AWD

GEFS 12z London ens trending colder; The mean (that's the red line) trending downwards throughout, hitting near enough -4c at the end. Nothing majorily cold yet, and neither would I expect so at this very early stage, but promising signs as we enter the last month of winter proper. Anyway, all in cuckoo land currently. The difference this time though is we have some stratospheric positivity for the first time this season.

Not often you see both the Op and Control run follow each other so closely right out to 384hrs; Pretty much neck & neck all the way. Both colder solutions in the extended timeframe but irrelevant at this stage.

Yay, more rain!! http://www.metoffice.gov.uk/public/weather/warnings/#?tab=warnings&regionName=wl

Enjoyed winter yesterday morning. Was a nice change. Back to DANK today! Hopefully Feb will give us a late wintry blast before we ascend into a convective spring and sultry but stormy summer.

GFS 0z still showing a significant warming at both the 10hpa level; And at the 30hpa level; Now roughly at 300hrs out, so considering the range, some sort of consistency shown in a broad brush sense here.

What's this??? A frost! I get to open that can of De-icer I brought in November now. Looks like a sparkling day coming up though.

That's not a bad set of 12z ensembles really; Take out a few of those milder runs and you would have a rather respectable 2m mean value.

Agreed, rain for most. But as the update mentions, an average to slightly below average temperature range in mid Jan could at least promote some hill snow for a lucky few and something a little more for the far north/north east.Not that I'm close to getting anything wintry IMBY though.

Not overly cold but nothing mild there either. I've known a lot worse.

BAN tweets from the MOD thread!!!! Vote Now!

Crystal clear blue skies and a rather pleasent feel to the day today. Feels like Spring is starting early!

Looking like the vortex will soon be leaving the states and heading towards our part of the hemisphere; Asian warming and an increase in wave 1 activity looks enough to re-jig the vortex more towards our side of the pole. European heights look like steadily lowering too. Wave 1 activity rising all the time; Hints of a possible wave 2 hit in the long run maybe; All in all it's looking like a game of wait and see where the vortex rests for now. Those looking for Greenland height rises are going to need to be rather patient I feel. The shorter term prognostics look like deepening the vortex intensity there.

I wouldn't bother just yet if I were you.

Pretty good agreement within the GEFS for opportunity 1 too fail now; However, can we move quickly on to "opportunity 2"? UKMO at 144hrs shows the trough attempting to cut off into the UK; Possibility therefore of another chance to bite into the cold airmass forecast over Scandi although how long the pattern would hold is open to debate with the possibility of the Canadian vortex reinvigorating the northern arm and sinking the blocking. GFS Op not quite as split and amplified as the UKMO, but not a million miles away either; Won't bother looking past 144hrs as this will change again as it frequently has done these last few days. The GEM remains the best at 144hrs still with a more elongated and negatively tilted trough; And goes into to show how, with a bit of tweaking, we could get opportunity 2; The full GEFS suite also showing potential for opportunity 2 around the 20th; So I think we have to let the first bite go now but dust ourselves off and move onto the potential for a second bite soon after. All in all a continuation of some much improved NWP output than of late with they key final ingredient just out of arms reach for now.

There is actually modest agreement on the wind direction for De Bilt being from an easterly quadrant there.When looking at the temperature plots, bear in mind these are for De Bilt and not the UK.There is a rough 50/50 split there (give or take slightly). From the 50% of members that do being in a more pronounced colder airmass, another 20% (again a rough estimate) are likely to have the boundary somewhere between De Bilt and the UK, therefore whilst they look cold on the De Bilt ens, they would look less appetising on the London ens say.So that leaves us with an approx 30% of members to play with.Therefore my rough guess what the London ens will say later will be a 70/30 split, the lesser in favour of a more pronounced colder airmass, the greater a less cold airmass.Off course, I could be totally wrong. We will find out at 23:00ish.

Negatively tilted trough on the 12z GME;

Latest from Ian Fergusson; "Colder spell next week nothing unusual for Jan, stress @metoffice. More pronounced to NE. Snow for various areas possible; ditto rain in S. The Express hyperbole well over-the-top, unsurprisingly. Yes, a different mode of winter weather but hardly anything exceptional."

Latest from Ian Fergusson; "Colder spell next week nothing unusual for Jan, stress @metoffice. More pronounced to NE. Snow for various areas possible; ditto rain in S. The Express hyperbole well over-the-top, unsurprisingly. Yes, a different mode of winter weather but hardly anything exceptional."

Not saying it is any more likely to verify than other operational output, but the EC 0z is rather like yesterday's Met Office medium range update. Turning cooler for all but struggling to get much below average for the south (excluding FI ). Cold enough for some snow further north, especially but not exclusively over the hills. Anyway, long way to go yet I feel before any finer detail can be asserted on the NWP output.

50% according to Ian;"With ca. 60% of EC & 50% MOGREPS members offering colder E'rly into next 6-10d, UKMO lean towards this but with caution: may flip other way"

EC has SW/NE tilted pressure to our north.

Ignoring the long term trends for now for the reasons Ian described above (although I must say there is little evidence of anything "mild" for the foreseeable), the GEFS highlight the split conundrum well next week; Still enough members suggestive of a "non easterly" there to give the option respectable credence. However, with the Op & Control supporting the cluster that do go "cold" for the past 4 GFS runs now, you have to at this stage, favour the easterly happening rather than not. 850hpa and PPN detail is irrelevant at this stage until the positioning and tilt of any pressure build in the GIN corridor is accomplished. This will then dictate the true source of any continental airmass we are to receive. Hopefully Ian could share the 12z Met Office assessment with us (or what pieces he is authorised too) later tonight to see what, if any, changes are apparent compared to the earlier publicised medium range forecast today. Although off course, we still await the all important EC date though, which could influence that greatly.

Far far too early to even speculate on any potential snowfall for our region yet.Being in the South & West, we are on the very edge of the current modelled cold airmass from the E/NE. Still all very borderline and volatile for us yet.Don't rush for the snowfall. IMO, even if things do go well and we become as cold as some of the operational output so far suggests, it's going to be a slow process to get any snowfall down to us.This time next week we should have a much better idea of where we sit.

Had a job down at Fairwater, Taunton this morning, first time since before Christmas. As soon as we went south of Bridgwater, the flooding was startling to say the least. Got some photos as I passed but bear in mind I was doing 75mph at the time so they aren't the best;

There must be a frost around the corner soon judging by the mood in the MOD thread!