North West Regional Discussion 30 December 2020 onwards

[PennineMark]

Unfortunately more likely washout than whiteout on Tuesday as things stand. Warning likely to be removed? Disappointing again. Luck just not with us. 

[Frost HoIIow]

26 minutes ago, PennineMark said:

That explains it, thanks. Looking at it again there are several zero looking sixes on that map . However, the point still stands that as is shown on this particular model, GM is an island of lower snow accumulation for all Foehn/snow shadow reasons. It is so difficult to get a perfect set up for snow locally.

Whenever there's a strong SE wind showing I'm always sceptical of snow as it just doesn't happen. So I'm thinking Tuesday will already be a bust. The Pennines create a big snow shadow which bizarrely doesn't happen in a East or NE flow.  Kasim when he was on here explained that the hills to our East and NE are more narrower so snow makes it over more easily but to the SE there's more hill track which creates the snow shadow. Makes sense really as you can see this on an elevation/ topography map.

Edited January 30, 2021 by Frost HoIIow

[Chris.R]

WRF is now out to 12 pm Tuesday.

For Low ground it looks like 4–5 hours heavy snow followed by 4-6 hours ice pellets gradually turning to rain. Not much change there since this morning’s run.

for high ground above 100 m though it will be snow to ice pellets to freezing rain with freezing rain continuing into the afternoon. Obviously the further north east in the region you are the longer it will stay as snow but I can see a significant risk of freezing rain heralded by ice pellets.

[Joe Bloggs]

8 minutes ago, Frost HoIIow said:

Whenever there's a strong SE wind showing I'm always sceptical of snow as it just doesn't happen. So I'm thinking Tuesday will already be a bust. The Pennines create a big snow shadow which bizarrely doesn't happen in a East or NE flow.  Kasim when he was on here explained that the hills to our East and NE are more narrower so snow makes it over more easily but to the SE there's more hill track which creates the snow shadow. Makes sense really as you can see this on an elevation/ topography map.

It wouldn’t be so bad if it was only a problem when the precipitation was moving east - west. The shadow effect kicks in no matter which direction the precipitation is coming from. Infuriating. 

You’re absolutely right - best to be cautious when the wind is from the SE. Kasim also said that a lighter wind and lower heights results in a more limited effect. 

Edited January 30, 2021 by Joe Bloggs

[SnowWatcher2]

 All going to pan already.. hoping next updates give me more hope.

[WillinGlossop]

46 minutes ago, Had Worse said:

Glossop  upto Midday WRF 12z run

At least it won’t be warm 

[Had Worse]

I had to double take on the MOD thread why it was going the way of the pear and it seems to be that N / S divide. S contingent not liking what the ECM is serving and saying there must be some mistake, we didnt order this.

[Chris.R]

Whether the 850 mb temp is above 0 or not is not necessarily the key factor as it might not represent the centre of the inversion. In this case it seems to be more like 900 MB which is the centre and this goes above 0 slightly before 850 mp. It’s important to think about the precipitation falling through the atmosphere and what it will encounter. Either way it will not just be snow to rain as there is too much of a cold layer near the surface for that. There will be a significant period of ice pellets everywhere in between.

[WillinGlossop]

2 minutes ago, Had Worse said:

I had to double take on the MOD thread why it was going the way of the pear and it seems to be that N / S divide. S contingent not liking what the ECM is serving and saying there must be some mistake, we didnt order this.

Mod thread has gone south in more ways than one... no pun intended 

[Joe Bloggs]

4 minutes ago, Chris.R said:

Whether the 850 mb temp is above 0 or not is not necessarily the key factor as it might not represent the centre of the inversion. In this case it seems to be more like 900 MB which is the centre and this goes above 0 slightly before 850 mp. It’s important to think about the precipitation falling through the atmosphere and what it will encounter. Either way it will not just be snow to rain as there is too much of a cold layer near the surface for that. There will be a significant period of ice pellets everywhere in between.

I knew my analysis was very basic! Cheers Chris. 

[Day 10]

Tuesday.

The GFS & UKV had been the most progressive but are starting to edge south. 

The ICON has been the most consistent with stalling the front over us for longest. 

The ECM had been consistent but now swings north east rather quickly. Too quickly in my view.

The mornings MetO update will be interesting. 

[SnowWatcher2]

UKV still being an a**se, but hoping its got it wrong with it being a few days away, usually is.

Tomorrow update be better... 

[Day 10]

2 minutes ago, SnowWatcher2 said:

UKV still being an a**se, but hoping its got it wrong with it being a few days away, usually is.

Tomorrow update be better... 

Note my post above was based on the old UKV update as on phone. 

Is this new update north or south to last one, can you check mate? 

[Wardlegacy]

I’ll be happy to see any snow on Tuesday but my real interest is one in a proper easterly developing. I’m slightly more confident of this now and I’m usually in a good location for these. If I’m not I’ll travel further east to my bubble. I know easterlies are not good for the whole region, we are one of the most varied regions.

 

[SnowWatcher2]

2 minutes ago, Day 10 said:

Note my post above was based on the old UKV update as on phone. 

Is this new update north or south to last one, can you check mate? 

These are todays and yesterday 15z runs for Tue 06:00

 

[SnowWatcher2]

03z run Sat for Tue

[Had Worse]

2 minutes ago, SnowWatcher2 said:

These are todays and yesterday 15z runs for Tue 06:00

 

Todays Fractionally further South 5-10 miles. 

[Day 10]

3 minutes ago, SnowWatcher2 said:

These are todays and yesterday 15z runs for Tue 06:00

 

Thanks, pretty similar. 

[Day 10]

Tomorrow - 

Nevermind The Big Short. 

The Big Shift (South). 

[SnowWatcher2]

It looks a beauty.. been keeping eye on it all day.

[Chris.R]

For anyone interested I have set up a Twitter account which automatically posts real-time observations from my weather station every 20 minutes. I’ve created a weather description generator using JavaScript through IFTTT. Because I have brightness and solar radiation I can pretty much tell when it’s sunny or not and things like that.
http://www.twitter.com/HalewoodWeather

[Day 10]

Graphics to go with today's Met Office warning.

Tuesday.

1 - 2am

6am

8am - turning to rain from the south.

[Chris.R]

With all my talk of ice pellets, here is the Wikipedia for anyone not sure exactly what they are or how to differentiate them.

 

Edited January 30, 2021 by Chris.R

[Chris.R]

Did the link work? I can’t see it for some reason.

[Day 10]

Don't think so mate?