Model Output Discussion 01/09/17

[Britneyfan]

Is there a storm Brian thread?

[knocker]

3 minutes ago, Britneyfan said:

Is there a storm Brian thread?

https://www.netweather.tv/forum/topic/88658-storm-brian-weather-discussion/?tab=comments#comment-3640502

[booferking]

Blocky runs are growing hopefully we can get a taste of winter early this year added a few just to ponder on.  Okay there is more than a few

Edited October 19, 2017 by booferking

[Decemberof2010]

Thanks for those booferking. Looking forward to all the ups and downs of the upcoming winter in the model thread.

And hopefully a cold early start will set us up nicely

[jules216]

was just about to post the latest ensembles run, wonder are they picking up on the MJO signal which might be a little more active and reach phase 7 and 8 soon.

[knocker]

This evening's ecm has storm Brian centred Galway 0600 saturday. Winds gusting between 50-60kts in the southern quadrant Fastnet, St Geoges Channel, Lundy and the western approaches Also effecting coastal areas in south Wales and the south west.

By 1200 it is in the Irish Sea just ENE of Dublin 980mb with the strongest gusts a tad further east and further up the Irish Sea.

By 1800 986mb near York  with the NW  gusts along the Welsh and NW coasts and in the upper 40s inland and still in the 50kt region along the Channel. Moderate to heavy rain at this time running down the west coast and inland in the north Midlands.

Edited October 19, 2017 by knocker

[Scorcher]

1 hour ago, booferking said:

Blocky runs are growing hopefully we can get a taste of winter early this year added a few just to ponder on.  Okay there is more than a few

This chart is the best part of 2 weeks away...all I can see in the reliable time frame is continued warmth.

[booferking]

24 minutes ago, Scorcher said:

This chart is the best part of 2 weeks away...all I can see in the reliable time frame is continued warmth.

No problem noted thanks for the heads up this is model thread and gfs ensembles have a growing trend at later stages of something more blocked where shall i talk about charts that show potential further down the line??  

Some of the charts are late next week i see you choose one of the deepest future runs.

 

Edited October 19, 2017 by booferking

[phil nw.]

After low Brian has moved away we see pressure rising and the models show another possible warm plume from further continental ridging.

Day 6

Probably not a blue sky period though as this looks like a tropical maritime flow so a lot of cloud around with perhaps drizzle/light rain in some places from trailing weak frontal systems.

GFS day 6 for example

 

A train of moist and mild air heading up from the Azores modelled at that time.In spite of the possible gloom daytime max's again possibly reaching the high teens in the south.

[knocker]

The ecm complicates matter once more towards the end of the run. It splits the trough to the west but at the same time allows some energy torun around the burgeoning HP in the western Atlantic that actually connects to the trough in eastern Europe resulting in quite a complex and bizarre 500mb analysis. On the surface the N/S split come to an end by the end of the run as low pressure swings in from the NW courtesy of these shenanigans.

[phil nw.]

5 minutes ago, booferking said:

No problem noted thanks for the heads up this is model thread and gfs ensembles have a growing trend at later stages of something more blocked where shall i talk about charts that show potential further down the line??  

This is the place booferking but be wary of setting too much stall in operational charts in those later stages.Certainly following the ensembles at this stage is best and then the daily runs in the Operational charts as we get closer.

[ANYWEATHER]

Both ECM and GFS  show unsettled weather until towards the eight day period when the brakes start to hold up on the jet stream.....a lot of weather to come and change before we get to the ten day period...

[blizzard81]

The Met Office have been stressing the uncertainty with regards to late October/early November for weeks now. If the Meto are uncertain at this relatively short time frame then the rest of us quite frankly don't have a scooby doo. The question is - why so much uncertainty?

[damianslaw]

Mmm quite messy charts at the moments longer term, there have been quite wildly different runs being shown at the longer time frame in recent days, hence lots of uncertainty. The GFS and ECM both show heights to the NW, to the SW, to the SE with a trough squeezed into the middle of all these, with no-one winning the battle.. so I am sitting on the fence. 

The forcing though appears to be on the ridge to the SE, with northern heights anchoring down on the trough, a split would be a plausible outcome with energy spinning away to the NE and to the SW, hence a build of heights over and to the north of the country could be the outcome tying in with the ECM output.

In the more reliable timeframe - .out to the middle of next week, firmly unsettled.

[ICE COLD]

Evening All

Been following this thread since march 2013 , when be last had a proper cold spell . Since then we have not had any really notable cold and snowy spells . Let's hope this winter is a lot more winter like than the last few . Got to say I love Mr Murrs posts and can't wait for him to start posting ready for winter . In fact there is a lot of very informative members on here so keep it up . As booferking pointed out earlier the GFS ensembles keep showing blocky runs towards the later time frames , hopefully these starting showing in the operational runs and don't stay in la la land . Cheers . 

[summer blizzard]

Looking at the models i think the low exiting Canada at day 6 is giving the models a lot of problems in the way it interacts with the Bermuda High and then downstream the Azores Low. 

Out to day 8 i think that both the GFS and Euro are plausible in that before day 6 we have a highly amplified pattern with the Azores Low supporting an upper ridge over Europe and to its west we also have a highly amplified Bermuda High (presumably it has its own east cost low supporting it) however at day 6 we then see the Bermuda High on both models toppled a bit such that the Azores Low gets caught underneath it. 

Now on the GFS this Azores Low does relatively retrogress which is what i think would happen.. however at day 9 the high suddenly gets eroded. In addition the GFS also has the Euro high likely too strong since with a retrogressing supporting low it's likely that it would weaken or join the Bermuda one to its north. 

On the Euro it's just plain wrong in that at day 8 the Azores Low suddenly lurches east even if the Bermuda (now mid-Atlantic High) does look to be in a more plausible position. 

If John or Nick have the NOAA discussion that would be great to see. 

One thing we can see from this is that models are tending to setup a pattern that will probably produce a Scandi-west Russia trough. 

 

[johnholmes]

1 hour ago, blizzard81 said:

The Met Office have been stressing the uncertainty with regards to late October/early November for weeks now. If the Meto are uncertain at this relatively short time frame then the rest of us quite frankly don't have a scooby doo. The question is - why so much uncertainty?

There is quite often uncertainty at this time of year. This partly due to the northern hemisphere switch from summer to winter mode. Additional to this it is still the Tropical Storm/Hurricane season. Both tend to throw the models of whatever length of period they are. Synoptic length 1 to 20 days or more and the anomaly type of 6-10 and 8-14. By late October/early November and both types are back to 'normal' although that can lead, especially with the synoptic models, to much gnashing of teeth as phantom cold spells appear only to disappear quite often.

[knocker]

Today will start blustery with the odd shower in places as yesterday's low lingers and loses it's identity but this will soon clear and there will be a quiet period for most which amounts to the lull before the storm Brian which by 00 is just west of southern Ireland 963mb. Prior to this the associated fronts will track ENE during later today and this evening, bringing heavy rain in some areas, particularly N. Ireland and Scotland near the triple point of the fronts. By 12 Tomorrow the low will be east of Belfast 976mb, Winds will start picking up as well particularly tomorrow but more below on that.

According to the gfs the band of strong winds at 06 are concentrated in the Fastnet, Lundy and Plymouth areas and obviously Cornwall gusting in the 50-60kt range. By 12 these will have abated a little but the whole of Wales and southern England will be in swathe of winds gusting 40-50kts.

By 1800 the low is 982mb in borders area with blustery showery conditions pertaining over England and Wales and in general (difficult to pin down gust speeds) in the range 35-45Kts.

All of this is followed by some transient ridging but meanwhile a deep Atlantic low is drifting north in mid Atlantic and it's associated fronts and rain have tracked east and are effecting the UK by 12 Monday. This clears but a second front quickly arrives with a little wave that has formed that scoots quickly NE skimming NW Scotland so more showery rain on Tuesday with only the far south escaping. But now we reaching the point where the frequenty mentioned amplification is set to occur and by 12 Wednesday the Atlantic trough is digging south flanked by the ridges west and east.

Also as has frequently been said the precise orientation of the trough and ridge are important when it comes to sorting the surface detail which is illstrated quite well on the 12 Thursday chart with the area of low pressure being kept to the west and the UK in a light southerly drift with temps up around 20C in the south. This status quo is reinforced through the weekend as the western arm of the high pressure commutes north into Greenland resulting in the UK remaining in the southerly drift with temps way above normal. I must emphasise again that this is miles away from being bailed down and this just this morning's take by the gfs.

[mb018538]

There is also a big ensemble split - and the GFS OP is a big warm outlier this morning:



Just your usual autumn model chaos!

[knocker]

And just to illustrate not being nailed down. By the middle of next week the ecm does initially follow the gfs with the amplification but crucially the ridging to the west does not block energy/troughs tracking east then south east via N. Canada/Greenland and by 00 Saturday northern UK  This suppresses the UK ridge resulting in a brief westerly regime and the perennial N/S split before the next depression swings south east into the North Sea initiating a cool, showery north westerly at the end of the run. All of this merely emphasizes the uncertainty from midweek onwards.

[summer blizzard]

Euro still has an odd evolution post day 8. 

GFS today handles the Atlantic Low very strangely at day 7.

Needless to say, i don't buy them. 

[jules216]

ECMWF ensembles seem to agree that we are going to phase 7 MJO, which give a reasonable representation as to where we are heading at the start of November, courtesy of this morning GFS, a weakish block north/west of Ireland and a tendency of Scandi/Central Eestern European through,after that the MJO singal weak, probably heading to circle of death? 

[knocker]

You can see where the ecm det. run is coming from looking at the EPS mean anomalies

.

[Man With Beard]

GFS 06Z unlikely to happen, but quite remarkable just how much warmth is available if all clicks into place. 17C-18C uppers in the last few days of October? Unheard of surely? In fact not that common at the height of summer.

[NorthernRab]

13 minutes ago, Man With Beard said:

GFS 06Z unlikely to happen, but quite remarkable just how much warmth is available if all clicks into place. 17C-18C uppers in the last few days of October? Unheard of surely? In fact not that common at the height of summer.

Both the GFS 00hz and 06z are quite bullish about this, beginning at 150 hrs or so - something to keep an eye on and quite interesting if it materialises.

For southern England it would be notable, but for the Scottish Highlands exceptionally so. Main pulse isn't until 200 hrs but this is an interesting chart nonetheless

Edited October 20, 2017 by NorthernRab