Northwest Europe 2024/25 winter - first freeze imminent!

[UK_Palms]

The first freeze of the season is already imminent for much of northwest Europe. A new phase of -NAO (North Atlantic oscillation) and high pressure over the arctic (northern blocking) means that cold arctic air is channeled straight down from Greenland and the high arctic into northwest Europe and Scandinavia.

Autumn has been very mild up until now for all of us in northwest Europe, with record high maxes and minimums in many places, but all that is about to change, at least temporarily with the arrival of this arctic blast on Monday/Tuesday. It is looking like quite a significant cold snap for mid-November in some places like Iceland, Norway and Ireland in particular.

 

The cold is already setting in tonight in Scotland with -7C in the Highlands currently but +12C in southwest England. I am reporting +9C at midnight ahead of the cold front arrival.

 

Maybe southern England, northern France, Netherlands, Belgium etc may escape much of it being further south and quite coastal. It probably won't do much there, although hPa 850 temps will still be down to about -7C or -8C in London. I am expecting about -2C air temps overnight, but I doubt central London will see an air frost from this event. Even down to -5C hPa 850 for the Isles of Scilly, but that translates as +9C days and +7C nights at ground level still there. So still fairly mild. The main cold is concentrated in northern England. The GFS model is showing this for mid-week...

 

I am expecting at least -10C to -15C in the Scottish highlands. The latest GFS has -11C at the Cairngorm summit later next week, which I think is on the low end. I wouldn't be surprised to see -15C there with a -10C hPa 850 air mass overhead. You can also really see how much milder the western and northern Isles of Scotland are as well, due to coastal proximity.

 

There are some members on here from Alesund in western Norway who are growing Trachy's, Butia, Jubaea, CIDP etc. That is supposed to be Norways mildest location, so it is looking pretty cold for November. Maybe lows of -7C and temps below freezing for 100+ hours. Quite a bit of snow as well in the forecast. That is already CIDP killer territory, especially for smaller ones in humid climates so this will put any microclimate there to the test already. @Palmfjord62degressnorth @Norwaypalmtrees

 

For the UK at least, much warmer air should arrive to relieve things by Saturday night with temps returning above average again. These are 6am minimums on Sunday...

 

Also one thing to add, it has been the driest first half of a November on record here with many places not even seeing 1mm of rainfall during the first 15 days. The south coast of England has been especially dry with both Shoreham and Thorney Island picking up 0.6mm out to 18th November. St Catherines on the Isle of Wight hasn't recorded any rainfall at all. Heathrow in west London is on 1% of it's normal total for November. So record low rainfall across southern England. Percentages anomalies visible below...

St James Park in London was on 0.6mm for the first 15 days of November., but has seen 0.8mm in the past 2 days now. Still only 1.4mm out to the 18th...

 

St Catharines on the Isle of Wight hasn't had any measurable precipitation this month so far, which is crazy for what is now 18th November. Statistically the joint wettest month too.

 

The Scilly Isles a bit wetter but VERY mild nights. Only 1 night this month that hasn't had a double digit minimum in C, and that was still +9.8C.