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Model Outooks: Winter 2008/2009
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GFS 12Z Parallel Run:
This run was exceptional in terms of cold, which is showed beginning for Ireland at the T+ 168 timeframe. This potent cold continued out to T+300 for Ireland. In the more reliable timeframe, up to T+180, this run was very very good.
For this operational run, 18Z, I want to show some charts from the higher resolution, more reliable timeframe as well as FI:
At T+135 Hours from now, we have cold to potently cold air about 300 - 400 miles to our east.
T+ 150.
At this point we have very high pressure over Greenland, with potently cold air again to our East. Ireland would also be entering a northeasterly airflow at this point of the run verified.
T+159
A bitter northeasterly airflow is now approaching Ireland.
T+168 - A snow risk now approaches Ireland from the Northeast, with upper 850hPA temps of -5 approaching the east coast.
AT T+180, Upper temps are between -5 and -7 over Ireland, with a potently cold northeasterly flow
If things continue to trend this way, then we are potentially on course for a wintry outbreak possibly beginning between the 3rd and 5th of January. If things continue like this, the incursion could be from a point north of east.
I will post FI charts shortly. But this is an excellent run out to T+180. Excellent news. But Extreme caution is advised at this point, nothing is certain as of yet.
SA.0 -
And here is the chart for Sunday 5th of January, with upper temps of -10 in the east of Ireland, and a substantial snow risk.
I must say, that something is possibly brewing in terms of potent cold.
However, this chart is still 204 Hours out from now, so please, extreme caution advised.
Substantial snow risk to all areas if this came off, but its still FI @ T+252
The cold continues almost for the whole run way out into FI, here is T+372:
For tonight's GFS 18Z run, the charts say it all, from about +165 to T+384. However, its still far too early to get too excited, just yet anway.
Regards to all,
SA.0 -
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Weathercheck wrote: »Best run ever.
Could we be on the verge?
A good while to go yet, but its looking good
Its hard not to get excited WC, because the building blocks and some of the potent cold have entered the high resolution, more reliable timeframe on the last two GFS operational runs.
As ever, extreme caution advised, but this could potentially be a top classic IMHO. Its still too early to be any way certain though.
Regards,
SA.
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Great ,I feel like not visitng this page now till the 5th of January :P It would be great if we could just bank the model outputs as they are now for the 3rd to the 5th onwards.
The main point from tonight's output is that all the building blocks shore up and potent cold arrives in the somewhat more reliable timeframe.
However, this needs to make it past T+72, even T+48 before being certain.
Very very encouraging is one thing I can say with absolute certainty tonight.
Note that GFS Operational may still be a bit too quick with the intro of the cold, maybe by 24 hours or so, however the trend is there for a very cold outbreak, but nothing is certain yet.
SA. 0 -
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I hate to admit it but you are probably right. But then again, we haven't had a significant snow event for over 20 years now (87 being the last that I can recall in Dublin). The law of averages needs to put this right.
In my memory we had significant snow in christmas 1995 and then in 2000
12 inches of snow here in donegal in 20000 -
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Well out to T+276 or the 8th of January there is STUNNING ensemble agreement for a colder outbreak, with the ensemble mean 850hPA temps approaching and reaching - 8 for Dublin on the 5th.
This is significant IMO.
Once again, the very sharp cooling drop is in evidence from the 3rd to the 5th of January.
Nothing is certain right now, but what I will say is that if we get 48 hours of more of these outputs, then it could potentially be:D.
However, still extreme caution needed as of yet.
GFS 18Z Ensembles
I think the chart below says it all, GFS Operational was not really a cold outlier, so the winter wonderland charts on this run had support.
A clear drop in upper 850hPA temperatures between the 3rd and the 5th.
Many ensembles trend towards -12 and -13.
The main onset of this cold is still 170 - 180 hours out, so it could all change yet, but certainly a very nice set of ensembles to say the least.
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-8?Snowaddict wrote: »Well out to T+276 or the 8th of January there is STUNNING ensemble agreement for a colder outbreak, with the ensemble mean 850hPA temps approaching and reaching - 8 for Dublin on the 5th.
This is significant IMO.
Once again, the very sharp cooling drop is in evidence from the 3rd to the 5th of January.
Nothing is certain right now, but what I will say is that if we get 48 hours of more of these outputs, then it could potentially be:D.
However, still extreme caution needed as of yet.
so its gona be -8, or is that the something else0 -
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ok thanks ,but what tempertures are the ones that u see on the weather forecast on tv, ground tempertures?Snowaddict wrote: »Hey Pangea, I've updated my post above.
This is the average upper 850hPA temp value, its not for the surface or the 2 metre temperatures. Here are the 2m temps for the 18Z run..
I've also updated my post above. Regards, SA.0 -
Snowaddict wrote: »Well out to T+276 or the 8th of January there is STUNNING ensemble agreement for a colder outbreak, with the ensemble mean 850hPA temps approaching and reaching - 8 for Dublin on the 5th.
This is significant IMO.
Once again, the very sharp cooling drop is in evidence from the 3rd to the 5th of January.
Nothing is certain right now, but what I will say is that if we get 48 hours of more of these outputs, then it could potentially be:D.
However, still extreme caution needed as of yet.
GFS 18Z Ensembles
I think the chart below says it all, GFS Operational was not really a cold outlier, so the winter wonderland charts on this run had support.
A clear drop in upper 850hPA temperatures between the 3rd and the 5th.
Many ensembles trend towards -12 and -13.
The main onset of this cold is still 170 - 180 hours out, so it could all change yet, but certainly a very nice set of ensembles to say the least.
Fantastic support there- most models are now predicting cold.
However remember the 23rd when we had fantastic charts but following days were awful- this could turn out the sam (hope not) but BEWARE.0 -
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Finally, I have seen it stated on TWO in the last few minutes that Francis Wilson, the well respected UK Weather Forecaster has stated on Sky News Weather tonight that the end of next week looks like becoming extremely cold.
I don't know if this is correct, but if this is the case, then something is brewing IMO for a veteran forecaster to make a statement like that.
Regards,
SA. 0 -
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Hi SA,
By "TWO" do you mean BBC Two?
If so did Francis give any extra info?
Snowfan
Nope TWO or the The Weather Outlook is another UK Weather Forum.
Not that I know of as yet, but if he did state this, its very encouraging.
Tonight, we stand at the brink of a potential wintry outbreak to be honest.
However, it may not come to fruition, but the signs are there (Although these are still largely in FI). Treat every output with caution over the next few days, always check the ensemble mean after every run, because these will show the way things are trending.
Regards to all,
SA. 0 -
Hmmm, if the models have been talked about having a certain inadequacy about them recently aparently on here and across other fora, what makes it certain that these are full on. These could quite reverse by this time tomorrow yet again.
Also the reliable timeframe. A forecast is considered to be 15% accurate at 5 days out thats upto T+120hrs (increasing to 73% for T+24hrs). As a forecast is usually based on model outputs (ECMWF and backed up by HIRLAM) this same rule applies anything therafter be taken very lightly.
I would not be stocking up on Winter supplies just yet and telling the families to emigrate to warmer climes.
Although it does look nice and i would like a bit of that but waaaay out of reach and is not knocking on the door by any stretch. I like this thread and good read but take note as SA says, caution needs to be taken in viewing these models as they are not reliable just yet. 0 -
Snowaddict wrote: »
However, it may not come to fruition, Treat every output with caution over the next few days, always check the ensemble mean after every run, because these will show the way things are trending.
Regards to all,
SA.
That is right SA, nothing weatherwise can be deemed even 75% certain until it is shown within the 72hr timeframe. These charts are painful to say the least because they are so far away. However, trends have been known to show up even at 374hrs, but no doubt much modification will occur IF this trend was to contiune.
But all the same, model runs today quite spectacular. 0 -
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Yup , anyways all anyone needs to do is just look outside and see that we are very much in a cold snap, theres ice everywhere here in donegal.
Theres ''Ice'' in Kerry too mate ........
But this may only be the tip ''Iceberg''........
The real ''Icing'' on the cake may be just around the corner ........
(refering to the Model Outlook Discussion of course :rolleyes:). 0 -
I wont be able to post much today, so just this brief post regarding 00Z ensembles. They are still very very good, with GFS operational being a mild outlier at the end of the run for deep FI.
However, there are also some milder solutions in there so extreme caution is still urged at this point. A lot of this potential colder evolution is still in FI, so give it another few days and see how it pans out.
EDIT: ECMWF is a stunner this morning. By T+120, almost all of the building blocks come into place.
T+144, A northeasterly flow is approaching the UK.
Now, after this we are really looking at the unreliable, so great caution needed, but the following are the best set of ECMWF charts I have ever seen for cold potential.
T+168, a northeasterly flow approaches Ireland, Sunday 4th - 1am
T+192, increasingly cold northeasterly flow
Then the final two charts are somewhat impressive to say the least: :cool:
I certainly hopes it works out for the best and will post again when I get the chance, but a word of caution once again, The majority of these charts are still in the unreliable timeframe, even when they reach the reliable you would have to be up to T+72 or T+48 with this type of setup to have any certainties
Shortwaves could play havoc with any cold potential in this setup, however things are looking quite good this morning.
Finally, the latest height anomoly charts show clearly the potential that is there, but it will be a tedious setup in tapping into that very cold air successfully. At the moment, the potential is there.
Regards to all,
SA. 0 -
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