Rough Day Ahead For Southern Britain On Tuesday, Uncertainly Over The Weekend (Includes Video!)

Written by on May 13, 2013 in United Kingdom & Ireland with 1 Comment

Well I guess I haven’t seen the threat of tomorrow’s big rains over Southern Britain until today due to the fact I wrote and released my initial thoughts on next winter last night. May seem strange to do so, so early, however I think it’s important to show you as a subscriber exactly what it is I’m looking at right now and what goes into making a long range forecast. I want to give you value for money. If you read my post yesterday, you well know that what was released is by no means a ‘forecast’ but initial thoughts. My forecast will not be released proper until late October or early November but through the next few months, I will be building that forecast package and you will know what I’m expecting.

As for the here and now, well we have a rather wild next 24 hours ahead for Southern Britain as a vigorous system pushes up from the southwest while cold air comes down from the north. I did allude to a very unsettled first half to this week with a strong low overhead Tuesday into Wednesday but the amount if rain and even wet snow expected, wasn’t seen till late on. Later than I would like. (See today’s UK & Ireland Regional Forecast for details on the next 24 hours)

Did you notice the vigor in those showers today and through the past weekend? The downpours packing hail, gusty winds, thunder, lightning and even wet snow is all because of the amount of cold air aloft and when you get sunshine warming the ground and lower atmosphere, this enhances the instability within the atmosphere, forcing the air to rise faster when the temperature difference is greatest.

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Within the heaviest showers, air is being forced downward towards earth and so that is why we see sharp temperature falls and all of a sudden it’s sleeting or in some cases snowing!

If you live anywhere from Devon to Nottinghamshire, prepare for some very heavy rainfall starting early Tuesday morning and lasting through much of the day with parts of Southwest England and South Wales picking up 2 inches within just 12 hours. This rain will be persistent with embedded pulses of heavier rain which could produce snow.

Here’s the latest GFS forecast for precip through tomorrow.

27 hr

Courtesy/Owned by MeteoGroup

Courtesy/Owned by MeteoGroup

30 hr

Courtesy/Owned by MeteoGroup

Courtesy/Owned by MeteoGroup

33 hr

Courtesy/Owned by MeteoGroup

Courtesy/Owned by MeteoGroup

The below 850 temps for 27 hrs shows why there is sleet falling and why wet snow may fall in the South of England and Wales tomorrow.

Within the intense bands, this cold at 5,000ft gets transfered down to the surface.

Courtesy/Owned by AccuWeather Pro

Courtesy/Owned by AccuWeather Pro

After this system clears out into the North Sea Tuesday night into Wednesday, cold air remains aove our heads and with plenty of sunny spells on offer, that means more of the same story, sunshine and showers through Wednesday and cool for the time of year at just 10-14C.

As for the upcoming weekend, as expected, the models are very back and forth. One run will show no low north of the main low which would allow warmth into the UK from the east, other runs show another low and block. As I write this, the new run of the ECMWF has just come in and interestingly it shows no upper low to the north of the main southbound low next Monday, meaning the potential for warmth drifting west.

Given the downward trend from positive towards negative in the NAO, this always suggested more in the way of troughiness and cooler weather for the UK and any ridging would be short lived.

Here’s the latest ECMWF from Sunday on into next week.



If the above holds true, the fly in the ointment with that scenario is the low SE of England which could present unsettled weather to SE England but plenty of warm sunshine would be on offer elsewhere.



The warmth doesn’t last as you can see from the above chart for Tuesday.



By Thursday it’s back to cooler and more unsettled.

The truth is, I don’t see any sustainable warmth through the next 2-3 weeks given the pattern and the trend back into negative territory with the NAO.

Snow On Both Sides Of The Pond: Great Trans-Atlantic Teleconnection

It snowed today on both sides of the pond and it’s all thanks to an excellent trans-Atlantic teleconnection with unseasonably cold air driving south over both the Eastern US and the UK with ridging and warm air being pumped north over the North Atlantic. It’s very much a negative NAO signal right now and over the next few days, the chill continues before the Eastern US warms late this week and for the UK, look out, 2-4 days later. Remember what’s been mentioned before about the 2-4 day lag between the US and UK. That’s another reason why we could see a brief return to summer early next week that other aren’t seeing.

Past 3 Out Of 5 May’s Have Produced ‘Unusual’ Cold With Snow

The Drumnochter Summit to Newtonmore stretch of the A9 through the Scottish Highlands saw a covering of snow this morning and while that may seem crazy for May 13th, interestingly we saw a very similar occurance a year ago yesterday, just a little further north. When looking back, recent May’s have produced some unusual cold along with snow. I recall driving south through the Southern Uplands last May and my dash temperature read -6C. Back in May 2010 following the tough winter of 2009-10, snow briefly accumulated on the Campsie Hills north of my house.

A couple of June’s ago, following 25C weather, the village of Aviemore in the central Highlands saw a covering of snow.

At the same time the UK has seen unusual snow and cold during May, so too has the Eastern US and it would appear that cold spells with freak snowfalls are becoming a little more common.

The reason for such a wild and very cold spring I believe can be traced back to the deeply negative AO during March and we saw similar events back in the late 1970s as well as the mid-90s. The mid-90s occurance was likely volcanic eruption linked as well as potentially low solpar activity. This time around I believe the low solar activity is possibly to blame.

With the further slump in the solar cycle, colder springs may become more frequent and winters could well become tougher. That’s another subject for another time.


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  1. Penny says:

    Oh god im still putting my heating on lol!!!!!brrrrrrrrrr

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