Hah! You've fallen for the trap.

Yes, the location is extreme but not in the way you're thinking. You see, given a dry continental easterly we're actually more likely to get ice days here than other places in the south - simply because there's less time for things to warm up.

Case in point: Manston has recorded 7 ice days in the 2nd half of February or later since 1972. To be exact: 15th Feb 79, 15th Feb 85 and the rest in Feb/Mar 86. The absolute latest ice day was 1st Mar 86.

Compare that to Heathrow - a little to the north, but something like 60 miles to the west:

https://en.tutiempo.net/climate/04-1991/ws-37720.html

Heathrow had just 4 ice days in the latter half of Feb or later since 1972: 15th and 17th Feb 79 and two more in late Feb 86. The latest ice day there was 25th Feb 86.

So if you look further inland you'll see that my point holds true: ice days down here are virtually impossible after the middle of Feb, correlating with the general warming that really kicks in around then. The only way you're going to get them is if there's already a deep cold layer in place, plus a decent cover of snow - and we all know what the odds of that happening "down south" are!

Of course, those further north will experience less warming from the sun as it'll still be at a lower altitude. There is, however, a marked switch around the middle of Feb here. I'd be interested to know when it happens further north, for example I'd imagine it's not until you get into March up in Scotland.

Originally Posted by: Retron 

It must be a different world in the south if snow cannot last in the south in the first half of February. In the right conditions up here it will last for days on low ground in early March. If the air is cold and dry enough at any stage in winter I would have though snow melt would be negligible? I’m not referring to a situation where the temperature briefly dips low enough for snow but rather days of cold and wintry weather.

The whole problem is getting that in the first place and with the random selection of charts we have had in the last few days anything is possible with still just under 5 weeks of winter left. As has been mentioned there is, once again, uncertainty by day 6. Lots of options on the the table and none really looks more favoured than another IMO.

Easterly? Northerly? Anticyclonic? Westerly? Southerly? Take your pick! If we claim to “know” what will happen we have probably ventured away from model output discussion and into psychology and mind games.

Originally Posted by: doctormog 

It must be a different world in the south if snow cannot last in the south in the first half of February. 

Originally Posted by: doctormog 

Hah! You've fallen for the trap.

Yes, the location is extreme but not in the way you're thinking. You see, given a dry continental easterly we're actually more likely to get ice days here than other places in the south - simply because there's less time for things to warm up.

Case in point: Manston has recorded 7 ice days in the 2nd half of February or later since 1972. To be exact: 15th Feb 79, 15th Feb 85 and the rest in Feb/Mar 86. The absolute latest ice day was 1st Mar 86. (For reference, there were 12 ice days in the first half of Feb in the same timespan and 27 in January.)

Compare that to Heathrow - a little to the north, but something like 60 miles to the west:

https://en.tutiempo.net/climate/04-1991/ws-37720.html

Heathrow had just 4 ice days in the latter half of Feb or later since 1972: 15th and 17th Feb 79 and two more in late Feb 86. The latest ice day there was 25th Feb 86.

So if you look further inland you'll see that my point holds true: ice days down here are virtually impossible after the middle of Feb, correlating with the general warming that really kicks in around then. The only way you're going to get them is if there's already a deep cold layer in place, plus a decent cover of snow - and we all know what the odds of that happening "down south" are!

Of course, those further north will experience less warming from the sun as it'll still be at a lower altitude. There is, however, a marked switch around the middle of Feb here. I'd be interested to know when it happens further north, for example I'd imagine it's not until you get into March up in Scotland.

Originally Posted by: Retron 

It must be a different world in the south if snow cannot last in the south in the first half of February. 

Originally Posted by: doctormog 

Hah! You've fallen for the trap.

Yes, the location is extreme but not in the way you're thinking. You see, given a dry continental easterly we're actually more likely to get ice days here than other places in the south - simply because there's less time for things to warm up.

Case in point: Manston has recorded 7 ice days in the 2nd half of February or later since 1972. To be exact: 15th Feb 79, 15th Feb 85 and the rest in Feb/Mar 86. The absolute latest ice day was 1st Mar 86. (For reference, there were 12 ice days in the first half of Feb in the same timespan and 27 in January.)

Compare that to Heathrow - a little to the north, but something like 60 miles to the west:

https://en.tutiempo.net/climate/04-1991/ws-37720.html

Heathrow had just 4 ice days in the latter half of Feb or later since 1972: 15th and 17th Feb 79 and two more in late Feb 86. The latest ice day there was 25th Feb 86.

So if you look further inland you'll see that my point holds true: ice days down here are virtually impossible after the middle of Feb, correlating with the general warming that really kicks in around then. The only way you're going to get them is if there's already a deep cold layer in place, plus a decent cover of snow - and we all know what the odds of that happening "down south" are!

Of course, those further north will experience less warming from the sun as it'll still be at a lower altitude. There is, however, a marked switch around the middle of Feb here. I'd be interested to know when it happens further north, for example I'd imagine it's not until you get into March up in Scotland.

Originally Posted by: Retron 

I think your point is generally correct but I have my doubts about citing Heathrow: firstly because of its acres of black tarmac, which we know lifts temperatures, and second because it lies west of a huge conurbation, which in an easterly flow will also have an impact.  Not necessarily significant but when you’re looking at ice days a few tenths of a degree is significant.

Originally Posted by: Gandalf The White 

The reason I chose Heathrow is because it's one of the few stations with an unbroken record on Tutiempo and it's roughly the same distance north as here - for whatever reason, daily data is hard to come by. That said, what little data is available elsewhere (Bristol, Odiham etc) all paints a similar picture.

Stansted (on a quick glance through the likely dates) actually looks very similar to Manston: it has a similar number of Feb/Mar ice days, including Mar 1 86 and similar matches in 85 (15 Feb 85) and 79 (latest date that year was 18 Feb 79). Like Manston it just missed out in years like 2005.

https://en.tutiempo.net/climate/02-1985/ws-36830.html

(And to Richard, read my post which has been quoted several times. It explains my reasoning and also explains your observations.)

Originally Posted by: Retron 

it is Feb 91 was fake news

Originally Posted by: ballamar 

The snow here in March 2013 lasted days. On the 24th, we had full sunshine, and virtually no snow melt at all, and the maximum temperature was a mere 1C. And of course the day before when we had heavy snow the temperature stayed sub-zero all day. On the 30th, we still had >50% snow cover. The snow first fell on the 22nd, so that's 9 days of snow covering the ground. In late March.

It's certainly possible well into March.. and easily done in February if we have the right synoptics. They've just been largely absent in February in recent years. We've had January 2010 and December 2010.. January 2013 and March 2013.. but February has been pretty lacking in the cold and snow department even by the standards of recent years. February 2012 came close.

Originally Posted by: LeedsLad123 

Hampstead in north London had an ice day in March 2013, for what it's worth. On the 23rd. So that's later - a lot later - than the absolute latest ice day at Manston.

Originally Posted by: LeedsLad123 

The reason I chose Heathrow is because it's one of the few stations with an unbroken record on Tutiempo and it's roughly the same distance north as here - for whatever reason, daily data is hard to come by. That said, what little data is available elsewhere (Bristol, Odiham etc) all paints a similar picture.

Stansted (on a quick glance through the likely dates) actually looks very similar to Manston: it has a similar number of Feb/Mar ice days, including Mar 1 86 and similar matches in 85 (15 Feb 85) and 79 (latest date that year was 18 Feb 79). Like Manston it just missed out in years like 2005.

https://en.tutiempo.net/climate/02-1985/ws-36830.html

(And to Richard, read my post which has been quoted several times. It explains my reasoning and also explains your observations.)

Originally Posted by: Retron 

I recorded an ice day on March 24th 2013. Min temp -1.9C, max temp -0.2C, mean temp -1.3C. 

Originally Posted by: Brian Gaze 

Only 90mb lower pressure around Greenland on the 6Z GFS than the 0Z. Ho hum...

Originally Posted by: Rob K 

That site is a great resource thanks.

Looks like Stansted in March 2013 came very close with 0c maxes on 11th and 24th.

Originally Posted by: Ally Pally Snowman 

As an aside, I understood the mean for the day to be the (max+min)/2?  Is yours based on continuous readings?

Originally Posted by: Gandalf The White 

I think there may be confusion in this discussion between snow melt and sublimation, but it’s too off topic to go into detail.

Originally Posted by: nsrobins 

Don't forget altitude as well as latitude in this debate. For example, both Stansted airport and Hampstead  Heath are above 100m, so about 1C adiabatic lower temp. It makes a massive difference in marginal and melting situations. Southend and the Kent Coast are of course at sea level.

Originally Posted by: fairweather 

The definition of Pete Thong? Watch this downgrade - Starting from Last nights 18z run of GFS:

Interesting how we go from bitterly cold wintry easterly set up like last nights 18z chart to cooler and drier and then to milder and zonal within space of a few hours.

Last nights 18z run at 300z

This mornings 00z run at 300z

06z run at 300z.

Originally Posted by: tallyho_83 

That site is a great resource thanks.

Looks like Stansted in March 2013 came very close with 0c maxes on 11th and 24th.

Originally Posted by: Ally Pally Snowman