London And The South East Regional Discussion Thread - Part 4

[danm]

bbc london's latest video forecast (updated online at 11:59 this morning) reporting sleet and quite warm on sunday, with perhaps a light dusting sat eve.

Have they really got it that wrong?

Just seen that. The symbols for Sunday (Sleet) and Monday (rain) are exactly the same as the five day forecast on the BBC website, which are best ignored! None of the models suggest (at the moment!) that Sunday will be 7c with sleet and Monday 4c with rain!

[VillagePlank]

Just to add my t'ppence worth here's the 850hPa theta-e temps for Sun 00z,

I've constructed a chart that should give a reasonably good indication of snow chances should precipitation occur against theta-e temperatures,

Putting the two together: Rochester has an 850 hPa theta-e of about 16C. Cross-referencing my chart gives an approx chance of snow of 50% (or 0.5)

Now, of course, this is all rule of thumb stuff, but it does imply that one must look at other factors, including surface conditions, dew-points, humidity, and rate of precipitation amongst others to confidently forecast snow!

Defo sitting on the fence given the GFS 6z this morning. I might get lucky as I am about 100m ASL at my location ....

Edited February 2, 2012 by Boar Wrinklestorm

[Guest archiesmummy]

Why are the BBC still insisting that its all turning to rain early hours of Sunday morning as the temps will be 5c+? Am I reading charts wrong I can be simple but.......

[Jo S]

Why are the BBC still insisting that its all turning to rain early hours of Sunday morning as the temps will be 5c+? Am I reading charts wrong I can be simple but.......

When i watched it on the red button video on tv they said significant snow and it will not turn to rain

[PureOcean]

This is what the current north sea is looking like from Whitstable. The tide is coming in over the mud flats and oyster beds in this image, but I wanted to show you the clouds, and general skyline.

This image is facing North.

Edited February 2, 2012 by PureOcean

[A.J]

Up here in the Midlands we're so looking forward to sunday on the forum, when we're plastered with meters of snow and the SE is bone dry as the block repels the atlantic attack!

Yes, to spice things up, it's time for a bit of inter-regional rivalry...lol

[Cheshire Freeze]

Up here in the Midlands we're so looking forward to sunday on the forum, when we're plastered with meters of snow and the SE is bone dry as the block repels the atlantic attack!

Yes, to spice things up, it's time for a bit of inter-regional rivalry...lol

Too right AJ

[Eskimo]

Up here in the Midlands we're so looking forward to sunday on the forum, when we're plastered with meters of snow and the SE is bone dry as the block repels the atlantic attack!

Yes, to spice things up, it's time for a bit of inter-regional rivalry...lol

I have declared war.

[spayne]

some weather warnings have now appeared on Metoffice site..............ah...only for ice...

Edited February 2, 2012 by spayne

[Bogman]

yeah, ice

[Radiating Dendrite]

Why are the BBC still insisting that its all turning to rain early hours of Sunday morning as the temps will be 5c+? Am I reading charts wrong I can be simple but.......

They have not updated there website yet that is all.

People really need to chill.............it is not that difficult to work out, surely?

[SMU]

boar your not considering the nature of the column of air from cloud base to ground.

whilst the cloud deck might not be that cold at say minus 2 minus 3 you have what I would call a super DALR, which means that column of air has NO melt layer from cloud base to surface.

Meaning 95% chance of snow.

This is because the surface flow is from the continent, if the front arrives at a less accute angle with more a westerly or even south westerly flow the column for air has a thicker warm layer moving over the surface cold, and whilst the surface may still be at or below freezing the DALR has suddenly become a saturated lapse rate SALR, so irrespective of surface temp the snow crystals fall through a wet layer of the atmosphere just below the cloud deck and melt and turn to rain.

As the rain pellet reaches the lowest levels of the atmosphere then its hitting the cold surface air that hasnt been mixed out and if thats below zero the particle of rain will become supercooled and can fall as freezing rain.

So if people have ever sat there wondering why it snows at 3c but can rain at 0c ( typically warm fronts moving into cold air) its because the damage is done to the snowflake in whats called the melt layer...

Best regards

steve

[Whereisthesnow?]

And snow. Friday and Saturday.

[Paul Sherman]

So where have I got this one from then ? Lol

A band of snow moving into eastern England from the North Sea is expected to give accumulations of 2cm or so quite widely, and perhaps 5cm in places. Although timing is uncertain the snow is likely to be most widespread and heaviest late on Friday evening. After midnight it will tend to die out, but untreated roads may remain icy well into Saturday morning. The public are advised that some travel disruption may result.

[polarlow2]

More and more convinced this is going to be a central southern England/Midlands/Northern England event on Saturday. Really to feel we are too far east.

[lewis028]

Yep as expected an advisory for snow the weekend

And Friday night..

Edited February 2, 2012 by lewis028

[Paul Sherman]

Also If you are in the Green then this is a VERY GOOD Thing as usually the areas in the Warnings from the Met miss out :rofl:

[Jo S]

ive

some weather warnings have now appeared on Metoffice site..............ah...only for ice...

Ive got snow and ice in my area

[danm]

http://www.metoffice...t_warnings.html

So far they've put up the warnings for snow showers into the far east (Suffolk, E Essex, E Kent) on Friday night, and warnings for snow in the west as the front marches east. I suspect they'll put out more warnings soon for saturday night/sunday for us as that front is forecast to push east.

As for the snow showers on Friday night, London, W Essex, Sussex, Surrey and W Kent not included in the warnings, but it will be a nowcasting event, and I suspect it's quite possible that a few stray snow showers could push further inland!

Edited February 2, 2012 by danm

[Guest archiesmummy]

They have not updated there website yet that is all.

People really need to chill.............it is not that difficult to work out, surely?

We are not all as wonderful and so clever like you, there has to be stupidity so clever teachers and wise people such as yourself can teach, that's simple enough..

[yamkin]

Severe alert has been issued to Croydon Council to expect disruptive snowfall throughout Sunday into Monday

I see MetO have also updated their website alert

[Radiating Dendrite]

We are not all as wonderful and so clever like you, there has to be stupidity so clever teachers and wise people such as yourself can teach, that's simple enough..

It is not about being clever, it is just common sense surely?

Anyway, let's move on!

Severe alert has been issued to Croydon Council to expect disruptive snowfall throughout Sunday into Monday

I see MetO have also updated their website alert

Oh dear, he is back!

Hope you have been gritting the roads Yamkin? I might be in Croydon on the Sunday!

[Paul Sherman]

Up here in the Midlands we're so looking forward to sunday on the forum, when we're plastered with meters of snow and the SE is bone dry as the block repels the atlantic attack!

Yes, to spice things up, it's time for a bit of inter-regional rivalry...lol

Did you just tamper with those Met Office Charts Aj

[danm]

http://www.metoffice.gov.uk/weather/uk/uk_forecast_warnings.html?day=4

...and the warnings for Sunday. All of eastern England and the central Midland eastwards are in the warning zone.

A band of snow will continue to move slowly eastwards across England during the first half of Sunday. This may be heavy initially but will tend to die out during Sunday morning. Total accumulations from this snow event are likely to be of order 5-10cm in many places; this includes low lying areas. The public are advised that this is likely to lead to some travel disruption, and should pay close attention to forecasts as the event approaches

[Lauren]

So how much snow are we lloking at, enough for me not to able to make it into work?