January 2013 CET (2012/13 Competition)

[damianslaw]

And for good reason, it was virtually snowless and very little happened. If you are a snow lover then winter 1991-92 is best forgotten! It was the latest date into the season that I saw my first snowfall, 18th February! It was a really boring season.

Yes it was a very snowless winter in the main, indeed I think we only saw a handful of days with snow falling, I think the 13th Dec delivered some snow, can't remember seeing any in Jan or Feb, March delivered a little bit of snow. The couplets of winter 91/92 and 92/93 were very poor overall for snow.. don't remember missing school because of snow during any of those winters. Things got better in winter 93/94 with a decent Dec and Feb in particular, followed by a lacklustre winter in 94/95 but then a superb winter in 95/96. Mind compared to winters of the last 90's winter 91/92 was very good for cold frosty weather.

[BornFromTheVoid]

Today's minimum is -2.1C, while maxima are around a little under 3.0C, so a drop back to 5.8C is likely tomorrow.

After that, the 12z GFS has the CET at

5.4C to the 14th (0.9)

5.0C to the 15th (-0.9)

4.5C to the 16th (-2.6)

4.1C to the 17th (-2.3)

3.8C to the 18th (-2.2)

3.3C to the 19th (-4.7)

3.1C to the 20th (-1.3)

[cooling climate]

Does not count I know but would say CET from the mid Jan to

mid Feb -1c or perhaps lower.

[reef]

Hadley is 5.8C to the 13th. Yesterday came in at 0.5C.

[Thundery wintry showers]

Yes it was a very snowless winter in the main, indeed I think we only saw a handful of days with snow falling, I think the 13th Dec delivered some snow, can't remember seeing any in Jan or Feb, March delivered a little bit of snow. The couplets of winter 91/92 and 92/93 were very poor overall for snow.. don't remember missing school because of snow during any of those winters. Things got better in winter 93/94 with a decent Dec and Feb in particular, followed by a lacklustre winter in 94/95 but then a superb winter in 95/96. Mind compared to winters of the last 90's winter 91/92 was very good for cold frosty weather.

Looking over the synoptic archives, it is unlikely that snow fell on the 13th December 1991, but it did fall quite widely from the following polar maritime incursion on the 20th:

http://www.wetterzentrale.de/pics/archive/ra/1991/Rrea00119911220.gif

This was by far the most widespread snow event of December 1991/January 1992 which says a lot about how snowless those two months generally were. February 1992 did have a brief wintry snap midmonth but many parts of the south missed out on that as well. In addition the late-January 1992 synoptics look like a fertile ground for "near-missed easterlies" that appear on the models until they reach T+96 and then vanish. It would certainly have been a frustrating winter for snow lovers, and goes to show that while temperatures and snowfall are inversely related overall, it isn't a hard-and-fast rule.

A second half of January 2013 as cold as that of 1992 would be a stretch, but then again, so would a comparably dry one.

[reef]

1991/92 was a strange winter. It was the third winter in four at the time that saw no lying snow here during the winter months at all, yet it had the most air frosts of any winter between 1987 and 2008. As a result it scores 39 on the winter index, which is pretty similar to winters such as 2001/02 and 2004/05.

Edited January 14, 2013 by reef

[mikeocarroll]

5.5C to the 14th (Hadley). Needs to fall a fair bit further for my guess of 1.7c to be in play

[BornFromTheVoid]

Today's minimum is -1.5C while maxima were close to 3C, so a drop tomorrow to 5.2C is likely.

After that, the 12z GFS has the CET at

4.7C to the 16th (-3.0)

4.2C to the 17th (-3.7)

3.8C to the 18th (-2.4)

3.5C to the 19th (-1.7)

3.3C to the 20th (-1.2)

2.9C to the 21st (-4.6)

2.7C to the 22nd (-2.4)

A pretty rare collapse in the CET likely to carry on. With the boundary between the cold continental air and the milder air so close to the UK during most of the run, things could turn out very different to today's 12z though.

[summer blizzard]

Today's minimum is -1.5C while maxima were close to 3C, so a drop tomorrow to 5.2C is likely.

After that, the 12z GFS has the CET at

4.7C to the 16th (-3.0)

4.2C to the 17th (-3.7)

3.8C to the 18th (-2.4)

3.5C to the 19th (-1.7)

3.3C to the 20th (-1.2)

2.9C to the 21st (-4.6)

2.7C to the 22nd (-2.4)

A pretty rare collapse in the CET likely to carry on. With the boundary between the cold continental air and the milder air so close to the UK during most of the run, things could turn out very different to today's 12z though.

Wow.

If we were going after the lowest monthly values of winter 2010 and Dec 10 what would we need to average to beat them.

[Relativistic]

Is there a chance we could go lower than January 2010...?

[summer blizzard]

Theres a small chance although an aim of 2C or below is more achievable.

[BornFromTheVoid]

If we reach 3.3C by the 20th (a big if) then we'd need to average -2.1C for the remainder of the month to beat January 2010. To get below 2.0C, we'd need to average -0.4C.

No chance at all of beating December 2010.

[Relativistic]

Ok thanks. 1.x would be nice.

[damianslaw]

CET taking a nose dive at present, 0.3-0.4 degrees being knocked off easily each day, tomorrow could deliver a knockout 0.5 degree drop and the trend looks like continuing for the foreseeable future, so after one of the mildest starts ever, at the half way stage we are I would say with some confidence likely staring at a below average finish and possibly decently below average i.e. at least 1 degree below average. I still expect february to be the coldest month of the winter. Statistically we are now entering the coldest 4 week period of the year, roughly 20 Jan - 18 Feb, and the time of year when for the first time since June we start to see a weakening in the strength of the atlantic - with the chance of easterly and northerly airstreams increasing.

[March Blizzard]

Not surprised to hear that the biggest chunk of the coldest 30 day period of the year falls in February, despite the supposedly "strong" sun at that time of year!

[DR Hosking]

5.2c to 15th

[Interitus]

Jan 1992 is often a forgotten month, the second half was decidely cold thanks to high pressure with some very cold nights.

Interestingly the coldest weather followed within a couple of days of an SSW on the 19th but NAO or AO were both mostly positive. Coincidental cooling or not?

Graphs of days following SSW.

Edited January 16, 2013 by Interitus

[Weather-history]

About a 2.8C drop in 7 days.

[BornFromTheVoid]

Should be at 4.7C tomorrow or 4.6C if today's maximum comes in below -2.5C.

[Roger J Smith]

The GFS seems odd-man-out among models at the moment, if its milder scenario were correct then this slide will halt at about 4 C and there could be some slight recovery with some days towards the end of the month looking milder than 5 C.

The other models don't go as far but as far as they do go, they are much colder than the GFS. And it's not a European-North American split this time, the GEM is also cold-ramping for next week. Based on all the other model guidance I would expect the CET to continue to slide down into the high 3s by mid-week and ending up close to 2.5 before the ECM 10-day guidance expires. Beyond that could see a further decline or a stabilizing.

Personally I suspect the GFS may be right and the trend may not continue down too much beyond Sunday, however I only rate this as a slight hunch and would not be at all surprised if the weekend storm materializes, dumps a lot of snow, and that anchors a longer period of cold even if uppers do recover.

Then there's February ... maybe I will post a thread opening list of averages and extremes in the next day or two because at this point February forecasts would be highly entertaining (my guess is they would range from -3 to whatever Craig says).

[damianslaw]

CET on a rapid descent at the moment, and can't see any upward movement for the foreseeable future. I'm not with the GFS, all signs suggest strong blocking in the vicinity of Greenland as we head towards the end of the month, with a very cold pool developing to our NE, good chance of a finish in the 2's, which would be decently below average.

Many places have seen an ice day today, and I can see plenty more ice days during the second half of the month. With a heavy snow cover, we don't need cold uppers to sustain cold, the upcoming conditions look ripe for a deep penetrating pool of cold surface air to develop over the country.

[DR Hosking]

4.7c to 16th

[Optimus Prime]

I fully expect (once climate-uk finally updates) the east of England to be pretty much bang on average upto 17th after the extremely cold last 3 or 4 days.

[reef]

I fully expect (once climate-uk finally updates) the east of England to be pretty much bang on average upto 17th after the extremely cold last 3 or 4 days.

After today we'll be on 4.6C (+0.1C), which is pretty impressive when you consider we were at 8.0C (+3.7C) a week ago!

[BornFromTheVoid]

The 12z GFS would have the CET around 2.5C by the 24th, and give us a 10 day mean (15th to 24th) of -1.8C.

Another cold pulse after that and sub 2C becomes possible. We'd need the cold spell to deepen over the remainder of the month to threaten January 2010 though.