Model Output Discussions 12z 01/09/2016

[Grimers]

The UKMO model shows a low over W Scotland, Northern Ireland and Ireland bringing strong SW winds to all parts of the UK on Monday.

Edited October 14, 2016 by Grimers

[weirpig]

Way out in Fl  but the Gfs 6z op  from aroud 240 to the end of its run brings copious amounts of rainfall for most of the uk  with a couple of  atlantic lows struggling to make inroads against the block thus causing it to stall just to the west of the Uk. One perb of many.

Edited October 14, 2016 by weirpig

[Grimers]

The WRF-NMM model shows showery conditions for all parts of the UK tomorrow.

   

Edited October 14, 2016 by Grimers

[Frosty.]

The Gfs 6z shows high pressure building in next week but further ahead is looking increasingly unsettled from the atlantic with bands of rain crossing the uk interspersed with sunshine and showers, temperatures fluctuating around the average with some cooler and warmer spells, the unseasonably warmer days mainly across the south.

[IDO]

I would not worry about after D10 as the GFS has been rather vague with regard to after the impact of the ex-Atlantic hurricanes. The spread is quite telling and the Atlantic quadrant has high uncertainty. As the GEFS highlight.=: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=312

Dr Cohen suggests a continuation in week 3-4 of negative NAO and negative AO, possibly more pronounced.He adds although the strat AO is likely to trend neutral in the near term, bottom up influence may reinforce the positive PCH's. No sign of any MJO cycle in the mid-term, so a pattern change may be slow to come forth. His latest blog: https://www.aer.com/science-research/climate-weather/arctic-oscillation

UK wise, difficult to know where the block will set up at the moment, and some cooler options after D10 quite possible.

 

[Grimers]

The GFS model shows a low over W Ireland giving strong SW winds for W parts of the UK on Sunday.

   

Edited October 14, 2016 by Grimers

[Frosty.]

The GEFS 6z mean shows high pressure nudging in from the w/sw next week and even towards late october a strong ridge is maintained with a gentle flow from the near continent so it looks like a very pleasant benign spell is on the way which could last a considerable while.

[Grimers]

7 minutes ago, Frosty. said:

The GEFS 6z mean shows high pressure nudging in from the w/sw next week and even towards late october a strong ridge is maintained with a gentle flow from the near continent so it looks like a very pleasant benign spell is on the way which could last a considerable while.

Yes, if it wasn't for this unsettled weekend, we would've had a very long interrupted spell of settled conditions.

Edited October 14, 2016 by Grimers

[Frosty.]

21 minutes ago, Grimers said:

Yes, if it wasn't for this unsettled weekend, we would've had a very long interrupted spell of settled conditions.

Agreed, the GEFS 6z mean looks settled until almost the end of the run and nothing like the progressive 6z operational through low res. It looks like perfect autumn weather could be on the way from the 2nd half of next week.

[Frosty.]

I even found a couple of interesting GEFS 6z perturbations showing wintry weather from the Arctic sweeping south for the turn of the month.

P7 is a cracker!

[Grimers]

18 minutes ago, Frosty. said:

I even found a couple of interesting GEFS 6z perturbations showing wintry weather from the Arctic sweeping south for the turn of the month.

P7 is a cracker!

I agree, if P7's charts were to materialise, there'd be snow across upland regions.

Edited October 14, 2016 by Grimers

[Mucka]

There is a fundamental difference between ECM and GFS handling of Nicole today - at least its interaction with the block to our NE.

GFS wants push more energy over the block whereas ECM has more of a split flow which ultimately results in some undercut and the trough pushed South and filling rather than just pushing against the block as with GFS

This results in the GFS continually attempting to break the block down with Atlantic incursions (largely unsuccessfully) while ECM wants to build an Atlantic ridge behind the remnants of Nicole.

 

The GFS is not a disaster as it generally has enough energy being forced South to maintain the Scandi block and there  is always the possibility of undercutting in FI, however it does also allow for the possibility of the pattern slowly flattening out over time.

ECM would be the better option for sustaining blocking I would think.

 

[Matthew.]

"Low sea ice and a persistent negative AO are favorable for the resumption of a more accelerated advance of Siberian snow cover. High Eurasian snow cover and low Arctic sea ice in the Barents-Kara seas favor first, a strengthening Siberian high and then a weakened polar vortex in winter" -Dr. Cohen. More NE heights in the GFS forecast:

Edited October 14, 2016 by Matthew Wilson

[Frosty.]

The Gfs 12z shows the friendly side of autumn as high pressure nudges in from the sw by next midweek with temperatures close to average but feeling pleasant in the sunshine and chilly overnight with slight frosts, mist and fog patches.

[SMU]

The end of October is traditionally when the vortex is cranking up-

however this year-

its gone on holiday- This is not normal- its so far from normal the polar height field is almost inversed !

[knocker]

Macole

[Ali1977]

1 minute ago, Steve Murr said:

The end of October is traditionally when the vortex is cranking up-

however this year-

its gone on holiday- This is not normal- its so far from normal the polar height field is almost inversed !

If this chart proved correct November would be very very interesting. Interesting ensembles on the way I reckon...

Edited October 14, 2016 by Ali1977

[Grimers]

7 minutes ago, knocker said:

Macole

Interesting chart there, just shows how unpredictable Hurricane Nicole's track is.

[knocker]

Still retaining the ridge anomaly and the vortex cranking up?

 

[Frosty.]

Another largely settled blocked Gfs run from the 12z apart from the next 3/4 days. There is no sign of a return to typical atlantic mobility in the next few weeks or more..completely different to the 6z in low res and much more like the mean.

Edited October 14, 2016 by Frosty.

[Matthew.]

10 minutes ago, Steve Murr said:

The end of October is traditionally when the vortex is cranking up-

however this year-

its gone on holiday- This is not normal- its so far from normal the polar height field is almost inversed !

Thanks Steve for your experience. I know where to set the bars in relation to other years. Looking forward to seeing the 2nd half of October develop. Neverknow the PV might fail completely only joking mildies

[Ali1977]

Just now, knocker said:

Still retaining the ridge anomaly and the vortex cranking up?

 

The GFS at 384 does not show the vortex cranking up surely - or am I missing something!!

[Matthew.]

Just now, Ali1977 said:

The GFS at 384 does not show the vortex cranking up surely - or am I missing something!!

A possible pull of the leg. Still looks good over Greenland.

[northwestsnow]

2 minutes ago, Matthew Wilson said:

A possible pull of the leg. Still looks good over Greenland.

Indeed, PV looks organized alright, north of scandy?!:D

[knocker]

5 minutes ago, Ali1977 said:

The GFS at 384 does not show the vortex cranking up surely - or am I missing something!!

No but it indicates a large area of very cold air swanning down into Europe.in a deep upper trough