Winter Model Output Discussion 01/02/2013 12z onwards

[Tom Jarvis]

What is the pub run showing??

[Continental Climate]

What is the pub run showing??

weather

[Weather-history]

Not if you have two opposite outcomes, say mild and cold, with the mean in the middle?

Does that apply to synoptic mean charts, though? The mean chart of 15 ensembles with a northerly and 15 with a southerly would be nothing and therefore you can say that there is a fine balance between the two.

[TEITS]

We are talking about mid December - daily temps averaged 6-7C for the 2nd half of December

During the failed E,ly spell max temps in my region didn't rise above freezing for a few days and mins dropped to -6C. The temps during this period were below average for 5 days.

http://www.peterboroughweatherwatch.com/reports/december2012.php

[shotski]

We are talking about mid December - daily temps averaged 6-7C for the 2nd half of December

you was talking about the so called failed easterly that gave me a week of sub zero temps

[Mair Snaw]

What is the pub run showing??

BEER

[Jason H]

I suspect the ecm ops are leading us up the garden path here guys.

Its a critical juncture now for the winter,last chance saloon as a matter of fact.

Last chance saloon? On the 2nd February? Give me strength.

[Glacier Point]

Day 10 GEFS H5 and ECM ensemble mean anomalies are reasonably in agreement.

That might superficially suggest a mean westerly flow. However, the logical evolution for both would likely be for a secondary build in heights in the Atlantic angling the track of any shortwaves NW-SE. Therefore, we could reasonably assume any cold pooling to remain in situ and begin to back west again (if it's not already there). The interest from my point of view is that the longer range ensemble means are suggesting a bouncing back and forward in angular momentum, which would typically favour this type of setup.

The diltution of T2 and 850 values will be greatest within the suite due to the range of outcomes. A better guide will be the H5 anomalies (if there is a clear pattern there) and for you to project temperature anomalies on that basis. For example, GEFS H5 anomaly at t348 is discernible and with a mean trough solution for the UK would be colder than normal (say 2-4C below average), yet this is not registering at this stage on the ensemble means at T850.

[Continental Climate]

going to be a better 18z i think http://www.wetterzen...s/Rtavn1021.png easterly flow to start by 120 is my guess!! Also atlantic blocked off

Edited February 2, 2013 by Continental Climate

[Mair Snaw]

Last chance saloon? On the 2nd February? Give me strength.

1ST week of April 2012 i had 30cm of snow in an afternoon!! so that still gives me two months left.

[Ian Brown]

What we need to remember here is the ECM ensembles are not going to show uniform support for what the OP shows at T168 - in any situation. Because there are so many hurdles to cross to arrive at the easterly - those who have been here long enough will know that you need such a set-up at T72/96 to have confidence in that outcome.

The GFS has been poor this winter beyond T120 and if it ends up being right then it will be by default as it has nearly always gone for the jet over the top, Azores High combo. In the light of the METO update the ECM must nonetheless be seen as a low probability outcome tonight - for the UK.

GP is posting right now to back the ECM !

going to be a better 18z i think http://www.wetterzen...s/Rtavn1021.png easterly flow to start by 120 is my guess!! Also atlantic blocked off

Minute differences only from the 12z ?

[Glacier Point]

..and the GEFS Ian !

[Cecil Hogmanay Melchett]

Nope,GFS not buying the 12z ecm solution as i suspected.

Over to the 0z runs,could be judgement day!!

[Weathizard]

Still no agreement at 120 with regards to systems around Southern Greenland and the low pressure system exiting the eastern seaboard that propels heights N/NE. The charts are fairly similar at 120 at first glance but there are key little areas where the GFS is very different to the ECM

[phil nw.]

We shouldn`t overlook the fact that even GFS mean ens line shows -4 to -5C 850hPa for much of the run.

We are debating degrees of cold here so if we get something nearer the ECM solution after T144hrs then the cold would intensify.

We know from model agreement up to then we are looking at a cold week to come with snow around so let`s remain upbeat and see where the models go after the Northerly -either way it`s still a cold outlook-GP`s post re.the temp anomalies point the way.

[Snowman.]

At first it looks worse but the low is in a better position and less energy going over

[Jaffusmaximus]

Nope,GFS not buying the 12z ecm solution as i suspected.

Over to the 0z runs,could be judgement day!!

I have a feeling every other run is going to be called "Judgement Day" by some!

[pdiddy]

Does that apply to synoptic mean charts, though? The mean chart of 15 ensembles with a northerly and 15 with a southerly would be nothing and therefore you can say that there is a fine balance between the two.

The exam question was: "is the mean the most likely outcome?" in your example, the answer is no, and that is the point I was trying to make. In a house with 2 adults and 2 young children, the mean age might be 20, with no one in the house that age, with two under 5 and two over 30...

[Snowman.]

If we keep the trend of less energy in greenland and north going over we could actually get somewhere.

[hilldweller]

1ST week of April 2012 i had 30cm of snow in an afternoon!! so that still gives me two months left.

Yup remember it well , it was the 4th of April to be precise !

[Long haul to mild]

Don't think the GFS 18z was ever going to solve anything! And the 0z runs probably won't either, but it will be fascinating to see if the ECM carries on where it left off.

[Mucka]

Is the mighty NOGAPS out performing GFS?

[SMU]

The consensus is COLD on the ECM, the split is PROBABLY 65/35 to cold, so the milder runs are distorting the 240 chart ( MEAN) removing the signal blocking to the north & NE-

THe MEAN at 240 appears to be atlantic driven but its not, all thats not showing is that +VE height to the north as its been smoothed out to nothing because you have the biggest MEAN difference in that region so the net is NO anomaly, but the consensus will have an anomaly.

Yee of no faith. Trust the ECM. Trust the people who have seen the GFS since 2000.

Even the 18z NOGAPS >PWNT the GFS.

S

Edited February 2, 2013 by Steve Murr

[Mair Snaw]

Yup remember it well , it was the 4th of April to be precise !

Yeah a mad day and it followed a very very warm 2nd half of march.

[It's just wind...]

Hi All - I was looking for a first posting opportunity, and here it is.

Do any of you know how much new observational data goes in to the 06/18 runs of the GFS compared to the 00/12? I work on the basis that it's a low number and thus the 06/18 are simply re-runs.