Bertha May Bring 80 mph Wind, 3″ Rain To UK & Get Caught In Trough Lingering Much Of Next Week!

Written by Mark Vogan on August 8, 2014 in Rest of Europe, United Kingdom & Ireland with 0 Comments

While we know the remnants of Bertha is coming, it’s now a question of how big the impact is and what next. The GFS is clearly much stronger with Bertha than the ECMWF. Interestingly the GFS has been consistent at taking Bertha into the central or southern UK, likely producing gales (maybe not just inland) as well as flooding rains.

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I recon somewhere up against a WSW facing beach just south of the centre will get a gust to 80 mph while some west facing upslope area within the Pennines will receive up to 3, maybe 4 inches of rain, especially given the slowing down of the system as it reaches the UK (according to GFS).

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The interesting thing however is that the GFS also shows Bertha getting caught in a larger scale trough, created ahead of a big ridge that’s over central and eastern Europe. This high, combined with a very strong August jet stream will allow a fairly weak entity to become pretty strong and deep. Pressure may sharply fall as Bertha approaches and crosses the UK. Notice in the below surface maps how the system deepens from 1000 to 988mb as it crosses between the Bristol Channel and North Sea… It also shows the system over a long duration (5+days) LOOPING around the UK!!

The abnormally warm water surrounding the UK, enough cold over Greenland and heat over the Sahara merging to support a strong jet will allow this system to rapidly intensify and pack a punch across central and southern parts of the UK as well as France and probably the Low Countries also.

Speaking of Greenland. Here’s the scene this morning from Summit Camp. It’s turned colder there of late. Air temp currently -22C/-8F.

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Here’s the latest GFS surface maps. NOTE the loop E, NE, N, NW and then back S, SE as a weakening feature, eventually crossing back out over the North Sea as a 1000mb low. It’s effects (wind, showers and longer spells of rain) may last through most of next week.

High pressure is scene building into the UK late next week through the weekend. Here’s hoping…