Model thread discussion - cold spell looming

[Lukesluckybunch]

Just now, sheikhy said:

Fightback again on gfs 06z at 120 hours!!

14 hours ago, mb018538 said:

Certainly possible - all luck though, much like thunderstorms in summer! Some places might see a string of snow showers, others may miss out. Keep an eye on the radar on the day is the best tool to use.

Ok thankyou,currently thr

 

Just now, sheikhy said:

Fightback again on gfs 06z at 120 hours!!

Yes needs watching this..could turn out to be amazing would you agree?

[SqueakheartLW]

My usual end of cold / predicted milder spell update and I have a fair amount to pack into this update after my rather brief one last night about the 12z models. As always I am looking out for key things to happen. The cold spell extended and the milder spell watered down till it doesn't exist.

18z GFS

With the colder spell generally extended a little during the 00z, 06z and 12z yesterday did the 18z complete the set and get full marks for the GFS yesterday in terms of extending the colder spell. On the 18z the cold comes to an end at 156 hours away which means no extension so an x here for that but only a small x as it at least hasn't brought the transition any closer in terms of time at least

The 18z is probably the worst of the updates in terms of the progression of the transition with more areas already into the milder air at the same stage as on the other GFS runs of the day so a big X for that GFS. However the colder anomalies ahead of the front look colder than on the other runs so GFS does at least get a tick for that one with a bigger snow risk as a result

The peak of the milder spell comes at 228 hours away on the 18z which allowing for 6 hours later run keeps the mildest period the same distance away as on the 12z so no x or tick really for that one.

The mildest part of the mild spell is high pressure dominated so a tick for GFS for that one at least since we could do with some dry weather after all this rain we've had. The anomaly chart however makes for grim viewing with those yellows and oranges so a big X for that one for the GFS 18z.

Mildest Earliest Member of the GFS 18z

Member 26     +132 hours     850hpa temp -2.5

Coldest for longest Member of the GFS 18z

Member 2     +312 hours     850hpa temp -4.3

GFS 00z

After a mixed update for GFS 18z it is time to see how the 00z fares against it. The average time for the colder spell coming to an end on this run is at 156 hours away. Same time as the 18z so allowing for 6 hours later 00z this is another 6 hour extension to the colder spell so a tick for the GFS on this one

Another low pressure bomb showing out to the west which gets a big X for me. However the anomalies look better than on the 18z with more colder air still present over the UK so 00z saves itself here with a tick to cancel out the big X

The peak of the milder spell comes at 216 hours away on the 00z. This compares with 228 hours on the 18z and allowing for the 6 hours difference this has brought the peak of the milder weather 6 hours closer, big X for that GFS

As with 18z it looks like a high pressure dominated milder spell so another tick for the GFS for that one but even milder anomalies showing up on the 00z compared with the 18z so a big X for you GFS for that.

Mildest Earliest Member of the GFS 00z

Member 3     +126 hours     850hpa temp -2.5

Coldest for longest Member of the GFS 00z

Member 30     +258 hours     850hpa temp -4.0

GEM 00z

How does the GEM stack up against the GFS as well as its own previous run the 12z. On the 00z the end of the cold spell is on average at 162 hours away which is a match for the 12z but allowing for the 00z coming 12 hours after the 12z this means a nice 12 hour extension to the colder spell so a big tick for the GEM for that one.

The peak of the milder spell on GEM 00z comes at 228 hours away compared with 234 hours away on the 12z. Although this looks like a bad thing with a lower number of hours away when you factor in the 12 hours difference between the runs this is in fact good as the milder peak is pushed back 6 hours so a tick for GEM on that one too.

Mildest Earliest Member of the GEM 00z

Member 8     +126 hours     850hpa temp -3.3

Coldest for longest Member of the GEM 00z

Member 9     +252 hours     850hpa temp -4.3

GFS Extended

After generally OK GFS runs, how will the extended fare against them. Today's extended run sees the end of the colder spell on average coming at 162 hours away compared with 186 hours away yesterday. Allowing for the 1 day difference between the runs this initially looks like a downgrade to the duration of the colder spell but in fact the end is no different as the difference between the hours away figures is 24 hours anyhow so a small tick for not bringing the end any closer at least

A slightly better looking pressure chart than on the other GFS runs so the extended gets a small tick for this as there's a chance of a slider event here. The anomalies also look better overall as more of the UK is under the blues so another tick here. It seems GFS Extended has performed best here of all 3 featured GFS runs for the end of the colder spell

The peak of the milder spell on extended comes at 240 hours away compared with 288 hours away on yesterdays run. Taking into account the 24 hour difference between the runs this is bad news as the peak of the mild has been brought forwards by 24 hours compared with yesterday so a big X for that one

The pressure chart makes grim viewing with low pressure dominating so not good news for the saturated ground and flooded areas so a big X here GFS Extended. The anomaly chart however is the least mild of the GFS options so at least GFS Extended does rescue itself a little with a small tick here.

Mildest Earliest Member of the GFS Extended

Member 18     +120 hours     850hpa temp -4.7

Coldest for longest Member of the GFS Extended

Member 30     +210 hours     850hpa temp -4.7

 

[That ECM]

Look at ne.

[Tim Bland]

Thursday lunchtime 00z Vs 06z ..

[Drifter]

3 minutes ago, sheikhy said:

Fightback again on gfs 06z at 120 hours!!

Yep, snow event on Thursday evening - let’s hope the snow band stalls and then fizzles. I’d prefer this to the ecm where the band doesn’t get to us at all.  

[phil nw.]

A couple of recent posts about snow with no model discussion have been moved to the cold spell thread. 

Just a reminder to keep general chat unrelated to the model charts about snow out of here please all. 

Thanks. 

[sheikhy]

Scandi high at 144 hours!!!everything shoved west on the 06z!!!this cold aint going anywhere without a fight!!

[Ali1977]

It’s coming. Scandy high building

 

6 hours later, BOOOOOM , game on!! 

Edited February 6, 2021 by Ali1977

[bradymk]

Scandi high building here at +144! 

[Drifter]

3 minutes ago, sheikhy said:

Scandi high at 144 hours!!!everything shoved west on the 06z!!!this cold aint going anywhere without a fight!!

Starting to get exciting now. I think by next weekend the snowfall could be quite evenly distributed  so no need for any jealousy or impatience on the forum.

Let’s be happy for each other!

Edited February 6, 2021 by Drifter
Typo

[Captain Shortwave]

Again the huge change is the orientation of the cold air around the developing high. A clear hook south westwards instead of south on previous runs.

 

00z

[Notty]

1 minute ago, Captain Shortwave said:

Again the huge change is the orientation of the cold air around the developing high. A clear hook south westwards instead of south on previous runs.

 

00z

Developing LP out in Eastern Europe helping I think

[Guest]

43 minutes ago, Man Without Beard said:

Strange to see this correcting north in the past 24 hours - usually they correct south. If this sticks, bearing in mind it's within T96, South Devon could see some disruption in particular (I recall almost getting stuck on Halden Hill in Feb 2009)

Its very unusual to see such a correction northwards, however I'm already getting nervous that if it gets much further north it'll bring the warm sector into play and it'll be rain or freezing rain on the south coast. We ended up under freezing rain with the BFTE in March 18 after snow as uppers ended being on -1/-2C. 

Infact the ICON lifts the uppers on the south coast to just -2C so already getting squeaky bum time, although the surface flow looks to remain east or just north of east so screams at the moment to be a snow to freezing rain event.  

[I remember Atlantic 252]

3 minutes ago, sheikhy said:

Scandi high at 144 hours!!!everything shoved west on the 06z!!!this cold aint going anywhere without a fight!!

Aye, feel the frontal snow sadly won't make it anywhere near N/E Midlands,

[Ali1977]

Look at that high building in a weeks time, after a deep freeze!! Europe is already freezing but look at the 850s in a week. If this falls right then this weeks freeze would just be a taster of what could come!! 

[CentralSouthernSnow]

Could be a wide spread snow event on Tuesday for the south according to icon. Gfs was on board earlier and now it’s only just scraping the coasts. This is knife edge! 

[Tim Bland]

Snow depths by next weekend on 06z ...00z had washed it away! 

[Notty]

Not really mild next Sat - cold for many

[Drifter]

1055hpa over Scandinavia. Must be almost record breaking?

edit - now 1060hpa!

Edited February 6, 2021 by Drifter

[Notty]

-8 over the snow fields next Sunday night for some

[Ice Day]

The 6z for 180 compared to the 0z for the same time

  

The 0c 850 line has moved from the east of Holland to the south west of the UK - that's significant!

[Howie]

At this rate the low pressure system won't even leave the eastern seaboard

[ALL ABOARD]

1 minute ago, Drifter said:

1055hpa over Scandinavia. Must be almost record breaking?

I see your 1055hpa and raise you 5hpa. 

1060hpa over scandi. 

It only gets colder from here, welcome to the ice club. 

[I remember Atlantic 252]

Starting to remind me a bit of early Jan 2002, max temps for this Sat!

[Notty]

... and below freezing during the day next Sunday !