Robbie Garrett
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Posts posted by Robbie Garrett
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I think the models are struggling post 120hrs+ - I suspect the low as people are already mentioning won't be as strong nor will it blast towards us. I suspect it will get stuck like a similar scenario that happened on 20-24th Nov 2010 (When the MetOffice started talking of a breakdown). NOAA was talking about a 3 out of 5 confidence with the strength of this sub-tropical/tropical low.
There was a barrage of low's against the Greeny block.
They all got stuck over New England.
With the odd low heading south of the Greeny block.
6 hours ago, Howie said:Am I the only one that thinks this new low to the south west is being way over done? How could it possibly become that intense, basically a hurricane in the northern Atlantic in December? Just seems wrong to me
5 hours ago, chionomaniac said:Passion. It takes a bit of self control to step back and look at the bigger picture. Just stick to day5-6 and past that just for fun.
In 2010, the models constantly showed the end of the cold spell, but this was put back time and time again. With this being a strong split into the lower Strat, rather than a transient Greenland High, I suspect the same will happen again.
4 hours ago, Notty said:and NOAA are not expecting any tropical storms there in the next five days and a storm like that would already be brewing and monitored by the NHC (in my opinion)
(Cross posted)
1 hour ago, clark3r said:I am starting to believe that I will get my snow cover for the first time since 2010. Excited by charts, it is def coming home England
It would be absolutely hilarious if England did win, that the victory parade was cancelled by Sadiq Khan due to heavy snow fall. (Another Crisis).
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I think the models are struggling post 120hrs+ - I suspect the low as people are already mentioning won't be as strong nor will it blast towards us. I suspect it will get stuck like a similar scenario that happened on 20-24th Nov 2010 (When the MetOffice started talking of a breakdown).
6 hours ago, Howie said:Am I the only one that thinks this new low to the south west is being way over done? How could it possibly become that intense, basically a hurricane in the northern Atlantic in December? Just seems wrong to me
5 hours ago, chionomaniac said:Passion. It takes a bit of self control to step back and look at the bigger picture. Just stick to day5-6 and past that just for fun.
In 2010, the models constantly showed the end of the cold spell, but this was put back time and time again. With this being a strong split into the lower Strat, rather than a transient Greenland High, I suspect the same will happen again.
4 hours ago, Notty said:and NOAA are not expecting any tropical storms there in the next five days and a storm like that would already be brewing and monitored by the NHC (in my opinion)
Posted on
1 hour ago, clark3r said:I am starting to believe that I will get my snow cover for the first time since 2010. Excited by charts, it is def coming home England
It would be absolutely hilarious if England did win, that the victory parade was cancelled by Sadiq Khan due to heavy snow fall. (Another Crisis).
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The Spanner in the works seems to be the sub-tropical low up the Eastern Seaboard. NWS CPC have already said this in there prognostic discussion. I suspect it'll be the next 120hrs of modelling to see if it'll stall or not. The +120 fax chart looks good, hopefully the low will stall due west of the HP cell.
Someone in the thread mentioned the difficulties with the models ECMWF/GFS are struggling with this feature.
5 hours ago, MATTWOLVES said:Perhaps they haven't been fooled...perhaps it's more likely to be that they do not make sweeping judgements on the back of each and every run! They say the weather is chaotic!!
Well this forum can be one hell of alot more chaotic!
Wow my head is well and truelly falling off now..can't believe how some have really lost the plot over that run!
Catch you all after Xmas folks...Time for me to get my faculties in order.
1 hour ago, Don said:Hopefully the WRONG trend!!
1 hour ago, TSNWK said:So what the heck is ecm op and many of its ensembles seeing? Or missing and vice Versa
1 hour ago, Ice Day said:Quite simply, they are two different models with their own inbuilt biases. If I had to put my money on one, it would undoubtedly all go on the ECM.... but it is sometimes wrong
48 minutes ago, Skullzrulerz said:-
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Just caught up, IMHO CPC are having none of it, just yet. The fuss seems to be the Greenland block and negative NAO favours and East Coast storm in the 6-10 day outlook, either way it results in a west-based negative NAO. Which obviously impacts us downstream. GFS looks like it throws that low across the North Atlantic and starts the North Atlantic storms train. Confidence in this forecast is 3 out 5.
The Greenland block looks set to remain, but with some difficulties in the forecast for 10-16 days out; here's the explanation which may support the UKMO change in long-forecast.
QuoteThe GEFS and Canadian ensemble means maintain a more amplified 500-hPa ridge over the North Pacific and Aleutians with a trough downstream and offshore of the West Coast. In contrast, the ECMWF ensemble mean shifts the anomalous ridging from the Aleutians eastward to the higher latitudes of western North America. Based on continuity and teleconnections derived from the well-agreed upon large positive 500-hPa height anomaly center near Greenland, the GEFS and Canadian ensemble means are preferred. However, the ECMWF ensemble mean is not completely discounted due to its higher 500-hPa anomaly correlation score during the past 60 days.
The resulting confidence being; "Below average, 2 out of 5, due to diverging model solutions on the longwave pattern across the North Pacific and western North America along with large ensemble spread with the Arctic Oscillation late in week-2."
The whole change is the upstream pattern it seems. So this may explain why, as ECMWF being the favourite because of it's higher correlations core.
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Just reminded Gatters to get it's snow mobiles out
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As per my post in the Models thread; wondering if anyone could share the background signals that led to 2010?
Then the signals that are leading to 2022?
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One thing I've not seen in this thread IMHO is the background signals to this weather;
- So the question will be what background signals are causing the -NAO (Greenland heights) in the models?
- What is causing the Polar vortex to be weaker as a result?
2010 was synoptically a 100 year event. Any SSWs I've seen, Easter 2008, Feb 2009, Jan 2010 and what not has been a short affair vs Nov/Dec 2010.
8 hours ago, Mike Poole said:Yes, my own conclusion is that that is becoming true for the second half of winter. But I have always pointed to 2009 and 2010 as evidence that a severe cold spell can occur in early winter without a SSW. These years are recent enough in the scheme of climate change to still be highly relevant possibilities, as we are seemingly going to find out this year!
7 hours ago, Ali1977 said:That’ll do , what a chart with another shot of WAA heading up through Greenland. This is gaining traction here, not just a cold spell now , maybe an extreme type event (longevity rather than extreme temps)
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UKMO FAX Chart for today
UKMO FAX Chart to +120hrs
I suspect the reason confidence is low and it's difficult to prog is because there's probably not much data for a big HP cell over Greenland and a North Atlantic stream, as weak as it is or has been. The Jetstream is heading south. Whilst we might not get deep cold alas 2010 (Jan/Nov/Dec) - we might get something else, and that's snowfall, and shed loads of it.
A lobe of PV into Canada, sending WAA into Greenland at 120hrs+
I was just reading the NOAA outlook; and this is there thoughts.
"Various aspects of the forecast have been in flux over recent runs."
"Operational models have been fairly chaotic with some of the specifics"
"The ensemble means providing somewhat more stability."
In terms of the pattern that will eventually effect us downstream.
QuoteMeanwhile the past 24-36 hours of guidance has trended toward a much slower progression of what troughing remains over the eastern Pacific/western U.S. as a portion of the system's energy shears out into the progressive flow downstream.
"Today's model solutions are in good agreement in predicting an amplified 500-hPa flow pattern during the 6-10 day period. Amplified positive 500-hPa height anomalies persist over the North Pacific and Greenland in dynamical model forecasts. Daily 500-hPa height forecasts show that an amplified ridge over Alaska on day 6 is forecast to de-amplify and reform over western Alaska during the period. A positively-tilted trough is predicted over the southwestern CONUS at the start of the period, and a negatively tilted amplified trough is predicted over the north-central CONUS early in the period. The trough over the West de-amplifies and reforms over the Pacific Coast later in the period in today’s ensemble means, while the trough over the north-central CONUS is predicted to progress eastward over the Northeast. The ECMWF ensemble mean predicts a more amplified trough over the Pacific Coast relative to the GEFS ensemble mean."
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IMHO, UKMO are very much on the fence till the cold is probably knocking on the door. Can't imagine being that person who then has to call HMG for a Cobra meeting and distribute the message of yet another crisis. How far will the cold remain? Our patterns have been locked in? The rain we've just had started in September, the warm spell before that, about May/June. What if the cold pattern locks in till February? The NHS is already overwhelmed, especially in rural locations, the motorways network isn't in a great condition, the railway isn't what it was in 2010, and the airports are barely breaking even vs (2019) - do they need another crisis of non-ops with SNOCLO?
Tuesday was a COBRA meeting about Winter, and I wouldn't put it past another happening this coming week.
45 minutes ago, johnholmes said:I agree with that mushy, thanks, a bit uncertain as to just how cold in the upper air, any minor troughs etc for 6-10 days and beyond. Would love to be in the operations main forecast room by the senior met forecaster over the next few days
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Yes, two convergence lines showing up on the North Sea on Sunday. 850hPA in the -5°C region.
SSTs forecast in the 8-10°C region.
You need roughly a 13°C different between the air at 850hPa and the surface to produce thundersnow and storms. Could go either way but most of the east coast might get a good dumping (albeit probably rain/hail) See full FAX chart below.
50 minutes ago, geordiekev said:I know we're a few days out to pin down flow direction, moisture etc but I recall recently a similar set up and the lake effect from Skagerrak straight was immense and walloped the East Coast. The kind of activity snow charts don't factor in
46 minutes ago, January Snowstorm said:It will be interesting to see how the very warm sea temps modify the flow. You would imagine the warm seas and cold temps will only enhance the shower activity. To get this type of weather so early in the season really is special, perhaps some younger folk don't realise the extremity of what could develop!
39 minutes ago, Snowmadsam said:agreed, could easily see very shallow areas of low pressure develop in such a flow, plenty of convergence lines too. Good luck to forecasters doing FAX charts with these synoptics.
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This last few days outputs have us all like.
Asian Porlar Vortex lobe sending some stuff our way.
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They must have seen more than enough. Feel for them as they only gave a 15% shot on there Contingency planning of cold weather. But you'd hope the councils have stockpiled with how cold *cough* warm it's been lately. Ahem.
12 minutes ago, Ghost of winters past said:The Met Office are very much bird in the hand..They DO NOT ramp.
If they are on board with this, then i for one shall take notice..
Ghost.
13 minutes ago, mountain shadow said:That's about as much as a ramp as you can get from the Met Office at that range.
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UKMO remaining less bullish in it's 1400 update with it's take on the models.
5th-14th Dec
A cold northerly flow is likely to develop, drawing temperatures below average and feeling even colder at times, particularly during fresh winds. This may bring some wintry weather, with an increased risk of overnight frost and perhaps snow showers, not confined to higher ground.
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By the way, the North Sea SSTs are 10-12°c + - far warmer the further south you dig. Lake effect snow as the difference in temperature at 850hpa and the surface will be almost 20°c.
Anyone have the Feb 2009 SSTs?
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Just a quick look at the NH pattern. The difference in divergence between the ECMWF & GFS models, which seems to be the 144hr mark. The amplified ridge over Alaska is forecast to become flattened and allowing a trough to settle in. There's a 4 out of 5 agreements in this pattern over at NOAA in the short-medium term due to good model agreement.
GFS - 144hrs
ECM - 144hrs
The heights over Greenland is consistent among model forecast along with a negative NAO. However, discussion over at NOAA stating a 3 out of 5 confidence level due to some uncertainties leading into week two.
UKMO Decipher -
Till 13th December -Temperatures below average, may even feel colder at times.
From 14th December - Confidence is low - not your atypical December, below-normal temperatures and spells of wintry precipitation, is slightly higher than usual.
Definitely a pattern change, and no return to what we've had recently. I'll take that. So, I'd take any divergence with a pinch of salt.
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Not sure if posted yesterday, but Aidan McGivern posted this yesterday. As I expected, UKMO very much on the fence - due to it being Christmas period and the threat to infrastructure.
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Just now, January Snowstorm said:
The GEM is the direction of travel that we want for the Holy Grail. The ukmo is very close and also picks up on the disturbance in the Easterly flow which kinks the isobars ever so slightly Northeast!! I would think the ukmo 168 will be a stunner!!
For me the gfs is messy and not the preferred route!
Wouldn't surprise me to start seeing some confidence messages from UKMO, but maybe they are waiting for the retrogression before sending out alarm bells to HMG/Councils up and down the country.
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IIRC a SSW can disrupt the pattern and put us out of a better synoptic pattern. I am sure that 2010 at the end had a SSW which changed our pattern. One thing I remember from 2010 was it being so dry and the Icelandic Volcano. It's been dry again this year and the Hunga Tonga–Hunga Ha'apai eruption.
Parallels to Nov-2010 a week before
Similar setup now in 120hrs
52 minutes ago, January Snowstorm said:Really what rhe charts are showing are reminiscent of an SSW where everything is reversed and we have an Easterly from Russia to the Atlantic. The Icon is first out this evening and is certainly an upgrade.
Of course we haven't had a strat warming so it's even more astounding! Folks buckle your seat belts because the Holy grail is within touching distance and tonight could set the tone!!
The key for me seems to be lower heights over Europe moving the HP westwards towards Greenland. The MetOffice long forecast clearly states the following "Confidence remains low for this period." - they don't even know. Madness to think we may get another 100 year event again, in 12 years.
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The pattern is not too dissimilar to Nov 2012?
Current Chart
The MetOffice report for NOV 2012 - https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/weather/learn-about/uk-past-events/interesting/2012/exceptionally-wet-weather---november-2012---met-office.pdf
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13 minutes ago, BruenSryan said:
? 2010 Atlantic hurricane season was one of the most active on record...
I stand corrected. But 2010 for the UK was very dry.
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2010 was very much a calm year for the Atlantic and the start of drought conditions across much of the UK. Wouldn't surprise me if synoptics follow a similar route with a quieter than average Atlantic.
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Didn't get to watch or photo the storms
but caught the immense rainfall, and flashes of lightning before work.
On the way to work, the anvils at FL330+ provided an amazing photograph.
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Madrid is nice
5 minutes ago, Weather Enthusiast91 said:The UK climate overall is rather boring if you are a weather enthusiast. But I do agree that spring is the most interesting season as there is more of a variety. But even then, spring can be bland in some years.
If it wasn't for finances, I would certainly consider moving to somewhere with a more continental climate.
Model Output Discussion. 3/12/2022. How cold will it get?
in Forecast Model Discussion
Posted · Edited by Robbie Garrett
By the way, in the real world; what happens when the lows start heading our way with a Greenland block and cold air firmly established
Quick look at the models, and they are already doing just that vs yesterday. For how erratic things are;
+120HRS on the 06z
+120HRS on the current run
Then look to 180hrs how much divergence between the runs for the same time. Photoshop overlay of the Current (C) centre of the Atlantic LOW and 06z of the centre of the Atlantic LOW.
Fantasy Island is currently +48HRS on the GFS!