Northern England, (NW & Yorkshire) weather discussion January 2021
January 17, 2021 at 3:37 pm #33January 18, 2021 at 7:02 am #107Snow LoverParticipant
Heyyyyy 🙂January 18, 2021 at 10:04 am #110
Good morning. Watching Wed night / Thu closely here at 400m, those at lower levels should keep an eye on the frontal undercut, the pivot and occlusion >> read my post on the snow thread :).January 18, 2021 at 1:06 pm #112
Southwards correction now favoured – Euro4 18z will be of interestJanuary 18, 2021 at 1:07 pm #113January 18, 2021 at 3:35 pm #123k8Participant
I reckon this will be restricted to hills tbhJanuary 18, 2021 at 4:20 pm #124
K8, whilst I agree >300m is favored, we need to keep an eye on the dynamics of the cold air undercut..January 18, 2021 at 5:04 pm #129Cheshire snowParticipant
Just signed up sorry to loose you from the other side looking forward to the rest of winter.
C.SJanuary 18, 2021 at 5:09 pm #130Wirral snow starved peninsularParticipant
Hi 😁 Thanks for the invite Kasim and sorry you got the boot 😬January 18, 2021 at 5:12 pm #132Slidergate 17. Sale , CheshireParticipant
Slidergate here, i have registered here from the darkside 😉. Look forward to hearing your ongoing input on all things weather!
ChrisJanuary 18, 2021 at 5:14 pm #133
It’s thanks to SouthYorks (Dave) that you’re here! And thanks for joining too.
I’m going to take a look at Wednesday evening / Thu AM soon, >250m asl favoured as the pivot looks less optimal south of Cumbria / Northumberland. This pivot zone needs to be watched as, whilst not favoured, some output has the pivot zone right over the “Central North of England” (I.e., Yorkshire, Manchester). This can be seen nicely on the WRF and would provide a more optimal thermodynamic environment for snow <200m. More prolonged evap cooling largely responsible.
When I get the chance I might do a couple of weather / snow videos
- This reply was modified 2 years, 10 months ago by Kasim Awan.
Attachments:You must be logged in to view attached files.January 18, 2021 at 5:32 pm #141Winterof79Participant
That pivot point would be fantastic but when do you think we can nail the pivot point?
Probably on the day
Kirkburton 163 mt ASLJanuary 18, 2021 at 5:42 pm #142
Ultimately the models will either narrow towards either a pivot or a less optimal straight-line front undercut, or even a mix of both. These dynamics will directly affect ground conditions so I will keep an eye on high res trends tomorrow. Met don’t have a warning out yet attesting to the complexity of this set up.January 18, 2021 at 5:51 pm #143Slidergate 17. Sale , CheshireParticipant
Obviously a huge amount of rain due in the next 48hrs in the west facing pennines, with the ground so sodden, could this impact chances of settling snow Thursday?January 18, 2021 at 6:06 pm #146
Slidergate17 – this is a complex area of study ultimately if the DP / wet bulb are both at or below 0 in Winter or at Night in Spring snow will begin to stick regardless of soil / ground saturation levels. If marginal there is some influence of ground temps especially on higher specific heat capacity surfaces – (i.e. NOT cars, exposed grass), we’re talking roads and pavements. Cars and exposed grass >> lower specific heat capacity so temp will change quickly according to the evironment. Hence > high ground temp & only marginally conducive air temps = settling restricted to cars and grass.
So >> surface water can modulate surface temp and therefore snow amounts in marginal situations (Thursday) however most atmospheric AND surface processes are on a balance meaning if temp parameters are ample these effects will be “overridden” from a mathematical / thermodynamic perspective.
A take away is also that the air temp thresholds for settling are slightly higher (lower temps needed) when the ground temp is higher. However, wet or somewhat warm ground ground will never stop the settling threshold from being reached if temps are low enough.
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