Model Output Discussion - 2nd March Onward

[SMU]

Heavy snow moving towards the sw at 216. The E and SE back in -10c air...

[Mucka]

From 240 we would have to endure a "warm" sector passing through before the next reload, very poor.

[nick sussex]

No waffle just the headlines:

GFS and ECM prog superb wintry snap with a strong e/ne flow, heavy snow showers and unseasonable cold for March.

UKMO joins the party sort of! but sinks the high and limits the snow.

The models seem to be playing musical chairs, the GFS went with sinking high but drops that in favour of more cold before imploding in the lower resolution part of its output.

The ECM drops its longevity and now has sinking high before a reload.

Questions asked at the UKMO for its poor handling of shortwaves to the north, for the first time in internet history or since we've been in here it has had to complete major backtracks at T96hrs from the weekend and now sensationally from just T60hrs within the space of a week!

The GFS which normally gets lots of derision especially from me deserves some praise for its handling of the mild to colder change over.

Overall good agreement in terms of pattern but snow potential still uncertain as the UKMO even though moving across to join the party still doesn't want to get up and dance!

[winterof79]

To put this upcoming weather into perspective - in the 10-12 years ive been on the forums right back to snowatch- I dont think ive seen a chart like this more than 2 or 3 times-

NEVER in March-

http://modeles.meteo...fs-1-120.png?12

The entire UK under -10c air & all of England under -12-13c air-

Truly remarkable charts ( not quite there yet for varification ) but if the GFS lands like this I would expect over 50% of the UK to have some form of snowcover with the E & NE seeing some deep snow- The gradient across the sea to 850's looks be be around 17c & the heights at the lowest ~ sub 528 DAM- With the sun slightly higher this should deliver deep convection & with such a strong flow the showers will penetrate a long way inland.

What I have noticed tonight from the GFS is a significant move to the ECM type longivity of the cold with now many runs throwing the -14c isotherm back towards the UK at 168- like this chart below-

http://modeles.meteo...17-0-168.png?12

The mean has dropped off at day 8 again ( 192 ) & staggering as it may sound is nearly back at -10c again -

http://modeles.meteo...21-0-192.png?12

& thats with only 50% of the members shifting west-

All in all a rare march occurance- possibly a once a 50 year event if the extreme charts land-

This is all being forced our way by the Extreme AO pattern & deep westerly gradient across Northern Russia- look!

http://modeles.meteo...nh-0-168.png?12

Monday looks to be the core of the cold with widespread -0c being predicted on the GFS, which could see locally -1c Maxes in heavy snow.

Spectacular GFS tonight, only muted slightly by the underwhelming UKMO which does need to come aboard the good ship snowmageddon before we can fully say the beast is coming!

S

Nice post Steve.Just heard Paul Hudson on look north say it could be quite sunny next week.I am for the convection but he,like Ian F,are in the know a little more.Any thoughts?

[TEITS]

Have to say putting aside the time of year the actual synoptics being shown at +96/+120 are probably some of the best I have ever seen. If the current output is correct then on Monday max temps will struggle to reach above freezing and those under a constant stream of heavy snow showers may even remain around -2C. Due to the projected strength of the E,ly flow plus the sun, snow showers will spread across many parts but obviously the heaviest across E areas.

Very happy with the synoptic agreement between the ECM & GEFS mean.

The UKMO is doing what we sometimes see from the GFS and that is slowly backtracking. This has not been a good period for this model. A lesson to be learn't here for newcomers is that all models have their ups and downs, especially the GFS, but when in doubt stick with the ECM.

[Tamara]

UKMO

[shaky]

A beauty of an ecm!!

[sebastiaan1973]

Incredible ECM charts. Over here, in the Netherlands perhaps 1-2 icedays. Almost record late in the season.

Please take a look at this site, you can put any place and see the direct output of the EC oper.

http://www.yr.no/pla...England/London/

Press long term (and check you english version, adjust in the right corner)

Edited March 6, 2013 by sebastiaan1973

[snowice]

Well at least theres no winter is over posts

[chionomaniac]

Not much in the way of precip going by the Icelandic charts on the ECM.

Best I could find for Monday was these two - mind you we know how unpredictable to forecast this can be but worth keeping an eye on.

[Timmytour]

Just catching up with recent developments....even reading the posts has made me reach to turn the heating up!

[weatherguy]

Spring is over...

[Mair Snaw]

Spring Winter

[MR EXTREMES]

i agree the models really are exciting but there does not look to be much precip i think heights just sink a little to much to bring in the instability for convection to be anything to exciting.

although very cold perhaps cloudy in eastern and southern areas i would be very suprised to see anything disruptive.

although gfs has this on offer

Edited March 6, 2013 by model rollercoaster

[SMU]

Nice post Steve.Just heard Paul Hudson on look north say it could be quite sunny next week.I am for the convection but he,like Ian F,are in the know a little more.Any thoughts?

Hi, on the last cold spell the very best run just had the SE in unstable air, so any correction south ( which what happened ) put the UK out of it-

Of note though the UKMO ( & IAN) maintained it would be dry with grains only- yet at the height of the instability South Suffolk & north kent still got hit with solid returns- ( green on the radar & 2-3mm per hour )-

So in -12c air it only took some moderate cloud heights even though they were capped to develop proper snow.-

Here was the chart-

http://modeles.meteociel.fr/modeles/gfs/archives/gfs-2013022300-0-6.png

The lower the heights on the 500 MB charts shows that the instability is increasing- & in the above case we got 536 heights into Kent-

Now take the ECM 120 Chart-

http://www.meteociel.fr/modeles/ecmwf/runs/2013030612/ECM1-120.GIF?06-0

the equivalent instability to the Feb outbreak is over Scotland- so there just a few flurries there- however as you go further south we go-

536,532,528 & onto 524 heights in -12c air with the flow all the way across the sea.

The Above chart is VERY VERY close to the Feb 2009 chart that brought 40cm to NW kent, the only difference is the windflow is slightly more north of East- so more widespread snow.

based on that chart ALONE on the ECM covering the timeframe T108 - 132 covering 24 hours there would be persistent heavy snow showers over England, & for counties all adjacent to the North sea- Kent, Suffolk, Norfolk, Lincs + yorks- almost solid snow oscillating light to heavy- deep accumlations.

Of course it hasnt varified yet-

So, sunny NO chance- however that update was probably based on the 00z euros that were a bit slower than the 12z-

I expect an update from Ian tonight with more direct focus on snow prospects- even the raw ECM ( NOT UKMO ) presents upwards of 10cm over the aforementioned areas -

S

[weather eater]

Spring is over...

No that was our summer.

[bryan629]

ECM + 216

ecm +240.

hiya,,, first of all fantastic charts and evolution from them all, and even more so some excellent posts on here, very informative and supportive with charts and explanations.

secondly i have a question relating to the evolution of the ecm at t216 and t240 , (above) . there is a distinctive south then westward shift of the chunk of pv heading in towards greenland, where the residents there are by now probably enjoying their bbq`s lol.

what i would like to know from anyone with all the warm air advecting deep into the arctic is the pv likely to head down our way.

thanks in advance.

P.S. see you in the spring atlantic !! haha

Edited March 6, 2013 by bryan629

[Barking_Mad]

Paul Hudson on his BBC Look North blog saying snow a possibility, unsure of timings obviously at this stage.

[snowice]

_{Not even the great winter of 1962/63 had uppers of -10 or below for 11March!}

[Snowman.]

No that was our summer.

Yup where in the New WINTER 2013/2014

[nick sussex]

If the GFS and ECM verified I would be very surprised to see a repeat of the end of February easterly. The two set ups are miles apart.

This to me looks much more condusive to convection so I'd expect to see some disruptive snowfall, the UKMO however is much drier, its been wrong all week so lets hope it suddenly hasn't found some consistency!

Edited March 6, 2013 by nick sussex

[MR EXTREMES]

in april 2008 i think we had snowfall on the southcoast sorry mods if this is of topic but what was the upper air temps on this event ?

[pjpauly2k]

Sorry if this should be in a different forum. I am getting a flight from Liverpool early Monday mornig. What do people think the chances currently are of disruption?? I know its difficult to say at the moment, but just based on current charts what do people think?

[winterof79]

Hi, on the last cold spell the very best run just had the SE in unstable air, so any correction south ( which what happened ) put the UK out of it-

Of note though the UKMO ( & IAN) maintained it would be dry with grains only- yet at the height of the instability South Suffolk & north kent still got hit with solid returns- ( green on the radar & 2-3mm per hour )-

So in -12c air it only took some moderate cloud heights even though they were capped to develop proper snow.-

Here was the chart-

http://modeles.meteo...3022300-0-6.png

The lower the heights on the 500 MB charts shows that the instability is increasing- & in the above case we got 536 heights into Kent-

Now take the ECM 120 Chart-

http://www.meteociel...M1-120.GIF?06-0

the equivalent instability to the Feb outbreak is over Scotland- so there just a few flurries there- however as you go further south we go-

536,532,528 & onto 524 heights in -12c air with the flow all the way across the sea.

The Above chart is VERY VERY close to the Feb 2009 chart that brought 40cm to NW kent, the only difference is the windflow is slightly more north of East- so more widespread snow.

based on that chart ALONE on the ECM covering the timeframe T108 - 132 covering 24 hours there would be persistent heavy snow showers over England, & for counties all adjacent to the North sea- Kent, Suffolk, Norfolk, Lincs + yorks- almost solid snow oscillating light to heavy- deep accumlations.

Of course it hasnt varified yet-

So, sunny NO chance- however that update was probably based on the 00z euros that were a bit slower than the 12z-

I expect an update from Ian tonight with more direct focus on snow prospects- even the raw ECM ( NOT UKMO ) presents upwards of 10cm over the aforementioned areas -

S

Many thanks for your time mate.I was a little puzzled with what he said,but it is way off yet.

[Stuie]

Hi, on the last cold spell the very best run just had the SE in unstable air, so any correction south ( which what happened ) put the UK out of it-

Of note though the UKMO ( & IAN) maintained it would be dry with grains only- yet at the height of the instability South Suffolk & north kent still got hit with solid returns- ( green on the radar & 2-3mm per hour )-

So in -12c air it only took some moderate cloud heights even though they were capped to develop proper snow.-

Here was the chart-

http://modeles.meteo...3022300-0-6.png

The lower the heights on the 500 MB charts shows that the instability is increasing- & in the above case we got 536 heights into Kent-

Now take the ECM 120 Chart-

http://www.meteociel...M1-120.GIF?06-0

the equivalent instability to the Feb outbreak is over Scotland- so there just a few flurries there- however as you go further south we go-

536,532,528 & onto 524 heights in -12c air with the flow all the way across the sea.

The Above chart is VERY VERY close to the Feb 2009 chart that brought 40cm to NW kent, the only difference is the windflow is slightly more north of East- so more widespread snow.

based on that chart ALONE on the ECM covering the timeframe T108 - 132 covering 24 hours there would be persistent heavy snow showers over England, & for counties all adjacent to the North sea- Kent, Suffolk, Norfolk, Lincs + yorks- almost solid snow oscillating light to heavy- deep accumlations.

Of course it hasnt varified yet-

So, sunny NO chance- however that update was probably based on the 00z euros that were a bit slower than the 12z-

I expect an update from Ian tonight with more direct focus on snow prospects- even the raw ECM ( NOT UKMO ) presents upwards of 10cm over the aforementioned areas -

S

Can you squeeze Essex in there Steve?