DAVE_ALLEN

I’m not sure it will track any further north. I think this is pushing it. Besides the northern edge of this warning area will be light patchy snow that probably will be to patchy to settle. Midlands will see some snow on Thursday on the leading edge as the low tracks across northern England.

Major upgrade just issued for more snow in the south via updated warning. . @nick sussex this defies the latest fax charts. One can only assume this evenings fax will have a significant adjustment. I admit I wasn’t expecting a significant upgrade in terms of warnings for the south. it’s interesting to note. The snow risk has just crept north of the M4 as far as Luton northwards. This northward movement is most likely a result of a deepening of the channel low.

Was the word “CORRECTION” emblazoned on the fax chart, @nick sussex?

So… this evening. Where is FI ? What do you reckon ?

Putting the meat on the bones as they say. Plenty of precipitation on a series of weather fronts coming south now across the UK. Snow already starting to fall from showers over the Scottish Mountains. Over the night as the cold fronts clear south much colder air arrives and most showers in the north will turn to snow or hail. the area of rain moving south east towards London. Needs to stall over southern England for about 12 hours for the cold air coming into Scotland now. To get down south quickly to be able to turn the back edge of any stalled front to sleet and snow. legend. Red = snow, blue = rain. Grey = wintry mix

Further insight into the meandering occlusion in southern areas and how the low tracking east can pep up precipitation as it passes. Whilst it appears the low will track through during the middle of the night. It would be beneficial for a frost to have set in before hand. The second low is a lot more vigorous and appears to usher in milder air very rapidly. Albeit there is a possibility of transient snow on the leading edge of this front. We will have to keep a close eye on the second low Thursday / Friday as this has the potential to bring high winds in northern and NE England. FullSizeRender.MOV

So the met office have called it. They appear to have gone against the latest fax charts for disruptive snow keeping it along southern counties and south of the M4. I expect the 12z ECM and this evenings fax charts to update on a par with this. The current runs seem to slowly coming together albeit there is still diverse solutions even at this short range. this would suggest more of a channel low set up moving E and then ESE up the channel rather than a frontal system moving NE up the country

The Azores low lends a hand to the Atlantic block development

Is that a figure of 13139cm in the highlands ???

So much information to digest on the fax chart for next Friday. Whoever does the week ahead forecast for the Met office today. Will have a lot to include this week On the chart blueline shows an approximate limit of the snow coming south. The Midlands looks to be particularly wet with possibly some very high rainfall totals. If that warm front waves over that region for long. This in part due today huge difference in temperatures to the north and south of the front. After probable heavy fall of snow, in southern counties of England, on Wednesday and Thursday, there could be a great deal of fog and a rabbit thaw , if the warm front moves north into northern England, as shown on the fax chart. The incoming low over Biscay has some very warm air behind the warm front, possibly up to 15 C. So there could be a particularly warm day one day this weekend down south. And finally, the low with a purple arrow could develop into something of a beast, as the jet is still to the south, and the low will be developing in the colder air close by the UK. If this happens, there could be some very stormy conditions along the south coast and in the south western parts. All of that follows the snowfall that we see in the days beforehand. If you check the radar this morning, you will see, see it is already falling across parts of Surrey and the borders to Sussex and there has been some wet snow passing close to Cambridge, and heading towards Suffolk and Essex. Original post: https://community.netweather.tv/topic/98450-model-output-discussion-a-cold-start-to-spring/?do=findComment&comment=4818337

One caveat to bear in mind regarding the frontal snowfall in southern counties is diurnal heating. if the front encroaches after midnight and before dawn. Snow, even settling snow is possible. Should the front arrive say between 3pm and midnight. Precip could be more borderline or sleety to low levels. It’s all to play for. But timings will be critical to some extent. What’s the key difference between the two ?

Interesting to note that none have piles of snow over northern France.

Need more runs and also the Iberian high to go on holiday to Greece. Most likely. MO are saying 60% change or southern counties getting most snow. 20# chance of the midlands generally seeing the snow and 20% chance the snow will pass through northern France. So you could say. Game on. Let’s see the in 24 hours time.

MetO week ahead will be an Interesting to watch. Alex deakin won’t be able to contain himself . separately, did you notice that whilst the Greeny upper high moves away to northern Canada, by the Weeknd a new surface high has formed in southern Greenland, I wonder what my thoughts are on this developing some Heights with the support of the second coming of the SSW ?

There is nothing in place to hold up the Atlantic lows. It’s entirely plausible especially when you consider they are supported by a bulging Iberian HP ridge.

That Friday low is a lot further north east @nick sussex it looks to be developing quite a lot too. Storm potential ?

So much information to digest on the fax chart for next Friday. Whoever does the week ahead forecast for the Met office today. Will have a lot to include this week On the chart blueline shows an approximate limit of the snow coming south. The Midlands looks to be particularly wet with possibly some very high rainfall totals. If that warm front waves over that region for long. This in part due today huge difference in temperatures to the north and south of the front. After probable heavy fall of snow, in southern counties of England, on Wednesday and Thursday, there could be a great deal of fog and a rabbit thaw , if the warm front moves north into northern England, as shown on the fax chart. The incoming low over Biscay has some very warm air behind the warm front, possibly up to 15 C. So there could be a particularly warm day one day this weekend down south. And finally, the low with a purple arrow could develop into something of a beast, as the jet is still to the south, and the low will be developing in the colder air close by the UK. If this happens, there could be some very stormy conditions along the south coast and in the south western parts. All of that follows the snowfall that we see in the days beforehand. If you check the radar this morning, you will see, see it is already falling across parts of Surrey and the borders to Sussex and there has been some wet snow passing close to Cambridge, and heading towards Suffolk and Essex.

The highest risk from frontal snow midweek is from a line from Bristol to Maidstone, southwards. oxford may well get some back edge sleet and snow over night Monday / Tuesday temps on Tuesday will determine if it thaws or not.

510 dam air approaching north Scotland’s coast. That’s very cold air. Over night lows sub -10C. I wonder how far south that 510 dam line will get. The 528 dam line is running east /west along the South Downs. Could get very snowy indeed over the South Downs midweek

Sadly rain is more likely. Some charts are showing temps climbing 10 to 15c by the end of the week. In many ways it could well be a rapid breakdown of cold to very mild in little over 24 hours. All is dependant on the track of the incoming warm front. London is some distance from the south coast and is a good example.

@Nick F there is a steep gradient of 850’s from -1C to -5C across Hants Sussex’s and Kent. Where, in your years of experience, would you hazard a guess at the boundary between heavy rain or snow falling at the surface if you were to include no other factors. ?

I highlighted this a few days back. Good to see others are picking up on this. we are approaching the spring high tides so if the storm force wind gusts coincide with the high tide. Some coastal flooding could occur as well as pebbles and other flotsam being tossed up in beaches and promenades.

The cold northerlies have turned into a rather benign col. There’s still hope or something wintry north of the 528 dam line on the fax chart.

Agreed any sign of mild, it’s FI. Positive thinking. It’s been working a treat this week as re intro mild on weds has been pushed back at least a couple of days. Deep snow over southern snow fields will help to enhance the block with the surface air remaining frigid