Northern England, (NW & Yorkshire) weather discussion January 2021

[Raul Alonso]

@kasim many thanks for the invite and sorry they have banned so experienced weather enthusiast like you on the NW forum!!

https://www.wunderground.com/dashboard/pws/ISALE43

[Kasim Awan]

Thanks Raul. Good to have you on board.

Also note my previous post explains why cars & grass experience settling first + why during certain setups (higher ground temp) the duration of snowfall appears to be a factor affecting settling of snow.

Give it a read.

K.

• This reply was modified 3 years, 10 months ago by Kasim Awan.

[Withington, Manchester, 38m ASL]

Room for one more ? 😀

@kasim I’m interested in the potential for Irish Sea showers Thursday night into Friday. Based on past experience I’d suggest snow showers could be fairly widespread. What are your thoughts?

Really pleased I can continue to read your posts btw. 🙂

[Kasim Awan]

Risk of organized temporary streamers (locally 3mm/ hour) on Thurs & Fri. Fully conducive above ~250m in these uppers / heights.
Below this & west of Manchester snow depends on longevity of showers & distance from coast, coastal strip will be plagued by a maritime layer throughout Thurs / early Fri. As winds ease into Saturday / Sunday >> the maritime layer will become less defined, heights remain low & uppers reach -5C so this is the better shot for lower levels & is the best time frame for lower levels.

Remember @ 950mb the “upper level” is only 1000 metres > so uppers of -5C are sufficient in absence of a maritime layer.

[Dkeane3]

Hi, thanks for the invite, love your posts Kasim

[Kasim Awan]

Thank you. Feel free to invite other people to the forum, great to have 27 on here so far, would be good to see 50 before the weekend’s more conducive conditions <200m.

[Chris Roche]

Hi Kasim.
Great to read your posts again; they were very highly valued and always very methodical and thorough which I like a lot.
I have been posting my thoughts on the upcoming days in the NW regional thread and I will summarise them below.

Wed night

WRF 12 Z is an upgrade again.

North of Liverpool heavy snow now showing 18:00-03:00 and above 150 m it’s more like 15:00–03:00!

South of Liverpool things are delayed a bit heavy snow more like 2100–03:00.

thinking Bury > Rawtenstall > Bacup could be the sweet spot.

Thursday and Friday looks good east of M6 for falling snow but as Kasim has noted too much of a maritime layer around the coast so expect graupel/sleet/ice pellets and maybe some lightning. Dew-points are quite low though so you never know during prolonged showers (evaporative cooling).

Saturday should see falling snow to within 1–2 miles of the coast and then right to the coast in the evening, With settling snow as far west as my location at times.

As noted, geo-potential heights are very low; (850 mb altitude down to 1000 m, and 925 mb down to 300 m or so) which is interesting to see.

Into Sunday morning there is a front which could give a surprise snowfall and there is nothing marginal about it so could be good.

Overall if you live over 150 m get excited because you’re going to be battered. Even here I should see some falling snow and hopefully settling snow at some point during the next few days.

I will keep popping in here to read the latest posts when I can.
Chris R

[Kasim Awan]

^^ Thank you for that contribution Chris – it largely mirrors my thinking especially for the weekend 🙂

The wind speed, heights and temperature are both key in forecasting the Irish Sea shower streamers. Showers > easier to forecast than troughs.

Based on the conditions of the above factors and what Chris has covered I would gauge at heavy wet snow showers above 150m asl >15 miles inland during Friday day, at night down to 50-100m >5-10 miles from the coast. This zone receiving isolated coverings – and more widespread coverings potentially on Saturday AM.

West of the M6 & up to the coast will always have an element of mixed precip even early Saturday AM. Plus, the wind speeds of 10-15mph means between the M6 & Glossop is the shower sweet spot, east of this showers tend to loose intensity in under 15mph surface wind. It is a delicate balancing act with this, though I do feel the conditions are just about right for low level snow showers on Fri night. The WNW wind will channel showers, with the rough boundaries stated above, from Blackpool bay, Moreacombe Bay, The Wirral into Chorley, Manchester and C/N Cheshire. Again this is dynamoc and subject to change as the flow is extremely mobile.

The other problem (as has happened before) is if troughs develop nearer the time, the Irish Sea shower activity will significantly downgrade. Luckily this is modelled to occurr on Saturday evening, which is a positive as before the trough and it’s cap arrives, the isobar gradient tends to

In terms of Wednesday night, it is far from resolved and there’s plenty of time for quite significant changes at all altitudes (even > 300m). We’re looking for a the slower eastwards shunt + heavier precip solution (Wrf). Though it is highly uncertain.

• This reply was modified 3 years, 10 months ago by Kasim Awan.

[Kasim Awan]

http://modeles12.meteociel.fr/modeles/icon/runs/2021011812/iconeu_uk1-1-75-0.png?18-16

Also worth pointing out the high convection rates seen on Thursday indicating the potential for “wrap around” occlusions & disturbances, however > the snow line will be higher than it may potentially be earlier with the (best case) wrf / gfs scenario. By now > 100m well inland (W Yorks & Pennine regions) & 250-300m near the coast due to the strong onshore wind.

[Kasim Awan]

If you want to add your location & weather interests visit your profile >> edit >> fields should appear

[Chris in Bramley, Rotherham]

Hey Kasim and everyone.
Cheers for the invite! 🙂👍
Always good to hear your input so I’m looking forward to joining in here.
Fingers crossed we can see some snow between Thursday and Sunday 🤞🌨️

[Had Worse]

Well, tea done, pots washed and… its raining… hopefully in a day or 2 i can say its snowing.

incidentally, my wife has just booked her jab for Wednesday evening. What could possibly go wrong whilst we are in Ashton under lyne.

Welcome to Royston Vasey, You'll Never Leave.

[WillinGlossop]

Glad people getting jabs…
My Nan had hers last week, my mum and her sister having theirs this week over 70s in Somerset… can’t wait til husband and myself get ours…
Damp out 6c hope we get some snow after all this rain… esp a streamer off the Irish Sea usually do well with a wnwly in 8 years I’ve been up here…

[Kasim Awan]

Hope conditions play ball for you both in Glossop. The rainMax accumulation of 210mm (high altitude) is very alarming indeed. Going to be some sad scenes by Wednesday from those currently being pressurized as it is.

[Dkeane3]

Certainly sounding interesting, however the GFS doesn’t get me too excited 😆

[Author]

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