North West England Regional Weather Discussion

[SP1986]

The Met Offices slant on thing is quite bizarre. I wouldn't expect this near the start of the event would cause this much confusion for trained Meteorologists. I can understand that 2-3 days in advance there may be slight confusion, but it's supposedly starting tomorrow.. and somewhere along the line, either there has been mis-communication, or an error in one of the model outputs that has thrown it. 

I'm not a trained Meteorologist, but to me, it's quite clear for the time period until Friday.

Tomorrow we will see a westerly orientated northwesterly entering the region, bringing forth relatively cold returning maritime Arctic air. At first the flow will be too saturated with warm dewpoint temperatures, so any light showers that start to feed into coastal regions will be of rain, for large amounts of the night time period. Unfortunately the showers at this time probably won't have the umph to continue inland, so they'll die away, leaving a clear, breezy night for many. 

On Thursday it will probably start pretty featureless, in fact some people may question the validity of any snow forecast. From late morning to early lunchtime, we will see showers developing in the Irish sea as a result of warm seas and convection, these light at first will start filtering in over north Merseyside and South Lancashire, getting heavier as the time progesses. Towards the coast these will probably be of a hail/graupel mix, but as they move eastwards towards parts of Gtr Manchester and Northern Cheshire, they will increasingly turn to snow, leaving coverings, although perhaps westernmost areas seeing only short temporary accumulations of snow. 

Towards the evening, as the wind direction back to more of northwesterly, we may see more general snow fall as a result of showers banding together from showers passing through the north channel (aka Cheshire Gap). This will bring more widespread snow, and possibly higher chance of accumulation on the coast.. perhaps a few cm.. however it will still be temporary covering on these parts.. but further inland, a more substantial, sustained covering of snow possible.

[I remember Atlantic 252]

4 minutes ago, SP1986 said:

The Met Offices slant on thing is quite bizarre. I wouldn't expect this near the start of the event would cause this much confusion for trained Meteorologists. I can understand that 2-3 days in advance there may be slight confusion, but it's supposedly starting tomorrow.. and somewhere along the line, either there has been mis-communication, or an error in one of the model outputs that has thrown it. 

I'm not a trained Meteorologist, but to me, it's quite clear for the time period until Friday.

Tomorrow we will see a westerly orientated northwesterly entering the region, bringing forth relatively cold returning maritime Arctic air. At first the flow will be too saturated with warm dewpoint temperatures, so any light showers that start to feed into coastal regions will be of rain, for large amounts of the night time period. Unfortunately the showers at this time probably won't have the umph to continue inland, so they'll die away, leaving a clear, breezy night for many. 

On Thursday it will probably start pretty featureless, in fact some people may question the validity of any snow forecast. From late morning to early lunchtime, we will see showers developing in the Irish sea as a result of warm seas and convection, these light at first will start filtering in over north Merseyside and South Lancashire, getting heavier as the time progesses. Towards the coast these will probably be of a hail/graupel mix, but as they move eastwards towards parts of Gtr Manchester and Northern Cheshire, they will increasingly turn to snow, leaving coverings, although perhaps westernmost areas seeing only short temporary accumulations of snow. 

Towards the evening, as the wind direction back to more of northwesterly, we may see more general snow fall as a result of showers banding together from showers passing through the north channel (aka Cheshire Gap). This will bring more widespread snow, and possibly higher chance of accumulation on the coast.. perhaps a few cm.. however it will still be temporary covering on these parts.. but further inland, a more substantial, sustained covering of snow possible.

Sounds quite promising, wonder if winds perfect angle for my location, had good falls here from this setup, but everything needs to be right, -8 uppers, 518 thickness, ground temps no higher than 0.5° and direct NW'ly

Edited January 10, 2017 by I remember Atlantic 252

[SP1986]

5 minutes ago, I remember Atlantic 252 said:

Sounds quite promising, wonder if winds perfect angle for my location, had good falls here from this setup, but everything needs to be right, -8 uppers, 518 thickness, ground temps no higher than 0.5° and direct NW'ly

Indeed.. well this is an interesting feature for tomorrow night, it seems, the showers band together and form a trough over our region.. how far south this gets I'm not sure, but it is fascinating to see.. best looked at now before it disappears with the 18z run update

This would be a very interesting feature, and marginality seems to be minimal.. so it's likely widespread snowfall would be likely. Lets see if this little feature is still here come tomorrow.

[Geordiesnow]

8 minutes ago, SP1986 said:

Tomorrow we will see a westerly orientated northwesterly entering the region, bringing forth relatively cold returning maritime Arctic air. At first the flow will be too saturated with warm dewpoint temperatures, so any light showers that start to feed into coastal regions will be of rain, for large amounts of the night time period. Unfortunately the showers at this time probably won't have the umph to continue inland, so they'll die away, leaving a clear, breezy night for many. 

 

Not sure if I full agree with the last bit in your paragraph here, I think showers will be quite widespread inland just down to the strength of the wind alone, not sure how widespread or even how heavy any showers will be but I'll be surprised if they are just going to be coastal showers as your suggesting. I also think they should start to be cold enough to fall as snow inland, especially if they do turn out to be heavy and quite frequent. Theres been a lot of talk in here about evaporative cooling but that can only have much of an affect if there is little to no wind around and in this case, the winds will be quite gusty and strong so a lot of mixing going on so I'm afraid evaporative cooling won't be on our side.

The BBC graphics do suggest Cumbria could get battered with shower activity tomorrow night but its a case of waiting and seeing what the radar says.

How Thursday plays out is all down to that waved occluded front, if its too far North, expect a lot of high cloud filling the sky and for convection to be limited, if its far enough South we should be in the showery airstream, ECM looks too close to call for me although the emphasis would be even if there is some high cloud on Thursday, the legacy of the front should clear our region quite promptly.

[SP1986]

6 minutes ago, Geordiesnow said:

Not sure if I full agree with the last bit in your paragraph here, I think showers will be quite widespread inland just down to the strength of the wind alone, not sure how widespread or even how heavy any showers will be but I'll be surprised if they are just going to be coastal showers as your suggesting. I also think they should start to be cold enough to fall as snow inland, especially if they do turn out to be heavy and quite frequent. Theres been a lot of talk in here about evaporative cooling but that can only have much of an affect if there is little to no wind around and in this case, the winds will be quite gusty and strong so a lot of mixing going on so I'm afraid evaporative cooling won't be on our side.

The BBC graphics do suggest Cumbria could get battered with shower activity tomorrow night but its a case of waiting and seeing what the radar says.

How Thursday plays out is all down to that waved occluded front, if its too far North, expect a lot of high cloud filling the sky and for convection to be limited, if its far enough South we should be in the showery airstream, ECM looks too close to call for me although the emphasis would be even if there is some high cloud on Thursday, the legacy of the front should clear our region quite promptly.

It's not that they wouldn't be blown inland, it's just that tomorrow night there won't be enough power in the showers to move inland (maybe they wont even make it to the coast).. the Irish Sea as far as can see, won't be producing them at that point in a streamer. I believe firmly it will take until Thursday morning to see those showers properly developing in the Irish sea, as the cold airmass digs in properly over warm water, to start an efficient production of shower cells.

Edit: apologies, yes Cumbria could well get some decent showers tomorrow night. 

I meant further south. A little IMBY apologies.

Edited January 10, 2017 by SP1986

[Weather-history]

18 minutes ago, SP1986 said:

 

I'm not a trained Meteorologist, but to me, it's quite clear for the time period until Friday.

Tomorrow we will see a westerly orientated northwesterly entering the region, bringing forth relatively cold returning maritime Arctic air. At first the flow will be too saturated with warm dewpoint temperatures, so any light showers that start to feed into coastal regions will be of rain, for large amounts of the night time period. Unfortunately the showers at this time probably won't have the umph to continue inland, so they'll die away, leaving a clear, breezy night for many. 

 

No, my experience is that showers are driven inland regardless how light. In such a strong flow as well? 

Manchester Airport TAF goes for rain showers tomorrow as well.

[Cheshire Freeze]

24 minutes ago, SP1986 said:

The Met Offices slant on thing is quite bizarre. I wouldn't expect this near the start of the event would cause this much confusion for trained Meteorologists. I can understand that 2-3 days in advance there may be slight confusion, but it's supposedly starting tomorrow.. and somewhere along the line, either there has been mis-communication, or an error in one of the model outputs that has thrown it. 

I'm not a trained Meteorologist, but to me, it's quite clear for the time period until Friday.

Tomorrow we will see a westerly orientated northwesterly entering the region, bringing forth relatively cold returning maritime Arctic air. At first the flow will be too saturated with warm dewpoint temperatures, so any light showers that start to feed into coastal regions will be of rain, for large amounts of the night time period. Unfortunately the showers at this time probably won't have the umph to continue inland, so they'll die away, leaving a clear, breezy night for many. 

On Thursday it will probably start pretty featureless, in fact some people may question the validity of any snow forecast. From late morning to early lunchtime, we will see showers developing in the Irish sea as a result of warm seas and convection, these light at first will start filtering in over north Merseyside and South Lancashire, getting heavier as the time progesses. Towards the coast these will probably be of a hail/graupel mix, but as they move eastwards towards parts of Gtr Manchester and Northern Cheshire, they will increasingly turn to snow, leaving coverings, although perhaps westernmost areas seeing only short temporary accumulations of snow. 

Towards the evening, as the wind direction back to more of northwesterly, we may see more general snow fall as a result of showers banding together from showers passing through the north channel (aka Cheshire Gap). This will bring more widespread snow, and possibly higher chance of accumulation on the coast.. perhaps a few cm.. however it will still be temporary covering on these parts.. but further inland, a more substantial, sustained covering of snow possible.

Agree, late Thurs through into Fri AM looks best bet down here. Before then, showers concentrated N Cheshire, Gtr Manchester as you say.

[SP1986]

5 minutes ago, Weather-history said:

No, my experience is that showers are driven inland regardless how light. In such a strong flow as well? 

Manchester Airport TAF goes for rain showers tomorrow as well.

I've seen situations where they have died out, even in windy conditions. It's not entirely unusual given fairly low dewpoints for light showers to die a death as they are blown inland, especially convective driven showers. 

It's a source of frustration.

But yes some may make it inland.. we will see. 

I presume the details will be clearer tomorrow

Edited January 10, 2017 by SP1986

[Day 10]

SP.

Thurs eve onward looks best shout for snow coastal areas.

[Cheshire Freeze]

1 minute ago, Day 10 said:

SP.

Thurs eve onward looks best shout for snow coastal areas.

Takes until 6pm Thurs to clear the legacy of that wave feature to the S. jaffa cakes poor from ECM in the closer timeframes it has to be said (compared to what it was showing a day or so ago). 

[cheshire snow]

1 minute ago, CreweCold said:

Takes until 6pm Thurs to clear the legacy of that wave feature to the S. jaffa cakes poor from ECM in the closer timeframes it has to be said (compared to what it was showing a day or so ago). 

Swear filter kicked in there CC

 

[Cheshire Freeze]

Just now, cheshire snow said:

Swear filter kicked in there CC

 

It did. You can see the flow straightens up far too quickly overnight Thurs to allow a proper Cheshire gap streamer to develop

Already pretty N'ly by midnight

[Day 10]

6 minutes ago, CreweCold said:

Takes until 6pm Thurs to clear the legacy of that wave feature to the S. jaffa cakes poor from ECM in the closer timeframes it has to be said (compared to what it was showing a day or so ago). 

Must admit that has been bugging me all day , wish it would just do one further south!

[Cheshire Freeze]

1 minute ago, Day 10 said:

Must admit that has been bugging me all day , wish it would just do one further south!

I wish we could see pre 72 hr UKMO...

All we have to go on pre 72 is the ECM and GFS...and the latter doesn't seem to be covering itself in glory just at the moment.

[Day 10]

1 minute ago, CreweCold said:

I wish we could see pre 72 hr UKMO...

All we have to go on pre 72 is the ECM and GFS...and the latter doesn't seem to be covering itself in glory just at the moment.

The 18z GFS might shed some light the situation

[Thunder Snow]

hoping to see a flurry or 2 

[damianslaw]

34 minutes ago, Geordiesnow said:

Not sure if I full agree with the last bit in your paragraph here, I think showers will be quite widespread inland just down to the strength of the wind alone, not sure how widespread or even how heavy any showers will be but I'll be surprised if they are just going to be coastal showers as your suggesting. I also think they should start to be cold enough to fall as snow inland, especially if they do turn out to be heavy and quite frequent. Theres been a lot of talk in here about evaporative cooling but that can only have much of an affect if there is little to no wind around and in this case, the winds will be quite gusty and strong so a lot of mixing going on so I'm afraid evaporative cooling won't be on our side.

The BBC graphics do suggest Cumbria could get battered with shower activity tomorrow night but its a case of waiting and seeing what the radar says.

How Thursday plays out is all down to that waved occluded front, if its too far North, expect a lot of high cloud filling the sky and for convection to be limited, if its far enough South we should be in the showery airstream, ECM looks too close to call for me although the emphasis would be even if there is some high cloud on Thursday, the legacy of the front should clear our region quite promptly.

Evaporative cooling occurs when you have heavy precipitation as well as light winds, so the heavier the precipitation, the greater cooling takes place. Over the Lake District, evaporative cooling has a major effect, air is forced over the western fells and cools markedly, inland parts of Cumbria often do very well in such set ups, thanks to the cooling effect.

[Geordiesnow]

27 minutes ago, damianslaw said:

Evaporative cooling occurs when you have heavy precipitation as well as light winds, so the heavier the precipitation, the greater cooling takes place. Over the Lake District, evaporative cooling has a major effect, air is forced over the western fells and cools markedly, inland parts of Cumbria often do very well in such set ups, thanks to the cooling effect.

Surely the affects are much greater in slack conditions and ideally without winds off the sea? Of course local geography might have an affect as the one you describe but I don't see evaporative cooling will have too much of an affect?

Still think the showers will make it as far as the Pennines at least even as early as tomorrow night and they should turn more to snow as the night goes on hence I won't be surprised if some parts of the region wakes up to some sort of a covering by the morning.

[chicken soup]

euro 4 6pm thursday

Edited January 10, 2017 by chicken soup

[Stratocumulus perlucidus]

Well the shortwave turned into a low pressure!

[frosty ground]

6 minutes ago, chicken soup said:

euro 4 6pm thursday

Right near that 7 10 12 line.... which is of course encouraging. Which ties in well with the auto generated forcasts 

Edited January 10, 2017 by frosty ground

[Joe Bloggs]

Crumbs... this is a little bit of a worry. 

 

 

The disturbance across the south of England has really developed within the past few runs. 

It's still a convective WNW'ly flow, but it now doesn't look as 'clean' if that makes sense. Still time for change. 

[Day 10]

The gfs so far is looking pretty good for snow showers. It look to me like snow showers out west Thurs then a more prolonged spell of snow affecting more eastern parts as that feature runs down the north sea Fri.

[chicken soup]

4 minutes ago, frosty ground said:

Right near that 7 10 12 line.... which is of course encouraging. Which ties in well with the auto generated forcasts 

That line goes right over my house.

[Miamay]

hows it looking for Liverpool?