If the pattern that’s evolving next week was to be 3 months from now, I would have had plenty of snow and cold in the forecast for the UK, unfortunately it’s only mid-Sept BUT we are likely to see our first ‘cold’ days with highs struggling in Scotland, Northern England and a large parts of Ireland to only 10 or 11C and factor in a NW wind and it will feel downright cooold..
The cold is already fierce up in Greenland and folks in Iceland are asking how mid-winter has arrived so early!
The Arctic Oscillation and North Atlantic Oscillation are both tanking in the next 7 days and this will respond with a hemispheric buckling with major ridging up the west coast of North America and over the North Atlantic, these blocks of warm high pressure will force heat up into the arctic region and in response the cold that’s been building over the past 15-20 days thanks to a positive AO and strong polar vortex, is coming south into two major troughs, one over the central and eastern US and the other over the UK.
Next week will be chilly by Sept standards with highs 5-8C below normal Tuesday through at least next weekend and looking out to the following week, I would be surprised if the mean trough doesn’t hold steady over us given both the NAO/AO signal.
Check out the current ECMWF charts for next Monday, Tuesday and Wednesday.
It’s worth pointing out that Greenland’s cold pool is much stronger than normal and the NCEP GFS has night temps dipping into the -40s C in coming days and with a dominant northwest flow into Iceland, it has felt more like January up there these days. Of course with our flow coming from here, there is no reason to not think that it will feel more like late October if not November around these parts next week and with this air mass, the first significant snows of the season are ahead for the mountains of Scotland.
Could it even snow to lower levels, say down to 1,000 feet next week? While not likely, it can’t be completely ruled out. The highest stretches of the A9 through the Central Highlands would have probably the best chance at seeing lower level snowfall while much less the Campsies on the northern horizon of Glasgow, the higher parts of the M74 but I guess there may be a slight chance of seeing a rain/sleet/snow mix believe it or not. I’ve seen it snow in May (2009) and a Sept snowfall for me would be a first (I think).
For such routes as the M74, anything of a wintry nature would likely come more at night when the air is naturally colder.
Where am I getting it this cold? Take a look at the latest ECMWF 850 temps (5,000 feet up) for next Monday, Tuesday, Wednesday off AccuWeather Pro.
BTW, check out the 850 temp over Iceland!! Brrrr! Models have night temps in coming days down to -10 to -15C in the interior would you believe.
Hopefully later tonight, I will get a post up on the correlation between the summer and following winter NAO signal. If you want a winter again like 2009-10 which was the best for repeat cold THROUGHOUT the period from late December all the way to April and in 2010-11 where the front end was brutal, then I think you’ll like what I’m going to show you.
Stay tuned!
Very exciting looking forward to the next update.