Model Output Discussion 13/11/13 >

[forecaster]

Interesting to note, the EC operational appears to be a massive outlier in terms of 850hPa temperatures across southern England at the end of the period. The spread in the ensemble is huge....pretty much from -8C up to +8C, with the operational at the bottom of that range. 

[Frosty.]

There is not even a sniff of an atlantic breakdown or any sort of change to milder sw'ly weather on tonight's Ecm 12z ensemble mean, quite the opposite in fact, it's keeping the generally east to west pattern intact through FI with cold settled and blocked weather with widespread frosts and cold bright days, with this type of alignment there is scope for something much more severe as time goes on.

Edited November 17, 2013 by Osbourne One-Nil
Because I cannot stand those sodding smileys.

[Summer Sun]

Is anyone else not getting the 12z ensembles on wetterzentral updated to today? I am still stuck on 12z yesterday

[bluearmy]

Interesting to note, the EC operational appears to be a massive outlier in terms of 850hPa temperatures across southern England at the end of the period. The spread in the ensemble is huge....pretty much from -8C up to +8C, with the operational at the bottom of that range. 

 

the spread is 4.4c and the mean is -1c. that gives a range of -5.5c up to +3.4c. given the direction that the spreads are moving (from north and east) it would seem logical for the spread to be applicable on the lower side rather than the higher.  however, your point in general terms is that the op is outside the spreads and over the south of the uk, at -7c, this is indeed true. its even moreso the case further south into france.  i wouldnt be making any forecasts based on the ecm op and i rather doubt anyone would, looking at the overall nwp.

[Gibby]

Is anyone else not getting the 12z ensembles on wetterzentral updated to today? I am still stuck on 12z yesterday

I can confirm that so can disregard my portion of the summary tonight  as I'd posted it before I noticed. Couldn't get a Jet Stream forecast on Meteociel either.

[SylvainTV]

I can confirm that so can disregard my portion of the summary tonight  as I'd posted it before I noticed. Couldn't get a Jet Stream forecast on Meteociel either.

 

FYI from NOAA :

 

"At this time, the NWS is investigating a large-scale internet issue.  It is unknown at this time if it is specific to the NWS network or the internet provider, but NCEP is are confident it is upstream from the NCEP network and systems.  This issue is affecting connectivity between external users and NCEP systems including NOMADS and the ftp server, ftpprd.

Our engineers are working with NWS Network Operations to resolve this issue.  We will inform you when we believe the problem has been resolved."

 

That's why we have had slow / missing data since yesterday.

 

Sylvain

[Paul]

We've finally just got the ensembles on line, lots of data probs at ncep today

http://www.netweather.tv/index.cgi?action=ensviewer;sess=

[Frosty.]

I like the GEM 12z tonight, high pressure migrating northeastwards into scandinavia and eventually with a southerly tracking jet there would be a risk of a snowy breakdown later.

[nick sussex]

I think these comments from NOAA sum up the current model confusion:

 

GUIDANCE HAS CONVERGED UPON A MORE COMMON OVERALL NOAM PATTERNEVOLUTION...BUT HORRENDOUS RECENT RUN TO RUN CONTINUITY ISSUESSUGGESTS SOME PRUDENCE WITH RESPECT TO RAISING FORECAST CONFIDENCETO MORE THAN AVERAGE LEVELS UNTIL VIEWING ANOTHER GUIDANCE SET ORSO.

 

The full discussion here:

 

http://www.hpc.ncep.noaa.gov/discussions/pmdepd.html

 

Although the ECM 12hrs continues with the same trend of this morning its a complex set up especially with a troublesome shortwave to the sw which hangs around for several more days, its not really a clean run and IMO could hit the buffers easily. It's very difficult to plot a route forward because of the model divergence so it's a case of waiting till tomorrows runs for a bit more clarity.

[Severe Siberian icy blast]

Looks to be a not insignificant cold cluster there towards the end.

I noticed that , it's certainly got sniff on something though !!

[phil nw.]

ECM Ht anomalies day 10 and the CPC 8-14 day forecast Hts showing a very similar pattern

 

 

A quiet Atlantic with the blocking still modeled across to our north.

 

The pattern not yet showing full Arctic blocking but with the upstream flow being split enough of the jet and lower heights holding the High far enough north.This will help to keep the cold that's coming south this week around W.Europe/and the UK.

Certainly there's no sign of anything mild in the forecast period.

Edited November 17, 2013 by phil nw.

[Cloud 10]

Even at it's coldest dips there are 6-7 members colder that the operational. So part of a colder cluster at times but it doesn't jump out as an obvious outlier for that location anyway.

 

The extended control run goes sub-zero and stays there which would have

made for interesting viewing!

 

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png?6767676767

[Ian Brown]

ECM Ht anomalies day 10 and the CPC 8-14 day forecast Hts showing a very similar pattern

 

EDH101-240.GIF 12z.png814day.03.gif

 

A quiet Atlantic with the blocking still modeled across to our north.

 

The pattern not yet showing full Arctic blocking but with the upstream flow being split enough of the jet and lower heights holding the High far enough north to keep the cold that's coming south this week around W.Europe/and the UK.

Certainly there's no sign of anything mild in the forecast period.

 

I don't dispute that Phil, but obviously the question is what happens next from day 10 onwards and the GFS sees the jet pressuring the Rex block .

[Snowy L]

Warm sector seems smaller in this run, GFS actually going for some snow in the precipitation.

[Frosty.]

I hope the Gem 12z will be the way forward with the high eventually migrating into scandi and a strengthening very cold and roar ene'ly flow and then an atlantic low undercutting the cold block and bringing blizzards and gale force easterlies.

[bluearmy]

and the GFS sees the jet pressuring the Rex block .

In low res? Shock horror! Btw, the cpc chart is automated naefs mean for week 2 so covers out to 14 days. No doubt a bit of ecm into the mix would have looked even more amplified though nothing dramatically different. (That last bit to keep JH onside)

[Eskimo]

GFS going for snow across the UK on Wednesday. 

[Bristawl Si]

I don't dispute that Phil, but obviously the question is what happens next from day 10 onwards and the GFS sees the jet pressuring the Rex block .

Let's get the first 10 days over with, first!

[phil nw.]

I don't dispute that Phil, but obviously the question is what happens next from day 10 onwards and the GFS sees the jet pressuring the Rex block .

That's for later i guess Ian.

I think things are getting far more interesting than a few days ago wrt the effects of the wave breaking into the vortex.

We are still seeing this and up to now the vortex has taken several hits,the buckling pattern is the result.

 

We will just have to see what the outputs for this show in the coming days but the PV looks very stretched between Canada and Siberia

http://www.meteociel.fr/modeles/ecmwf/runs/2013111712/EDH1-168.GIF?17-0

 

we can see the void around Greenland so not the usual pressure from up there to flatten the pattern.

[Skullzrulerz]

GFS going for snow across the UK on Wednesday. 

Can i see it?

[SMU]

2 little bits-

 

the ECM control as seen above must be a mirror image of the operational with 5 ice days....

 

The 18z is catching up as the shortwave at 90 circulating in the atlantic around the parent low is moving SE not NE-

so the GFS will be better tonight but probably not ALL the way..

 

The uppers suddenly are lower around that low culminating -8c air ( a pocket off) over the UK weds with snow maybe as far as the south midlands!

S

Edited November 17, 2013 by Steve Murr

[Mark Neal.]

 Not much in the way of snow countrywide, but some areas will see wintry conditions over coming days here is the 18z NAE... & GFS 18Z

 

00Z Tuesday.. Some snow moving into the Northern Ireland and NW Scotland, wintry showers to lower levels.(GFS)

 

6Z Tuesday... Snow showers to the NW and Scotland seeing a band of light snow. Back Edge snow to the SE showing again as winds swing around once the front passes with cold air?

 

6pm Monday... NAE shows some Wintry showers to the NW Scotland as cold air heads down..

 

00z Tuesday... NAE shows some snow into Western Scotland and potential for some in N Ireland with Elevation.

 

Nothing to get overly excited about, but still potential for some to see there first wintry mix of the year and perhaps snow falling of the season, especially further NW.

Edited November 17, 2013 by Mark N

[Panayiotis]

Low exiting the USA on the 18z is a little more south on this run, this should allow better movements of heights towards Greenland:

[Cheshire Freeze]

GFS is actually exhibiting a significant shift towards ECM this evening RE LP in the Atlantic. Doesn't look to be nudging NE into the block as significantly as the 12z had it.

 

Steve Murr beat me to it!

 

EDIT: still not there but certainly shifts earlier on.....how many times do we see the GFS do this.

Edited November 17, 2013 by CreweCold

[bluearmy]

Can i see it?

Its not so impressive on the france higher res screen. snow over the north and mainly high ground + wales.