American Heat & Storms Amplify Pattern Enhancing Wet, Windy UK, Mild Europe Weekend

We’re in for a pretty unsettled weekend with slow northward moving low pressure providing wet and windy conditions.

The reason for the slow NORTHWARD movement extends west to the other side of the pond.

An unusual surge of early summer heat and consequential severe thunderstorm outbreak over the USA has created somewhat of an atmospheric ripple.

As the atmosphere explodes with the merging of warm and cold over the Eastern U.S and swept out over the Atlantic, rapid cyclogenesis occurs but helped by the heat release of the thunderstorms which enhances buckling of the Atlantic jet stream with knock on effects downstream.

Credit: chorleyweather.com

The wild amplification or blocking of the Atlantic jet slows and even stalls the atmosphere’s westward motion and the recent storminess over North America can be traced back to the Pacific as a simple but strengthening storm hit California and crossed the Northern US, tapping heat from Mexico and lifting it all the way to Vermont. On the backside of this low pressure circulation, cold arctic air was being drawn out of Canada and so the thermal imbalance enhanced the storm’s cold front creating the rare February line of severe and damaging thunderstorms.

Wxcharts

The merging of summer heat and winter cold creates a perfect environment for RAPID CYCLOGENESIS east of Newfoundland. Just like a seesaw, the jet dives south with the deepening trough while forcing building heights and northward push of jet stream and warmth up towards Greenland.

Further downstream, this then forces a deeper Ireland and the UK trough while the ridge comes back up to the east over Europe.

Check out the GFS 850mb temps.

Credit: chorleyweather.com

Credit: chorleyweather.com

This skipping rope effect has deepened the trough over the UK and built the Europe ridge which essentially holds the low in place which makes for a longer period of wind and rain for the UK and spring warmth over the continent.

The GFS surface shows the winding up of a hurricane-force low south of Greenland and low pressure lifting slowly north over the UK this weekend.

Credit: chorleyweather.com

Credit: chorleyweather.com

Earlier radar and satellite.

Credit: BBC Weather

After a clear, cold night here across Scotland, cloud is now spreading north in advance of the rain now over England and Wales. Expect a wet night to come across Scotland.

Expect a cold stiff easterly with steady rain through the Central Lowlands Saturday. This rain could cause issues later in the day due to slow progression north. 40-50mph gusts possible.

Credit: wxcharts.eu

Then later tomorrow into Sunday, severe gales may effect both SW and NE UK.

Credit: wxcharts.eu

With the freezing level down to around 1,500ft, snow is likely to affect high road routes through N Pennines and Highland/Grampian with significant accumulation about 2,000ft through the weekend.

Credit: wxcharts.eu

Interesting to see the downslope warming over southern France due to strong stacked southerly winds (east edge of trough) crossing the Pyrenees and warmth as a result.

Credit: wxcharts.eu

Credit: wxcharts.eu

Credit: wxcharts.eu

Credit: wxcharts.eu

That’s despite very impressive snowfall in the mountains.

Credit: wxcharts.eu

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