posted on Dec, 4 2011 @ 04:45 PM
I live in just outside Aberdeen, Scotland and since i live in the snowiest city in the UK, i'm quite well versed in our winters. My family all come
from here and the storys and photos i have seen from days gone by are a far times worse than we've had over the past few years. Threads like this
just simply illustrate that the majority of people in the UK have not seen a real winter, nor do they understand why they happen.
My father and other members of teh family all grew up in rural Aberdeenshire. I have seen photos of snow over 8 feet deep, i have seen pictures of my
grandfather digging sheep out of the fields, i have seen cars buried in snow and i myself have been fortunate enough (or unfortunate enough) to stand
waist deep in snow with temperatues of below -15oC here in Aberdeenshire and i'm only 28.
Yes times are different and the UK as a whole cant really cope very well, but believe me, Scotland can and Scotland does. Today, we have already had
a couple of inches of snow, with blizzard conditions at times and themax temp here has been only 2oC but this cold weather will only last til tuesday
with the majority of the UK missing out on this "very little" snow event, exception being Scotland and probably parts of NW England and Wales.
To better understand why we have had the ad winters we have over the past few years, you first need to understand how the weather patterns that are
occurring case the snow.
In recent years there has been a "blocking" effect that has caused the heavy snow and widespread disruption. This blocking effect is caused by a
high pressure system over scandinavia/siberia that stretches over the UK because the Jet Stream has shifted further south than "normal". Prior to
teh past 3 years and for about a decade leading up to 3 years ago, the Jet Stream usually sat over the UK or just above it, causing mild warmer
Atlantic air to flow in over the Uk, limiting any snow to higher ground. The past few years has seen the Jet move down over southern France and
Spain. This has allowed the Scandinavian High to flow over the UK. At this time of the year there is also a usual High over Greenland. This HP is
usually blocked from progressing further south because of the Jet, but likewise in recent years, it has been allowed to migrate south to fill the
"void" left by the departing Jet.
These Greenland and Scandinavian High Pressure systems have created a blocking effect. This blocking effect has prevented the Jet from returning north
to the UK and allowed cold air either from the Pole or Siberia to flow over the UK. As the blocking effect is a strong effect, it can take many
months, occasionally an entire winter for the blocking to be dislodged...last year it took nearly 3 months.
This year there hasn't been a blocking effect in winter. There was in October and November, which is why it was mild but it wasnt a blocking effect
that braught cold air, it brought mild air. Some models are suggesting a prolonged cold spell in January and February but predicting that far in
advance is harder than winning the lottery.
Last years snow events mainly came from the NE. This is because the colder air flows over the warmer North Sea and convection occurs. Just like
Thunderstorms in summer. This convection creates an effect known as "lake effect snow", similar to the great lakes in the US. The cold snowy air
hits and land and hey presto it snows. A NW wind brings a more limited chance of any prolonged snow event, which is what is occurring at the moment.
If the winds turn E or NE with High pressure over he Atlantic, you'll get some good cold weather.
What we are experiencing is wholly explainable and normal. My rudamentary attempt isn't very good, simply because i dont have time to explain it all
but if you wish to know more just ask and i'll try my best.