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Paul

Model output discussion 25th Jan onwards

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The vortex has been nowhere near the UK this winter and is wrong  to suggest otherwise.

The models are showing some amplification to the north and northeast but the ECM is still outside

the timeframe when this will be beneficial for the UK I think. It will be several days yet before we

see more consistent signs of a more wintry flavour to the output for the UK.

Of course these are just my thoughts on how things may develope based on the warming that is taking

place in the mid to upper stratosphere. If we are not to see a worthwhile potent wintry period either

before winters end or the first half of spring then hopefully we will see a quick transition to a very mild

and dry spring and summer.

No immediate sign in the NWP modelling that we'll see anything of a notable wintry period. May be a different story as we head into March though.....a sort of a no-one wins scenario.

 

P.s a dry spring/wet summer combo would work for me....followed by a dry and cold winter.....

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Good evening. Here is tonight's report on the 12z outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Saturday February 8th 2014 and taken from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm
 
All models show a deep depression near Northern Ireland drifting North through Scotland tomorrow and away to the North thereafter filling steadily. A very showery period is to come with some heavy and thundery showers in places but with some drier spells too, these becoming more prevalent through Monday. On Tuesday a vigorous trough looks like tracking East over the UK with squally winds and heavy rain sweeping East followed by further showers.
 
GFS then shows further unsettled weather thereafter as the blustery Atlantic theme continues with further vigorous Lows delivering further spells of rain and gales towards the end of next week and weekend. Through the latter stages tonight the theme is still generally an unsettled one but with a little more in the way of drier weather possible between rain bouts later.
 
The GFS Ensembles show a reduction in rain amounts later in the run but until then it's more of the same from most members with rain and showers at times. There is a lot of spread between the members later in the run.
 
UKMO tonight shows complex Low pressure over the West of the UK later next week with further rain at times in less strong winds than of late and with temperatures close to average. The rain could be heavy in places especially towards the west and South-west.
 
GEM maintains very unsettled conditions tonight throughout the final section of it's run with strong winds and heavy rain at times continuing to dominate the UK weather. A ridge of High pressure does edge in from the West at Day 10 to bring a temporary respite from the wet of late.
 
NAVGEM shows next weekend as unsettled and probably a little chilly with Westerly winds decreasing with time but continuing to feed occasional rain and showers across the UK with snow on hills of the North.
 
ECM tonight tries it's hardest to get us into something a little drier and more average instead of the extreme conditions that has afflicted the UK for so long now. We have another week or so before such improvements become apparent due to Low pressure moving to more Northerly latitudes taking the heavier rain and windier conditions with them.
 
The Jet Stream Summary shows the flow remaining in an Eastwards motion across the Atlantic and through France and Spain. Through Week 2 the flow shows signs of migrating Northward over the British Isles.
 
In Summary tonight the weather remains generally quite unsettled and windy with heavy rain and gales at times for the next week at least. There are some indications of a slow improvement through Week 2 as the pattern weakens and the Jet flow steers Low pressure areas further North. I get the feeling though that improvements at a meaningful level are going to occur painfully slowly with many rocky roads to negotiate along the way and even probable setbacks.

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I often like to read your analysis of things me ole Mucka Posted Image , but I'm not sure why you think they're (the ensembles spreads) notoriously poor forecasting tools when in the netweather guides, it states the following.

 

Many leading agencies now believe that ensemble forecasting is the way forward for anything beyond 5 days – and sometimes even shorter.

 

I personally use them and have done with great success in the past, as they often enable you to pick out specific dates for given weather events within the reliable timeframe. It may be that you're referring to the GFS and its more usual traits of exaggerating things such as deep lows and/or its default zonal tendencies, also the way it differs from one run to another. Anyway, moving on, no respite from the current pattern state, bar the potential back edge snow event on Tuesday evening, its a strong case of de ja vu. Perhaps eventually (mid Feb onwards) there will be a better chance of more drier interludes than actual rain days, now wouldn't that be most welcome. Posted Image

 

Hi GTLTW, likewise.

I was referring specifically to the snow percentage probabilities on the GFS ensemble graphs when referencing as being a poor forecasting tool - not the ensembles themselves which I agree can be helpful with probability forecasting, sorry if I didn't make that clear.

Edited by Mucka

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Reference Tuesday/Wednesday snow:

Ugh for further East on Tuesday, Wednesday ok but precipitation dependent. Then again it is the GFS.......

Posted Image

Posted Image

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Tuesday and Wednesday look fairly good at the moment. Tuesday the best day while Wednesday it should start turning to more familiar rain which we're used. After that we're struggling again away from high ground.

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Tentative signs of low pressure tracking further north at the end of the ECM.

 

Posted Image

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Tentative signs of low pressure tracking further north at the end of the ECM.

 

Posted Image

 

GFS ensemble also showing similar hints

 

Posted ImagePosted Image

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A closer look at ECM T72 - only affects a small part of the UK but - oh - my - goodness -

Posted Image

According to this chart, near-on hurricane force winds in the English Channel surely. Thank goodness this isn't backed-up by GFS/UKMO. Turns out forecasting a late-developing low is as hard as forecasting snow.

 

 

looking at the Iceland Met Office (which uses ECM data for its forecasts) the storm tracks across SE england and leaves via East Anglia.

it has storm force 10 winds on its southern flank!

 

Posted Image

 

Posted Image

 

 

link here- http://en.vedur.is/weather/shipping/atlantic/#type=wind

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looking at the Iceland Met Office (which uses ECM data for its forecasts) the storm tracks across SE england and leaves via East Anglia.

it has storm force 10 winds on its southern flank!

 

 

 

link here- http://en.vedur.is/weather/shipping/atlantic/#type=wind

 

What is slightly concerning is the fact Thursday's rain got pushed further North as the models got closer to the event. Hopefully this one stays away or weakens...

Edited by Chris K

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The high-res HIRLAM which initialises with the ECM data does not develop the discrete little low - similar to GFS, it has a tight little wave crossing northern France at the +66 hour extent of the run.

 

Posted Image

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What is slightly concerning is the fact Thursday's rain got pushed further North as the models got closer to the event. Hopefully this one stays away or weakens...

 

lets hope it just doesn't happen at all. if it does as shown, we miss the worst of the winds but the south west gets drowned. further north, we get battered, further south and we all get drowned. it seems to be dragging in a fair bit of rainfall on its NW flank

 

Posted Image

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lets hope it just doesn't happen at all. if it does as shown, we miss the worst of the winds but the south west gets drowned. further north, we get battered, further south and we all get drowned. it seems to be dragging in a fair bit of rainfall on its NW flank

 

Posted Image

 

If you look at Wundermaps, a lot of it is actually snow

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That channel low is now appearing on GFS 18z

 

Edit it goes across Northern France and not as intense as ECM.Posted Image

Edited by Blizzardof82

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If you look at Wundermaps, a lot of it is actually snow

 

 

hmm... i wunder......

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That channel low is now appearing on GFS 18z

 

Edit it goes across Northern France and not as intense as ECM.Posted Image

hmmm ecm might be onto something here!!could well be right and I think some places could get a dolloping of snow if ecm is right!!

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Still looks on for snow Tuesday/Wednesday Posted Image

 

An upgrade in the 850 temps as well.

 

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An upgrade in the 850 temps as well.

 

Posted Imagegfs-1-78.png

 

Sorry this is OT but that snow risk map, is green snow?

 

How do these maps work as I've seen them posted previously but have no idea what they mean!

 

Hope someone can enlighten me ...

 

Thanks in advance.

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Sorry this is OT but that snow risk map, is green snow?

 

How do these maps work as I've seen them posted previously but have no idea what they mean!

 

Hope someone can enlighten me ...

 

Thanks in advance.

 

The colour denotes ppn rates while the hatched colours denote snow. They are not very good predictors of actual conditions though, you are better off with using hi res models designed specifically for the task such as Euro4 when the event comes within 48 hours.

Edited by Mucka

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Which model runs at higher resolution up to 72 hours?

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There isn't a run goes by at the moment without some sort of horror LP being predicted.

 

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