Lettucing Gutted

8C...

I play my Half-Life 2 and Synergy games on Steam when the weather looks dull.

Although it was not renowned for snow. I remember a temporary dusting of snow on the morning of 17th May 1996. This was the only time I have ever seen snow in May and at School in Blackpool of all places.

8.5C

Since ChrisHell's website has died I'm going to slowly but surely reconstruct his list of CET month halves since 1772.

Yeah 6C-7C sounds very reasonable. As much as I would love for November 2012 to be below 6C or even 5C we must be realistic with expectations. Post 1998 only 2 Novembers have failed to reach 7C for the final CET which were Novembers 2005 and 2010 and both of those Novembers had unbelievable switcharounds of the highest magnitude and stretching the statistical probability of such CET crashes in one month even for cooling months.

I read in my "Introduction To Atmosphere, Weather and Climate" textbook that Calgary can reach 21C even during January in westerly Chinook events. Calgary must surely be furthest north a temperature of 20C or higher can be experienced in December through February.

That means we have also seen the first thundersnow event of winter 2012/2013.

Another great snow setup which benefits practically all areas of Britain is the Polar Low in an Arctic Northerly flow.Here is an example from the 4th March 1970. http://www.personal....970_weather.htm http://www.meteociel...70&map=0&mode=2

I bet there won't be much difference between either half of October 2012 and the second halfs of December 2011 and February 2012 and both halfs of March 2012. By the way I forgot the name of that website that had the C.E.T for each half of every month.

Stratosferric, North Easterly Blast, Ian Brown,Tamara and Snowmaiden should see this.

This situation also occurred in February 2009. In late January 2009 the Arctic Stratosphere experienced a record breaking increase in temperature in terms of both rate and magnitude and yet similar to February 2012 we had a very cold first half followed by one of the warmest second halves of February on record.

I wish for a very cold Arctic and a raging southerly tracking Subtropical Jet and a raging southerly tracking southern arm of the Polar Jet. This combined with a gentle and highly amplified northern arm of the Polar Jet with a sub 540 HPA upper level trough digging all the way down from the North Pole into Scandi and Western Europe to create the coldest ever summer Continental Polar Northerly blast to rival the likes of even 2nd June 1975, July 1888 and August 1912. This should reload all summer long.

10.5C

Indeed. I know this is FI and only for the end of October but the beauty with this Polar Vortex setup is that unlike the recent "Warm Arctic-Cold Continents" pattern which brought very cold winter weather to many mid-latitude areas (including the UK) in the winters of 2009-2010 and 2010/2011 but also exceptionally warm conditions to the Arctic which then resulted though modification in the Arctic of the Arctic airmass dramatic flips from very cold to very warm conditions throughout the Northern Hemisphere in the late winter/early spring. This Polar Vortex setup from the GFS 18z on the other hand if sustained allows the constant regeneration and maintenance of Arctic air over the Arctic aswell as its sustained and unmodified advection into the mid-latitudes so its a "Cold Arctic-Cold Continents" pattern like the classic setup from the winter of 1962-1963. http://www.meteociel...12&map=0&mode=0

Top 25 warmest Octobers. Here we come again...

Interestingly although the Polar Vortex in the winters of 1962-1963 and 1978-1979 was very distorted the remaining centres still had very low (purple) and extensive very low heights over the Canadian Arctic, Siberia and the far north of Scandinavia and even the North Pole. In effect the Polar Vortex setups of the 1962-1963 and 1978-1979 winters was a halfway house between the very distorted and diluted (less extensive purple heights) centres of the winters of 1995-1996 and 2009/2010 on the one hand and the slightly distorted and very deep North Pole centres of the 1986-1987 winter on the other hand.http://www.meteociel...12&map=0&mode=0 http://www.meteociel...12&map=0&mode=0 http://www.meteociel...12&map=0&mode=0 http://www.meteociel...12&map=0&mode=0 In the very cold Northern Hemisphere winters like 1962-1963 the persistence of those purple heights in the distorted and expanded Polar Vortex allowed the constant maintenance and generation of extremely cold air throughout the Northern Hemisphere though deep Cold Air Advection, radiative cooling and adiabatic cooling in the very dry and steep lapse rates. It was thanks to this and the wholesale Southerly Tracking Arctic, Polar and Subtropical Jetstreams that the very cold and extensive Continental Polar airmasses only began to warm out in late winter almost in Spring.

We managed that as recently as October 2009.

That is a rare sight on the 29/12/96 forecast chart. 3 cold fronts in 1 easterly flow on the same day.

Another target to aim for would be that this is the first October since 2004 not to achieve a maximum temperature of 20C or higher anywhere in the country.

The winter of 2009-2010 showed that even a strong El Nino is very good for cold weather here. The great thing about that El Nino was that its toasty Warm Pool was West Based i.e. in the Tropical Western Pacific Ocean in contrast to the more common East Based El Nino Warm Pools in the Tropical Eastern Pacific Ocean. With the strong El Nino Warm Pool West Based this actually enhanced the signal for a Negative Pacific Decadel Oscillation phase. The West Based El Nino signal also combined with the -ve PDO to create a Positive Pacific North America Pattern phase. This whole setup created an Upper Level Trough over the Midlatitude North Eastern Pacific Ocean, an Upper Level Ridge over the Western United States and an Upper Level Trough over the Eastern United States. This combination also means the main Upper Level Westerly Jet Stream leaves the United States on a Southerly Track which also sets up a powerful Negative North Atlantic Oscillation and Negative Arctic Oscillation phase.

14C

In modern times every month from March 1962 to February 1963 inclusive was below the 1961-1990 average CET.

Wow! That frigid Bartlett Polar Cell would be a cold lovers dream just in mid-winter... but in November... incredible! Not even the classic November cold snaps of 1919 and 2010 produced 500mb heights THAT low over Europe.

This situation reminds of 1993. In that Summer and Autumn there was a big cold pool in the High-Latitude North Atlantic and at the same time a weak El Nino was being canceled out by a Negative PDO phase. This led to one of the coldest Autumns of the 20th Century and even the average CET for winter 1993/1994 masked the classic cold zonality of December 1993 and January 1994. February 1994 was a classic month with two big easterly cold spells!