In Katesbridge, a small village in County Down was measured only -3.7°C (25°F) in Sunday, 27. September morning — it is the new lowest minimum temperature recorded in September in Northern Ireland in all-time history. /electroverse.net/
Previously, on Thursday, 24. September, Altnaharra in Scotland recorded a low of -5°C (23°F), the UK’s lowest September temperature since 1997. Temperatures in Corgarff and Boultenstone also reached -5,0°C. /electroverse.net/
These anomalies could be linked with the weakest Gulf stream for last 1600 years /https://www.theguardian.com/environment/2018/apr/11/critical-gulf-stream-current-weakest-for-1600-years-research-finds/ caused by climate change - in the Farm Strait, Labrador cold stream pushes Gulf stream to lower and more southern waters of northwest Atlantic and it is subsequently linked with more southerly path of the warm waters above the all Atlantic.
These changes are associated with a "Global warming hole" anomaly southwesterly from Iceland /more about Global Warming Hole here: https://mkweather.com/2020/07/17/siberian-heat-38c-100f-flowed-above-north-pole-arctic-ice-loss-reached-the-newest-mid-july-record-pattern-strenghing-global-warming-hole-anomaly-which-can-make-british-isles-cold-til//. This anomaly is during Arctic melting in autumn extremely strong and their arms is sending to the coasts of western and northwestern Europe, with unusual coldwaves, as at the end of September 2020 in Scotland and Northern Ireland.
Effect of the Global Warming hole is episodically seen on the coasts of western and northern Europe recently and is expected, that its power will be during the next decades stronger and stronger, with possible cooling effects of Great Britain and Ireland more than -5°C till 2100. It can be colder across the all coast of W/NW/N Europe from Portugal to Norway with cooling effect -1/-3°C, in some parts of NW Europe (e.g. Faroe Islands) -10°C.
Furthermore, cold ocean surface temperature anomaly is linked with southerly shift of stormtrack (tracks of Icelandic lows) in the region, mainly in the autumn, after record-melting seasons in Arctic. Results can be colder and more rainy, cloudy and windy autumns in parts of Europe. Mkweather seasonal forecast for Autumn 2020 is linked with these changes, too /https://mkweather.com/2020/08/22/europe-autumn-2020-forecast-mkweather-accuweather-maps-and-analysis//. Situation is often persisting up to winter /https://mkweather.com/2020/07/29/first-forecast-for-winter-2020-21-early-powerful-coldwaves-nov-dec-then-weakening-of-cold-pattern-and-warm-jan-feb-mar/; https://mkweather.com/2020/09/24/updated-forecast-for-winter-2020-21-still-nao-ao-in-first-half-of-winter-nao-ao-in-second-half-of-winter-permanent-la-nina-and-surprisingly-easterly-qbo-possible//, although, there are more important parameters such as Global Change, sometimes (NAO, AO, ENSO, QBO, MJO,...).
it remains to be hoped that the worst-case scenarios will not realize until 2100, or maybe, sooner, around 2050, with possible collapse of Gulf stream circulation and very unexpected next Little Ice Age in parts of Europe despite of general widespread global warming. Global Warming Hole over Northern Atlantic is namely the largest cooling anomaly in the world nowadays.
Cold waters from Arctic pushes Gulf stream to more southern tracks:
Trend of surface temperature in the world during the period 1901-2012, with evident Global Warming Hole southwesterly from Iceland
Projection of expected temperature until year 2100 with extreme Global Warming Hole reaching of up to northern and western Europe
Difference between the coldest and the warmest year during Little Ice Age - with evident warmer Northern Atlantic during the peak of Little Ice Age (reverse than during global warming):
Rahmstrof, S., Box, J.E., Feulner, G., Mann, M.E., Robinson, A., Rutherford, S., Schaffernicht, E.J., 2015. Exceptional twentiethcentury slowdown in Atlantic Ocean Overturning circulation, Nature Clim. Change, publ. online 23 March
Hansen J., Sato M., Hearty P., Ruedy R., Kelley M., Masson-Delmotte V., Russell G., Tselioudis G., Cao J., Rignot E., Velicogna I.,
Tormey B., Donovan B., Kandiano E., von Schuckmann K., Kharecha P., Legrande A. N., Bauer M., a Lo K.-W., 2016.: Ice
melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C
global warming could be dangerous, Atmos. Chem. Phys., 16, 3761-3812, doi:10.5194/acp-16-3761-2016.