Weather Monkey
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I took a gander at the Model Discussion Thread back in late December 2009 to see how things compared. The discussions were quite similar to the last few days here but one thing I noticed, and l do remember from lurking back then, was having model agreement at 96hrs. This morning I highlighted comments from the pros over the pond in the NCEP discussion that "The UKMET was removed on day 4 due to its significant divergence from the rest of the guidance regarding the shortwave energy in the East Pac/Northwest U.S." Day 4 is of course 96h.
So, where are we at as things stand at 72h and 96 hours from today's runs? Are the models in agreement at this early juncture?
ECM+72h
+96h
EC Mean
+72h
+96h
GFS (I could only get the 18z so times adjusted to 66h & 90h accordingly)
+66h
+90h
GFS Mean
+66h
+90h
UKMO
+72h
+96h
GEM
+72h
+96h
And because IanF used to mention the JMA, here they are for the same time frames.
JMA
+72h
+96h
Finally we have the MetO faxes. The 84h+ hadn't updated on Meteociel when I looked so we can directly compare Sat 12z.
9.1 12z +72h
9.1 0z +84h
9.1 0z +96h
And as a bonus here's tonight's ECM Op run in gif form.
The EC Op looks appears so well supported by the Mean that I had to check I hadn't saved the image twice. As for the rest, they have similarities at 72h but more differences by 96h. Events over the pond at that short timeframe make it difficult to call. Fascinating to watch though.
Original post: https://community.netweather.tv/topic/99706-model-output-discussion-into-2024/?do=findComment&comment=5004360-
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I took a gander at the Model Discussion Thread back in late December 2009 to see how things compared. The discussions were quite similar to the last few days here but one thing I noticed, and l do remember from lurking back then, was having model agreement at 96hrs. This morning I highlighted comments from the pros over the pond in the NCEP discussion that "The UKMET was removed on day 4 due to its significant divergence from the rest of the guidance regarding the shortwave energy in the East Pac/Northwest U.S." Day 4 is of course 96h.
So, where are we at as things stand at 72h and 96 hours from today's runs? Are the models in agreement at this early juncture?
ECM+72h
+96h
EC Mean
+72h
+96h
GFS (I could only get the 18z so times adjusted to 66h & 90h accordingly)
+66h
+90h
GFS Mean
+66h
+90h
UKMO
+72h
+96h
GEM
+72h
+96h
And because IanF used to mention the JMA, here they are for the same time frames.
JMA
+72h
+96h
Finally we have the MetO faxes. The 84h+ hadn't updated on Meteociel when I looked so we can directly compare Sat 12z.
9.1 12z +72h
9.1 0z +84h
9.1 0z +96h
And as a bonus here's tonight's ECM Op run in gif form.
The EC Op looks appears so well supported by the Mean that I had to check I hadn't saved the image twice. As for the rest, they have similarities at 72h but more differences by 96h. Events over the pond at that short timeframe make it difficult to call. Fascinating to watch though.
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It's always worth gauging the thoughts of the professionals over the pond to see how things are shaping up further upstream of us. This is from the 7.33am (GMT) update
Guidance/Predictability Assessment...
The latest numerical models are quite dispersed in their handling of the overall evolution of the synoptic pattern over the lower 48 during the medium range period. There's plenty of run-to-run variance in the deterministic Euro with respect to the incoming East Pac low on day 3. The 12z UKMET/CMC and 18z GFS are also all over the place with their placements of that system so this system's details are yet to be considered certain. The models are in reasonable agreement about the evolution of the wound up eastern U.S. storm through day 5. A general model blend consisting of the 12z EC/UKMET/CMC and 18z GFS were utilized on day 3. The UKMET was removed on day 4 due to its significant divergence from the rest of the guidance regarding the shortwave energy in the East Pac/Northwest U.S.. The Canadian is dropped from the day 5 blend in place of the 12z ECE and 18z GEFS because it (CMC) has the parent low centered over the Upper Midwest while the EC and GFS and Canadian ensemble have it much farther north in Canada. The Canadian ensemble is introduced briefly on day 6 and removed on day 7.
That's quite the blend!
Looking at the 850s and SLP for the 0z GFS run for Berks we see scatter really start in 3 days. You'd think <T72 would be more reliable but it is what it is. Let's see where we lie tomorrow.
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5 minutes ago, leemondo said:
Just been informed by my almost 8 year old, that I am to check the weather at 1 or 2am and if its snowing I have to wake him, real danger of him wanting to go out in it too!
I am tempted to stay up tho, this doesn't happen very often and after so many near misses and barren winters, it will be worth the wait! Good luck everyone
Wake them up at your peril! I was woken for snow at the same age and never went back to sleep l as I was to busy looking out the curtains every few minutes until I was let out to play in it. Several decades later I still do the same
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1 hour ago, CreweCold said:
The thing is, at this point it could just be a first stab at what happens after the SSW...and it could be completely wrong. We just don't know.
In model watching you need to view dispassionately - with the good and the bad. Many times over the decade I've watched, it's worth holding judgement a day or two, taking the John H approach, and having patience rather than knee jerking to every run. We get downgrades and upgrades that often flip as the models seek the solution but ultimately, what will be will be. Yet in the reliable timeframes there's chances in most places, more so in the North (which is usually, but not always, the way) and beyond that considering what the strat is doing anyone saying they know is being presumptuous.
I've really enjoyed @Catacol's musings/ramping and I'm also excited for the same reasons. Historic events do happen to us - who would have thought Dec 2010, Mar 2013 and Feb/Mar 2018 were going to happen? but sometimes you spot the seeds sprouting, other times it's gone by the next morning. We could have a decent spell, an historic spell/event or a squib - I've seen so many naysayers be right and horribly wrong. We seriously don't know but like most here at this time of year we live and breathe for snow and ice because we don't live in Scandinavia or Canada. Even @mushymanrob has been perked up for something out of the ordinary!
What I will say is the ens for Berks are surprisingly solid showing a steady cool down until the 6th - next Weds - when the scatter builds - it may tighten up or down or scatter further. Cold periods can wax and wane - or disappear, but 7 days of steady cooling with good agreement is not bad at all and chances may pop up (or not) but we're in the game before January has even started with a great stratospheric roll of the dice about to be thrown. I'll take it!
My glass is anything but empty in what hemispherically and model wise is possibly the most interesting I have seen. At least this winter isn't boring
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3 hours ago, NewEra21 said:
Think it's fair to say the GFS 12z was a bit of a warm outlier in terms of 850s
At least it does seem to be more settled in the near term. First chart Suffolk for comparison then a snapshot down the spine; Berkshire, Leicestershire and Perth and Kinross. Very much as John said based on the 500mb anomaly charts:
13 hours ago, johnholmes said:No signal for a late summer but a mix some days not unpleasant and a few not pleasant is a non meteorological summing up!
As it's peak hurricane season all subject to change.
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20 minutes ago, Tim Bland said:
It’s a very cold run no doubt, but for most of England it’s snowless. As I said though we would be very unlucky not see snow in such cold air with those lows floating around. FWIW i’d bank this run though given the chance! Fingers crossed for a good ECM ..
If the cold comes in anything like the runs are showing, I wouldn't worry about the detail as many a feature will pop up at short notice. Always a lottery where and when but fun to see churn out nonetheless. Long may it continue. Get that cold in!
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On 10/01/2019 at 12:05, Summer Sun said:
UK Outlook for Friday 25 Jan 2019 to Friday 8 Feb 2019:
During the last week of January and into early February, there is an increased likelihood of cold weather becoming established across all of the UK. This would bring an enhanced risk of snow and more widespread frost, particularly across northern parts. However, there is uncertainty over the extent of the cold weather and it is still possible that some milder and wetter interludes will intersperse this generally cold period, especially in the south.
Although there have been changes, that wasn't a bad forecast from 3 weeks out.
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40 minutes ago, The Eagle said:
Another positive run on the 18z ICON. Ever so slightly more amplified by 120hrs (only goes to 120 on the 18z)
I couldn't see much difference at first but in gif form you can.
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Purga you showed a chart from +T196 then +T240? From what I see the potential (and it is just that) was +T96/120. Bit misleading then to show much later FI charts? Are we are talking about a transitory event on Tue/Weds 4/5 days away or 8-10 days? As I see the spreads fairly aligned until the ~10th this is (current) deep FI you are using to compare? What period do you mean?I think with a strong westerly flow that despite decent low 850hPa temps there is so much surface mixing and flow off a mild sea that any wintry precipitation is likely to be veor ginal and confined only to the highest hills / mountains.
Anyway if a sleety mix were to ensue it would be extremely brief as ECM shows a powerful mild pulse blasting in
Wet & mild more likely at +240hrs
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Deep breath then back to lurking and enjoying a very informative thread again this year :-) Overall pattern is promising rather than conclusive - dice in hand ready to roll - so let's just let it play out and enjoy whatever happens. Even if the UK misses out it will be instructive and fascinating for wherever in the Northern Hemisphere that benefits. I'm with the view a broad concensus of runs should be taken rather than hanging onto every run. Don't need the inter run drama of the mod thread here...please...this place is light relief by comparison ;-)Yes but today even the 6z wasn't that great! The last hot run was last night's 18z. Karyo
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Some lovely output, not unexpected, but I was reading this last week when things looked bright. From TWS (6th Jan 2013)
"The GFS is all over the place at the moment, so I don't think too much should be read into it at this stage, but I retain a view that snow lovers should not get too excited, particularly as far as snowy easterlies or north-easterlies are concerned, unless they appear inside T+72."
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Agree. When you watch weather the extremes draw you. It does not mean as some seem to imply in response to you that we hope anyone is hurt but the raw power of mother nature is something to behold. Mark Vogan fesses his fascination started with the 87 storm (mine was an 83 snowstorm), which I recall well for putting the tree in my garden at 45 degrees (next doors tree grew at 22 deg after) and the multiple cars whacked I saw to the way to school (a half day). It does not mean we want anyone hurt nor facing big bills from damage (last years mild storms took out my fence, 06 another) but we do not live in benign climate. These storms are not that unusual despite the decade long gaps that may occur. It is also part of the natural order removing weaker trees etc (The Great British Year on the the beeb suggested trees developed the structure they have and in part shed leaves because of autumn storms). Prepare, be safe by all means but there is nothing wrong with enjoying the weather (we can hardly change it) - those lovely heatwaves so beloved of many on the model forum (and I say this passing no judgement) are killer indoors or out. We should put it in perspective as well - it's not exactly that much of deal when compared to those who deal annually with several intense tropical systems over the otherside of the Atlantic or the Pacific (poor Japan). I lived on the equator for many years and I have yet to see anything here (North excluded) that has come close matching the intensity of a passing squall (less wind but sheer volume of rain is something else). Believe me, having experienced weather in many places globally, we British have it very easy compared to many others around the globe. As Joe Bastardi says 'Enjoy the weather, it's the only weather you've got.' Stay safe everyone.Sorry but I want this system to be as strong and severe as the very worst charts have predicted. Maybe it is just me but for the life of me I just cannot see the point of being a weather enthusiast / nerd without the promise of extreme weather potential. Isn't that that what most of us are in it for? I accept there are some posting who genuinely want it to pass without incident but what's the point of getting all excited then saying but I hope it's not as bad as that chart is showing...Yes trees may get blown over, some cars destroyed and people even hurt or killed. Now it goes without saying that the less of that (obviously moreso the latter), the better but... it my eyes it is collateral damage. I say bring on the 90+mph gusts, bring on the sting jet, bring on the tornados, bring on the the worst storm since 1987!!! There, now I've said it.
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At this time of year I'd gladly take a toppler, something more sustained is better after solstice. Frosty has pulled up a few yoyo patterns so at least some interesting changeable weather could be in the offing. Long way to go but some short sharp colder shots *potentially* there. As ever more runs needed and with the uncertainty over Monday's low a long long way to go modelwise for further reaches.<
Not bad if you're wanting cold.
Shame it would be a toppler.
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Looking at the 18z upto +87 so far looking settled with high pressure sat over us. The GEFS for 12z show a similar story with the period 1-3 Mar where the divergence begins. Temps for South/South East showing little variation with a slow incline upwards in temps.
I don't think deep cold is what anyone should look for but as Nick S alluded to earlier at 1909:
On a positive note at this time of year you need to be chasing the coldest source of air and its there waiting to break through the UK's defences!Â
Mar 06 and Apr 08 are the type of event I'm hoping we see in s/se. Be more than happy with that.
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The GFS is then quickest to try and bring the Atlantic in
Now if I had a penny for everytime..... :-)
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He did say 'near record breaking cold in February', if he's right he deserves a knighthood.
If he's wrong, he needs to take a cold shower and go back to the drawing boards.
RJS said
This looks exceptionally promising for severe cold by the middle third of February.The dive-bombing low on Tuesday will turn into a wintry hurricane for northern regions of the UK and in itself is a major severe weather event, but after a couple of days it will reach a position over central Europe that will allow a retrograde cycle just showing signs of life now to develop gradually and feed the coldest Siberian air west across northern Russia into Scandinavia.I think there will be near-record cold in mid-February and that means daily means in the -5 to -10 C range, so a very severe frost and with a northeast flow there may be heavy snowfalls even without any organized low pressure, but this winter also has shown a tendency to storminess so I have the feeling once this very cold air starts moving in, there could be epic snowfalls with itWhen other members dare to make a forecast rather than being dismissed it may be worth holding fire or at least offering something constructive. He could be wrong but the record cold is in deep FI so is a moot point with model disagreements in the near term let alone so far out. I hope he's right but no one knows.
Hurricaine is impossible as they are by definition tropical but the winds in the Met Office warning are gusting to hurricane strength - forecast as frequently 60-70mph or 80+ . Poor choice of words by RJS maybe and I'm sure he will place caveats in future.
As for the models I see a fair degree of difference at t72-96 (5-6th) on the London ENS with 6-7c difference (last image) so I would be wary of inferring too much yet. As is often said get the cold in first. I'm just glad to have had a clear day and nice frost with more in the offing after a mucky grey week.
Top 18z middle from weatherweb.
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Ah Chio has clarified this as I was writting.
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Before the SSW I read on here about three SsWs.
1) Is the current continued warming (going on the red highlight by weathermaster 25 Jan 2013) a new SSW or part of the same event moderating?
2) Are any further events showing? I have seen no red areas posted in recent charts posted recently as there were before the SSW.
3) Is it unusual to have more than one SSW per season and at what point does an SSW become standard warming (looking at the average the current rise looks normal rather than sudden).
4) Chio you mentioned the NWP would respond about now. It seems to be changing but is this what you expected and is more entrophy to come as the SSW propogates down. I see the cold sopell just gone as a bonus with the real effects to come.
5) Has the record snow cover in the Northern Hemisphere made any difference to the SSW or any further events going forward (i.e. a feedback)
6) GP/Chio, you mentioned the uptick in solar activity in Dec may have offset the cold potential. Has the recent Jan uptick, now finished, made any difference in how this period has been affected? You seem to have this period of warmth nailed well but I wonder if anything has thrown a curveball (which may have the same end result but increased uncertainty). As an aside from my reading Dec was a potential bonus which never came to pass cold as it briefly was.
7) (sorry for being greedy) how does wave activity relate to solar effects - or does it? I can't see the link but I understand the effects on UV higher up - is this like bouncing a ball passing through a more/less viscous membrane or wind sheer throwing off the trajectory? The mountain torque has thrown me as I thought solar effects would be polar regions (sorry for the basic view and I understand I could be wide off the mark so hope I make some sense).
Can I also say thank you for this thread. I've found it of more use than FI trends and fascinating. To think I mostly ignored the strat last year.
Thank you and keep up this valuable work.
Sorry when I said 3 SSWs I meant potential. No fait accomplit.
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Model Output Discussion - Colder but how cold and for how long?
in Forecast Model Discussion
Posted · Edited by Weather Monkey
That pretty mutch echoes the thoughts of the professionals at NOAA over the pond discussing the +72-168hrs period.
I've highlighted a few bits from the which show how uncertain we are moving into wk3 of Jan. The full discussion is linked and I highly recommend for anyone who wants to learn.
Valid 12Z Sat Jan 13 2024 - 12Z Wed Jan 17 2024
Early in the period, consensus looks quite good for the deep storm tracking from the Great Lakes into eastern Canada during the weekend. The average of recent guidance has held up well for depicting the storm's depth which may be similar to the preceding storm currently taking a similar track. Meanwhile the guidance spread is gradually narrowing for the system arriving into the Pacific Northwest/central West Coast. The GFS has consistently been on the northern side of the spread (but with a subtle southward trend over the past day) while the farther south UKMET has adjusted northward somewhat...
Heading into early next week, the shortwave energy moving into/through the West should shear out/accelerate underneath more pronounced northern tier U.S. energy. Dynamical models and ensembles plus machine learning models continue to diverge considerably for the details of how this northern tier energy may evolve as it reaches the eastern U.S. This leads to a remarkably broad spread for the strength and track of any low pressure system(s) from the eastern U.S. into the western Atlantic/CanadianMaritimes. For example, forecasts valid early next Tuesday show the potential for best-defined low pressure to be anywhere from the Southeast U.S. (12Z/09 ECMWF and a couple machine learning models) to the Canadian Maritimes (06Z GEFS/00Z CMCens means). Surface low depth from Tuesday into Wednesday is just as diverse, with ensemble member spread leading to a weak depiction in the means, while other solutions range from moderate to very strong surface development. The combined high uncertainty of surface low track and strength at any particular valid time continues to favor a conservative approach for the deterministic forecast (a north-south mean frontal zone with embedded waves) until better clustering arises...
Recent ECMWF runs have been oscillating for the relative strength of mean ridging versus southwestern Canada shortwave elongation (00Z runs favoring the latter and without great support from other guidance). Also of note, already by Monday the new 12Z UKMET becomes an amplified/western extreme with the Pacific ridge, throwing its downstream trough out of sync with the model/mean consensus. Forecast considerations based on 00Z/06Z guidance led to starting with a composite of 00Z/06Z operational models for the first half of the period, followed by a transition to a model/mean blend along with splitting the ECMWF input between the 00Z and 12Z/09 runs.
With that in mind upstream and from what we have seen with a lot of different output, is that, as of yet, we not have model agreement - and at fairly close range. Monday is a mere 5 days or +120h from the 12z output. Years of skulking over the volumous pages here, with many wonderful knowledgeable contributers, have taught me of the importance of continuation and agreement in the modelling. If it's not the first rule of Model Fight Club it should be. We are clearly in the game still and at a good time of year for once.
Tonight the grass was crispy underfoot, surfaces sparkly and I could see the stars not endless cloud. I can see clearly now the rain has gone [I'll get my coat]