The week ahead looks rather different to this past week with a lot of heat spreading north into Europe from Africa. While it looks highly likely we’ll see the first 37C (100F) readings over parts of France and Germany, there’s a lot of uncertainty over exactly how far west that Saharan heat will spread due to the position and movement of a southbound upper low as well as a frontal system approaching Scotland from the NW. This is no clear cut 7 day forecast that’s for sure but very interesting though.

Without coming across arrogant, the ‘potential’ warmth of this upcoming week is old news if you’ve been reading these posts and watching the videos as the next warm-up was on my radar even before the last one was done. Your getting the heads up long before others catch on, that’s why your subscribing after all. So far, the timing of these warm-ups are turning out well and a lot is down to the NAO being an excellent long range signal. Many so called forecasters are now all over the obvious. However, I would urge caution on this week as it’s complex and no picnic to forecast. It’s a busy weather map. Though there’s plenty of heat, there’s also plenty of nearby low pressure and fronts which can easily redirect that heat away from the UK. It could just as easily be raining and 20C as it can sunny and 30C.

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In a post issued last Tuesday, I included, what was then the 192 hour ECMWF upper chart and the ‘significant’ warmth trying to push into SE England. 6 days on and it continues to show this. The evidence to back up what the ECMWF was showing 6 days out was the fact the NAO was seen to go back positive around the 20th. Pretty much every time the NAO has gone positive, we’ve seen warmth and more settled conditions. The GFS NAO ensemble has shown the NAO going positive since last weekend, when it was yet to go negative.

Here’s last Tuesday’s 192 hour ECMWF chart for next Wednesday (19th) which was shown on a post the same day.

Here’s today’s ECMWF chart for Wednesday the 19th. Very little difference, both runs for the same day are 6 days apart. This shows the superiority of this model compared to others.

The cities of Paris, Brussels, Amsterdam, Copenhagen across to Berlin should all reach 30C (88F) or greater over the next 3-4 days!

Some Detail To The Forecast

The low which we’ve been watching closely throughout the second half of the week will have far less impact than might have otherwise been as it attempts to spread moderate rain north over the SW UK and southern and central parts of Ireland. This band looks poorly organised as it pushes into a stronger height field over the next 24 hours.

There will and is more in the way of sun today for many areas with fewer showers and into Monday it’s looking even better with decent sunshine across a large chunk of England and Wales, just an odd shower popping with highs likely to push 18-21C widely. High pressure is not only building over the UK as the low departs to the south but that low is helping draw hot air from the Sahara north, northwest over France. The million dollar question is how far does this hot air get. Paris looks to see low 30s (around 90-92F) by Tuesday, but can it reach London and SE England by Wednesday? If so we may be looking at the first 30C (88F) of the year on Wednesday.

The below GFS 2 metre temperature chart for Wednesday afternoon shows a large area of 80+ (27C) over a large chunk of Southern England extending north into the Midlands and an area of 85F (29C) The 75F (24C) line extends as far up as Manchester and York while the 70F line enters the Scottish Borders.

There is a void between the back edge of departing low and an approaching front. A warm front sitting almost directly over the English Channel may destabilise the atmosphere along the South Coast, helping fire thunderstorms and downpours, especially with warm, humid air around. The UK will sit within the void between the warm front associated with the departing low and the approaching front trying to work into Scotland and I am curious as to whether this heat can squeeze in between, presenting the warmest few days of the year before the window closes things turn cooler and perhaps wet by Thursday.

Here’s an up close of the ECMWF upper chart with 850 temps for Tuesday and Wednesday.

Tue

Wed

Monday should see locally 21-23C (72-75F) while Tuesday should warm towards the 25 or 26C (79F) mark but by Wednesday it MAY approach the 30C mark but it largely depends upon cloudcover.

Away from Southern, perhaps Midland England and it’s much cooler with lower heights due to that front to the NW. Though cooler, it’s mainly dry and pleasant.

Here’s the GFS surface chart for the next 120 hours and you can see the system to our SW tries to spread it’s shield of rain north. But it’s clear that it never quite makes it and by 48 hours it’s heading south as pressure build over the UK.

24 hrs

48 hrs

72 hrs

As you can see, the front waiting in the wings off Scotland, eventually brings down the ridge over the UK and that means the return to more unsettled weather. In saying that, this is not a big deal and doesn’t look likely to bring too much rain.

96 hrs

As you can see, that feature quickly moves S and E with another ridge building up from the SW during Friday.

120 hrs

This of course is not the large scale blocking ridge that we saw earlier this month but I wouldn’t be surprised if we continue with the more settled theme from next weekend into the following week due to that NAO signal but if you notice, the ensemble does so a downward trend towards the closing days of June. It will be interesting to see whether this occurs or whether the signal stays more positive.

Even if we do see the mean ridge over the next 10 days and then a return to more unsettled, that unsettled pattern should, like this one, be short lived. July continues to look good with an increased likelihood of a prolonged warm to hot, dry spell.

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Tags: Europe heat, Europe heatwave, France Heatwave, June heatwave