Winter Model Discussion - Cold Hunting -12Z 03/01/13

[Summer Sun]

Oh dear I just let it slip to one of my family members about the potential we're starting to see hinted at so if this all ends coming to nothing again you can all feel free to blame me.

Don't anyone tell the Express if they find out we are doomed I tell you doomed

Edited January 3, 2013 by Gavin.

[chionomaniac]

As for the shortwave debate its for another time to investigate- If you look at the archives there seems to be endless easterlies, never scuppered by anything always seemless in delivery-

However we dont have any memory of the ones that missed- of course have any dodgy model data that suggested an easterly that was scuppered last minute-

Our first real bitter blow was 2001 with the Kettley high that never arrived- because the angle of the jet-

However whats notable is the presence of shortwaves on the SW flank of Scandi Highs- they will be products of the jet flow, however sadly because they are so shallow they are usually picked up very late in proceedings- when the models start to get visibility of the pattern...

Lets se what the pub run brings...

S

Steve - I think that where the ridge is strong enough we have a trough form in the flow and where it isn't we get shortwave hell. But that is for another day.

No matter what the pub run throws at us, the strat warmings leave us in a favourable position, but most of all the latest GFS MJO forecast is far more favourable. This will give us the amplitude needed to sustain any downwelling from the strat. Let's hope the UKMO and ECM will also show this when they update.

[mcweather]

Perfect phraseology ;-)

Ian I would like to pass on my thanks to you for taking part in this forum it is good to have your professional input.

Can I take it from your reply to Crewe colds post that your fellow pros at the Meto are also refraining from saying anything to the (weather watching) family but are also quietly confident of something a bit more seasonal?

Edited January 3, 2013 by mcweather

[fergieweather]

Can I take it from your reply to Crewe colds post that your fellow pros at the Meto are also refraining from saying anything to the (weather watching) family but are also quietly confident of something a bit more seasonal?

They're geared up for the potential. It was expressed in their last detailed seasonal update to public bodies issued back on around 22 December. But varied possible outcomes require great caution in public message at present. That said, there's sufficient likelihood that you can anticipate more mention of SSW as early heads-up on various BBC forecasts herewith.

[Timmytour]

Don't anyone tell the Express if they find out we are doomed I tell you doomed

I honestly believe the models have been programmed to recognise the influence of Express headlines on the weather and compensate with milder solutions!

Steve M...(and others)...there's talk of Jan 85, but as I recall Feb 86 was a pretty cold month as well, after a pretty mediocre winter...was this also accompanied by an SSW?

[chionomaniac]

They're geared up for the potential. It was expressed in their last detailed seasonal update to public bodies issued back on around 22 December. But varied possible outcomes require great caution in public message at present. That said, there's sufficient likelihood that you can anticipate more mention of SSW as early heads-up on various BBC forecasts herewith.

If a cold spell comes off as a result of the SSW, I think that it is only fair that you give it credit in one of your forecasts!!!!!!

[cooling climate]

It wasn't the shortwave and never will be - the upper pattern dictates the lower!!

The shortwave is always a consequence of the upper pattern - not the other way around as some would have you believe.

Yes quite right.It may have looked like the shortwave was the culprit on the H5 models

but the battle was being lost higher up.

Looking at the latest model output and the trend continues with heights developing to the

north of the UK and a east to northeasterly flow feeding down across Europe and the UK.

This to me continues to be the form horse to follow in the 10 to 20 day time frame.

[SMU]

^^ I doubt the public will even recognise the stratosphere- as far as most are concerned its where episodes of star trek are filmed...

It would need a decent amount of forecast time to convey a message, something the beeb are very poor at given to the met office.

S

As for the shortwave argument- its due to the positioning & speed of the jet- it not to do with the upper pattern im afraid-

The reason the high pressures didnt retrograde together in December will have been the jet that was FORECAST to split in the atlantic & move east through svalbard, when in reality the Jet split in the atlantic & lopped north, then moving south through norway- hence the development of a shortwave in that region.

Edited January 3, 2013 by Steve Murr

[Cheshire Freeze]

They're geared up for the potential. It was expressed in their last detailed seasonal update to public bodies issued back on around 22 December. But varied possible outcomes require great caution in public message at present. That said, there's sufficient likelihood that you can anticipate more mention of SSW as early heads-up on various BBC forecasts herewith.

Yes, that backs up what I was told a couple of days before Christmas at work by a customer. Apparently there had been a heads up about mid Jan that had just come through regarding an advisory stock piling of grit.

EDIT: found original post from 23rd December

''Poor 18z....

Though a snippet of info.....Spoke to a guy in work today (customer). Anyway, he was discussing the flooding in the southwest and then went on to say this will continue over Christmas and into Jan. Now for the interesting bit......he said the highways agency have been given a heads up and told to stockpile grit for the middle of Jan as a potentially major cold spell may be on the cards.

No idea who he works for etc but seemed quite convincing that this is what he's been told and seems to tally with the potential warming event''

Edited January 3, 2013 by CreweCold

[mcweather]

They're geared up for the potential. It was expressed in their last detailed seasonal update to public bodies issued back on around 22 December. But varied possible outcomes require great caution in public message at present. That said, there's sufficient likelihood that you can anticipate more mention of SSW as early heads-up on various BBC forecasts herewith.

Many thanks for your reply Ian. I can totally understand why the Met office have to be cautious with the public message until they are pretty sure on the outcome. As The National body in terms of forecasting. Their reputation is on the line especially with so many uneducated journalists ready to take a pop.

[bluearmy]

Steve - I think that where the ridge is strong enough we have a trough form in the flow and where it isn't we get shortwave hell. But that is for another day.

No matter what the pub run throws at us, the strat warmings leave us in a favourable position, but most of all the latest GFS MJO forecast is far more favourable. This will give us the amplitude needed to sustain any downwelling from the strat. Let's hope the UKMO and ECM will also show this when they update.

Thy updated ed. low amp phase 6 in week 2.

[Chris W]

It has certainly been very interesting and encouraging to see the models develop from the late December Atlantic-fest to show heights building north of us and increasing signs of a favourable response to the SSW. The non-easterly was difficult to take, but this looks like a well-based route to cold weather from my understanding. Credit to those in the strat thread for calling this, whatever comes of it they seem to have been ahead of the game in there!

I would like to see the Azores high shift from around these parts though, it is looking a bit difficult to shift and seems to block all comers (east or west) for now, though I'm sure with potential northern blocking and a more south-flowing jet then it could well happen. It will be fascinating to continue watching this.

[ChartViewer]

Yes quite right.It may have looked like the shortwave was the culprit on the H5 models

but the battle was being lost higher up.

But do not 99% of us view the H5 , the jet, the pattern...not something happening very higher up in the strat?

Anyhow as you say the 18z looks like building a ridge....

T108

T132

Edited January 3, 2013 by ChartViewer

[chionomaniac]

Thy updated ed. low amp phase 6 in week 2.

That's a lot better now. (I only checked 30 mins ago and they hadn't!!!)

One more step to go to phase 7!

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

Bring it on.

[lorenzo]

^^ I doubt the public will even recognise the stratosphere-

Am not so certain.. thanks to this chap..raised awareness well so the stratosphere may be in the public minds..?

[SMU]

http://modeles.meteo...nh-0-114.png?18

A sharper pattern developing on the 18z-

When you see a 'Sharpening' of the ridges & troughs the jet is more amplified & slower-

I would expect the 18z to show a more BOM like scenario tonight--- the GFS is certainly leading in the way in what most of us are thinking should be developing through the SSW propergation phase-

remember- decrease in zonal windflow increases the amplitude of the flow, negative zonal wind flow has a VERY high amplitude flow with stationary blocking & 2/3/4 wave patterns...

S

PS true Lorenzo- perhaps we should send him up there again in his birthday suit !

Edited January 3, 2013 by Steve Murr

[chionomaniac]

^^ I doubt the public will even recognise the stratosphere- as far as most are concerned its where episodes of star trek are filmed...

It would need a decent amount of forecast time to convey a message, something the beeb are very poor at given to the met office.

S

As for the shortwave argument- its due to the positioning & speed of the jet- it not to do with the upper pattern im afraid-

The reason the high pressures didnt retrograde together in December will have been the jet that was FORECAST to split in the atlantic & move east through svalbard, when in reality the Jet split in the atlantic & lopped north, then moving south through norway- hence the development of a shortwave in that region.

Perhaps we are agreeing here, because I see the jet stream as part and parcel of the upper pattern (200-300 hPa). The jet stream and upper ridges 500 hPa are forecast together in tandem...

[Chris W]

Am not so certain.. thanks to this chap..raised awareness well so the stratosphere may be in the public minds..?

He could do it weekly to measure what the strat is up to and how far down its effects are reaching...he'd be well up for it, right?

Edited January 3, 2013 by Chris W

[Isolated Frost]

Run sharpens up and de-zonalises the arctic upper high... look at the energy settling into Scandi- superb start

[on the coast]

Looking to be a very good run from 144? Interesting times ahead

[Isolated Frost]

Am not so certain.. thanks to this chap..raised awareness well so the stratosphere may be in the public minds..?

Take him to Siberia's strat... positively balmy!!

Suncream and shades at 30,000m!

[TEITS]

I think we can say F.I is becoming increasingly closer. Still wouldn't rule out what ensemble No 5 was suggesting from the 12Z.

[SMU]

http://modeles.meteo...nh-0-150.png?18

near vertical advection through ireland-- Anything vertical is a good sign - Also as per post earlier- the artic high looks nice on this run- the 12z was poor IMHO

S

Edited January 3, 2013 by Steve Murr

[-uksnow-]

A good run so far....

Low has virtually stalled in the Atlantic just pumping in the air supporting the ridge

[lorenzo]

PS true Lorenzo- perhaps we should send him up there again in his birthday suit !

It's a toasty 28 degrees in his neck of the woods soon up there...wouldn't fancy the frostbite on the way down..