstorms.
DAY 1 OUTLOOK - 06Z MONDAY 29TH MAY - 06Z TUESDAY 30TH MAY
... S ENGLAND, E WALES, MIDLANDS, LINCS AND E ANGLIA ...
Atmosphere in the morning will likely be largely turned over by overnight storms, with a cap in place. However, abundant mositure (dew points 16-17C) and surface heating combined with breeze convergence ahead of cold front moving in from the west across England and Wales may trigger isolated thunderstorms during the afternoon across the above areas. 30-40 knts of deep layer shear should favour organisation of storms, bringing a risk of localised torrential rainfall leading to flash-flooding, isolated large hail and gusty winds. Also, an isoalted tornado can't be ruled out with storms forming along breeze convergence zones
What do the risk levels mean?
Thunderstorms - Severe thunderstorms unlikely to occur, slight risk of hail, gusting winds and localised flooding.
Slight Risk - A slight risk of severe convective weather exists. Hail >2.0cm diameter, wind gusts exceeding 50mph or 5-10% risk of a tornado within 50 miles of a point, or > 30% risk of localised flooding.
Moderate Risk - A moderate risk of severe convective weather exists. Hail 4-5cm in diameter, or wind gusts of 60-70mph, or a 10-15% chance of a tornado within 50 miles of a point, or >50% risk of localised flooding.
High Risk - A high risk of severe convective weather exists. Rarely, if ever used on the UK. Hail >5cm, or wind gusts in excess of 80mph, or >20% risk of a tornado within 50 miles of a point, or >70% risk of localised flooding.