With a strong upper level ridge of high pressure is parked over Scotland, we continue to enjoy a coastal California-like May with gloomy low cloud and sea mist morning’s which give way to glorious blue sky and 20s by afternoon.

This was the scene in Oban yesterday.

Even with the slackest of easterly flows, North Sea fog and mist (created by warm air over cold water) always rolls back onshore and inland, particularly where there are gaps (Central Lowlands) as the land cools but once the sun returns and land begins to heat again, so that marine layer retreats back to the coast just like we see in coastal California at this time of year.

Gloomy morning’s give way to glorious afternoons.

While much of the North Sea coast of Scotland enjoyed warmth and sun yesterday, the previous day was quite different due to a more pronounced easterly wind which held the sea haar against the coast which locked Edinburgh in gloom for much of the day and therefore it only topped 10.7C.

Like we see in California, our haar or ‘marine layer’ is deepening as the daytime warmth and high pressure is less. Burn off is slower.

The strong sinking and capping under the high supresses the atmosphere’s ability to rise and so sunshine prevails but where pressure is lower (England and Wales), the strong daytime heating forces strong upward motion and development of shower and thunderstorm clouds. This has been ongoing for the past week with spectacular lightning displays and prolific downpours within individual cells.

https://twitter.com/WeatherCast_UK/status/1001170030413873153

https://twitter.com/weather_king/status/1000837106086875136

As well as dramatic and frequent lightning, rainfall rates were prolific.

https://twitter.com/Kaaaaaaaaaaath/status/1000832381379661831

https://twitter.com/bbcmtd/status/1000850814288760832

FEATURED IMAGE CREDIT: LDN fromthe Rooftops
@London_Rooftops

Tags: haar, marine layer, uk flooding, uk thunderstorms