Winter/Spring 2013 (Model Output Discussion)

Since this is a winter discussion, I hope you don't mind, if I post my winter outlook charts here.

This is basically just a composite (NOAA/NCEP) or a blend of the winters in the past. I used certain winters and blended them together. I have chosen the years and months, based on the overall global setup and similarities in the oceanic and atmospheric features. The graphics were made on October 29., when I finished my analysis process and first published on November 1st on a weather forum in my country. So lets say I have 1 month "lead time" before the start of the forecasted period. This is my first attempt of "statistical" forecasting, so I don't really expect much success to be honest, but I need to test it, so i decided to make a "public test", by posting it on weather forums.

Some interpretation is required. This is basically an average picture, so it has its respected deviation. But just the average or "middle" picture will suffice for now. I posted this on a forum in my country, so the text on the graphic is in my language (Slovenian). But some words, like the names of the months are similar, so I think you will understand what period is represented on the graphic.



I can also post the precip. and temp. anomalies if requested.

This is the December outlook that I made with the same system on the same day as the 3-month winter graphics.


Here are the CFSv2 monthly forecasts for December, issued on Nov. 1, and Nov. 13 (latest).





Best regards.

The ensembles look very interesting, at least in my view. (I look at operational runs only up to 6-8 days. From there on, its ensembles only, for me. )

GEFS "drops" the trough from Greenland into UK and Ireland.


ECMWF ensembles agree.


The operational drops it more south than the ensemble mean, meaning it would amplify the ridge/blocking to its east side.


GEFS gets even more interesting further down the road. It has a fair anomaly on the ridging near Greenland, indicating that the deviation between members is not really that big (given the range). When looking GEFS mean from 10-16 days, it looks like this ridge is propagating nN/NE, towards Greenland.




Just ensemble games for now (but I think they are fairly realistic), but something worth monitoring down the road.

Regards.

Well, as I said, its just fun and games with ensembles for now. But my main point was to give some more support or maybe "explanation" for the negative NAO trend evolving and the corresponding weather that goes with the Atlantic/Greenland ridging/blocking.

I have to add, that I live in Central Europe. So when looking at weather patterns and oscillations like NAO, I might sometimes have a different idea than most of the forum members, on whats a good or a bad pattern, varying on the persons love towards more "extreme" or less "extreme" weather. I hope I haven't over complicated this segment.

Just to back up what Wolfe_IRE said.

The temperature anomaly for November so far (let me point out, that these reanalysis charts cannot really represent local anomalies, like from town to town. But they are great when looking at the bigger picture):



The temperature anomaly above, corresponds with the pattern so far. Central and East Europe are under positive temperature anomalies, due to the overall SW flow and the warm air advection in the jet exit region, while Ireland, UK and west Europe, were under more NW flow on the back side of the troughs and under cold air advection. The trough looks triangular, due to the fact that most of them were positive tilted, with some help of the Azores High.







September+October temp. anomaly:



GEFS 10-15 days temperature anomaly.


Best regards.

t|nt|n wrote: »

MT's Firecast mentioning the possibility of colder at the end of the month

don't you mean coldcast :P

Interesting to see ( IN THE FAR REACHES OF FI ) the GFS a CFS both building the high to our NW ...





Opens the gates then for Northerly flow to flood down south ...

Interesting models indeed!

DOCARCH wrote: »

I'd say Greenland blocking.....well for the east coast anyway.

id say the opposite

cyclops999 wrote: »

Why do you say this?

As far as I know with a scandanavian high the wind blows primarily from a easterly component or NE thus exposing eastern areas greater than a Greenland high which has more of a Norherly component

DOCARCH wrote: »

I'd say Greenland blocking.....well for the east coast anyway.

I agree, our best chance for snow is an airflow originating in the Arctic rather than Russia. We're usually too far west to benefit from a Scandinavian high - last winter was a perfect example when Europe froze and we sweltered out in the Atlantic. An NE'ly is possible with a greenland high with the clockwise rotation around an anticyclone.
Interesting to note that the two big winters, 47 and 63 were very different, 47 was dominated by high pressure over Scandinavia and in 63 it was in the Iceland / Greenland area.

Wolfe_IRE wrote: »

Plenty of divergence in today’s GEFS (computer forecasting model) ensembles in relation to our weather at the end of the month. Overall, the trend is for temperatures to be below average up to the end of the month and during the early days of December. It is likely to remain unsettled for the next 7-10 days at least with the wind being a major factor in our weather, particularly next week (see MT's forecast for more). There are no clear signs at this point, that our weather will turn significantly colder during the next two weeks as has been reported widely elsewhere. However, we should be keeping a close eye on the progression of a blocking high feature possibly developing across northern Europe, which if it transpires will have a bearing on our weather.

Incidentally, JOE Bastardi's latest:

"Much of US next week awesome nice weather ( still worry about e coast) Dec 2012 globally may challenge Dec 09. UK better get ready too"

Wolfe

Has any one seen the headline express is claiming? Is it true wolfe as sccuweathet and metcheck seem to be leaning to a bit coldet weather