London And The South East Regional Discussion Thread - Part 3

[matty40s]

@KentishKiwi

I yearn to see that sort of again two years on the trot. Doesn't seem likely this year though for anyone.

well ,I am suprised at you, not far south of you is the start of some real streaming activity from the wash eastwards. and looking at the met office sat pics, there is some serious ppt coming down through the north sea and being picked up bt the easterly.

[steveinsussex]

As Im off work right now some snow over the weekend would be lovely please weather gods.....

[ZONE 51]

Thanks for the Insight into how the Lake Effect works on your side of the pond Roger.

Btw at the moment I am not even looking at the weekend and how it all breaks down and like Roger said we should be concentrating on Micro events before an event which is T72 to T96 Away!

taking each hour at a time! exciting!

[ZONE 51]

THE DEWPOINT TEMPERATURE

One of the important weather factors that growers should pay attention to in the frost forecast is the dew point temperature. The dew point temperature is the temperature to which the air must be cooled before dew or frost begins to form. The dew point temperature is also a measure of the amount of water vapor in the current air mass. The higher the dew point, the more water vapor there is in the air. Air holds water in various amounts in the invisible gas state, called water vapor. The amount of water vapor in the air, and therefore its dew point, varies with the different air masses that move in and out of the eastern Washington. Therefore, knowing the dew point gives an idea of how moist or dry the air is.

At night, the temperature of the air cools down and often reaches its dew point temperature, so the water vapor in the air changes to a visible liquid (dew) or solid (frost). During this change in state, from vapor to a liquid or to frost, a large amount of heat is released. It is this release of heat during the change in state from a gas to a liquid or solid that is important for frost protection. If the dew point is high, meaning more water vapor in the air and dew forming while temperatures are fairly warm, then the heat released slows down the normal fall in temperature at night and keeps the air temperature from getting too cold. On the other hand, if the dewpoint is low, meaning dry air and dew or frost not forming until temperatures get colder, then heat from the change in state is not released until much later at night, or possibly not at all if the air is so dry that dew or frost do not form. In this case the air temperature can drop rapidly and reach dangerous levels.

Usually, the dew point temperature runs in the 30s and 40s in the air masses that cover eastern Washington in the spring. This means that on most nights, when temperatures are falling toward the low 30s, dew will form and slow the temperature fall, keeping temperatures either above critical, or at least from falling so low as to make frost protection difficult. Occasionally, very dry air invades eastern Washington in the spring, resulting in dew points in the teens and low 20s. These dew point values are considered dangerously low. When dew points are this low, the dew point temperature will not be reached so little or no heat will be added to the air. Temperatures will drop steadily and rapidly and can reach critically cold levels. Protection is usually more difficult and must be started well before critical temperatures are reached, due to the fast drop in temperature. Fortunately, low dew point cases are fairly rare and usually occur early in the frost season, when buds are hardier.

Very often the dew point temperature is nearly the same over a fairly large area and usually changes only slowly with time, especially when the dew point is in its normal range. This means, for example, that the dew point reported at Yakima airport in the early evening will likely be representative of much of the Yakima valley and will stay about the same or fall slightly during the night. When the air is very dry, with low dew point temperatures, there is often more variability and fluctuation in the dew point over the area. During these very dry cases, growers may need to look at several stations over a period of a few hours to assess a representative dew point for the area.

In sum, growers should pay attention to the dewpoint temperature. Dewpoints in the 30s to low 40s are normal and while not ensuring against freezing temperatures, they usually mean temperatures will not fall extremely fast or reach critically low levels and frost protection measures will usually be successful. Dew points running in the teens and low 20s are critical and could mean a long, cold night with possible difficulty in keeping temperatures above critical levels. Clearwest gives the current dewpoint temperature for several sites in eastern Washington in their daily frost forecast. Growers can also select the “Current Washington Weather†button on our web site to get the latest hourly weather, temperature and dew points values (shown under the DP heading) from reporting stations in eastern Washington

After reading something about dew points/drier air/frost or no frost back in the thread, found this thought it would be good to post it.

Edited February 2, 2012 by ElectricSnowStorm

[ZONE 51]

Created a snow forecast map, looking at the model data there is the risk of snow showers setting up from the North sea from Thursday early hours(if they fire up earlier than expected we would be looking at them moving in from wednesday night late-tonight, but the risk rises really into thursday morning and afternoon, although the models indicate more potential into EA i would expect some swing across the SE, the increase in convective activity on friday looks like more widespread snow showers, the chances are only lighter precipitation would materialise through the first risk period(thursday)but things can change! its hard to pin point this stuff but the increasing chance of snow is there through thursday/friday, at the moment a drier air slot is around and this lasting though wednesday(today) with sunny skies! then cloud increasing as we go into the night time.

Here is a recent radar snap..

and zooming our region..

and further north..

So the snow showers further north becoming a streamer, with a light snow shower just around London,

i might post later an update on Thursday snow streamer/Shower potential for the SE.

(wind swing just right!)the streamer now present further north is heading in from the Wash,(see map below)

i was also expecting the snow showers further south of that zone to, see my map below posted wednesday morning-see blue box streamer zone, on thursday i expect a Thames type zone to set up like this and friday.

Edited February 2, 2012 by ElectricSnowStorm

[SMU]

http://modeles.meteociel.fr/modeles/gme/run/gme-0-72.png?00

overnight GME is very extreme front doesnt get to england

very very cold in the SE by then with some snow

S

[ZONE 51]

Cloudy and breezy this weekend, with several bands of snow or sleet likely to pass across the region

Outlook for Saturday to Monday:

Cloudy and breezy this weekend, with several bands of snow or sleet likely to pass across the region. Possibly drier for a time Monday, with further rain or snow later.

Updated: 0321 on Thu 2 Feb 2012

http://www.metoffice.gov.uk/weather/uk/se/se_forecast_weather.html

[ZONE 51]

But before that potential, we have possible snow showers/streamers for some areas(thursday/friday and into saturday), depends where they set up, not everyone would see these so its radar watch! certain places would see streamers or prolonged periods of snow showers following one another, these do not need to be really that heavy to mount up some snowfall on the ground-the snow settling fast as its so cold, but if they do become heavy then of course we are talking alot of snowfall, the weather can change in these situations of convective activity from the sea, so nothing is set, its a difficult situation when you have severe cold to the East and milder air trying to push it back to where its from, this is called a battleground, so the weekend is the battleground and where that line is then alot of snowfalls, if the battle front stalled/slow moving over an area then precipitation would be prolonged for a long time-many hours-and this is quite possible to happen, so what im expecting is leading up to the frontal situation at the weekend is snow shower phases giving quite a covering around/over parts of the SE/EA, possible features/developments popping up in a short time frame... then the battle snow front(as i call it!) slowly progressing across at the weekend giving a lot of snowfall!

The future ahead looks to me as cold and potentially very snowy for EA/SE, i do not expect any form of mild prolonged periods, small brushes that is pushed away again, i expect snowevents to be more frequent or likely during the month rather then rainfall being the main type, this being because i expect the cold air to stay around, and never being to far away-if it does move away!

Edited February 2, 2012 by ElectricSnowStorm

[Roger J Smith]

Vic can moan at me if he wants, in fact he can come to my house and throw snowballs at me, although that won't work unless he brings snow.

Cloud spreading north into the Franco-German border region which could be seeding for projected mesoscale event Friday.

No shortage of cold air upstream, -15 to -20 almost everywhere from the Rhine to Warsaw and -25 behind that.

Longer term, model consensus seems to be growing that southeast England stays cold for all next week and weak frontal ripples moving east across central England could set off further snowfall. And any snow that does fall will not melt but will serve to drop the surface temperatures by as much as 5-7 degrees especially outside of greater London.

In a way, you want to see a bit of a weaker ridge so that Atlantic moisture can get at the cold air (next week that is).

For later today, would suspect streamer development might initiate around late morning and spread in during afternoon with peak intensity evening hours. Thunder snow most likely by evening partly due to geomagnetic cycles.

[Floatylight]

I dont think i have ever known it so cold ,with no frost. Its as dry as a bone here.Nothing on cars nothing in garden

[kate1]

Well, Kaddy has just predicted snow for tomorrow, Saturday and Sunday in no uncertain terms...the most definite BBC prediction I have seen so far...think it really is going to happen this time...

[Snowy Easterly]

Outlook for Saturday to Monday:

Cloudy and breezy this weekend, with several bands of snow or sleet likely to pass across the region. Possibly drier for a time Monday, with further rain or snow later.

Updated: 0321 on Thu 2 Feb 2012

http://www.metoffice...st_weather.html

it says that as well for my region, you couldn't ask for a better upgrade im still not convinced though

[NO LONGER POSTING]

Right okay..I am blown away with what I see on the charts this morning! Not only does it look like the front stalls over the south east..It looks like 24 hours of snowfall now! The event hitting us in under 72 hours so confidence is growing now....BUT things can change!

This is the total amount of PPN for Monday..From over the weekend I expect this to be a slight understatement really..Also if the front is stalling then this would back it up because look into France..Not a drop of rain..

Edited February 2, 2012 by Surrey

[Anthonyb]

No showers for our region YET. Looks like the areas towards the wash are having reasonably snow flurries this morning- these are now pushing into the NE midlands.

As for our region - east Kent looks to be a good place tonight but that's it.. So once again London area herts/Essex is in no mans land for convection today!

The weekend is looking very good. We look set to keep the cold and snowfall amounts look promising.

Edited February 2, 2012 by Anthonyb

[TheMoonman]

Both BBC and ITV going for snow on Saturday. "Enough to make a snowman" according to the BBC

[Tom Montalbano]

Yes, that persistent stream has affected The Wash area all night, helped by that long fetch off the Danish coast, while we stay mainly cloud free. The next few days continue to be a forecasting nightmare.

We now have the Norwegian coast short-wave saga.

http://nwstatic.co.uk/fax/PPVE89.png

Fax has it clipping our east coast midnight Saturday.

http://nwstatic.co.uk/fax/PPVI89.png

And then there's the stalling front for the week-end, edge of the seat stuff!

Regards,

Tom.

[Neilsouth]

Nothing for tonight then Tom?

[Jayces]

Soooo, something between 0 an 30 cm between now and Monday for us then.

Wonder who will be the lucky ones?

Hope I am not amongst the unlucky ones

[Neilsouth]

"Tonight:

Dry and clear for most, with a widespread frost. Snow showers may develop later in the night over Kent and East Sussex, with snow possibly settling in places. Minimum temperature -5 °C."

"Friday:

Snow showers in Kent and East Sussex should ease during the afternoon, but becoming locally heavier and more persistent overnight. Generally dry and bright for the rest of the region. Maximum temperature 2 °C."

[95 Degrees]

This is getting silly now, -1.2C here, clear skies all night and light winds, but no frost again, c'mon. might be because humidity is too low.

Edited February 2, 2012 by BrightInBrighton

[Tom Montalbano]

Nothing for tonight then Tom?

Cant see much chance, tbh. Although I see a little convergence going on , around the mouth of the Thames, in the early hours of Friday.

I suppose that could trigger a few snow flurries!

http://cdn.nwstatic....0/27/ukwind.png

Regards,

Tom

P.S VM, just seen your post re. Met Office take on things for today and tomorrow. Some hope there for parts of Kent and Sussex.

Edited February 2, 2012 by TomSE20

[Charltonkerry]

Can't believe it, got the wife to buy me a very good weather station for Christmas, unfortunately had major tendon operation on my shoulder just after, and cannot fit the outdoor bits, so with all this good weather about, I still have to rely on you lot for all the temperatures etc, will be another 2 months before I can fit it, mind you I have got the future son in law traveling up with the gran kids to set it up for me on SUNDAY, can't even get that right. Lol

Hopefully we can all enjoy the upcoming weather.

Edited February 2, 2012 by Charltonkerry

[Coast]

Morning SE Snowfans!!!!!

I see Kaddy Lee-Preston didn't let us down this morning on the BBC SE today weather, snow for Kent and possibly others later!!

[NO LONGER POSTING]

http://www.weatheronline.co.uk/cgi-app/weathercharts?LANG=en&MAPS=n&CONT=ukuk&LAND=__&DAY=4&ZEIT=201202052100 this is a lot of PPN!

[Gowon]

Good morning everyone, are we expecting any snow today or has it been put back again?