The East/West split coming up next week

[carled]

So I'm only a novice and I don't understand quite how there is going to be such a huge variation in weather over such a short distance. There's all sorts of excitement in the forecast model discussion about upcoming 32C on Tuesday but...

As at 10am on Saturday 10th, the BBC forecast has the following for Tuesday:

• 20C and rain for Newquay
• 22C Sunshine/Showers for Exeter
• 26C and bright sunshine for Bristol

That's, what? 100km spread approx?  In metereological terms that doesn't seem that significant.  I realise that with any weather system there's got to be a metaphorical "edge" somewhere but even so, that seems to be an amazing variation in a short distance.  Is it purely to do with the positioning of the low pressure off to the SW that is affecting the incursion of warmth from the continent?  If so, how likely is it to shift any more?  If, for example, it shifts another 100km east, does that then affect the midlands or is it not as simple as that? 

 

 

[cheese]

Cornwall and Devon don't usually get very hot during heatwaves. 

[carled]

Just now, cheese said:

Cornwall and Devon don't usually get very hot during heatwaves. 

Er... ok. Doesn't really explain much, but fair enough.  I presume this is for geographical as opposed to poltical reasons? ;-)

 

[cheese]

Just now, carled said:

Er... ok. Doesn't really explain much, but fair enough.  I presume this is for geographical as opposed to poltical reasons? ;-)

 

If you look at the GFS chart for 2pm on Tuesday you'll see that the centre of the low is close to Cornwall, so that region is affected by rain - if the centre of the low was further west you'd probably see an improvement. 

[Nick L]

21 minutes ago, carled said:

So I'm only a novice and I don't understand quite how there is going to be such a huge variation in weather over such a short distance. There's all sorts of excitement in the forecast model discussion about upcoming 32C on Tuesday but...

As at 10am on Saturday 10th, the BBC forecast has the following for Tuesday:

• 20C and rain for Newquay
• 22C Sunshine/Showers for Exeter
• 26C and bright sunshine for Bristol

That's, what? 100km spread approx?  In metereological terms that doesn't seem that significant.  I realise that with any weather system there's got to be a metaphorical "edge" somewhere but even so, that seems to be an amazing variation in a short distance.  Is it purely to do with the positioning of the low pressure off to the SW that is affecting the incursion of warmth from the continent?  If so, how likely is it to shift any more?  If, for example, it shifts another 100km east, does that then affect the midlands or is it not as simple as that? 

 

 

In this case it's mainly to do with the fact that the east is likely to see lengthy sunny spells, while the likes of Newquay and Exeter will be under fairly extensive cloud and showers. The actual air mass itself is fairly uniformly warm across England and Wales. 850hPa wet bulb potential temperatures are a good gauge for the general temperature of the air mass, and most areas are seeing these at 17-18c. But because the daytime heating is greater across the east with clearer skies, it of course is going to be much warmer here. If we saw clearer skies further west too then temperatures would indeed be into the high 20s.

It seems a lot but that's nothing compared to what you get in continental climates. One such example...

 

This is apparent temperature rather than true temperature, but still. That's apparent temperatures in the 20s about 100km from temperatures around freezing. So what we're seeing is diverse for the UK's fairly bland climate, but in general meteorological terms it's not really that impressive!

Edited September 10, 2016 by Nick L

[carled]

Thanks for the explanation. Makes sense. So we picked a bad spot to go on holiday next week then?! (Newquay).

Only chance now is for the low pressure system to move further west and allow the warmer/drier air to move with it then I presume?  Chances of that happening - who knows.

[Evening thunder]

I recall at least one GFS run showing 15C in west Devon and 25C in east Devon this Tuesday
 

1 hour ago, cheese said:

Cornwall and Devon don't usually get very hot during heatwaves. 

Sometimes that's the case (especially with Cornwall) but it depends on the synoptics really, plumes can do that especially if they are a bit too far east, but the one in July still gave temps of 32C in Bude and parts of North Devon, not far off the 33.5C recorded nationally.

A high overhead or an easterly drift during a very warm or hot spell (not that unusual through the archives), would also give very warm/hot conditions even if the usual sea breezes make it cooler near the coasts. July 2013 and 2014 did that on many days with low 30's and high 20's respectively.

This year (and last) has been a bit frustrating for the absence of such set ups and plumes/hot weather being a bit far east...

[March]

9 hours ago, Nick L said:

In this case it's mainly to do with the fact that the east is likely to see lengthy sunny spells, while the likes of Newquay and Exeter will be under fairly extensive cloud and showers. The actual air mass itself is fairly uniformly warm across England and Wales. 850hPa wet bulb potential temperatures are a good gauge for the general temperature of the air mass, and most areas are seeing these at 17-18c. But because the daytime heating is greater across the east with clearer skies, it of course is going to be much warmer here. If we saw clearer skies further west too then temperatures would indeed be into the high 20s.

It seems a lot but that's nothing compared to what you get in continental climates. One such example...

 

This is apparent temperature rather than true temperature, but still. That's apparent temperatures in the 20s about 100km from temperatures around freezing. So what we're seeing is diverse for the UK's fairly bland climate*, but in general meteorological terms it's not really that impressive!

*in your miserable opinion!

[Nick L]

13 hours ago, March said:

*in your miserable opinion!

Well, it's partly opinion, partly fact. We have a temperate climate so extremes of any kind are very rare. If you relocate someone from a continental location they'd find our weather very samey. There is very little about the UK climate that I find exciting. I see a decent snowfall every few years and a decent thunderstorm about every 5 years!

And just because I happen to think differently to you it doesn't make me miserable, wasn't much need for that tbh.

Edited September 11, 2016 by Nick L

[Evening thunder]

Still at least we don't live in Arcata, California.
https://en.wikipedia.org/wiki/Arcata,_California#Climate

Almost makes our climate look continental.. lol

[mountain shadow]

The NW /SE split has been evident for most of the Summer. Whilst the SE is burning at 32 degrees Iwill getting rain and 16 degrees.