Southwest & Central Southern England Regional Discussion 18th December 2012>

[Dorsetbred]

Squall line has fragmented down here before it arrives, now about 30-35miles to our west. Light rain has just started

[Evie]

Very strong winds at 3am this morning for a good few hours, waking me up! Raining heavily for last couple of hours, it's the last thing we need here in Exeter

[AWD]

Squall just passed through here. Some very strong wind gust considering I live in an urban environment. Heavy rain too.

Rain & wind both backed off a little now.

[AWD]

Looks like a very convective night tonight with a lot of shower activity around, whig could contain anything from hail, thunder, sleet & lightning.

Be interesting to see the 12z data for tonight.

[littlemissy]

Not very cheeful here .Plenty of rain here too.Wind abated.

[Dorsetbred]

11:36 squall line hits.

11:40 squall line ends.

1mm does it

Edited December 29, 2012 by Dorsetbred

[khodds]

Have to say, as much as I hate the rain, I love this kind of squally weather. Its quite exciting! Just a shame we have had months of it. If I look back on 2012, I have to say that my favourite part weather-wise was the thunderstorms July/August. Absolutely amazing. The one on 2nd August dropped 53mm. Never seen rain like it!

[MP-R]

Brief spell of torrential rain around 9am this morning and been moderately raining with little wind since. Looking forward to the convective spell later today and tonight.

[ARTDEMOLE]

Too Much Wind ..Too Much Rain...7c,Now Wind 10 mph ,,Quite a difference...Silence is golden.

[cerneman]

Wind calmed down stopped raining

[Dorsetbred]

Wind calmed down stopped raining

Wind calmed down, and pouring down

[Mapantz]

Wind calmed down, and pouring down

Yep! Quite a heavy shower here 1.8mm falling in a few minutes.

[cerneman]

Wind calmed down, and pouring down

Remember sitting on Quay in Poole back in 60s watching the filming of Hero's of Telemark, was raining then

[ARTDEMOLE]

6c.The wind picking up slightly...

[AWD]

A mass of shower cells starting to move eastwards, currently south of Ireland heading towards the Bristol Channel.

Could get rather interesting, convective wise, later tonight.

[jethro]

Popped down to Cheddar Gorge this afternoon, blimey is it wet down there! The road down through the Gorge is shut and has been for for at least a month, goodness knows when that will re-open; there was a big landslide a few weeks ago but now the road has also been washed away. Couldn't see much from the cordon off point but according to the local cafe owner, there isn't a lot of tarmac left further up the Gorge. The caves were shut due to flooding, not that it needed a sign to explain that one, the water was pouring out the opening, flowing down the road like a river. The river it's self is the highest I've ever seen it, none of the arches on the bridges were visible, they're all below water level and the speed it's flowing at is incredible. Trade is normally fairly quiet down there during the off-peak season but lots of the shops have simply given up and closed, some with signs in the window saying they'll be open again at half-term time in February, some shut and completely cleared. It was really dismal down there today, felt so sorry for anyone trying to make a living.

Roll on some dry weather, don't care if it's warm or cold, just no more rain please.

[noggin]

It sounds very grim there in Cheddar, Jethro. The aftermath of the floods doesn't seem to be making the news any more, but the heartbreak is still there for those poor people whose homes and businesses have been devastated.

There are fields around here that have been under water for months.

It is very sad, although "sad" seems inadequate a word to describe what has been going on and what continues to go on.

What is the answer to it? I don't know. Wish I did.

Edited December 29, 2012 by noggin

[Dean E]

It sounds very grim there in Cheddar, Jethro. The aftermath of the floods doesn't seem to be making the news any more, but the heartbreak is still there for those poor people whose homes and businesses have been devastated.

There are fields around here that have been under water for months.

It is very sad, although "sad" seems inadequate a word to describe what has been going on and what continues to go on.

What is the answer to it? I don't know. Wish I did.

Russian High and an active Atlantic...

Low pressures have been stalling over us constantly recently, adding more and more rain to soil that cannot take any more moisture!

SM

[Andy Bown]

I hate days which are dull and wet then it clears up at sunset!

Today the sky began to clear just as the sun was setting, allowing 5 minutes of brightness and a pretty sky before darkness fell.

Almost 150mm for December with downpours tonight/tomorrow and another deluge due Monday!

[Dorsetbred]

Remember sitting on Quay in Poole back in 60s watching the filming of Hero's of Telemark, was raining then

They also shot some "African Queen" down there too.

[AWD]

Can definetly feel a nip in the air tonight. Temperature currently 4.8c but feels a couple of degrees colder than that.

Manager to avoid the showers so far, but plenty more yet to come through the night.

[Raidan]

The wind was mental here last night was paranoid the windows were going to smash lol,rain hasn't been bad at all the last few days except on boxing day when a dry walk to Tesco became a flooded walk home,I'm hoping for some heavy intence thundery showers tonight but hope is about as far as I'll probably get.

[littlemissy]

Wellington hasn't missed the showers this evening.Very blustery and wet.Heavy at times and aa definite nip in the air.:-)

[AWD]

So, we now approach the end of a year & what a year its been, most notably for starting in a drought & ending in one of the wettest years on record. What does the new year have in store for the South West then.

Currently we are in a cool rPm westerly flow bringing showers off the Bristol Channel into many areas of the West Country throughout the night. These may contain hail & sleet on elevated ground, with the odd rumble of thunder possible around channel coasts;

Uppers are actually quite chilly, but they will rise throughout tomorrow;

Tomorrow looks like a largely dry day after the mornings showers move east, with some sunshine breaking out as the day progresses;

Temperatures around average for most, high single figures;

New Year's Eve looks like starting on a wet note, with another 10mm of rain widely across the SW, more on the uplands;

I'm confident however that this system will clear well east of us by New Year's Eve evening, allowing skies to clear & temperatures to fall back a little;

By dawn New Year's Day there could even be a patchy ground frost in places;

New Year's Day and we start to see the first signs of high pressure coming up from the SW, also known as the Azores High. This should help to settle things down in our part of the world and give us a much welcome break from the relentless rainfall most us have endured this month;

The GFS;

And the ECM;

Both agree on this and provide us with some settled, possibly sunny and rather mild days.

A strong high pressure cell over most of the UK blocking the Atlantic systems in the opening week of the new year, sending the Jet Stream and the depressions north of the UK;

And bringing rather mild temperatures to the SW;

I'll leave it a couple more days yet to see whether we have a sunny high or a cloudy high, but early signs do suggest that the air may come from an Atlantic influence, brining some cloud over at times, but equally the chance of breaks as the high assets itself more by the end of next week, especially lea of high ground.

The ECM keeps the SW under high pressure for next weekend and into the following week before pushing the high SE as a deep depression forms in the mid Atlantic;

This may go on to aid in WAA advection into favourable places for colder weather to affect the UK however, but at 10 + days away its pure speculation at this stage, with further runs needed to support such a scenario.

The GFS also shows a lengthy settled spell for the SW before pressure slowly falls away by early week 2, as Atlantic depressions make inroads into the UK once again;

That's as far as I will look in operational model output as the upper air pattern will be undergoing various changes in the beginning of January, most notably & well documented is the Stratosphere which I will touch upon in a minute. Also however, there are signs the MJO will finally leave phases two & three & head towards something more interesting for cold lovers;

Both of the above phases are conducive to something a little less zonal & a little more blocked.

You can see below on the GFS Ensembles for Devon;

And Gloucestershire;

That things dry up and become rather mild next week before becoming a tad more unsettled and cooler as we progress through January, with some colder options well into FI.

It's been widely documented that the Stratosphere is about to undergo a major mid winter warming, with a likely SSW around the 6th January (give or take a day). This is shown nicely by the ECM, with a reversal of the mean zonal winds at the 10hpa level;

With a big increase in wave 2 activity as well;

Leading to vast drops on the zonal wind speed and a shift in the direction of the EP Flux;

This by no means guarantees the UK colder weather, but what it will do is change the northern hemispheric pattern considerably. This is why I would be very weary of any long range NWP output currently, until the stratospheric warming had happened, as the NWP models are going to have a busy and difficult time in January.

After the first warming/SSW in early January, the GFS is interesting in that it brings another warming in Mid January over Svalboard/Greenland area. If this verifies this would absolutely destroy any remaining PV;

Which suggests very interesting times ahead for cold lovers as January progresses. Nothing guaranteed of course, when is anything in the weather world ever guaranteed, but with the above forecasts, what it does do is increase any cold potential which is all we can hope for currently until things start happening. Like a football match, if you play with four strikers rather than two you have a much better chance of scoring, but not guaranteed. Similar here.

So to summarise:

- The next few days see a continuation of the wet & windy theme, with further rainfall likely either in the way of showers or longer spells of rain.

- Midweek seers things settle down and become much drier as High Pressure influences our weather. Mild temperatures and a mixture of sunny spells and cloudy spells. This scenario looks like staying with us over next weekend and into week 2.

- From Mid Week 2 onwards uncertainty increases has you would expect, but its looking more likely that the Atlantic will become more influential to the SW again. It doesn't look like being as active as what it has been however, but there does look like some rain could return. Various options on where pressure goes, retrogression is one of them. I don't expect a zonal train to arrive again as the models indicate pressure quite prominent around Europe & the Atlantic area.

- Mid Month onwards is really difficult to see. The first affects of the Stratosphere warming could be felt then, which could mean colder than average conditions. The ensembles and anomaly charts do indicate something more favourable to colder conditions too, but a lot of weather and time to get through before we get here. If your looking for cold/snow though, this is the time period you ought to he looking at, as there is unlikely to be anything cold before mid January.

Hope that kind of helps in where we currently stand going into the new year. Whether we do get some colder weather in January or not, I think this month is going to be a fascinating month model watching with so much going on and so much we can learn & take from it.

Thanks all.

Edited December 29, 2012 by AWD

[Bristawl Si]

Incredible hailstorm right now - intense for only 5 mins - left everything white!