Model output discussion - after the beast, what next?

[Man With Beard]

9 minutes ago, karyo said:

Is the north looking dry?

I think there's so much going on its hard to keep up with what's happening outside of one's own region.

Let's summarise. The HIRLAM wants to turn the UK into a ski resort by midday Sunday.

Though I think it's best on N Sea convection, I have this nagging fear it will be proven to be exaggerating the frontal snow quite considerably. Hope not!

[JamesL]

18 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:

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

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

 

I'm intrigued to see how this plays out across southern central and SW England as well as Wales and whether we may see further amber warning appear further west. 

[Luke Best]

3 minutes ago, Man With Beard said:

I think there's so much going on its hard to keep up with what's happening outside of one's own region.

Let's summarise. The HIRLAM wants to turn the UK into a ski resort by midday Sunday.

Though I think it's best on N Sea convection, I have this nagging fear it will be proven to be exaggerating the frontal snow quite considerably. Hope not!

I'm still very hopeful for this weekend but from an IMBY point of view (and yours I suspect), my fear is that the frontal snow will be more prevalent in the far SW, with most of the convection in the NE, leaving us in a drier middle section.  

[bluearmy]

3 minutes ago, Man With Beard said:

I think there's so much going on its hard to keep up with what's happening outside of one's own region.

Let's summarise. The HIRLAM wants to turn the UK into a ski resort by midday Sunday.

Though I think it's best on N Sea convection, I have this nagging fear it will be proven to be exaggerating the frontal snow quite considerably. Hope not!

I am a little  suspicious of hirlam snow forecast. It did ok last time on occasions and also the Dec slider but I recall that it was always best when ec op was in agreement. 

[khodds]

4 minutes ago, JamesL said:

I'm intrigued to see how this plays out across southern central and SW England as well as Wales and whether we may see further amber warning appear further west. 

Just been updated!!

[Frosty.]

A perishingly cold weekend for the time of year across the board according to the Gfs 12z with maxima struggling to get above freezing point on both days and indeed minus 2 or 3 on higher ground with snow cover, there is a good chance of snow quite widely..more like deep mid winter than mid march..wonderful stuff for coldies!..hopefully further cold shots to come during late march into april!

Edited March 16, 2018 by Frosty.

[Mike Poole]

8 minutes ago, JamesL said:

I'm intrigued to see how this plays out across southern central and SW England as well as Wales and whether we may see further amber warning appear further west. 

And right on cue, one has just been issued exactly there, looks like the Met Office going with the HIRLAM - almost to precision.

Edited March 16, 2018 by Mike Poole

[JamesL]

1 minute ago, Mike Poole said:

And right on cue, one has just been issued exactly there, looks the Met Office going with the HIRLAM - almost to precision.

Haha notification just came through. Almost exactly the same warning area as the red one issued for us just over 2 weeks ago. 

[bluearmy]

19 minutes ago, Mike Poole said:

And right on cue, one has just been issued exactly there, looks like the Met Office going with the HIRLAM - almost to precision.

As hirlam only goes to T48, it’s only just showing this but ec op has been consistently picking this area for a couple of days now. (See my post from early this morning).

Be intersdting to see updated faxes 

[Come rain snow or shine]

Get ready for a possible polar lowor two in about 10 days time, give or take :-)  

[nick sussex]

Putting aside the uncertainty at short range the cold now extends into Monday.

The UKMO raw output has the whole of the UK in sub -8 850s with a few sub -10s towards the sw.

Even by Tuesday it’s still looking pretty cold.

Given this some convection might continue towards the east and se especially late Sunday into Monday morning. There is less instability so showers likely to be more scattered but this is an upgrade compared to a few days ago when the high was already sinking .

[WalsallWeather123]

GFS snow depth chart

[AWD]

12z Hirlam in numerical figures by midday Sunday;

Quite bullish with it's snow accumulation predictions, although this doesn't take into account meltage between showers etc.

[danm]

1 minute ago, AWD said:

12z Hirlam in numerical figures by midday Sunday;

Quite bullish with it's snow accumulation predictions, although this doesn't take into account meltage between showers etc.

Ties in well with the Met Office amber warnings for the London area and across Lincs/Yorkshire etc

[Cloud 10]

Looking further ahead.....happy Easter from GFS.

 

[Derecho]

Longer term - more of the same , plenty of blocked members in there, a lot of stormy runs with transient northerlies as well...

[nick sussex]

Latest  T36 hrs fax chart has something for coldies further north .

It shows a convergence zone from the Wash right across to North Wales , the T48hrs has that small low close to Cornwall judging by the earlier one this forms near Normandy and tracks wnw.

I should stress the situation is volatile so don’t bank on these features till closer to the time .

Edited March 16, 2018 by nick sussex

[John Michael How]

10 minutes ago, Cloud 10 said:

Looking further ahead.....happy Easter from GFS.

 

That's ok I'm flying to Mauritius on 30th March if beast 3 doesn't arrive lol. Also on that hirlam precip chart does it show 12 or 17cms over NW kent/SW Essex?

Edited March 16, 2018 by John Michael How

[blizzard81]

That twig is heading towards my house 

[bluearmy]

9 minutes ago, nick sussex said:

Latest  T36 hrs fax chart has something for coldies further north .

It shows a convergence zone from the Wash right across to North Wales , the T48hrs has that small low close to Cornwall judging by the earlier one this forms near Normandy and tracks wnw.

I should stress the situation is volatile so don’t bank on these features till closer to the time .

EC op looks the same as the previous run for most of England/wales but slight reduction in snow qty over midlands and se England and increase in sw England. nearly whole area west of a line central and west somerset/dorset (burnham down to bridport) min 2" snowfall by end sunday with 15/20 cms possible on Dartmoor. a line from Cardiff to Swansea north across the welsh hiulls shows similar. 

so we have a stand off between hirlam and ec with ec not picking up the same qtys in the se as hirlam.  2-4 cms from the 'thames streamer'

[nick sussex]

12 minutes ago, bluearmy said:

EC op looks the same as the previous run for most of England/wales but slight reduction in snow qty over midlands and se England and increase in sw England. nearly whole area west of a line central and west somerset/dorset (burnham down to bridport) min 2" snowfall by end sunday with 15/20 cms possible on Dartmoor. a line from Cardiff to Swansea north across the welsh hiulls shows similar. 

so we have a stand off between hirlam and ec with ec not picking up the same qtys in the se as hirlam.  2-4 cms from the 'thames streamer'

Could the mighty ECM be humbled by the Hirlam ?

I think it’s just down to nowcasting given the model disagreements at short range .

PS typical the UKMO fax charts for T60 and T72 hrs haven’t appeared yet , of all the times !

Edited March 16, 2018 by nick sussex

[bluearmy]

6 minutes ago, nick sussex said:

Could the mighty ECM be humbled by the Hirlam ?

I think it’s just down to nowcasting given the model disagreements at short range .

PS typical the UKMO fax charts for T60 and T72 hrs haven’t appeared yet , of all the times !

its pretty much all over by then nick (for eng/wales!)

[MR EXTREMES]

1 hour ago, nick sussex said:

Putting aside the uncertainty at short range the cold now extends into Monday.

The UKMO raw output has the whole of the UK in sub -8 850s with a few sub -10s towards the sw.

Even by Tuesday it’s still looking pretty cold.

Given this some convection might continue towards the east and se especially late Sunday into Monday morning. There is less instability so showers likely to be more scattered but this is an upgrade compared to a few days ago when the high was already sinking .

Well said nick Sussex I agree this not such a bad event after all.

Also very much great data being collected due to the decent stratosphere events.

It's becoming a very useful tool for possible forecasts although only one part of a bigger Jigsaw.

But certainly some clear indication of yet another wintry episode.

2018 has been very interesting.

[nick sussex]

8 minutes ago, bluearmy said:

its pretty much all over by then nick (for eng/wales!)

Really ! I think some colder air gets pulled west again between T48 hrs and T60hrs.

Those slightly higher uppers towards the south and se in relation to the low in the Channel are replaced by something colder.

Although the instability falls it looks just enough to continue to produce some convection , late Sunday into early hours Monday.

We’ll see...

PS the ECM day 8 ! It’s a shame all this is happening so late.

Edited March 16, 2018 by nick sussex

[bluearmy]

4 minutes ago, nick sussex said:

Really ! I think some colder air gets pulled west again between T48 hrs and T60hrs.

Those slightly higher uppers towards the south and se in relation to the low in the Channel are replaced by something colder.

Although the instability falls it looks just enough to continue to produce some convection , late Sunday into early hours Monday.

We’ll see...

PS the ECM day 8 ! It’s a shame all this is happening so late.

Yes indeed - I think it will correct a bit further se too