Model Output Discussion

[Ben_Cambs]

Fax for Monday look good http://www.meteociel...fax/fax120s.gif Should be all snow on the cold front at least.

Yes, GFS shows this aswell, looks like rain preceded by snow, then backedge snow according to the latest charts

Edit: GFS actually shows a snow event on Monday, barely shows any PPN on Monday without the hashes in them, meaning that it seems to be snow throughout

Edited February 10, 2010 by Snowman0697

[Weather-history]

Fax for Monday look good http://www.meteociel.com/ukmo/fax/fax120s.gif Should be all snow on the cold front at least.

It looks to me the Met Office has slightly modified their UKMO 120hr chart. The central pressure is to the north of Shetlands instead to the west of it.

[Tim Bland]

GFS l8z looks good to me so far. A bit of rain to start but then snow for nearly everyone. Temps 1c uppers -5 Dews -2c. What more can we ask for?

[Geordiesnow]

Seems difficult to tell if the 18Z is a snowy run or not but i am pretty sure some places will recieve some snowfall on that front, especially as it bumps into the colder air further South.

Its one of those that if it starts as snow, it could remain as snow for a while. If the PPN is heavy enough, it will bring the fairly cold uppers down with it. I would prefer if the low is further east but i do think snowfall is a possibility if the 18Z occurs. All very fine balances.

[mountain shadow]

Illogical looking 18z with the 'warmer' air to the north west nearer the colder uppers. Big mild sector which doesn't look right. Roll on the 0z

[Ben_Cambs]

Near the end of high resolution marginality becomes a problem for areas south of the M4 corridor, or really south of London

[bluearmy]

http://www.ecmwf.int/samples/d/banner/page.html

A good day to get the postage stamps. i reckon the op is pretty well spot on with the mean - not many members going east. normally we get these as the freebie again within a couple of days.

[karyo]

Seems difficult to tell if the 18Z is a snowy run or not but i am pretty sure some places will recieve some snowfall on that front, especially as it bumps into the colder air further South.

Its one of those that if it starts as snow, it could remain as snow for a while. If the PPN is heavy enough, it will bring the fairly cold uppers down with it. I would prefer if the low is further east but i do think snowfall is a possibility if the 18Z occurs. All very fine balances.

I agree, however, it has certainly shifted everything west, compared to the 12z and it is similar to the Euros. Not the trend that we want to see!

Karyo

[Liam J]

looking at the fax charts and gfs 18z thats coming out monday should be very interesting, with very unsettled conditions from the north not what we have been used to this winter with easterly winds with snow showers,

looking at strong winds heavy rain turning wintry back edge, winds veering NW'ly with sqaully bands of sleet/snow/hail along a cold front with possible thundery wintry showers.. and thunder snow, potentailly severe wintry weather on the horizon. not to be under estimated.

uppers should be ok at -5c (ish) but most importantly below freezing uppers and thickness sub 528 and heavy ppn.

alot can change in the next 5 days upgrades/downgrades.

[cold snap]

Well intrest remains for another week of winter.this has been so exhausting but fun at same time this winter.

Okay some experience members are saying Snow regarding GFS ,some are saying Rain.

So with that taken into account next week is marginal,I personally thought that the models would carry the easterly on at the weekend .how wrong was i.

[swfc]

Seems difficult to tell if the 18Z is a snowy run or not but i am pretty sure some places will recieve some snowfall on that front, especially as it bumps into the colder air further South.

Its one of those that if it starts as snow, it could remain as snow for a while. If the PPN is heavy enough, it will bring the fairly cold uppers down with it. I would prefer if the low is further east but i do think snowfall is a possibility if the 18Z occurs. All very fine balances.

Good points there.Is it me but take a look at the uk at around 160+.Its totally surrounded by high pressure and we have a crappy low slap bang over us.unbelievable how it holds things up

[snowking]

I'm pretty amazed that there hasnt been as much discussion about the longer-range FAX output this evening

It clearly demonstrates

a ) the potential of the unfolding situation (though it must be noted too the potential volatility)

and

b ) the fact that the guys down at exeter obviously see the models being a little over-progressive at present

Encouraging stuff

SK

Edited February 10, 2010 by snowking

[Cheese Rice]

Excellent GFS, all the fun and games start on Monday when we will all see a band of snow sweeping down from the north, expect all areas to have lying snow from this. From then on plenty of showers and troughs providing longer spells of heavy snow. However the precipitation may fall as a wintry mixture in the south but this could just as easily fall as snow. I would say anywhere Midlands North wards is likely to see a real pasting next week.

[mountain shadow]

I;m failing to understand why the low is travelling south west against an eastward moving small jet pulse?

[January Snowstorm]

Updated thoughts from GP would be welcome.

A sleety mess looks the most likely result for most, though snow on highground is likely.

Also it doesn't look like too much ppn around to me

[Geordiesnow]

I agree, however, it has certainly shifted everything west, compared to the 12z and it is similar to the Euros. Not the trend that we want to see!

Karyo

Nope its not the trend we wanted too see but i do think this run is more likely than the GFS 12Z run but i don't think that run should be totally ruled out just yet.

Model watching will be interesting tomorrow though thats for sure because some places in the UK could indeed see snowfall next week.

Edited February 10, 2010 by Geordiesnow

[karyo]

http://www.ecmwf.int/samples/d/banner/page.html

A good day to get the postage stamps. i reckon the op is pretty well spot on with the mean - not many members going east. normally we get these as the freebie again within a couple of days.

Thanks for posting those. As you say, not many members take the low east so unlikely to see major adjustments!

Things for next week look interesting but marginal away from high ground!

Karyo

[cooling climate]

The trend with the blocking over the Arctic is excellent with the Arctic high pushing further

down into Svalbard. This trend will continue I feel with the block moving down into northern

Scandinavia. The models will then trend the low further south and east over the coming days,

I am convinced of this and finally a very potent and wintry spell will ensue.

Daytime temps on this run are lower for the weekend as well I see.

This is of course just my interpretation on how the models will play out so any newer members

please do not take this as Gosbel or of what the models are showing at the moment.

[J10]

I think people are underestimating the snow potential for the low pressure next week, certainly areas to North and West are favoured but a small eastward push which is possible and possibly even seems likely according to the tele-connections at the moment, could result in a more widespread snow event.

[stewfox]

I'm pretty amazed that there hasnt been as much discussion about the longer-range FAX output this evening

It clearly demonstrates

a ) the potential of the unfolding situation (though it must be noted too the potential volatility)

and

b ) the fact that the guys down at exeter obviously see the models being a little over-progressive at present

Encouraging stuff

SK

When in the last 3 weeks has F1 (+T96) ever been close

A chart that shows potential and volitility all F1 charts have been largely encouraging , not sure you should get excited about them

[john mac]

The trend with the blocking over the Arctic is excellent with the Arctic high pushing further

down into Svalbard. This trend will continue I feel with the block moving down into northern

Scandinavia. The models will then trend the low further south and east over the coming days,

I am convinced of this and finally a very potent and wintry spell will ensue.

Daytime temps on this run are lower for the weekend as well I see.

This is of course just my interpretation on how the models will play out so any newer members

please do not take this as Gosbel or of what the models are showing at the moment.

I'll hold you to that one CC.

Encouraging signs, let just hope that it verfies.

[MR EXTREMES]

I;m failing to understand why the low is travelling south west against an eastward moving small jet pulse?

i notice this earlier look at jet pattern i reckon thats a very weak residual jet flow not enough really to have an effect.

as for the models i still think another shift east is on the cards as it stands tea time gfs was better tonight ecm and gfs is not as good ukmo not good either.

i still find it hard unless we get the gfs 12z to come up trumps it would be marginal with the rest of the model out puts -8 uppers would be better but -2 to -4 is to risky.

but in anycase the southern half of the uk is not likely to see much anyway rain i mean.

maybe drizzle.

but m4 north with the gfs 12z would be rather exciting for the rest of the country.

Edited February 10, 2010 by badboy657

[Tom D]

It's too early to call details - even saying M4 corridor northwards for example. The next couple of days (8-10 GFS outputs) will all have the low further east or west as it comes down, as it draws closer the detail can be pinputted re snow potential.

Taking snow out of the discussion for the moment, the set up looks good for beefy convective showers countrywide regardless of how it ends up tracking, which is something this winter has been lacking on somewhat so far! In that scenario, rain, hail, sleet and snow is possible at this time of year (someone mentioned April Showers earlier). With that comes gusty winds and sudden drops in temperatures.

Don't take beyond +144 seriously unless you want to be disappointed.

Edited February 10, 2010 by Tommyd1258

[Duane S.]

I think people are underestimating the snow potential for the low pressure next week, certainly areas to North and West are favoured but a small eastward push which is possible and possibly even seems likely according to the tele-connections at the moment, could result in a more widespread snow event.

Great post and exactly how I see it at the moment. Even as a mean of most model ops tonight, next week is shaping up to be VERY interesting I would say. Speaking for my location, I'm not a massive fan of Northerlies generally but I do like the instability of the air and the uncertainties they can bring. I know it is not a classic northerly in terms of where the air is being sourced but with the JS sat way south and the whole of the UK in relatively low uppers there will be some surprise heavy snowfalls for many I suspect next week (not just on Northern hills either).

I think that we will see a further shift East as well. I was surprised not to see it today (although it has a tad I suppose) but I think over the next 2 days we will see it happen.

Then there is the Iberian trough. I feel this is lurking and will have a pivotal role to play later on next week.

All to play for still!

Edited February 11, 2010 by s4lancia

[yamkin]

Very interesting WMC Moscow 12Z 120h chart.