Penellype's Weather Channel

[Penellype]

Time to take precautions if you have anything that doesn't want to be too cold. By Friday morning the temperature will have dropped considerably and it is looking like staying there for the forecastable future. For York, the highest forecast temperature for the following 8 days is 3C.

[Penellype]

ECMWF going for significant snowfall on Sunday - this is the prediction map for mid day:



The purple colours show 4 inches (not cm) or more of accumulated snow.

These useful snow depth charts can be found at https://weather.us/model-charts/euro...210-1800z.html (you may need to adjust the date etc).

The track of the low pressure system producing this snow is currently uncertain and may change, but well worth keeping an eye on that page for updates.

[Lumpy]

Thank you Pen...............I am trying so hard not to be exited by the propect of snow.............I must not like snoe................I must............

On a serious point I've quit watching the TV weather as yor forecasts are much more reliable - Thank You.

[1Bee]

*gets down on her knees a prays for snow* The boys would go bananas....

But, typically, the snow map has us just into the blue bit in the NW of Cumbria. Mind you, that's still a few inches.

*squeeeeeeeeee!

[Jay22]

I'm excited Lumpy...go for it! Although on saying that we are meant to be going to South Ayrshire for the weekend, we may well get snowed in. No phone, no internet...better buy some food and more importantly wine!

[Penellype]

Remember that there is still considerable uncertainty attached to this low pressure system. Snow is likely to the north and east of the low, so the further north it goes the further north it will be rain rather than snow. But if it goes too far south it could miss us altogether, meaning neither rain nor snow.

This is the chart that produced the snow map above:



and this is the very latest run of the GFS, hot off the press:



You can see that the GFS has the low a little further south than the ECMWF.

We probably won't know for sure until Saturday where the low is going, but I suspect that even if this one does miss us there will be further opportunities for snow before too long.

[WPG]

About an inch of snow here, and it's freeeeezing out.

[1Bee]

And now we have to worry, because it's likely the weather will send visiting grandparents home early.

[Chippy Minton]

The kids school said they may be closed due to the weather warnings. We woke up to........ next to nothing and the school gleefully proclaiming they're open. Cue 2 x grumpy kids. They DEMAND a re-snow. Luckily Sunday looks like providing.

Dog's going nuts around the garden, greenhouse is getting full, chicken house is leaking.

Keep up the good work Penellype,let us know when we can come back out, off out to the log store now, if I'm not back in half an hour send a St Bernard.

[Penellype]

Update on the snow situation this weekend.

There are yellow and amber warnings for snow on Sunday for a large part of the UK, plus yellow warnings for snow today in the west and wind on Sunday in the south:
https://www.metoffice.gov.uk/public/weather/warnings

Snow showers continuing today for Scotland, N Ireland and Wales and through the Cheshire gap. Not everywhere will get one, but the risk is there, particularly this morning.

Tonight into tomorrow a low pressure system tries to move in from the west. As this hits the cold air the rain turns to snow on the northern and eastern side of the low. The position of these lows is incredibly difficult to forecast and a difference of a few miles can make huge differences in what happens at a particular location. There is still time for things to change slightly. This low is also likely to bring strong winds to the south on Sunday.

The snow forecast map from the GFS for midday Sunday is:



The ECMWF has the low slightly further south, and the snow accumulation map for 9pm CST (3am Monday GMT) is:



With these situations one of the headaches for forecasters is the formation of small troughs or lows around the fringes of the main system. One such small low is forecast to form in the bay of Biscay and move north east across France on Monday, and this could give some snowfall in the south east. You can see the beginnings of this low from the pronounced kink in the isobars over Biscay and Spain on this chart:



The GFS forecasts this for mid day Monday:



the band of snow moving east through the afternoon. Whether it turns to snow or not in the south east is a finely balanced situation - it may be rain, sleet or snow and it is impossible to tell. The ECMWF has it as snow, so that by the end of Monday the snow depth chart looks like this:



I can't stress strongly enough that snow is incredibly tricky to forecast. The purple areas on these charts are pretty certain to get a considerable amount of snow. The dark blue areas are likely to get something (which will be snow if it arrives north of the purple area) the pale blue and paler areas may or may not get snow and the south is a toss-up between rain, sleet or snow. There is also the possibility that tomorrow's low could still be a little further north (as the GFS forecasts) and that Monday's low may be further south and miss us altogether.

There will be an in-depth live analysis at 5pm this evening at http://www.gavsweathervids.com/ which should last about 90 minutes and is likely to be very informative.

[Lumpy]

The weather goddess of the forum has given yet another accurate prediction. It's snowing...................Ta Pen.

[Penellype]

A couple of very cold days coming up, particularly where there is snow cover, which tends to keep the temperatures down. Parts of Wales where there is deep snow could join parts of Scotland with temperatures nearing -10C at night.

Slightly milder on Wednesday when rain will probably melt most of the snow at low levels, but there could be more snow on Thursday as winds turn back into the north. Once again next weekend looks like being cold.

Beyond that the models are hinting at possibly milder, more westerly weather in the run up to Christmas, but I wouldn't bank on it, as this is the default setting for the models. All depends on the position of high pressure, which could become established over Scandinavia, or over us. If it is over us and to the east, that is milder, but over us and to the west is cold, and over Scandinavia brings the wind in from the east, which is very cold. As always there is a lot of uncertainty in the longer term.

[Jimmy]

-7.5 overnight in Preston.
I had to put the sump heater in the greenhouse to protect my Bay tree, I hope !
Supposedly even colder tonight.
Jimmy

[Penellype]

Slightly milder and damp today but rain could turn to snow this evening as the wind once again turns into the north. It shouldn't be as cold or as snowy this time though.

Models are firming up on the idea of milder weather next week:



However, this is the upper air temperature under high pressure. At this time of year, with clear skies and little wind, nights can be cold even if the upper air is warm. There is also the possibility of fog where the wind is light. The north and west should be on the western side of the high, with more wind and therefore milder temperatures (but more chance of cloud and rain). The further south and east you are the greater the possibility of frost and fog.

Towards Christmas there is a large amount of uncertainty - this seems to me to be uncertainty about when the high pressure will move away to the east and allow wetter, windy weather to arrive from the atlantic (most of the lines start to move sharply up and down indicating low pressure systems, although there is not all that much rain). It is still too far away to tell, but I suspect we are likely to see some mild, wet and windy weather before the end of the year, although it may not last all that long.

[1Bee]

Raining here now. We did get some very hard frosts (a bottle of diet coke froze solid in my car....!) but no snow where we are. The Grandparents made it, and stayed the whole weekend, and it was lovely.

Thanks Pen.