Tracking The Developing French Low

[SteveB]

Update, the area of moderate snow in northern France is approaching the Channel now, expect some fairly extensive development of heavy snowfall into southeast and south central England by mid-day (where not already in progress from sea-effect bands). Further north, it will be a case of the existing sea-effect becoming heavier later on as this energy phases, the situation will still essentially be a nowcasting radar-watching exercise for many, but I do expect the spread of heavier snowfall amounts to be a big factor in the total outcome of this situation. Some have already seen a lot of snow and will get a lot more, others have seen very little and will get a lot in a while ... and some will miss out, but this has the possibility of spreading snow into districts that cannot get any from sea effect bands. Much depends on the actual path and strength of the meso-scale low, which is just beginning to push into the frontal band now in south-central France.

Is the Bristol area likely to see anything out of this?

[PompeyFC]

Update, the area of moderate snow in northern France is approaching the Channel now, expect some fairly extensive development of heavy snowfall into southeast and south central England by mid-day (where not already in progress from sea-effect bands). Further north, it will be a case of the existing sea-effect becoming heavier later on as this energy phases, the situation will still essentially be a nowcasting radar-watching exercise for many, but I do expect the spread of heavier snowfall amounts to be a big factor in the total outcome of this situation. Some have already seen a lot of snow and will get a lot more, others have seen very little and will get a lot in a while ... and some will miss out, but this has the possibility of spreading snow into districts that cannot get any from sea effect bands. Much depends on the actual path and strength of the meso-scale low, which is just beginning to push into the frontal band now in south-central France.

roger do you think it will allow snow in south hants, southampton/portsmouth area?

[BLAST FROM THE PAST]

Hi Roger

The good old North Downs have prtected me from the streamers, huh protected!! My boy is still happy though with what we currently have. However, I think I am in very good spot for this afternoons event. Very good thread by the way.

BFTP

[patrickshere]

Not sure what to think of the positioning.. It's looking like I could well be too far west for the low? Looks like the main front is gonna plow through EA.

[Rich44]

I hope so, we've had a little more than a dusting and it'd be great to see some more, having said that with what we have I can't get out to work as it's a C road so ungritted and I live in a valley so can't get up the hill lol.

[snowking]

Not sure what to think of the positioning.. It's looking like I could well be too far west for the low? Looks like the main front is gonna plow through EA.

Its really pretty difficult to tell

The best thing to do is use a european radar and forecast it yourself.....i think too many people are falling into the trap once more of following bbc weather graphics too literally

SK

[patrickshere]

I hope so, we've had a little more than a dusting and it'd be great to see some more, having said that with what we have I can't get out to work as it's a C road so ungritted and I live in a valley so can't get up the hill lol.

Yeah we've got about 2-3cm here I think.. A little but nothing special, had much more during the couple of days in February 2007 that whited out our area.

[Basil_Fawlty_Walks_On_Water]

heads up for those asking if they're too far west... this SHOULD pivot westwards, although it should be heaviest in the east, but many in the east will struggle to remain all snow.

[patrickshere]

heads up for those asking if they're too far west... this SHOULD pivot westwards, although it should be heaviest in the east, but many in the east will struggle to remain all snow.

Ah great, well we're slightly north east of you guys in Reading. Things have a habit of not doing what they're supposed to though with the weather!

[jazzy]

Roger, please put me out of my misery, are we likely to see any snow in Devon today, kids a re climbing the walls with all the snow on the t.v. and not a single flake as yet here, should I prepare them for the chance we will not see any white stuff or is there an outside chance we might. Regards

[Damp and dreary]

Well as the low south over france is approaching i can say that it certainly is starting to produce more snow on the south coast, here in eastbourne there was no snow after about 9pm but started a few hours ago and you can clearly see on the radar an area of snow getting larger, and this is before the man area of precipitation due to hit in a few hours.

[watcheroftheskies]

Its really pretty difficult to tell

The best thing to do is use a european radar and forecast it yourself.....i think too many people are falling into the trap once more of following bbc weather graphics too literally

SK

Hi all, you can see the deeper cloud (frontal snow?)moving up from france on this meteosat link http://wind.met.fu-berlin.de/cgi-bin/meteo...playmode=Endlos

Not sure if it will give much here but snow is falling steadily as I type.

[Basil_Fawlty_Walks_On_Water]

Hi all, you can see the deeper cloud (frontal snow?)moving up from france on this meteosat link http://wind.met.fu-berlin.de/cgi-bin/meteo...playmode=Endlos

Not sure if it will give much here but snow is falling steadily as I type.

cheers for the link...

you can see the trough here starting to tilt, which should bring the frontal snow westward.

[Roger J Smith]

Just some ideas in general for this developing situation ...

** southeast will see a heavy burst of snow from the Channel moving inland, probably it will mix with sleet and change to rain mostly in the Kent coastal districts and up to about 50 m asl inland, not so much further inland, and in any case the first part of the precip will be heavy snow before the changeover where it happens.

** south central and southwest England, parts of south Wales should do better, where snow has not yet fallen at least a covering of 1-2 inches is likely but higher inland sections could see 4-8 inches developing and then with the further evolution of the system as it comes in overhead and rotates back into France, there is no particular reason why this region should see a changeover unless it's very close to the south coast at sea level.

** further up the east coast and into central England (as defined north-south if you get my drift) the situation is complex, the atmosphere will try to sweep a rotating mild sector around over the snow cover, but at very marginal increases in upper support, which is going to make the forecast tricky, the precip may change over to sleet at times but it seems like the rain-snow dividing line situation that could affect the southeast will fizzle out to more of a question of how much snow turns to sleet, so I expect some higher locations to keep getting a moderate to heavy snow buildup despite a somewhat milder "feel" later on. By the time the atmosphere has warmed enough to consider a phase change it looks like the system will have rotated the cold air all the way round and back into England from the south.

** eastern Ireland could start to get very heavy bands of snow later as the frontal dynamics pile into the existing sea effect squall bands on the Irish Sea. The problem here is the warmer SST values in the Irish Sea which could just turn any marginal conditions to sleet or rain temporarily.

** would keep a close eye on radar in the southwest, in case there is explosive development especially from about noon to 6 pm. By this time, the trough is strong enough and the low close enough that a frontal band to the WEST of the upper trough will be more dynamic than the band to the NORTH of the warm front further east. (remember, WEST is BEST when the cold air is on your side of the front).

[Rob]

i really hope we get this heavy snowfall, weve only had a few inches here overnight and im off work, hopefully will have another day off tomorrow.

[Lynxus]

Just some ideas in general for this developing situation ...

** south central and southwest England, parts of south Wales should do better, where snow has not yet fallen at least a covering of 1-2 inches is likely but higher inland sections could see 4-8 inches developing and then with the further evolution of the system as it comes in overhead and rotates back into France, there is no particular reason why this region should see a changeover unless it's very close to the south coast at sea level.

I was not expecting this french band to come this far west?

from what the BBC say it looks like its hugging the east. maybe im one of those people following their predictions to literally?

Any comments?

[Nights King]

i hope your right about west country so far its been one of my worst snow event winters ever here with 0 days of laying snow on the mendips!! the average is like 15.

[patrickshere]

Just some ideas in general for this developing situation ...

** southeast will see a heavy burst of snow from the Channel moving inland, probably it will mix with sleet and change to rain mostly in the Kent coastal districts and up to about 50 m asl inland, not so much further inland, and in any case the first part of the precip will be heavy snow before the changeover where it happens.

** south central and southwest England, parts of south Wales should do better, where snow has not yet fallen at least a covering of 1-2 inches is likely but higher inland sections could see 4-8 inches developing and then with the further evolution of the system as it comes in overhead and rotates back into France, there is no particular reason why this region should see a changeover unless it's very close to the south coast at sea level.

** further up the east coast and into central England (as defined north-south if you get my drift) the situation is complex, the atmosphere will try to sweep a rotating mild sector around over the snow cover, but at very marginal increases in upper support, which is going to make the forecast tricky, the precip may change over to sleet at times but it seems like the rain-snow dividing line situation that could affect the southeast will fizzle out to more of a question of how much snow turns to sleet, so I expect some higher locations to keep getting a moderate to heavy snow buildup despite a somewhat milder "feel" later on. By the time the atmosphere has warmed enough to consider a phase change it looks like the system will have rotated the cold air all the way round and back into England from the south.

** eastern Ireland could start to get very heavy bands of snow later as the frontal dynamics pile into the existing sea effect squall bands on the Irish Sea. The problem here is the warmer SST values in the Irish Sea which could just turn any marginal conditions to sleet or rain temporarily.

** would keep a close eye on radar in the southwest, in case there is explosive development especially from about noon to 6 pm. By this time, the trough is strong enough and the low close enough that a frontal band to the WEST of the upper trough will be more dynamic than the band to the NORTH of the warm front further east. (remember, WEST is BEST when the cold air is on your side of the front).

Hey roger,

Hate to be a pain, I always struggle with the central south, central areas, south east, etc as to where to classify myself! I'm in Aylesbury, Bucks:

http://maps.google.co.uk/maps?f=q&sour...amp;t=h&z=7

Be great if you could let me know what you think, deciding whether to go out in the car or not..

[finny]

snow starting to fall now on east kent coast 1.4 oC

[Roger J Smith]

Well I don't know how it will be perceived, what evolves out of this, the French band will mainly move north but as the low gets closer to the Channel a second round of development will probably take place in situ, with the remnant moisture from the streamers being part of the seeding, some radar echoes moving inland from the Channel, but also just a frontal development in place during the afternoon and evening. So I can't really say what people will think is happening from what's there now to what may be there later, but this is what I expect to be there later for whatever reason.

By the way, it's groundhog day on this side of the ocean.

[NickSomerset]

Hi

Getting a bit of the fine stuff here now.....come on bring it on....PLEASE!

[watcheroftheskies]

Thanks for the updates Roger,always worth reading your input, most appreciated.

Will just have to wait and see how this develops later, going to work now, getting back could be the problem!

[yamkin]

Well I don't know how it will be perceived, what evolves out of this, the French band will mainly move north but as the low gets closer to the Channel a second round of development will probably take place in situ, with the remnant moisture from the streamers being part of the seeding, some radar echoes moving inland from the Channel, but also just a frontal development in place during the afternoon and evening. So I can't really say what people will think is happening from what's there now to what may be there later, but this is what I expect to be there later for whatever reason.

By the way, it's groundhog day on this side of the ocean.

Roger, I posted this in another thread. Sorry if it ditto's what you already said.......

There is something about this snow formation which is heading our way from France.

There is a possibility of two separate bands of snow arriving to our shores.

The first I believe will be within 2-3 hours and the other during rush hour time.

[john w]

I have to admire your bravery RJS....My main concern for the snow lovers (I like snow too) is that mild air from the atl may just become enrenched in this low to give rain further inland than predicted...However, this is a fear and the models at current show exactly what RJS expects.

It will be very very interesting to see exactly where and when this system does its u-turn...places seeing 2 dumpings from this system or being under it when it stalls and reverses could get some significant accumulations.

For RJS's benefit please do not post (will it snow here....will it snow there questions in this thread). MODS can we open a will it snow question thread which mods answer lol....

For poster above (and i vary rarely assist on geographical placing) Aylesbury...south bucks is erring on south central england....to just about south south south midlands...you should see flakes from the event due today

[conor123]

http://www.wetterzentrale.de/pics/Rmgfs153.gif

Certainly looks like nowhere should miss out on the snow as when it moves into Northern England, Wales, Northern Ireland, Scotland & SW England it slows down, in fact pretty much stalls so these areas should have snow all through the night and much of tommorow.