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. WPC Discussions WWW.WPC.NCEP.NOAA.GOV 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]

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

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.

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.

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

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

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: As it's peak hurricane season all subject to change.

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!

Although there have been changes, that wasn't a bad forecast from 3 weeks out.

I couldn't see much difference at first but in gif form you can.

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?

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 ;-)

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." http://forum.netweather.tv/topic/75464-winter-model-discussion-cold-hunting-12z-060113/page-6#entry2466592

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.

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.