FI Charts ( T120+ onwards) Winter 2020 **READ MOD NOTE IN FIRST POST**

nacho libre

There seems a consensus now about this much milder weather across the models.
We alll know what happened the last time we had anomalous warmth in February. Be careful what you wish for, at least when it comes to charts showing Summer in February!

icesnowfrost

sdanseo wrote: »

Hopefully sign of things to come.

Snow prospects are gone, bring on the heatwave now until about October please.

All eyes on the end of this month. Cold weather is not done yet.

Kunta Kinte

icesnowfrost wrote: »

All eyes on the end of this month. Cold weather is not done yet.

With your username you should know.

MJohnston

Gonzo wrote: »

Summer 2021 can only be better than last year, however I didn't expect it to start in 9 days time!

You know we're getting into Spring when mild weather is possible without strong winds:



This would be a tremendous lockdown salve for the South East anyway:

Huge Bartlet high on the ECMWF anyway

Gonzo

Unless there is a big change in the models within the next few days I think our chances of decent cold before the end of the month is slipping away into March. The GFS has been hanging onto hope in the form of cold outliers that we may see a return to cold within the next 10 to 14 days but that seems to be slipping away based on this mornings GFS runs. Still time for this to swing back in our favour but getting a proper cold spell to Ireland is like hitting the bullseye on the dart board on your first throw.

If we are going to get a cold spell around the 25th of February we would need the models to start trending in that direction very soon otherwise any cold is just going to get delayed and it could be the 1st or 2nd week of March by the time we cool down again. For now this mild spell is looking prolonged.



The models in general seem to have lost interest in building that high pressure to Greenland, keeping it either over us or to our south.

MJohnston

GFS and ECM ensembles fairly consistent there too:

Gonzo

It does appear the models are now backing away from the chance of one more bitterly cold run end of February/first week of March with a generally dry and mild signal. We may still get some frosty nights into the first week of March if the high pressure builds towards Greenland but the hints of heights retrogression to Greenland or a Scandinavian high appear to be fading. CFS has backed away from the cold potential and replaced it with a dry start to March and then the westerlies come back. GFS/ECM generally now look mild and mostly dry into the first week of March.

nacho libre

I was hoping for one last shot at cold weather, but its very unlikely to happen now. A return to westerlies after the settled period is quite likely now given the Stratopheric Vortex has completely recovered after all the warmings. The lag period between this happening and the response in the troposhere is likely up as well. Also given the effects of a ssw generally last a couple of months it would fit too. Well i suppose its good news for sheep farmers and those that are happy to see the back of winter.

Nqp15hhu

I’m sorry. But I just don’t agree or believe that winter and cold weather is gone. Snow is almost guaranteed here in March.

I expect the cold to return in the next two or three weeks.

Gonzo

Nqp15hhu wrote: »

I’m sorry. But I just don’t agree or believe that winter and cold weather is gone. Snow is almost guaranteed here in March.

I expect the cold to return in the next two or three weeks.

We may still get cold at some stage in March or even April but that is no longer winter and we will need something along the lines of March 2013 or March 2018 for widespread snowfall that is more than just a few cm here and there. March 2013 was cold but the snow melt was very rapid during the daytime. We did have several snow falls during night time but none of them in the republic were to a level that could outlast the strong daytime sunlight. March 2018 was better as it began in the final days of February and the depth of cold was much better than the recent cold spell along with the instability and Storm Emma on top of it.

I am still trying to remain hopeful that we will see a change in the models over the next week but today is not looking very promising with many of the cold outliers gone and the models have lost interest in developing a decent Greenland or Scandi high for the time being. We'ere going to have to be patient and hope for a big shift in the models as soon as possible, not really interested in a cold spell by the 3rd or 4th week of March.

pauldry

The latest Good For Snow (GFS) is much colder than this time yesterday. Cool but no 15 or 16c and FI looks freezer.

PokeHerKing

pauldry wrote: »

The latest Good For Snow (GFS) is much colder than this time yesterday. Cool but no 15 or 16c and FI looks freezer.

Yes a nice Greenland high to start March off on the GFS!

highdef

Gonzo wrote: »

We may still get cold at some stage in March or even April but that is no longer winter and we will need something along the lines of March 2013 or March 2018 for widespread snowfall that is more than just a few cm here and there. March 2013 was cold but the snow melt was very rapid during the daytime. We did have several snow falls during night time but none of them in the republic were to a level that could outlast the strong daytime sunlight. March 2018 was better as it began in the final days of February and the depth of cold was much better than the recent cold spell along with the instability and Storm Emma on top of it.

I am still trying to remain hopeful that we will see a change in the models over the next week but today is not looking very promising with many of the cold outliers gone and the models have lost interest in developing a decent Greenland or Scandi high for the time being. We'ere going to have to be patient and hope for a big shift in the models as soon as possible, not really interested in a cold spell by the 3rd or 4th week of March.

Just to reiterate the strength of the sun in March.

At solar noon (when the sun reaches its highest point in the sky) today, we have:

Derry: 23°
Mullingar: 24.4°
Cork: 26°

On 1st March, we have the following:

Derry: 27.7°
Mullingar: 29.1°
Cork: 30.7°

By mid-March:

Derry: 33.2°
Mullingar: 34.6°
Cork: 36.2°

That's a massive 5.5° increase in about 2 weeks between 1st March and 15th of March and is a huge increase in solar radiation with the rate of increase nearing its maximum, which is the spring equinox, at which point the rate very slowly decreases until it reverses after summer solstice.

Note that between today and 1st March (almost exact same time period as 1st to 15th March), the differences are a good bit below 5° owing to the reason I explained immediately above this paragraph. And from today to 15th March (about 1 month), the difference is over 10°. Bear in mind that difference between the suns highest point in June and lowest point in December is only about 45° (give or take a few degrees) so it's clear to see that the sun gains near a quarter of its annual increase in altitude in the sky in about a month, close the the spring equinox.

Gonzo

The post by highdef highlights how difficult it is for snow to settle and stay on the ground by mid March compared to the 1st of March. During March 2013 it snowed several times at night from easterly streamers with several cm but this snowfall didn't stand a chance of staying on the ground and you had to be up early to see the snowfall before the rapid thaw each morning.

In order to have snow on the ground all day around the middle of March at low levels you need a substantial cold pool in place and the snowfall to be fairly deep if it is to last through daylight hours and into the following night. Severe frosts at night also help to keep the snow on the ground that little bit longer to give it more of a fighting chance of survival.

GFS 6z is beginning to play around with a cold spell during the 1st week of March. It remains to be seen if the 12z holds onto this idea for Ireland. The 00z brought a severe cold spell into eastern and south-eastern Europe instead so there is a big variation in the location of this cold spell from one run to another.

Nqp15hhu

PokeHerKing wrote: »

Yes a nice Greenland high to start March off on the GFS!

Great!

Nabber

highdef wrote: »

Derry: 23°
Mullingar: 24.4°
Cork: 26°

On 1st March, we have the following:

Derry: 27.7°
Mullingar: 29.1°
Cork: 30.7°

By mid-March:

Derry: 33.2°
Mullingar: 34.6°
Cork: 36.2°

Ah the old egg cup and fist measuring system spliced in with some decimals :pac::pac:

FI - At least the GFS is trying

Nqp15hhu

highdef wrote: »

Just to reiterate the strength of the sun in March.

At solar noon (when the sun reaches its highest point in the sky) today, we have:

Derry: 23°
Mullingar: 24.4°
Cork: 26°

On 1st March, we have the following:

Derry: 27.7°
Mullingar: 29.1°
Cork: 30.7°

By mid-March:

Derry: 33.2°
Mullingar: 34.6°
Cork: 36.2°

That's a massive 5.5° increase in about 2 weeks between 1st March and 15th of March and is a huge increase in solar radiation with the rate of increase nearing its maximum, which is the spring equinox, at which point the rate very slowly decreases until it reverses after summer solstice.

Note that between today and 1st March (almost exact same time period as 1st to 15th March), the differences are a good bit below 5° owing to the reason I explained immediately above this paragraph. And from today to 15th March (about 1 month), the difference is over 10°. Bear in mind that difference between the suns highest point in June and lowest point in December is only about 45° (give or take a few degrees) so it's clear to see that the sun gains near a quarter of its annual increase in altitude in the sky in about a month, close the the spring equinox.

I’ve seen snow stick around in March in east Anglia with a 30 degree sun angle.

Furthermore NE usa would have around a 30 degree sun angle in winter and their snow lasts many weeks.

Nqp15hhu

Sun angle 22nd December Chicago: 24.6 degrees

Rochester: 23.3 degrees

New York: 25.6 degrees

Philadelphia: 26.4 degrees

15th January: 27.2 degrees

26.0 degrees

28.3 degrees

29.1 degrees

So to mid March snow can certainly lie around. I am not giving up on cold and snow. I would welcome a strong northerly with open arms!

Arduach

If it's cloudy and snowing and you get a covering of snow, height of sun angle matters less.

highdef

Arduach wrote: »

If it's cloudy and snowing and you get a covering of snow, height of sun angle matters less.

It most certainly does matter when the snow stops falling and skies clear. Unless you have a very decent covering in March and beyond, all it takes is one vehicle to drive on an asphalt road, clearing the snow along it's track in the process. Any March/April/beyond sun that shines on those tracks will quickly heat the ground and the snow either side of the tracks will begin to melt, beginning a process that can clear the roadway of snow in a relatively short period of time. A dusting or light covering (say <5cm) will not last long in Spring sunshine. With the sun getting higher and higher in the sky, there are less shaded areas were snow usually lasts longer.

Also bear in mind that the chances are that after a spring snowfall, there will most likely be milder winds soon after and they will also make mincemeat of non-deep snow.

There are exceptions, of course, early March 2018 being the biggest exception of most of our lifetimes.

Many places, myself included also had a half decent fall of snow on the 18th March 2018. Despite a relatively decent coverage, it still wasn't really that much that fell and it was gone fairly quickly, once the snowfall ended.

Gonzo

GFS 12z drops the cold and continues with mild south westerlies into the first week of March. Perhaps there might be a few cold outliers showing a cold spell but we are a long, very long way from this cold spell in early March being in any way confident that it will happen and affect Ireland.

Arduach

highdef wrote: »

It most certainly does matter when the snow stops falling and skies clear. Unless you have a very decent covering in March and beyond, all it takes is one vehicle to drive on an asphalt road, clearing the snow along it's track in the process. Any March/April/beyond sun that shines on those tracks will quickly heat the ground and the snow either side of the tracks will begin to melt, beginning a process that can clear the roadway of snow in a relatively short period of time. A dusting or light covering (say <5cm) will not last long in Spring sunshine. With the sun getting higher and higher in the sky, there are less shaded areas were snow usually lasts longer.

Also bear in mind that the chances are that after a spring snowfall, there will most likely be milder winds soon after and they will also make mincemeat of non-deep snow.

There are exceptions, of course, early March 2018 being the biggest exception of most of our lifetimes.

Many places, myself included also had a half decent fall of snow on the 18th March 2018. Despite a relatively decent coverage, it still wasn't really that much that fell and it was gone fairly quickly, once the snowfall ended.

Not so much where I'm from, with lack of traffic and narrower shaded roads, altitude. That's if there's a good depth of snow. Up to around St. Patrick's Day. I was snowed in back in 1979 an 17th, snow on St. P's Day in the mid 80s, 2006 etc. March isn't January, it needs the perfect setup like early 2018. But it can deliver.

It's the equivalent of 10 days over 25C in September..like 1991.

bazlers

Arduach wrote: »

Not so much where I'm from, with lack of traffic and narrower shaded roads, altitude. That's if there's a good depth of snow. Up to around St. Patrick's Day. I was snowed in back in 1979 an 17th, snow on St. P's Day in the mid 80s, 2006 etc. March isn't January, it needs the perfect setup like early 2018. But it can deliver.

It's the equivalent of 10 days over 25C in September..like 1991.

Yea we had over a foot here too in march 79.

highdef

Arduach wrote: »

Not so much where I'm from, with lack of traffic and narrower shaded roads, altitude. That's if there's a good depth of snow. Up to around St. Patrick's Day. I was snowed in back in 1979 an 17th, snow on St. P's Day in the mid 80s, 2006 etc. March isn't January, it needs the perfect setup like early 2018. But it can deliver.

It's the equivalent of 10 days over 25C in September..like 1991.

As I said, there are exceptions but snow that stays on the ground for a period of time longer than half of daylight hours and causes disruption is very rare. It's over 40 years since March snow stopped you from travelling which does further show how rare an event it is plus you have also said that you are located in a place that is at some kind of altitude so I'm assuming you're higher up than the vast majority of the population.

I'm in a rural enough area too with narrow shaded roads. I'm at very modest altitude though @ just under 90m with small hills around me, one of 135m ASL and the other of 146m ASL - the approx 50m increase in altitude between myself and the tops of the hills often see quite large differences in the amount of lying snow or ice present.

Gonzo

The GFS extended range is showing a cooling trend beginning around the 3rd of March and is showing cooler than average temperatures for the first half of March after a few milder days at the start. This seems like the most likely period for a cold spell. This also showed up in last nights pub run extended run.

Kunta Kinte

Gonzo wrote: »

The GFS extended range is showing a cooling trend beginning around the 3rd of March and is showing cooler than average temperatures for the first half of March after a few milder days at the start. This seems like the most likely period for a cold spell. This also showed up in last nights pub run extended run.

How cooler than average temperatures? Similar to what we got last week?

Gonzo

Kunta Kinte wrote: »

How cooler than average temperatures? Similar to what we got last week?

At this stage it's hard to know. By the time it happens it will be a month after the last cool spell and we will be into the Spring. As this is in the GFS extended it is unknown at this time if the cold spell will be a northerly, north-westerly, northeasterly or easterly, it could even be a dry spell of cold weather with very little or no precipitation. Given the time of year I'd expect something similar to the last cold spell or March 2013 at the most severe. This will hit slightly later than the 2018 BFTE so very unlikely it will be anywhere nearly as severe as that. Models could also change between now and then and no cold spell happens for us at all. Anyone hoping for a particularly cold and disruptive cold spell will have to wait till next winter, we have missed that boat at this stage.

nacho libre

With the PV back home, i think the best we can hope for is a cold surafce high over us. It looks like the horse has bolted on deep cold, unfortunately. This could have been a classic winter in terms of snow and cold, but it was not to be . We can cite the mjo not going to phase 7 or 8 at the right time, the pv being displaced after the initial SSW, it's all nonsense. The real scientific reason is Oneiric 3 refused to do a snow dance. Get him!

Gonzo

We've heard so much about this winter being a 'teaser winter', not sure I totally buy into that myself as there is no guarantee next winter is going to go for severe cold. This winter certainly delivered for Scotland, Spain, Greece, Netherlands, Germany as well as the traditionally cold eastern Europe and Scandinavia after a very mild December but it all went a little pear shaped for Ireland unfortunately, particularly for eastern, midland and southern parts. Not too bothered about the potential for a cold spell during the first or second week of March. If we do get a couple of cold days and some snow then great, but if not it's not worth getting upset about as by then we are beyond the time period for a sustained and snowy spell. It's still possible to get that in March but we need a truly exceptional depth of cold and instability to deliver something special that will please everyone.