Model output discussion - after the beast, what next?

[frosty ground]

28 minutes ago, TEITS said:

Have to be honest rather underwhelmed with the snowfall predictions in the model output for my location. If I was honest the Arpege, Hirlam have been posted this morning but personally I have always found the Euro 4 to be most reliable.

The locations that seem to hit the jackpot is Lincs to Northumberland. The problem for my location and others is the lack of a N,ly element to the E,ly flow. I have seen the wash streamer mentioned but this will not occur from a direct E,ly flow.

I will add even for the far SE the Euro 4 only suggests light snowfall.

Isn't that chart a 3 hour accumulation chart? 


This chart from 0 to +48
 

[Midlands Ice Age]

On ‎12‎/‎03‎/‎2018 at 23:49, Midlands Ice Age said:

Hi guys....

I thought it might be worth updating my data for this min- beast to give an indication of what is actually happening. I have just updated the March figures, for this posting. 

I have decided to take it seriously, and go back myself through the analogue to ensure that we have all the cold spell as BB stated it may not be comprehensive.  (hopefully watching the snow fall).

I will set up my data on a PDF doc so that it can (hopefully) be altered  more easily in the coming winters

Anyway for now (and using BB's latest posting)  -

     March

     ======

      1/3/2018                8/3/1917           5/3/1971    2/3/1965     11/3/2013     17/03/2018             

     -15C                           -14C                  -12C          -12C             -12C           -14C

     -20C                           -20C                 -20C           -16C             -16C            -18C (although -20Cs just hit Scandinavia)        

 

A bit rough and ready, but it gives an indication.

Note as stressed by BB it does not show the impact of the winter, for that one needs to include longevity. 

 

It is clear the upcoming event will still be extremely potent and is probably without equal for this time of year. It will also be beating many of the previous top events in January and February in many years.

As I finished in my last post on Monday of this week 

'What will make it 'special' is the date - much later than anything else comparable'.

MIA 

 

Edited March 16, 2018 by Midlands Ice Age

[mulzy]

11 minutes ago, frosty ground said:

Isn't that chart a 3 hour accumulation chart? 


This chart from 0 to +48
 

A lot of that is the rain that is expected to fall on Friday.

[frosty ground]

4 minutes ago, mulzy said:

A lot of that is the rain that is expected to fall on Friday.

Yes it is, but I'm not sure what use a 3 hour chart is to show the total PPN in the previous 24 hours is?

[snowy weather]

19 minutes ago, Steve Murr said:

Nice southerly correction on the IKON - alligning the flow more E / EENE as oppose to ESE...

It's looking very  very good for the southeast

Is the snow set to hit a little earlier now?

I.e on Saturday afternoon rather than night?

Edited March 16, 2018 by snowy weather

[Derecho]

Great model output this morning, with the GFS looking snowier again, a few things to note:

1) There is some uncertainty over the timing in which tonights front turns into snow across NE England, if things do come together well it could provide some good covering at lower levels tonight/around midnight before it moves south and turns into snow completely

2) The HIRLAM model which I found performed best during the last cold spell for short range precipitation forecasts, has the front reinvigorating over the south

3) There could be quite an organised band of snow showers for NE England if HIRLAM is correct, especially for saturday afternoon across Humberside. Lets hope that is correct.

4) The incoming low on sunday looks snowy and the south coast could have an ice day under all the cloud. I'm hoping snow risk extends further north for the likes of Mucka too on Sunday. Again HIRLAM certainly shows this.

5) The uppers have nudged a bit higher again but dew points and air temperatures are still verty favourable even down here. Better then storm Emma

6) Can the NE sneak in a cheeky snow event later on Monday?

To finalise things here is a swingometer for next week onwards till the end of March



Here are the scenarios

High pressure/warmer weather - An emergence of Spring

Average/westerlies - Either a cool zonal pattern or milder and colder phases cancel each other out.

Transient northerlies/below average - Cooler airmasses are more dominant though generally no sustained pattern

Cold with northern blocking - Potential for a sharp cold spell which may last longer

Signal for strong northern blocking has weakened after being quite strong in recent days. General theme is for a cool zonal theme or some transient northerlies (though may pack a punch for some) to see out the month.
 

• I'm hoping we get some strong cold to see out the month, then some Spanish plumes or high pressure for a warm April 

[Panayiotis]

I have to disagree with the EURO4 being reliable, especially when it comes to predicting convective showers. It almost every time under-estimates the intensity and area of these showers and this was particularly seen when we had  the beast from the east earlier in the month.

[frosty ground]

2 minutes ago, TEITS said:

I simply posted that chart to illustrate the precip forecast for that particular time and which locations are favoured. Im not sure what use posting total accumlations are when some of this will fall as rain!

Not sure how tha fitted in with....."I will add even for the far SE the Euro 4 only suggests light snowfall."

 Total PPN by 27 hours Vs 48 hours 

Looks like the SE gets a decent amount of PPN..... 

[minus86BriJ]

2 hours ago, J-Man said:

Slightly annoying that the media are referring to this as the mini beast. By the model output and snow potential it differs very little from beast 1, I think many average folk will be surprised by this over coming days. Its a beast its going to be pretty exceptional and something to remember again.

Try telling that to us here in Ireland, as far as I can see this weekend will be a like beast #1 sneezing sarcastically on the east coast.  It definitely will be stupidly cold for the time of year and there will be accumulations but nothing compared to the craziness that went on here a couple of weeks ago.  The foreign visitors who flew in for paddy's day are in for some shock to the system tomorrow!

Anyway it looks good for a lot of you in the south of England from this mornings updates, here's hoping you all get your fill.

[NO LONGER POSTING]

10 minutes ago, frosty ground said:

Not sure how tha fitted in with....."I will add even for the far SE the Euro 4 only suggests light snowfall."

 Total PPN by 27 hours Vs 48 hours 

Looks like the SE gets a decent amount of PPN..... 

Euro4 was the worst performance last easterly 

[NO LONGER POSTING]

1 minute ago, frosty ground said:

Yep it had no where near the amount of snowfall for my location during the last spell.

Yep, it did very poorly infact I don't rate the model at all anymore its been poor for a long time the likes of the HILRAM won out last time by far followed by the Arepge and Arome 

[musehead]

HIRLAM 6z gives 10cm in London for the 24 hour period between 7am Saturday and 7am Sunday, and 15cm on the South Downs.

I will be interested to see what happens as I usually use EURO4 for short term predictions.

[bluearmy]

The transition from Sinking ridge to upper trough over nw Europe is beginning to sing undercut/slider. Given the time of year, this is going to be difficult to wring anther snow event out of but elevation further north could well be seeing charts of further interest quite soon 

[Purga]

Super chart to welcome in the new month!

A number of cold options on the ENS run @ 06z e.g.

26th March

28th March

Could April become another bone chiller??

Edited March 16, 2018 by Purga

[Interitus]

On 3/12/2018 at 23:49, Midlands Ice Age said:

Hi guys....

I thought it might be worth copying in my post of Feb 23rd where I analysed BB's posts showing some of the more potent easterlies -

 

I have been busy analysing the charts that BB produced to try and get some ideas of intensity of cold for each of the spells..

Below I present the results by month of the coldest 850that BB presented for the UK,  and also for the coldest part of the cold in that wave,(which since most of them are easterlies) is Europe. Where it is not I have indicated as such.

So the results are -

November                                                                                        December  

========                                                                                        ========

27/11/1890                                                                                        1/12/2010

-16C   (in UK)                                                                                     -16C    (In UK)

-20C  (In Europe)                                                                               -20C    (in Europe)

 

January

=======

12/1/1987      17/1/1940             21/1/1979                24/1/1947             31/1/1947         21/1/1881       

-18C                 -16C                     -16C                       -16C                        -16C                 -14C                      

-24C                -28C (Russia)        -21C                       -20C (Russia)          -16C                 -20C               

9/1/1979    30/1/1972

 -14C           -14C 

  -16C             -16C

 

17/ 1/1963      21/1/1982              7/1/1985               7/1/1891                                          

  -13C               -12C                      -12C                    -12C

  -22C               -28C (Russia)        -20C                    -16C

 

February

========

22/2/1956         7/2/1895     7/2/1991        13/2/1929      2/2/1963      28/2/1969                  20/2/1986                  

   -18C                -16C            -16C               -14C            -14C                -12C                          -12C                             

   -22C                -18C            -16C               -24C             -16C               -28C (Greenland)       -24C                     

 

7/2/1958       23/2/1947           26/2/1962        21/2/1942      

  -12C                -12C                      -12C             -12C 

  -20C                -20C                      -14C             -14C  

 

March

======

      1/3/2018                8/3/1917           5/3/1971    2/3/1965     11/3/2013                

     -16C (probable)          -14C                  -12C          -12C             -12C

     -20C                           -20C                 -20C           -16C             -16C        

 

A bit rough and ready, but it gives an indication.

Note as stressed by BB it does not show the impact of the winter, for that one needs to include longevity. 

Anyway - Where is your favourite winter?

---------------------------------------------------------------------------------------------------------------------------------------------------

 

 

It is clear the upcoming event will be one of the most potent for many years if it comes off as is being depicted at the moment.

What will make it 'special' is the date - much later than anything else comparable,

MIA 

You might like to check out this link posted previously from the journal Weather - An historical and climatological note on snowfalls associated with cold pools in southern Britain - http://onlinelibrary.wiley.com/doi/10.1002/wea.666/full

Unfortunately they do not consider events outside Dec-Jan, but I notice Feb 1948 had -20°C 850 isotherm grazing the south east and large swathes of -16/-18°C across the country.

 

[Weathizard]

15 hours ago, J-Man said:

Slightly off topic but in terms of "sun strength" as we all know the further north we go the weaker the sun so here is a little info comparing sun height when beast 1 hit compared to beast 2. I've used dates of 1st and 17th March for comparison -

Brighton 31.7 & 37.9

Birmingham 30.1 & 36.3

Hull 28.8 & 35.0

Newcastle 27.6 & 33.8

Dundee 26.1 & 32.3

Lerwick 22.4 & 28.6

 

So we can see that by the 17th the the sun strength Newcastle northwards is just marginally stronger than it was in the south during beast 1, so for these areas any snowfall shouldn't melt off that quickly, in fact we still have lying show in my coastal area of Northumberland from beast 1 where it drifted.

Bit late to quote this but the snow melted exceptionally quickly here in Brighton when the sun came out being honest, so I would expect lying snow to melt very quickly in any sunshine.

Im sure I'll be shot down but even as a snow lover I'm hoping for some warm weather around the corner soon after this cold snap the heating bill last month was a shock  That being said doesn't look like much chance of any particularly early spring like weather with the ensembles painting a mostly average picture.

[Derecho]

Looking to the last week of March, a notable swing again with some colder solutions. A few develop a strong Greenland high and one or two beasts in there.

[Polar Maritime]

A few posts have had to go, Please use the report button for off topic posts. And another quick reminder that snow probabilities will chop/change right up until the event when only the radar will be of use. Please use the regionals for Imby snow discusion as not to derail this thread, And please keep meto warnings to the correct threads.

Thanks please continue.

 

 

Edited March 16, 2018 by Polar Maritime

[Man With Beard]

Right so we have a very clear contrast between some of our favoured short-term models by Sunday 6am:

    

EURO4 has a lot of snow in SE and N England but tending to be localised and favouring high ground, but large areas below one inch of snow

HIRLAM much more widespread on the streamer and on activity moving up from the SE, with most areas receiving an inch at least. Also a lot of snow on the E Anglia coast

ARGEPE like EURO4 puts a good amount over hills but rather less at sea level in the north. It generally has more for central areas than the EURO4, but does not really see the activity in the SE and indeed is a rain/snow mix on the S coast.

 

Based on previous cold spells this winter, I'm going to guess:

HIRLAM will be right for N England

ARGEPE will be right for S England, except I don't think it will be sleet on the S coast, as the flow is never south of east, it's a very cold continental draw, dew points are low - and besides the ARGEPE is pretty much alone in this respect.

 

[Frosty.]

Well looking at the Gfs 6z, a marked change from today's  mild in the south with temps around 13c 55f and then struggling to reach freezing point tomorrow..saturday looks the coldest day but sunday will be very cold too and there is a significant risk of disruptive snow across parts of southern uk too..Amber warnings already in force!!..if this is to be the last hurrah of major wintry weather it's going to be a memorable one but if the 6z is right, we would be seeing an arctic blast around 7-10 days later..fingers crossed for that and enjoy this weekend coldies!⛄⛄⛄⛄⛄⛄⛄❄❄❄❄❄❄❄❄

Edited March 16, 2018 by Frosty.

[Frosty.]

March roars out like a lion on the Gfs 6z..this would suit me just fine!!⛄⛄⛄⛄⛄❄❄❄❄❄❄?????

[Mike Poole]

HIRLAM 12z out now, takes us to Sunday lunchtime, and showing the risk of snow for wider part of the south:

Just adding the 6z (to 6am Sunday) for comparison:

12z brings Wales and SW into the game later on Sunday.

 

Edited March 16, 2018 by Mike Poole

[karyo]

2 minutes ago, Mike Poole said:

HIRLAM 12z out now, takes us to Sunday lunchtime, and showing the risk of snow for wider part of the south:

 

Is the north looking dry?

[ARTDEMOLE]

Anybody use sat24 for guidance..... 

[feb1991blizzard]

1 minute ago, karyo said:

Is the north looking dry?

No, there's dumpings to varying degrees right across the country.