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Nao Forecast For Winter 2012/2013


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#21 summer blizzard

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Posted 07 July 2012 - 10:12

So now that we are in July, we are approaching the time of year when the first signs of the northern winter arrive, namely in this post the -10C isotherm which was present by the 1st August in 2000, 2002, 2003, 2010 and 2011.

Personally i am a great believer that the earlier the cold, the earlier the snow and the greater the feedback later in winter on a hemispheric scale.

Only a month or so before winter arrives in Siberia again!
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#22 damianslaw

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Posted 08 July 2012 - 20:51

So now that we are in July, we are approaching the time of year when the first signs of the northern winter arrive, namely in this post the -10C isotherm which was present by the 1st August in 2000, 2002, 2003, 2010 and 2011.

Personally i am a great believer that the earlier the cold, the earlier the snow and the greater the feedback later in winter on a hemispheric scale.

Only a month or so before winter arrives in Siberia again!


Yes will be interesting to see how quickly the -10 isotherm appears. Those years you mention brought a mixed variety of winters, only 2010 delivering a notably severe cold spell in the preceeding winter at least in our neck of the woods, for europe I think there was quite alot cold in winter 00/01, 02/03 and winter 10/11 hung on longer in europe and of course we have last feb in 2012.

Isn't a warmer northern hemisphere in the autumn better though for promoting high pressure and less cyclogensis to our north, but yes perhaps what occurs in siberia has a much greater influence overall on the wider picture - I remember the build of strong heights during late october in 1995 which brought a early cold spell in NW Russia - a sign of things to come.

#23 summer blizzard

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Posted 08 July 2012 - 21:19

Yes will be interesting to see how quickly the -10 isotherm appears. Those years you mention brought a mixed variety of winters, only 2010 delivering a notably severe cold spell in the preceeding winter at least in our neck of the woods, for europe I think there was quite alot cold in winter 00/01, 02/03 and winter 10/11 hung on longer in europe and of course we have last feb in 2012.

Isn't a warmer northern hemisphere in the autumn better though for promoting high pressure and less cyclogensis to our north, but yes perhaps what occurs in siberia has a much greater influence overall on the wider picture - I remember the build of strong heights during late october in 1995 which brought a early cold spell in NW Russia - a sign of things to come.


Indeed, some summers even lose the -5C isotherm although we managed to have kept it so far.

Yes, while they are variable for the UK being a small island i believe that there is a decent correlation between Europe and the eastern USA as 03 and 10 were both notable for being cold (pretty sure that 01 was as well). Hopefully we should keep a -PDO to enhance any effect.

There is a strong correlation between above average October snowfall (on a hemispheric scale) and a -AO (also a correlation between the -PDO and -AO), this is likely a result of outgoing radiation and its stratospheric feedback as snow cools the area around it and below -15C you typically see a surface high.

If there is one thing we have learnt in recent winters, it is that the stratosphere will override most other signals.
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#24 syed2878

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Posted 10 July 2012 - 00:39

hey guys i would like to heare what u guys think of this winter 2012-2013 winter forecast.
This is the update to the 2012-2013 Preliminary Winter Forecast. We will start off with an ENSO update and go from there.

enso_update/sstanim
In the last month or so, we have seen warm sea surface temperatures making a rebound to areas just north of the ENSO monitoring area, with a little cooling
actually occurring in Nino areas 1+2. Warming has actually receded north as a whole, slightly cooling down the western portions of the ENSO monitoring
area. However, an indication of what's to come is underwater.

anim/wkxzteq_anm
(Refresh page if it stops looping)
As seen in this animation, warm water has recently been welling up from a depth of about 100-200 meters in the Nino 3.4 and 4 regions. This warm water has
been steadily progressing upwards towards the surface, but also shifting east as it does so, indicating that warm water in the east is being supplied by
the west, which only means that this warm water in the western ENSO region will have to come up sooner or later. As the seasons progress into July and
August, we should start to see enhancement of these warm areas and an eventual upwelling of the warm water in the western ENSO regions.

An El Nino Watch was issued just over a week ago by the Climate Prediction Center, as seen in
this post.
An El Nino Watch is issued when conditions are at least 50% favorable for an El Nino to form in the 2nd half of 2012. As a recap, an El Nino is warming
of ocean waters in the Pacific Equatorial region.

The next thing we can see indicating an El nino is something called Outgoing Longwave Radiation, or OLR. Basically, a negative OLR value means more thunderstorms,
which signifies an El Nino, whereas a positive OLR index tells of less convection than normal, AKA a La Nina. Let's take a look at the last 5 months of
OLR observation.

s400/Screen+Shot+2012-06-08+at+2.27.47+PM
The OLR has been strongly positive in January and February, where we did have a solid La Nina. However, it is evident that this La Nina did weaken in March
and April, and last month in May, we did have a very slight negative value on the OLR, which tells me that the La Nina is officially over, and we are beginning
to wane into a potential El Nino situation for the 2nd half of the year and into 2013.

s400/01mb9065
Something else we watch for is the stratosphere. Here, we see that temperatures at the 1mb level are right up against the 1979-2008 minimum levels, which
does indicate that warmer weather should prevail for a little while. If the stratosphere drops below average levels going into the winter months and stays
like that, we could very well have a repeat of last winter, where the stratosphere couldn't either warm or stay warm long enough to provoke typical winter
weather. This abnormal cooling is also occurring at the 70mb level, which is where warming in the stratosphere becomes significant enough to provoke winter
weather into action around the winter months.

s400/ssn_predict_l
The sun will be a player in this winter, and this sunspot cycle will be abnormally low. The maximum number of sunspots will occur next year, and it will
be just around 60- much lower than the 110-something sunspots in 2000. This will be a more interesting around 2020, when the number of sunspots stands
at around 0. However, there will likely be some small effect on temperatures, and it should be a little lower than what it would be at normal sunspot level.
Let's look at this new solar cycle 24 in comparison to previous cycles.

s400/cyclcomp1
The graphic above shows the current solar cycle in violet compared to the previous few cycles. Cycles 21 and 22 were fairly normal and very similar, but
Cycle 23, in red, came out weaker than the previous two cycles. And now, since 2008, Cycle 24 has been the weakest of all, exhibiting a trend that the
sun is indeed cooling down. I expect that this lower than normal cycle will probably not affect our upcoming winter that much, but in the next several
years, a cooler than normal trend should be observed.

Something I really want to share with you is the relation of the Pacific Decadal Oscillation to this winter.
s400/ENSOandPDO
In the image above, you can see the PDO and ENSO effects on the Pacific ocean. A Positive PDO induces cooler than normal waters across the area to the southwest
of Alaska, with warm waters in the Gulf of Alaska and in the ENSO area, suggesting that a +PDO and El Nino may have a slight correlation. The same potential
correlation happens with a La Nina and -PDO, with warm waters in the areas southwest of Alaska and somewhat cooler waters in the ENSO areas. That said,
let's look at the PDO forecast I posted a little while back from the ESRL's LIM PDO model forecast, which I am unable to like to due to technical difficulties
at the ESRL.
s400/pdoplum
The PDO is forecasted by the ESRL to stay strongly negative going into the next year. This does appear to be likely, as we are currently in a negative phase
at the time of writing (
source).
Considering that we are in and will be staying in a negative PDO, it can be expected that a generally warmer body of water than usual will be sitting in
the areas off the Asian coast.

I decided to put in another set of analogues, but this time trying to pinpoint the scenarios that may happen for us. I used years with El Ninos and Negative
PDO values (
source 1)
(
source 2).

s400/cd64.53.178.223.164.18.34.10.prcp
Temperature Anomalies in El Nino and Negative PDO Years
s400/cd64.53.178.223.164.18.38.19.prcp
Precipitation Anomalies in El Nino and Negative PDO Years
Temperatures in these years were pretty warm in the western half of the US, including the Rocky Mountains. Near-average temperatures were observed in the
eastern US, with cooler than normal temperatures in the Northern Plains. As for precipitation, values were pretty much average across the nation, with
above average precipitation in the Northwest. By the way, I did compare observed drought values for these years (
source)
compared to May 2012 (
source),
and they correlated very nicely, indicating that these years do indeed have a correlation with this situation. Again, this is just an observation into
what could happen with an El Nino and negative PDO.

Now we get into the analogues that I am using to make a much better determination of this winter's potential.
Now, let's check out years that followed two La Ninas in a row. The years I used were:
•1963
•1972
•1976
•1986
•1997
•2009
It should be noted that while some of these years could be called neutral, I was looking to see if they were still in negative territory and it seemed
that the two years in question remained connected by the same La Nina event, by one way or another.

s400/cd64.53.178.223.165.14.40.13.prcp
Temperature Anomalies in December - February for the years mentioned above
s400/cd64.53.178.223.165.14.40.28.prcp
Precipitation Anomalies in December - February for the years mentioned above
What we see as the result are basically El Nino conditions, which is a given, considering an El Nino is expected this winter. It should be noted that the
strength of the El Nino was not taken into effect this time around for these years. Looking at temperature anomalies, we see warmer than normal conditions
in the northern US, with cooler than normal temperatures and wetter conditions along the Southern US. Dry conditions prevailed in the Ohio Valley.
Now, let's take the same years listed above and pick the ones with weak to moderate El Ninos (classified as +0.5 to +0.9 for a weak Nino, and +1.0 to
+1.4 for a moderate El Nino).
As a result, we have:
•1963 (Moderate El Nino)
•1976 (Weak El Nino)
•1986 (Iffy Moderate El Nino)
•2009 (Can Pass for a Moderate El Nino)

1972 was thrown out as it was a very strong El Nino, as was 1997. I did include 1986, which was classified as a strong El Nino. I included 1986 because
it was a moderate El Nino in December -February. 2009 was a tough choice. i did decide to include it, despite the fact it was a strong El Nino, because
it was borderline strong, and it is one of the analogues that is being buzzed around the weather world recently.
Putting the 4 years listed above, we have these results:

s400/cd64.53.178.223.165.14.49.36.prcp
Temperature Anomalies in weak or moderate El Nino's following a double dip La Nina
s400/cd64.53.178.223.165.14.49.50.prcp
Precipitation Anomalies in weak or moderate El Nino's following a double dip La Nina
This result turned out substantially different than the previous images. We now have a cool eastern half of the US, with only a bit cooler temperatures
in the Northern Plains than the previous 2 images. Precipitation remains roughly the same, with a wet Southeast and dry Ohio Valley and Northwest regions.
Let's discuss analogues in specific. 1976 is a good one, in my eyes, because I compared charts for Chicago, Illinois, from this year and 1976, and found
both years to have well above average late winters and springs. Towards fall and winter of 1976-77, the temperature sharply dropped and averaged below
normal for those seasons.
1986 was a little less on the ball. 1986 involved temperature swings that seemed to equal themselves out, with no defined above average phase or below
average phase. However, there are some sharp spikes in Chicago temperatures from 1986 in the first half of the year, and that could correlate with the
upcoming winter.
2009 was a curveball. There were small phases of above normal temperatures, and small phases of below normal temperatures throughout the year in Chicago.
The first half of the year involved a mainly below normal temperature phase, but the first few months eventually brought a nice, warm temperature swing.
This analogue could be a fair one.
1963 had a fairly similar situation as 1976, but 1963 began cool and stayed warm throughout the year before completely tanking in the last month or so
of the year. They both follow a cool-down in the last part of the year, but 1963 began a little too cool for my complete satisfaction.
It should be noted that the 1950-1980 timeframe involved a negative PDO, whereas the 1980s were in a warm PDO. That said, I think I will discount it. 2009
was a pretty neutral PDO, on its way to a negative phase, where we are now, so I want to keep it in the game.
As if this wasn't long enough, let's make up one final analogue set using 1976-77, 2009-10, and 1963-64.

s400/cd64.53.178.223.165.15.5.37.prcp
Temperature Anomalies for Weak/Moderate El Nino years following a double dip La Nina in a -PDO
s400/cd64.53.178.223.165.15.6.5.prcp
Precipitation Anomalies for Weak/Moderate El Nino years following a double dip La Nina in a -PDO
Temperature anomalies changed dramatically with this, and it shows that the eastern half of the US, as well as the Northern Plains, are now on the cooler
side of things. Precipitation didn't change too much, so temperature is the real big thing now.

Something else I am watching is an index called the Quasi Biennial Oscillation, or QBO. It involves wind patterns in the stratosphere. When the QBO is
negative, winds are going in a westward direction. A positive QBO leads to winds going in an eastward direction. Now, last winter there was a lot of hype
over sudden stratospheric warmings, or SSW's. An SSW has enhanced potential when the QBO quickly changes from positive to negative, leading to intense
and sudden warming in the stratosphere.
Now, I decided to look around and see if I could find a relationship between the QBO and equatorial convection. I did find an interesting article, and
I was able to determine from the information provided that tropical convection is deeper, or stronger, in the Negative QBO than in the Positive QBO. That
said, it would be logical to find a negative QBO in an El Nino situation, due to the fact that El Ninos are characterized by abnormally high levels of
convection. This is also logical, as a negative QBO contributes to a Negative NAO, which in turn combines with the El Nino to produce intense Northeast
snowstorms.

I also found a correlation between Outgoing Longwave Radiation (OLR) and the Quasi-Biennial Oscillation (QBO). When there is enhanced convection in the
equatorial region, the OLR becomes negative. That said, a negative OLR is more tilted to be indicative of an El Nino. Deep convection is characterized
by a low OLR, as stated earlier. If the Negative QBO supports deeper convection, then it would only make sense that both the QBO and OLR have a relationship
with each other and the ENSO pattern. However, not all of these will definitely happen, but they do have an increased likelihood of happening in correlation
with each other.
Right now, we are in a neutral ENSO situation that appears to be heading towards an El Nino, and this has been reflected by a very weak negative OLR anomaly.
However, the QBO has recently been tanking to very low levels in recent months. I find that this is not a surprise, as I showed above the upwelling of
warmer waters in the ENSO region. Since the QBO is negative, I would expect at least one ENSO region to be in an El Nino state of warmer than normal waters.
To be quite honest, I have a feeling that the eastern ENSO areas could pass off having an El Nino right now. If the QBO is negative, I would expect the
OLR to become negative soon, as warmer waters at the surface increase convection, keeping the QBO and OLR in negative territory.

Keep in mind that just because the QBO and/or OLR are negative, an El Nino is not guaranteed to form. It is just in the favor that these align with an
El Nino.

All of that said, here is my forecast for winter 2012-2013.

-Weak to Moderate El Nino will be here for winter.
-Cool temperatures have the potential to take the eastern US by storm this winter.
-Precipitation could be on the below normal side in the Ohio Valley, but that is not for sure just yet. A weak El Nino can bring above average precipitation
to the eastern US, while a stronger Nino does not.
-Considering we may be heading into an El Nino, I am liking the idea that the South US and East Coast will get above normal precipitation. Yes, that means
more snow for the East Coast.
-Cold shots ought to reach across much of the Eastern US, so some crops in the Southeast may be at risk.

Thank you so much for reading.
Andrew.

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#25 AWD

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Posted 10 July 2012 - 08:16

A according to Matt Hugo, the EC seasonal forecast update signals a -ve pressure anomaly to the NW of the UK, meaning a +NAO, ultimately meaning wet, windy & mild.
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#26 Don

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Posted 10 July 2012 - 12:04

A according to Matt Hugo, the EC seasonal forecast update signals a -ve pressure anomaly to the NW of the UK, meaning a +NAO, ultimately meaning wet, windy & mild.


Very early days but the current signs don't seem to be good for Winter 2012/13. Cold weather lovers may well have to pay for this cool Summer in 5/6 months time!

#27 AWD

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Posted 10 July 2012 - 14:49

Very early days but the current signs don't seem to be good for Winter 2012/13. Cold weather lovers may well have to pay for this cool Summer in 5/6 months time!


Unfortunetly not.

As Matt Hugo has said, the EC Seasonal output back in March did forecast the current +ve pressure anomaly we have now to our north west correctly, and it has been upgraded from system 3 to system 4 ( ie higher res ), so it shouldn't be ignored.

This and the QBO do forecast a rather mild and wet winter. However, at this stage, we obviously do have plenty of time.
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#28 summer blizzard

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Posted 10 July 2012 - 15:52

Very early days but the current signs don't seem to be good for Winter 2012/13. Cold weather lovers may well have to pay for this cool Summer in 5/6 months time!


That is actually debatable.

The -PDO which seems to be persisting bodes well.
The -QBO could peak as late as September (or now) so winter will be neutral.
The +MEI (El Nino) is unlikely to be strengthening through winter and is not a bad thing necessarily anyway.

Ultimately depends on which of those signals is the most powerful but i would be leaning towards a -AO in December and January at this stage.
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#29 feb1991blizzard

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Posted 10 July 2012 - 23:16

That is actually debatable.

The -PDO which seems to be persisting bodes well.
The -QBO could peak as late as September (or now) so winter will be neutral.
The +MEI (El Nino) is unlikely to be strengthening through winter and is not a bad thing necessarily anyway.

Ultimately depends on which of those signals is the most powerful but i would be leaning towards a -AO in December and January at this stage.


Agreed, 2009/10 winter had a strong Nino and it was the coldest for 30 years, thank god there wont be a significant Nina event this winter, anything around neutral ENSO or above will do for me, i know this is not massively scientific but if you look at the ENSO signal for the last few winters then one would be forgiven for thinking that La Nina is what has given us the shocking last winter and a half.

#30 Ladyofthestorm

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Posted 13 July 2012 - 10:59

just a hunch with no scientific reasoning whatsoever.... NAO negative going into autumn, an indian summer on the way me thinks....then turning positive till January, wet windy early winter... then something a little more seasonal.... Negative NAO from January onwards...as I said no reasoning just a hunch and gut feeling.
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#31 CanadaAl

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Posted 17 July 2012 - 16:39

It does seem at this stage that the jet stream is heading north over the next week or so giving us more typical summer conditions. I am starting the think we will end up with another indian summer like that we have had over the last 6/7 years again, as a strengthing Azores high begins to appear. I really don't understand why people are already going for a average/above average winter in terms of rainfall and temperature. I could really see a possible repeat of 2009 (But not to the same extent) What do you guys think?

#32 summer blizzard

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Posted 18 July 2012 - 21:32

Have been looking at the quarters since 1950 which have seen at least 2 months 1.5C or more below the 1981-2010 averages.

Data indicates that actually El Nino is the better bet for a cooler Q4 and Q1 with a transitional QBO (it must be a miracle but that is the conditions expected in the upcoming winter).

Raw data is below.....


oct: 10.7
nov: 7.1
dec: 4.6
jan: 4.4
feb: 4.4
mar: 6.6

jan
1952
1954
1955
1959
1963
1966
1977
1979
1980
1982
1985
1987
1997
2010

feb
1954
1955
1956
1963
1968
1969
1970
1978
1979
1983
1985
1986
1991
1996
2010

mar
1951
1955
1962
1969
1970
1971
1975
1976
1979
1980
1984
1985
1986
1987
2006

oct
1952
1955
1964
1974
1980
1981
1992
1993
2003

nov
1952
1962
1966
1967
1969
1985
1988
1993
2010

dec
1950
1952
1961
1962
1963
1968
1976
1981
1995
1996
2009
2010

q1

1954*: e1
1955**: l2
1963*: l1
1969*: e2
1970*: e1
1979**: e1/+1
1980*: e2/-1
1985**: l1/+1
1986*: e1/+1
2010*: e2/-2

70% El Nino
60% +QBO

q4

1952**: e1
1962*: l1
1981*: e1/-1
1993*: e2/-1
2010*: l2/+2

60% El Nino
66% -QBO
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#33 summer blizzard

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Posted 22 July 2012 - 10:50

http://jisao.washing.../pdo/PDO.latest

Confirmed - 4th longest -PDO streak (one more month puts us into 3rd, a couple of months puts us into second).

The comparable periods are 1970-1972, 1961-1963 and 1948-1951.
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#34 Summer Sun

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Posted 22 July 2012 - 11:21

After this awful summer I hope we get another mild winter, last winter was lovely with just the one short lived cold spell

3596892559.png


#35 syed2878

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Posted 22 July 2012 - 12:02

Well the summer been so crap lets hope the winter makes it up with lots of snow and cold.
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#36 summer blizzard

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Posted 22 July 2012 - 12:09

After this awful summer I hope we get another mild winter, last winter was lovely with just the one short lived cold spell


I find it interesting how much the Brits expect in winter because that 'short lived cold spell' delivered a 12 day mean below 0C, not short at all historically.
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#37 Aaron

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Posted 22 July 2012 - 13:45

After this awful summer I hope we get another mild winter, last winter was lovely with just the one short lived cold spell

Be prepared for people to quickly put you down in the winter season like people but cool lovers down during the summer - because you're in the very small minority.
2013 stats

Highest temperature 11.2°C (3 Jan)
Lowest temperature -7.1°C (19 Jan)
Highest minimum 9.4°C (3 Jan)
Lowest maximum -3.7°C (19 Jan)
Deepest snow depth 25 cm / 10 inches (26 Jan)
Wettest day 20.5 mm (26 Jan)

#38 Summer Sun

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Posted 22 July 2012 - 14:42

The current IOD maps for winter (December to February) suggest it to be a drier than average again for many parts

Posted Image

Temperature wise some parts of the north west, scotland and northern ireland are below average but for england and wales were average or just slightly above average

Posted Image

3596892559.png


#39 Eugene

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Posted 22 July 2012 - 14:56

A drier than average near average temperature winter will do me just fine Posted Image

Edited by Eugene, 22 July 2012 - 14:56 .

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#40 damianslaw

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Posted 22 July 2012 - 16:37

I find it interesting how much the Brits expect in winter because that 'short lived cold spell' delivered a 12 day mean below 0C, not short at all historically.


Yes, last winters 'one cold spell' was for England a preety potent one all the same with a mean below 0 degree over a quite lengthy 12 day period and not the 3-4 day cold spells we endured through most winters from 07/08 through to 08/09. I think it will be forgotton quite quickly unfortunately because of the severe lengthy cold spells in late Nov - Dec 10 and more generally mid dec - mid jan 09/10. It was also a proper wintry spell with snow on the ground for quite a number of days and a notable freezing rain event took place.

Edited by damianslaw, 22 July 2012 - 16:37 .