Model Output Discussions 06z 04/11/16

[Scandinavian High.]

There  is good chance of a snow event Tuesday evening for parts of the north  mainly  On the hills but some getting down to low levels in the north at times as a front moves in from the west this rain band looks to stall on the eastern side of country and never makes it in Eastern Europe the cold block is not going nowhere to north east Europe..

[IDO]

The medium term is taking shape over the last few days (GFS) with the omnipresent Azore/Atlantic High, the Russian/Siberiian High, and a mobile westerly pattern (with the demise of the block/ridge over the US).

The good, no sign yet of the PV getting organised.

The bad is that the UK is down the line for the Atlantic depressions and with the block to the east, these are slow moving at times. The GFS in FI maybe showing its usual Atlantic bias, so probably more time between each depression passing.

There follows that the block over Russia will lead to a trough to its west and the UK will, be a stop on the route.

The D8 mean summing up the GEFS consensus now, something the GFS picked up a couple of days ago, but wavered a bit since: 

GEM also now in the same ball park, but with the jet a bit further north and less of a  NW/SE axis.

So a period of average temps as cyclones pass, drawing air from different sources as they trundle through the UK (interspersed cool and mild). Lots of showers and some bands of organised rain more than likely.

Basically normal November fare. Hopefully the promise from the strat will in the intervening period keep any long term quasi-zonal pattern from establishing, which will take us nicely into December with more hope than I usually have for that month.

 

[Methuselah]

2 hours ago, phil nw. said:

Just to illustrate the uncertainty past day 4-the London temp. graph

showing a lot of colder members and the Op runs on the warmer side.Maybe the Operational runs are leading the way-but some could say the ens. leave room for further trough disruption holding up any real Atlantic incursion.UK model at day 6 showing this further west across the UK than the others.

 

 

You are right enough, phil...But (where's the Edvard Munch's Scream smiley when you want it?) there are also quite a few warmer members?

[Dancerwithwings]

6 minutes ago, Nouska said:

This was the UKMO 168 hour chart from today's 00Z run.

They don't always update if there are no tropical systems but no harm in checking after about 8pm to see if the 12Z run has been added.

http://ruc.noaa.gov/hfip/tcgen/

Great link, the GFS as clear difference's at D7 

[andymusic]

one comment - the gfs is still "making it's mind up" bucks fizz style - about the atlantic front - moved back again and temps are just that little bit lower too!

[Cheshire Freeze]

4 minutes ago, IDO said:

The medium term is taking shape over the last few days (GFS) with the omnipresent Azore/Atlantic High, the Russian/Siberiian High, and a mobile westerly pattern (with the demise of the block/ridge over the US).

The good, no sign yet of the PV getting organised.

The bad is that the UK is down the line for the Atlantic depressions and with the block to the east, these are slow moving at times. The GFS in FI maybe showing its usual Atlantic bias, so probably more time between each depression passing.

There follows that the block over Russia will lead to a trough to its west and the UK will, be a stop on the route.

The D8 mean summing up the GEFS consensus now, something the GFS picked up a couple of days ago, but wavered a bit since: 

GEM also now in the same ball park, but with the jet a bit further north and less of a  NW/SE axis.

So a period of average temps as cyclones pass, drawing air from different sources as they trundle through the UK (interspersed cool and mild). Lots of showers and some bands of organised rain more than likely.

Basically normal November fare. Hopefully the promise from the strat will in the intervening period keep any long term quasi-zonal pattern from establishing, which will take us nicely into December with more hope than I usually have for that month.

 

Aye, more than a whiff of 2009 about upcoming synoptics...namely Atlantic depressions meeting a block to our east and thus becoming slower moving around UK shores. 

Can only hope it starts to mirror 2009 when it really matters i.e into December!

[bobbydog]

It should be (strongly) noted that these "atlantic depressions" being shown in the later stages of the GFS are not coming from their usual southwesterly direction. They are forming over Greenland and dropping through iceland and down the North Sea. That is not standard autumnal storminess. Bearing in mind that the arctic is nowhere near it's coldest at the moment, if this was mid winter, these storms could bring some serious snow to some parts. 

On another note, the GFS seems to be hinting at the beginnings of an SSW. (Not to be taken too seriously at this stage) nevertheless...

(If only I'd had the money to buy those snow tyres for my land rover when they were going cheap...)

[Frosty.]

The Ecm 12z looks chilly throughout the working week, even after we lose the colder uppers (T850's) there is then a blink or miss it milder interlude on Friday night which is swept away southeastwards on saturday, then it's back to chilly air. High pressure then starts to build eastwards into the uk early week 2.

Edited November 6, 2016 by Frosty.

[January Snowstorm]

ECM continues the trend from yesterday's gfs of atlantic driven weather taking over later in the week (atlantic as in westerly winds - not roaring jet)

At 168hrs it's business as usual though of course the background signals remain mostly good for later in the month.

The one thing I hate to see more than any roaring jet is a large azores high. It's been our bogey for many of the last few years - though I accept maybe it's other factors at play in its development 

Edited November 6, 2016 by January Snowstorm

[Mucka]

144 comparisons suggest GFS 12z out on a limb if not much else.

JMA first to sniff out possible incoming Easterly?

Edited November 6, 2016 by Mucka

[January Snowstorm]

16 minutes ago, Frosty. said:

The Ecm 12z looks chilly throughout the working week, even after we lose the colder uppers (T850's)

Granted it is for the East but for the West esp Ireland it's almost baking

[Frosty.]

1 minute ago, January Snowstorm said:

Granted it is for the East but for the West esp Ireland it's almost baking

Hardly baking, and its soon turning cooler again.

[swfc]

big change again on ecm be it in lala land.pv locks in on greenland and large swathe of high pressure threw europe.fi would be?????

[Frosty.]

The Ecm 12z ends with the south of the uk in a kind of limbo, more unsettled further n / nw.

In summary, the week ahead is rather chilly, especially in the east up to midweek and after a largely sunny day tomorrow apart from showers on eastern / western coasts, tuesday could be mainly dry and bright but becoming cloudy across the west heralding rain spreading east midweek with sleet / wet snow on northern hills and then thurs / fri look cool and showery before a band of rain pushes east with slightly milder temps followed by a cooler showery weekend before pressure rises from the west with more settled conditions developing for a time but then the northwest of the uk becomes windier and more unsettled..phew, a lot going on then!

Edited November 6, 2016 by Frosty.

[Cheshire Freeze]

18 minutes ago, Frosty. said:

The Ecm 12z ends with the south of the uk in a kind of limbo, more unsettled further n / nw

I said this last night and looking at that chart it still applies

 I can't help but think that or the time being we may have to suck it up and put up with an abundance of more mid latitude type blocking with the Azores high loitering with intent close to our W/SW in preparation for a more favourable upstream pattern. What I'm seeing in the output at the moment is attempted ridging N in the Atlantic before a flattening of the pattern once again.

[Connor Bailey Degnan]

  

At the minute, some longer range models are still wanting to go with a cold and snowy end to the month. It's a very very hard topic to talk about because it's so very close to happening and I can see a lot of disappointment occurring if it ends up mild/not cold.

There are plenty of factors whilst looking at the end of this month. The Pv being one. Stratospheric warming and the possibility of the models getting very confused. Not one model seems to be agreeing after about 144hrs.

Personally I can't see a 2010 repeat this winter, unfortunately, however I can see more periods of snow and cold temperatures through the winter, especially early on, December/ early January. 

As it stands the NAO is expected to return to negative after mid month, and with a weak PV and the warming taking place, I see a good chance of a cold end to the month.

Edited November 6, 2016 by Connor Bailey Degnan

[Frosty.]

The thing that strikes me most about the GEFS 12z mean is how it's never terribly mild or cold, it's different shades of grey in between and another feature is how unsettled it becomes in the mid range after some initial ebb and flow of the Az high and lower heights to the nw / n but then by mid month as the Azores high retreats, our weather becomes more trough dominated.  

Edited November 6, 2016 by Frosty.

[ANYWEATHER]

Good Evening All! What stands out this evening as there wont be any sicklymild southwesterlies  !!! The gfs is again over progressive but even this model is struggling with a block to the east!  The Ecm however shows a more substantial block to our east at T+192,  Its a very blocked pattern and models will continue to struggle with this scenario. One thing is certain , the Uks weather has gone from Summer warmth to Winter cold in just a few days

[IDO]

^^^ Hi

It is in my opinion the same old same old from ECM. If you look at the T216 chart you will see it has blown up the HP in Russia to 1045hPa. This pumping up HP cells happened as early as D6 and clearly that will have an effect on the surrounding pattern. Compared to the mean at the same time the HP is 1030hPa and that is why the mean is similar to the GFS mean:

Something to watch for as that is likely outside the standard deviation, so probably low confidence (with weather you can never say never). I do not know what the issue is with these blown up HP cells after D7 on the ECM op but it does make it hard to take it seriously in blocked scenarios. That is why the PV over to the NW cannot be taken as given as that sort of bunching is a factor of that erroneous (assumption) core Russian HP cell;the mean backs that up.So more runs needed from the ECM op as it remains seriously out off kilter with its mean.

[bluearmy]

Extended eps and GEFS continue on broadly the same sheet days 10/15 wth the upper trough sinking across w Europe 

[Singularity]

The 'big picture' problem to resolve does look to be the polar vortex trying to move to a location where blocking highs are happily entrenched.

There could be a standoff if the vortex spawns a particularly deep storm or two (illustrated by the 12z ECM), but in theory it'll only take a lull in activity and the vortex will be interfered with sufficiently to trigger a vacation to the mid-latitudes. What's currently far from clear is when exactly that lull in activity will be.

This weekend, it's been a struggle to produce a coherent outlook beyond Thursday - I've been left completely exhausted! Yet I still couldn't resist casting my eye over the ECM run 

[karlos1983]

4 minutes ago, Singularity said:

The 'big picture' problem to resolve does look to be the polar vortex trying to move to a location where blocking highs are happily entrenched.

There could be a standoff if the vortex spawns a particularly deep storm or two (illustrated by the 12z ECM), but in theory it'll only take a lull in activity and the vortex will be interfered with sufficiently to trigger a vacation to the mid-latitudes. What's currently far from clear is when exactly that lull in activity will be.

This weekend, it's been a struggle to produce a coherent outlook beyond Thursday - I've been left completely exhausted! Yet I still couldn't resist casting my eye over the ECM run 

Agreed, it's pretty difficult to put anything on what will happen past Thursday this week, the models are all over the place, chopping and changing with every run! The only thing that looks certain right now, is that a return to zonal dross is extremely unlikely, by that I mean a strong jet throwing low after low at the uk and Western Europe. I am exhausted already and it's only November 6th 

certainly not boring though, unlike the past couple of novembers! 

[northwestsnow]

Got my eye on Tues now- Beeb going for a few hours of heavy snow up here, just up the road is Grains bar which is over 300m asl so might get first dusting of the season,just watching 18z....:)

Obviously going to be marginal, GFS going for temps around 1 degree at midnight !!

Edited November 6, 2016 by northwestsnow

[Scandinavian High.]

This looks interesting I do feel this winter is going  to be very very interesting. 

Edited November 6, 2016 by abbie123

[swfc]

18z looks like an upgrade at the 190h mark.possibly the longest northerly ever running into scan also