Model Output Discussion

[nick sussex]

It looks like the eastern seaboard off the USA will be important for downstream events after the northerly with the models handling of low pressure here, the UKMO takes the main low further west and throws the energy ne'wards this allows that ridge to get pushed ne'wards, the GFS pushes the energy eastwards off the main trough.

We have to hope the models are keeping the upper high too far south and will model this further north with time and so this can get pushed ne'wards towards Scandi, i don't really see any other way of hanging onto some surface cold in the outlook.

A few of the ensembles aswell as the GFS operational run try and cut a low se'wards but overall many of them have the high to the south or southwest, its evident from the colder ensembles for southern Europe that high pressure mainly is in that unfavourable position for the UK but which still allows colder easterlies on its southern flank in southern Europe.

The ECM much later looks interesting with pressure building westwards from eastern Europe but as we"ve seen from recent days it's not so easy to get the cold air westwards to the UK.

At least the northerly looks okay with a few days of snow chances so whatever happens at least January looks to go out on a cold note.

[Frosty.]

At least the northerly looks okay with a few days of snow chances so whatever happens at least January looks to go out on a cold note.

It looks better than ok for those who live around northern and eastern coasts of the uk but that's a typical Northerly for you, coastal heavy snow showers and 15 miles inland it's unbroken sunshine.

[nick sussex]

It looks better than ok for those who live around northern and eastern coasts of the uk but that's a typical Northerly for you, coastal heavy snow showers and 15 miles inland it's unbroken sunshine.

It's hard to say what troughs will show up from this far out but generally you're right it will always favour those coastal regions exposed to the northerly.Perhaps the best chance for inland areas is with that feature heading south but theres still some uncertainty over that. Anyway I'm keeping an open mind as northerlies have a habit of either disappointing or throwing up a few surprises for areas not initially favoured.

[Ben_Cambs]

It's hard to say what troughs will show up from this far out but generally you're right it will always favour those coastal regions exposed to the northerly.Perhaps the best chance for inland areas is with that feature heading south but theres still some uncertainty over that. Anyway I'm keeping an open mind as northerlies have a habit of either disappointing or throwing up a few surprises for areas not initially favoured.

Although Coastal areas are favoured, Im sure there will be troughs associated with the flow, which would bring snow to inland areas

[Snowyowl9]

Ian,

The ecm12z IS a downgrade from the previous two 12z's.....Because the Northerly shows rain for most

with Western, Cenral and South Central not seeing much out of a snow event.......No reload

to my eyes........No need to start going 0n about the early Jan synoptics as they have gone

and have NO bearing on what we are seeing now....Which is a Mid atlantic High toppler end of

Sorry but the synoptics arent that great

Regards

CV

It`s not a normal recent winter toppler as what happened before 2005.

http://www.wzkarten.de/pics/Recm1441.gif

Treat this as a bonus cold 5 days we didn`t really expect to get and snow showers even out west now.

Synotics aren`t special but this will pack a punch.

Off to watch the big freeze now.

[Thundery wintry showers]

Ian,

The ecm12z IS a downgrade from the previous two 12z's.....Because the Northerly shows rain for most

with Western, Cenral and South Central not seeing much out of a snow event.......No reload

to my eyes........No need to start going 0n about the early Jan synoptics as they have gone

and have NO bearing on what we are seeing now....Which is a Mid atlantic High toppler end of

Sorry but the synoptics arent that great

Regards

CV

Looks like a bit of mild hopecasting to me, because even the GFS only shows rain for Friday for the south-western third of Britain, while UKMO and ECM would support rain only for a select few. Lack of snowfall will be mainly down to lack of precipitation (the wishbone effect) not abundance of rain.

[Frosty.]

It's hard to say what troughs will show up from this far out but generally you're right it will always favour those coastal regions exposed to the northerly.Perhaps the best chance for inland areas is with that feature heading south but theres still some uncertainty over that. Anyway I'm keeping an open mind as northerlies have a habit of either disappointing or throwing up a few surprises for areas not initially favoured.

With the Northerly looking as though it will last between 72-96 hours, i'm sure there will be at least a few troughs pushing south into scotland but whether they will penetrate further south than the highlands is questionable. We really need a NE'ly tilt to the flow but i'm not sure we will get one.

Edited January 25, 2010 by Frosty039

[Yeti]

Although Coastal areas are favoured, Im sure there will be troughs associated with the flow, which would bring snow to inland areas

And indeed some showers will penetrate further inland, especially in places like northern Scotland and here for us in EA (hopefully!). There is a period (Friday) where winds may swing more NNE as well, which would only help matters.

[cold snap]

With the Northerly looking as though it will last between 72-96 hours, i'm sure there will be at least a few troughs pushing south into scotland but whether they will penetrate further south than the highlands is questionable. We really need a NE'ly tilt to the flow but i'm not sure we will get one.

A ever so slight hint of a north easterly on ECM http://www.wetterzentrale.de/pics/Recm1441.gif

I think it might just come off.people are talking about this on other forums ive noticed.

Edited January 25, 2010 by cold snap

[Severe Siberian icy blast]

Remember also folks that this is just one run and things change and will change , im confident this northerly will bring troughs , and when it does it will be snow , its the middle of winter and a northerly on its way straight from the pole, so most of the ppn will be snow , also aythin beond 144hrs is f1 and changes every day .

[MP-R]

Remember also folks that this is just one run and things change and will change , im confident this northerly will bring troughs , and when it does it will be snow , its the middle of winter and a northerly on its way straight from the pole, so most of the ppn will be snow , also aythin beond 144hrs is f1 and changes every day .

I look with interest at this chart here:

http://www.wetterzentrale.de/pics/Rtavn961.png

Surely, judging by the origin of the isobars around that feature to the south of the UK, anything falling would be snow or at least sleet - not rain.

[tinybill]

Remember also folks that this is just one run and things change and will change , im confident this northerly will bring troughs , and when it does it will be snow , its the middle of winter and a northerly on its way straight from the pole, so most of the ppn will be snow , also aythin beond 144hrs is f1 and changes every day .

http://www.meteociel.com/modeles/gfs/precipitations/69h.htm

all i say its looking very wintry from 28 jan to at least feb 2nd at the moment

[aspire27]

Any hints of an Easterly developing from this non exciting northerly?

[bluearmy]

http://en.vedur.is/weather/forecasts/atlantic/#teg=temp&type=prec

ecm 12z sees friday morning as pretty wet/white. unforunately, the warm sector makes it all the way to the east coast. lets see what it thinks tomorrow. tonights T96 FAX should be illuminating.

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

am i the only one thinking the ops are over progressive ??

Edited January 25, 2010 by bluearmy

[Lewis]

http://en.vedur.is/weather/forecasts/atlantic/#teg=temp&type=prec

ecm 12z sees friday morning as pretty wet/white. unforunately, the warm sector makes it all the way to the east coast. lets see what it thinks tomorrow. tonights T96 FAX should be illuminating.

Thats the worst outcome, even still im in the colder 850s

[BLAST FROM THE PAST]

Well here are my general thoughts re models output. Like I said a couple of days ago they have latched onto the evolution. HP to our W and NW bringing northerly and at times NE'ly winds with trough in Scandi. With a little bumping around the synoptic set up will not break down as progged T168 onwards and watch for models to latch onto this as we get towards end of the week. I think we will see a shift north of the ridge and a strengthening of the block as we get to end of first week of Feb. With the HP being bumped around winds will veer from n'ly to ne'ly to e'ly but into second week 9-13 say we may see our coldest spell of Feb with biting NE'ly airflow. Around mid month we'll see the end of the block to the NW as an LP moves from NW to SE. I think HP will then gradually sink from arctic to Scandi and slowly sink SE as we go to last week with a southerly flow for the last part of the month generally milder/less cold. [however, the block ending to ouir NW could be the signal for the much milder setup to take over and should be monitored..as I wouldn't be suprised at all to see that].

For now though look no further than this northerly for model accuracy, things will change, and considerably from what FI shows now. I do believe that we won't match the severe cold of Jan ie -22c etc but -10c should be well within reach on numerous occasions.

BFTP

Edited January 25, 2010 by BLAST FROM THE PAST

[BristolBaggie]

Any hints of an Easterly developing from this non exciting northerly?

???? Do you mean the Northerly thats likely to bring widespread snow for Bristol on Friday ?

Forget Easterly's they rarely deliver for the West (we got lucky with the last Easterly)

[Ben_Cambs]

Looking at the GFS 18z PPN charts, It suggests widespread snowfall on Friday regarding the small system/trough, but rain the South west, with back edge snow.

Edited January 25, 2010 by Snowman0697

[damianslaw]

It's hard to say what troughs will show up from this far out but generally you're right it will always favour those coastal regions exposed to the northerly.Perhaps the best chance for inland areas is with that feature heading south but theres still some uncertainty over that. Anyway I'm keeping an open mind as northerlies have a habit of either disappointing or throwing up a few surprises for areas not initially favoured.

The longer the northerly embeds itself the greater chance of trough features developing, the flow looks to be quite unstable, the models won't pick up on any trough features until the much nearer timescale.

At this stage, the usual suspects will likely catch the most precipitation, favoured spots, the N Isles, NE Scottish coast and North East England and Yorkshire coast, perhaps also N Ireland coast with more of a NW wind at least initially.

Central parts look mostly dry, but every chance widespread snow could occur if a trough develops.

[Jason T]

Looking at the GFS 18z PPN charts, It suggests widespread snowfall on Friday regarding the small system/trough, but rain the South west, with back edge snow.

I agree, models really pretty awesome. Cant wait untill early am models few nice surprises yesterday and today.

[Geordiesnow]

The longer the northerly embeds itself the greater chance of trough features developing, the flow looks to be quite unstable, the models won't pick up on any trough features until the much nearer timescale.

At this stage, the usual suspects will likely catch the most precipitation, favoured spots, the N Isles, NE Scottish coast and North East England and Yorkshire coast, perhaps also N Ireland coast with more of a NW wind at least initially.

Central parts look mostly dry, but every chance widespread snow could occur if a trough develops.

I think western areas will do better than eastern areas regarding this northerly as it does have a NW'ly tilt to it and from previous experience, showers tend just to stay off shore when the wind is a NNW'ly.

I can't see it veering Northerly enough for some of the locations you menturned to get coastal showers but as ever, there is still time for a few changes i suppose.

[LomondSnowstorm]

Upgrade in the 18Z as far as I'm concerned, with much more widespread precipitation across the UK and particularly eastern Scotland, which looked like seeing very little PPN on previous runs http://www.wetterzentrale.de/pics/Rtavn784.png Sadly though this means the dewpoints are much less favourable further west due to the warm sector so much of the precipitation would fall as rain, though this is likely to change back and forth over the coming days http://www.wetterzentrale.de/pics/Rtavn7810.png http://www.wetterzentrale.de/pics/Rtavn8410.png

As damian says, troughs in northerly flows can appear out of nowhere - the 18th to 23rd December here produced the most snowfall for quite a few years purely from troughs not really picked up on until about 36 hours out. Similarly, I don't think the major snowfall to hit Manchester, the Midlands and South Central from a cold front was really forecast until about 72 hours before it came off.

LS

[swilliam]

120 fax has a nice snow streamer for the Irish Sea - could be good for West Wales and SW England

[nick sussex]

Siberian high looks like its blocking the trough over Europe low pressure out west has nowhere to go. The best thing is for the Atlantic high at this stage to be further west, this will force a shortwave se wards. As long as pressure remains low over central Europe it's very difficult for milder air to get into the UK.

[TonyH]

120 fax has a nice snow streamer for the Irish Sea - could be good for West Wales and SW England

That would be a nice Birthday present!