Model output discussion - the beast arrives

[Tim Bland]

GFS more like icon than earlier. Low further east and disrupting. Also notice the tenancy for light snow band in th south in a Thursday ahead of the main course on Friday. 12z v 18z for comparison..

[Snowy L]

Hmm in the context of our little island that is a substantial shift southeast at t96 compared to the 12z.

[Zakos]

 excellent, a significant increase in pressure over Scandinavia at 93 hours, forcing the jet stream to take a more southerly track. This is far from over!

Edited February 26, 2018 by Zak94

[Derecho]

Far better 18z with temperatures around freezing at best on Friday, even down here making this a snow event down south too!

[Mike Poole]

I think the GFS 18z is starting to get there, here at T102

Compared with on 12z

 

Small margins but I think the trough is disrupting more on 18z.

[Frosty.]

How often does the jetstream attack us from the NE?...very rarely!..this week is very special..hope it never ends

[Captain Shortwave]

For Saturday morning, the 18z has the front over Central/Southern England, last run it was already into Southern Scotland.

   

A fairly sizeable reduction in the northwards push of the front.

[Weathizard]

5 minutes ago, Quicksilver1989 said:

Far better 18z with temperatures around freezing at best on Friday, even down here making this a snow event down south too!

Not the far south though with onshore winds! Not looking to much into this 18z, the early changes show the fluidity of the situation, a few more moves like this? Who knows.

[Mark Neal.]

18z seems to hold back the milder enroachment once again. Signs of the cold air and block playing its hand now as we draw closer. The system on Friday moves up much later and does still push N/NE but with snow away from South Coast freezing rain showing up again by the front in some areas. Interesting model watching continues. 

 

First push from South is very small affair with patchy snow coming inland. The main front pushes SW/Ireland & Wales. 

The following is Friday daytime into evening. 

   

Edited February 26, 2018 by Mark N

[Derecho]

2 minutes ago, Mike Poole said:

I think the GFS 18z is starting to get there, here at T102

 

Small margins but I think the trough is disrupting more on 18z.

Yeah the Greenland block also looks a bit stronger with pressure around 5mb higher in Svalbard for example at T120. May let the northerlies put up more of a fight later. Milder air creeps north on saturday but if GFS carries on further in the same direction the cold surface air could remain stagnated leading to more snow on saturday. That's a bigger ask but a step in the right direction with the GFS OP anyway (about time!).

[Singularity]

 

The wind streams view offers a good perspective on the GFS 12z v 18z difference; the E flow is not shoved so far north as of mid-morning Friday. So you still have a feed from locations east of the UK that are very cold at that time;

That's the max temps to 9 am. So never mind the 850s as long as they don't get more than a degree above zero (while zero is certainly more reassuring, a degree above can actually still be fine as with the warm front riding over the cold air, the freezing line can still be high up in the clouds).

 

These adjustments are toward what forecasting experience suggests ought to happen, which makes the 12z ECM rather disappointing it has to be said.

I believe that if the low doesn't take the more S track it will be because of another factor changing unexpectedly. This possibility is of course very real and may well keep us speculating for at least a day longer.

[Philbill]

14 minutes ago, Tim Bland said:

GFS more like icon than earlier. Low further east and disrupting. Also notice the tenancy for light snow band in th south in a Thursday ahead of the main course on Friday. 12z v 18z for comparison..

See how the low has flattened a little as it hits the cold air.

[nick sussex]

And the low drama continues!

A flatter low as Phil just mentioned, this is better at keeping the colder flow ahead of it.

I really wouldn’t look past T96 hrs at the moment because as we’ve seen the models are making a real soap opera over this low.

You also have to factor in what the later output is showing , will that stay the same as they get closer in or will more forcing cause a southwards adjustment .

 

Edited February 26, 2018 by nick sussex

[bluearmy]

Day 5 fax is pretty well raw ukmo with a few small adjustments. 

[wiltshire weather]

Updated 96 and 120 hr faxes

[SMU]

GFS will catch up tomorrow

UKMO 168 meanwhile - straight Easterlies

 

[SLEETY]

Gfs finally getting the track correct,it’s been miles out.

Always so progressive ,lots of us said it was way to Northwards with its tracking of the low,probably fail to hit the U.K. by Friday at this ratev

[AmershamMike]

1 minute ago, Steve Murr said:

GFS will catch up tomorrow

UKMO 168 meanwhile - straight Easterlies

 

Steve, does that mean that we’re heading back to colder over the weekend?

[SLEETY]

3 minutes ago, AmershamMike said:

Steve, does that mean that we’re heading back to colder over the weekend?

Why cant we see a proper 168 chart,so annoyingly stupid,think it shows bitter easterlies returning

[Duane S.]

6 minutes ago, ANYWEATHER said:

Can you please put that In English

He has. Very clearly.

I honestly don’t understand why you bother to post on this forum. All you seem intent on is creating a reaction and bringing your own brand of blinkered doom and gloom. 

 

[bluearmy]

5 minutes ago, AmershamMike said:

Steve, does that mean that we’re heading back to colder over the weekend?

No one knows yet ..... looks unlikely but can’t be discounted with the current icon and ukmo output 

[snowice]

2 minutes ago, SLEETY said:

Why cant we see a proper 168 chart,so annoyingly stupid,think it shows bitter easterlies returning

why do they do that? Showing a chart in mid Atlantic? 

[chionomaniac]

15 minutes ago, ANYWEATHER said:

Can you please put that In English

You're wrong lol!

[Nick F]

18z GFS more of a negative tilt to the frontal trough moving NE toward UK on Friday morning compared to 06z this morning, which means less mixing of the cold easterly flow ahead of the frontal boundary.

For 09z Friday

06z 18z

Temperatures and DPs struggling even to south coast Friday afternoon for max temp, despite T850 0C line creeping in, which shows its not all about the 850s but in this situation the surface flow is important

[Rob Walker]

While I'm enjoying the favourable "corrections" so far in tonight's GFS for any southerners hoping to see some of the white stuff, and the rather decent looking ICON run; I'm still fairly apprehensive about the chances until I see this trend continue tomorrow.
Just seems like there a lot of uncertainties regarding Friday and on into the weekend that I feel still need to be resolved by the models somewhat over the next 24/48h, certainly before I get behind any trend! (whether staying cold or getting milder)

Edited February 26, 2018 by Rob Walker