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