leicsnow
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Posts posted by leicsnow
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In the last couple of decades, with the exception of the winters 2009/10 and 2010/11, the UK has generally had snowfall late in the winter season, often in early spring, rather than the December-January period. We had a lot of snowy occasions from late February to early April a lot of the time. Examples:
-Probably the best example was winter 2004/5. Hardly any snow for many parts of the UK in December or January, widespread in late February/early March.
-Snow for many in February and March 2007.
-Most parts of the UK received very little snowfall in December 2007 or January 2008 but snowed fairly widespread in March and April.
-February 2009 sort of but that came early in the month.
-Even though there was lots of snow in December 2009 and January 2010, there was some particularly in Scotland in late march and the 1st day of April with some accidents.
Why is this?
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Late February under a 'cold high pressure system' can still deliver widespread very low maxima, extreme examples include 1956 and 1986 - under brilliant blue skies we saw intense cooling at night with mins widely below -10 degrees and maxima struggled to hit 0 degrees. It all depends on the synoptics. Even in 2005 when uppers were less favourable maxima did struggle to get much above 4-5 degrees. Northerlies can be very very cold indeed in late feb especially in the north even under blue skies and sunshine, temps often struggle to get above 2 degrees at best..
Snow does have a harder battle to stick to low ground by late feb esp in the south - but a deep cover can be much harder to shift.
It can happen like this in early March too.
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I think we can actually measure the 'sun strength' for the different months in UV Index. Does any one know what sort of UV Index it is in February and November, etc?
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Whenever I look at any online weather station, if the temperature is 9C (48F) or less, the 'wind chill'/feel like temperature is always something less like 6C. However, if it is 10C (50F) or more, the feel like temperature is ALWAYS the same as the real temperature. Why is this?
E.g. if the temperature is 10C, it says it feels like 10C also. Then if the temp drops to 9C the wind chill will go down to 6C or something.
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Where I am, It was cloudy and mild overnight at 12-13c, but cleared up as the sun rose and got colder as the day went on! It's 9C now and very windy. The forecast is for temperatures to drop overnight so maybe a frost?
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Re Feb and snow it very much depends where in the country you are.
by the last week in feb the sun gets pretty strong in the far south(i.e dorset), because of this a very very cold air mass is needed to stop it from melting over a few days.
In December though there probably isn't enough sun strength to actually melt fallen snow down here, hence when it does fall it tends to stay around longer, particularly so in Jan.
I've got a feeling futher north and definately in scotland the sun doesn't make much difference in Feb.
In the Midlands,
The sun does tend to heat us up to about 5C during a cold spell, although as it's clear it can bring a pretty chilly feel overnight. However this wasn't the case in Feb 2009, as we pretty much had continuous snow at some point every day from 1Feb through 13Feb, and I had three days at home from college in that period. They were unprepared as they were expecting snow earlier in December or January.
Towards the end of February, the sun does tend to heat us up to double figures assuming it's regular February air.
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Does sleet count for the last time it snowed where each of us are?
Because where I live, some very fine sleet fell on the morning of 20th November a week ago tomorrow. Looks like I won't be in the club if sleet counts.
If it concerns just snow, 21st February.
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For Leicester, in my lifetime:
which date/month is the latest that your location has ever received? - April
which date/month on average has the last snowfall? - March
which date/month is the earliest that your location has ever received? - November
which date/month on average has the first snowfall? - December
which month is the snowiest when it comes to snow lying? - December
which month is the snowiest when it comes to snow falling? - February
which month is your snowiest (lying and falling, and depth) in your records? - December 2010
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I think this is right on the mark. For example, the easterly spell at the end of February 2005 brought very marginal temperatures, the northerlies in February 2009 weren't sourced from very far north, and February 2010 was characterised by frequent wet snowfalls and marginal temperatures. Even so, some parts of lowland Britain were snow-covered for about a fortnight during February 2009.
The easterly outbreak in February 1991 was pretty exceptional, but lasting snow cover was also pretty widespread during the easterly spells in mid to late February 1994, and from the north-easterly incursion on the 19th-21st February 1996. During the northerly outbreak of the 7th-10th February 1999, the areas that got just a dusting of snow had it melt quickly in the sun, but those with bigger snowfalls had a more significant period of snow cover, e.g. 7 days at Lowestoft.
Btw re. some earlier posts, daytime maxima of 4-5C would tend to do a lot of damage to a snow cover regardless of whether the month was December or February. If the dew point creeps above freezing, an established snow cover will often melt more quickly than it will in the same temperatures with bright sunshine but dewpoints well below zero. The main issue as we head towards March is that unless we get a potent cold blast, the stronger sun will often lift the temperature to 4-5C, but on the other hand, in December marginality more often translates to sleet rather than snow, particularly around the coasts.
I second the bit about the high dew point making snow melt more quickly.
It can often snow at 3C with a low dewpoint below freezing with low humidity levels. It can also potentially rain at -1C with humidity close to 100% and a high dew point. E.g. it is snowing at 3C with 70% humidity...humidity rises to 80% and the dew point is also now higher, it's now sleeting...humidity rises to 90%, the dew point has risen and rain is falling.
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February can be outrageously cold - Colder than anything possible in December. Coldest December CET on record is -.0.8, coldest February on CET record is -1.9 Its just that we've not had much deep cold in February for a long, long time, so people have tended to become blase about what February can be like.
Agree dude, in fact last winter for many was the first snowless February for years. But it was also the first 'snowfull' November for time as well.
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February is colder than October because there is a solar heating lag effect. In October, after months of strong solar heating, the land and seas have more latent energy contained within them than February which comes months after the peak of solar heating in June and July the previous year.
Late January is when cold pooling reaches its peak ~ a month after the time of lowest solar heating (December 21st/22nd), this is also due to lag effect. Therefore you are more likely to see cold in Feb than Oct. I must also point out that sea surface temperatures are at their lowest around March. This is because the physical composition of water allows a slower release of latent heat than a land mass (hence why you can acheive frosts in September and October).
I suppose that explains why each season is a month on from what it should be. It should be winter November to January, spring February to April, Summer May to July, Autumn August to October. But for the reasons you stated it's winter December to February, spring March to May, summer June to August, autumn September to November.
Thanks for the answer.
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I was recently involved in some somewhat off-topic discussion on another topic, and I thought I'd start one on it here!
Anyway, we were talking about 'sun strength' and how it affects the likelihood of a seasonal cold spell.
We established that November and January are almost identical in terms of sun strength as looking at statistics they have the same length days in a given place in the UK, rather than February having a weaker sun than November as it is considered Winter and November is considered Autumn.
I then clocked that October and February have the same length days, but I'm sure you know as well as I that you are much more likely to experience a cold snap in Feb in the UK than Oct.
So what makes February, on average, more cold than October, if they have the same length days? Same with September and March really.
I know this may sound like a stupid question but I have only recently developed an interest in weather.
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Wait, if we are comparing the day lengths for probablility of seasonal cold spells, then october is the same as february, and february is almost always colder than october. In fact, february 2011 was the first snowless february for many in the UK whilst most cities have almost never experienced snow in october.
With the exception of last winter, most snow arrives where I live in February rather than November to January.
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No I think he is right, the sun has gained a fair bit of strengh especialy by the second half of febuary and can get to work on any laying snow faster however ground temperatures do tend to be lower then which often helps.
Got to remember shortest day is around 21/22 of december so november would have similar solar strengh to january?
Ah, that is something I overlooked so thanks for pointing that out
. Maybe if we look at sunrise/sunset times for a given date in February and a given date in November for, lets say the city of London and compare?This year for November 15th was 07:18 surise and 16:12 sunset.
February 14th 2012 will be 07:17 sunrise and 17:13 sunset.
And that's compared to December 22nd 08:04 sunrise and 15:54 sunset.
I guess you were right! Also, it would be hard to compare days in October or March as they are when the clocks change! (well you can count the day length overall)
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Great forecast looks like another mild month to come, this Christmas could be the first widespread Green one for a few years.
One thing if February is a cold month the snow doesn't tend to last long with the day's becoming longer I remember back in 2009 overnight snow fall was all gone by mid day thanks to the sun been higher than it is in November and December.
Isn't the sun actually stronger in November than February, not the other way round, since November is considered a month of Meteorological autumn and february winter? I've always thought that November had a similar 'sun strength' to March, October to April, and September to May, except getting weaker in Sep, Oct, Nov and getting stronger Mar, Apr, May. In other words, the start of March is sort of like the end of November, etc.
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From what I can remember the snow in late Feb 2005 continued into early March in the East Midlands.
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A good old cold February...! Just like Feb 2009 hopefully. Stuff all the James Madden rubbish.
. Maybe if we look at sunrise/sunset times for a given date in February and a given date in November for, lets say the city of London and compare?
Spring Snowfall
in Historic Weather
Posted · Edited by torrch
I think a lot of British people who don't have an general interest in weather do underestimate the snow potential in February, March and even April. I think a lot of people think February is early Spring although I think even March is late winter.