Scottish Weather Chat

[Tugmistress]

looking like we'll all get a touch of the white stuff on friday, i know it'll be windy here too so if it does come down it could make for some interesting driving conditions. guess it's time i got the woolly knickers out because you can guarantee something will go wrong with my windy thing and i have to get up there! lmao

[weathermaster]

Looks good for snow on Friday and Saturday Sunday the more north you are the better.

[scanman]

As is often the case in this type of synoptic setup, it looks like the north and east will bear the brunt. As well as the north getting a bit of a battering, conditions in Aberdeenshire could be quite tricky too if the weather runs as progged.

[Budgie]

And as per usual, here we'll see a few showers of snow pellets and lots of wind. 

[munrobaggins]

I have been watching my WxSim fcsts over the last few days with keen interest...the graphic certainly shows that for a little while we (Elgin) will be below the famous 528 thickness line...Likewise the MetO synoptics are showing a plunge of cold air mass

ie from the MetO:

Thickness lines

Pressure decreases with altitude, and thickness measures the difference in height between two standard pressure levels in the atmosphere. It is proportional to the mean temperature of this layer of air, so is a useful way of describing the temperature of an airmass.
Weather charts commonly show contour lines of 1,000-500 hPa thickness, which represent the depth (in decametres, where 1 dam = 10 m) of the layer between the 1,000 hPa and 500 hPa pressure levels. Cold, polar air has low thickness, and values of 528 dam or less frequently bring snow to the UK. Conversely, warm, tropical air has high thickness, and values in excess of 564 dam across the UK often indicate a heatwave.

[scanman]

Same here in the Fort. Don't forget though, that WXSim uses the GFS data - ie WXSim does not predict the thickness, but merely imports it. Consequently, if the GFS runs change, so will your WXSim forecast.

[Tugmistress]

Well the last of the white stuff is nearly gone now, woke up this morning to about 6" in the garden, most i've seen in any one time since moving up here in 2002, but it was raining lol
work was interesting in the slushy stuff, slip sliding along the pier lol

on a side note just managed to get a 2nd webcam up and running on my website you can even watch semi live video feed to see how quiet it is lol

[Budgie]

Well it's still not done raining (23.2mm since midnight!  ) and blowing over here.
Had to sit here with the lights on since I got up as it's been like dusk all day.

[scanman]

Well, I am rather impressed with the old WXSim. Despite the weather on TV telling us we were going to get snow, my own thoughts based on model runs and WXSim was that we would be unlikely to see snow here in the Fort. And so it turned out. Interesting that my WXSim said "no snow" (and we didn't) and Munrobaggin's was saying "snow" and I think that is waht Elgin got!

[weathermaster]

Highest gust here today 81mph I was in bed at the time around 7am the gust came with heavy hail showers.

[munrobaggins]

WXSim said "no snow" (and we didn't) and Munrobaggin's was saying "snow" and I think that is waht Elgin got!

Yes, we did get the snow...quite a bit during the early sunday am....it has all just about gone now(melted away) ..wxsim has been pretty accurate despite the critical loss of the GFS data during Sat etc...I wasn't quite quick enough in re-setting up my READY semi-auto download to overcome the shortfall in data....and am still trying to get the new Broadstairs (Stuart) script to fully work through the run...ahh well more fun!!!

[masseyjim]

No Snow in sunny ayrshire  thank goodness i had the wifes car over the weekend she wanted my old 4 track lol and i dinna fancy driving it on top of a skiff of white stuff  180 bhp on the front wheels and 235  40  17  black rubbber bits pitting it on the road

[skyewright]

We are largely sheltered from NNW-NNE so not much wind here over the weekend, and no sign of snow other than a light dusting seen at a distance on the Mainland hills (and on Blaven when we drove up to Broadford this morning). We did however have 30mm of rain yesterday, which almost counts as being wet. 

[scanman]

Came across this, and thought it may be of interest, especially for those using WXSim.

For predicting the likelihood of snow, ensure that after the forecast run, you have the graph for WXSim/WRET set up so that it displays thickness as 850-1000. This is apparently, a bit more accurate than just relying on the 528dam.

Then apply the following:

Because the layer from 1000 hPa to 850 hPa covers the lowest 1500 metres or so of the atmosphere, it is better suited to deciding on which phase precipitation will reach the ground ( i.e. whether snow will melt to sleet or rain), than the 'total' thickness layer 500-1000 hPa. Statistical relationships have been produced:

The following are un-adjusted critical values and adjusted values for the 850-1000 hPa partial thickness found by statistical analysis: snow probability:

Probability:............................90%.....70%.....50%.....30%.....10%
850-1000 hPa(gpm)..............1279.....1287....1293....1297....1302 (un-adjusted)
850-1000 hPa(gpm)..............1281.....1290....1293....1298....1303 (adjusted-see below)

The original source document and explanation can be found at http://www.weatherfaqs.org.uk/node/152

[weathermaster]

This morning at 10am we had a very heavy hail shower mixed with sleet then a hour later it SNOWED