Jump to content
Cold?
Local
Radar
Snow?

Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!


Recommended Posts

  • Replies 1.5k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Seeing as it's nice and early in the day, perhaps we can see the remainder of Saturday through without the hysterics expressed on the forum yesterday? Critical points of note are simple: 1. Amplifi

Well... good support in new EC Monthly by mid-Feb for GloSea5 signal re increased incidence of blocking. Indeed, by week 4, first output we've seen all winter with NO low MSLP anomalies anywhere on th

??? No warnings have been issued *because areal (and accumulation) continuity has been totally lacking*. Now we are seeing that manifesting in UKV/UKPP and other output, you can expect Ops Centre to

Posted Images

Yes indeed. Plus differences between Euro4 and Euro4 Parallel; plus now 18z UKMO-GM. However, Tues night reliably the period with greatest chance of some lower-level snow in parts of south (and Weds AM for SE: UKMO cite 40% probability e.g. Heathrow/Gatwick, but low (30%) likelihood troublesome... Chilterns perhaps at greater chance, especially with 18z GM widening the PPN envelope in SE through colder air). However, forecast remains under constant refinement and the broad theme (snow *mostly* Midlands northwards but some in south) is now where the nitty-gritty detail is being sought-out. Tricky one.

sorry ian could you elaborate further if you dont mind about tomorrow nights snowfall and what those models that you have mentioned are showing!! I've never seen such a difference in the Model output at such a short time frame! ! Gfs has everything east! Euro4 has everything west and ecm has the snowfall slap bang in the midlands! ! What is going on?
  • Like 1
Link to post
Share on other sites

Yes indeed. Plus differences between Euro4 and Euro4 Parallel; plus now 18z UKMO-GM. However, Tues night reliably the period with greatest chance of some lower-level snow in parts of south (and Weds AM for SE: UKMO cite 40% probability e.g. Heathrow/Gatwick, but low (30%) likelihood troublesome... Chilterns perhaps at greater chance, especially with 18z GM widening the PPN envelope in SE through colder air). However, forecast remains under constant refinement and the broad theme (snow *mostly* Midlands northwards but some in south) is now where the nitty-gritty detail is being sought-out. Tricky one.

That's does look like it's going to be a cut off low. You can see the potential for more precipitation to be of snow. Also could be a small window for convection off the North Sea. Maybe???

Link to post
Share on other sites

Yes indeed. Plus differences between Euro4 and Euro4 Parallel; plus now 18z UKMO-GM. However, Tues night reliably the period with greatest chance of some lower-level snow in parts of south (and Weds AM for SE: UKMO cite 40% probability e.g. Heathrow/Gatwick, but low (30%) likelihood troublesome... Chilterns perhaps at greater chance, especially with 18z GM widening the PPN envelope in SE through colder air). However, forecast remains under constant refinement and the broad theme (snow *mostly* Midlands northwards but some in south) is now where the nitty-gritty detail is being sought-out. Tricky one.

Thanks Ian for the usual informative stuff. But a word of caution....don't go using the phrase "nitty gritty" on TV or radio or you'll have the Political Correct Police after you! :)http://www.phrases.org.uk/meanings/nitty-gritty.html

  • Like 2
Link to post
Share on other sites

Could be quite a bit of snow for the Humber on this run, with about 6-7cm. Most snow over the pennines of course. Increased risk of a Humber streamer affecting East Riding and Northern Lincolnshire once the easterly winds kick in with -7C 850's and warm(ish) SST's.

27-779UK.GIF?20-030-779UK.GIF?20-033-779UK.GIF?20-039-779UK.GIF?20-042-779UK.GIF?20-045-779UK.GIF?20-036-779UK.GIF?20-0

Edited by PerfectStorm
  • Like 2
Link to post
Share on other sites

cfs-0-912_cqt6.png

 

 

 

Not looking brilliant this morning folks, but don't despair. Remember the date everyone. 26th February 2015. Coldies heaven, courtesy of the ever reliable CFS.

Edited by metrosnow
  • Like 1
Link to post
Share on other sites

Thanks Ian,

That excellent summary is worth more than a hundred pages of waffle and hope casting you read on here!

No offence intended to any individual but I think we are all guilty of seeing what we want to see and Ian's 'View from the Bridge' is very welcome.

I have to say the MetO has earned it's funding in the last 12 months with mostly superb short, medium and long range forecasting.

Andy

No hopecasting from me.The GEFS remain interesting in to early Feb again this morning,I can't post charts but my post from last night has the links.The HLB not on our side of the Arctic but the PV is split our side due to it.All in the model output.I remain very interested as the GEFS have raised the bar recently.

  • Like 1
Link to post
Share on other sites

As others have mentioned the signs look promising right at the end of the month beginning of Feb. As I mentioned last night it appears we need to look N rather than E.

 

Just look what happens on the GEFS control from a N Hemisphere perspective. I have chosen this run because the same trend keeps emerging.

 

Note the PV.

http://modeles.meteociel.fr/modeles/gens/runs/2015012000/gensnh-0-1-192.png

 

Watch how we see a split PV

http://modeles.meteociel.fr/modeles/gens/runs/2015012000/gensnh-0-1-228.png

http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-1-252.png?0

 

Look at that cross polar flow!

http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-1-288.png?0

 

I realise I am always promising jam tomorrow! However at least this time im not predicting an Ely lol. Also the period of interest isn't deep F.I and at the moment is consistent in the GFSOP/GEFS control.

 

So at the moment the summary from me is any milder weather appears shortlived before we intially see bursts of NW,lys which could potentially be replaced by a much colder more sustained N,ly.

 

That chart is a thing of beauty, absolutely mouthwatering. :cold:

 

I dare to say maybe the russian high retreating eastwards is a blessing in disguise.

  • Like 1
Link to post
Share on other sites

Yes the turn of the Month remains of interest this morning, With the GFS showing heights pushing up into Greenland drawing a cold Northerly of sorts.

 

gfsnh-0-264.png?0gfsnh-0-336.png?0gfsnh-0-372.png?0

The problem there of courseis the PV segment over Greenland. As wwe get closer to T+0 shortwave energy will appear cutting of the Northerly quickly

  • Like 2
Link to post
Share on other sites

There is a very small cluster of GEFS in FI showing some sort of Atlantic heights but I would expect that in a pattern where the PV is mobile and there is phasing between each low from the NW. I suspect that is just background noise and until it's signal grows I suggest it will remain that. Though because of these baby troughs we will see the jet slip south so I would be hopeful of a colder zonal flow again, favouring the NW/W coasts and high ground for wintry weather.

 

The means at D13 and D16: post-14819-0-03423000-1421739902_thumb.p  post-14819-0-51268700-1421739901_thumb.p

 

The MJO loses its drive for the next week as it goes into the COD but maybe returning in phase 5:

 

post-14819-0-84298300-1421740216_thumb.g  post-14819-0-23201800-1421740216_thumb.g

 

However it is not all doom and gloom. With another episode of strat warming moving towards the reliable (for the strat that is) there must be a chance that the cumulative effect on the PV will this time be more effective for some real HLB'ing. This spell of wedges of highs were always going to struggle longevity wise. So enough to maintain the interest in the medium term despite the Met's obvious caution re a Major SSW.

 

So it looks like we will have at least a week of zonality after this cold spell as more energy spills from the Siberian vortex towards the NE Canadian one, balancing it up. At D10 none of the models suggest that either vortex will become the more dominant and that is why I don't expect anything like last year's raging zonal onslaught. In the shorter term hopefully snow for some in the next 36 hours.

Edited by i'm dreaming of...
  • Like 4
Link to post
Share on other sites

Couple of points

A) my analysis of the ec32 for day 24+ wasn't good (note to self not to do this when you're trying to get to bed)

Anomolys to the south and over Europe in general are on the high side.

B) the background noise on a coldish trough n Europe as head through the later stages of week 2 getting very loud. Anomolys on gefs in good support now. ECM mean due shortly though this held the lowest a bit further west.

Either way, if this theme continues, plenty of wintry looking output on view over the next week though with low heights on meteociel, these always look colder than they actually are! the phrase of choice could soon become 'secondary features'!

  • Like 3
Link to post
Share on other sites

Looking at the models and it looks as though the next few days will remain chilly. Some of those who are after wintry weather could be in for a snowy treat today. The band of precipitation over Wales and Ireland will slowly move East throughout the day in response to an area of Low Pressure out West tracking East/South-East. The precipitation falling as sleet and snow over the hills, although some of it could extend to lower levels at times, particularly over the South of Northern England and into the Midlands, where the front engages with the cold air over the UK. This being helped out by the fact that the front should reach these areas during the evening and night period. But snow possible for Wales earlier on today, too. The models do show a wedge of less-cold 850 hPa temperatures associated with the system, so possible some places, especially those with elevation below 100 meters could just see more in the way of rain or sleet instead. Where snow does fall, some accumulations are possible, most especially over the hills and peaks. It's then possible the wintry precipitation over central or Eastern areas (if it does make it far enough to the East) could become showery tomorrow with perhaps some brighter spells showing up for places during the afternoon. Some frost and icy conditions possible for places where skies clear overnight. Thursday looking to be another chilly day, but should be mostly dry and bright for most as the models show a shallow wedge of High Pressure over the UK linking up from the Azores and Scandinavian High Pressure systems.

(quick example from the GFS)

post-10703-0-30979200-1421741619_thumb.j

The odd isolated shower could be possible, though, towards the South-East with perhaps the odd showery piece of precipitation towards the far North-West. The weather then looks as though it will turn milder for most during Friday. A Low Pressure system from the Atlantic looks to try to beat up the Scandinavian block and break through further East with Westerly or South-Westerly winds returning. This likely to be associated with a spell of rain and hill snow spreading West to East through the British Isles.

While their doesn't look to be any real stormy conditions around this week, it looks as though it could provide some varied weather for places, and apart from Friday, staying mostly on the chilly side with wintry weather for some places. And some frost and/or fog at night.

  • Like 1
Link to post
Share on other sites

cfs-0-912_cqt6.png

 

 

 

Not looking brilliant this morning folks, but don't despair. Remember the date everyone. 26th February 2015. Coldies heaven, courtesy of the ever reliable CFS.

That's the 78/79 evolution we're looking for! :)

Link to post
Share on other sites

I'm feeling discouraged this morning. I had expected a decent cold spell this week, but it is fizzling out with barely a whimper.  It just seems that if the weather gods can find a tiny mild spanner to throw in the winter works of the British Isles, then they always find a way! 

 

Moving forward, February is usually the least mobile month, and there are tentative signs of something juicy from the North, although I reckon that the NE will ultimately provide the interest for coldies. 

  • Like 1
Link to post
Share on other sites

A dynamic situation today  for today through to Wednesday highlighted by the fluctuating EURO04 output for 12z tomorrow

 

Tues 00z for Wed 12z

 

 

15012112_2000.gif

Mon  18z for Wed 12z

15012112_1918.gif

 

Mon 12z for Wed 12z

 

15012112_1912.gif

 

I think the warnings will be out for Midlands and Central Northern England also Pennine spine and North Wales.

Edited by winterof79
Link to post
Share on other sites

So the models pretty much in agreement for it to remain cold today through to Thursday. Friday looks less cold as a series of fronts sweep through. These clearing Friday night to leave a cool and fresh weekend with temperatures a little below normal accompanied by night frosts and a few wintry showers in the north west.

gfs-0-84.png?0

gfs-0-108.png?0

gfs-1-108.png?0

 

Into the first half of next week, it does look like the Azores high will ridge in closer, alongside this more Atlantic weather systems will sweep eastwards but will stay north of the UK. The south might stay mostly dry with any rain being on the light side. Temperatures near normal.

gfs-0-156.png?0

gfs-0-192.png?0

 

In the second half of the week, it does look like a more meaningful Atlantic attack will begin with the jet sinking southwards, this will bring more widespread rain and strong winds.

gfs-0-240.png?0

ECM1-240.GIF?20-12

 

Now with this in mind I guess there are two options on the table here. The first is we see a successful split in the tropospheric vortex which may allow a ridge to build in the Atlantic and allow a northerly down. The other is we enter a very unsettled period of weather as Atlantic systems continue to push through the UK. The GFS at the moment keen on the first, but I remain rather wary of this as the models have a habit of trying to clear low heights from our north west which never really materialises within the reliable timeframe. A lot of interest developing relating to the strotosphere and MJO again, lets see how it pans out.

 

Anyway lets enjoy the last few days of cold weather and the potential snow it can bring.

Edited by Captain shortwave
  • Like 1
Link to post
Share on other sites
Guest
This topic is now closed to further replies.
×
×
  • Create New...