Blessed Weather

The question many people in the US are asking as they currently shiver under the early season cold blast is how long will the onslaught continue? Here's the view given in two WSI Weatherwise blogs today & yesterday which includes talk of an "abrupt end" to the cold spell: HEADLINE: The current unusually strong cold snap in the Midwest does not necessarily increase the odds of a cold December Given the moderating trends in the models as we head towards the end of the month, the question on all our clients’ minds is “will the cold reload and unload again in December?†Our current December forecast is rather dismissive of this idea.... http://www.wsi.com/blog/energy/extended-and-extreme-november-cold-in-the-midwest-doesnt-portend-cold-december/ HEADLINE: Highly anomalous arctic cold will continue to grip a vast portion of the nation during the remainder of the week and into middle of next week. However, the pattern responsible for these arctic intrusions may break down during the 11-15 day period allowing for a moderating and warming trend.There is reasonably good medium range model agreement that the large scale pattern responsible for these cold air intrusions may break down during the 11-15 day period. http://www.wsi.com/blog/energy/us-cold-air-locked-in-place-through-the-middle-of-next-week-but-a-potentially-abrupt-change-is-possible-by-the-11-15-day-period/

The trend that is catching my eye at the moment is the drift east of the west Russia block that has been so persistent over the last several weeks. Not only has this block been the cause of the stuck trough just to the west of the UK, but to my eyes it’s also been the reason why, with the PV so disrupted and lobes looking for somewhere to go, they’ve not been falling into a position to benefit the UK. I nearly posted such back at the start of the week but in the end didn't. The ECM chart I didn’t post for 12 Nov : So the indication from this morning’s ECM and GFS P output that the block may move further east is IMO good news. And although deep FI, the GFS P shows how this may open the door for a PV lobe to finally drop down into a position that brings a blast of artic air into northern Europe. 22 Nov block still there 30 Nov block finally starts to move east

A very interesting final OPI Report, made more so because we find ourselves in the position of having the mainstream forecasters using their LRF models to predict "no real cold" for the winter and we have the OPI and SAI clearly disagreeing. A fascinating winter ahead. Good luck to the OPI Team!!

Just a quick look at the coming week's weather for the Alps and it's not a set-up that the piste teams will be wanting to see last much longer as the coming season approaches. The problem is the persistent trough over the UK which is resulting in a S to SW'ly flow for the mountains and (generally across Europe) bringing above average temperatures. Not much difference between the start and end of the week on today's GFS P 12z 850hPa charts: Mon 10th Fri 14th The 'stuck' pattern is resulting in plenty of precipitation for the south western Alps (French, southern Swiss Alps & Italian Alps), but with freezing levels sticking around 2,500m (and higher the further east you go) it's only benefitting the very highest of slopes. The Euro4 chart below shows the snowfall accumulation for the 48 hours from today to Tues 11th Nov and clearly highlights where the snow is falling. The second chart from GFS suggests it will still be raining/snowing out to next Thurs 13th Nov. Euro4 48 hour snowfall GFS 13th Nov

Weather Underground have issued their Winter 2014/15 forecast for the USA: LONG RANGE WINTER FORECAST A colder than normal winter, especially during the first half appears likely for the Great Lakes, Upper Midwest and New England region, while below normal Temps are also likely across the entire Gulf coast region. However, while Temps will likely average below normal, it’s very unlikely that this winter will be even remotely close to last years’ frigid winter. Full forecast: http://www.wunderground.com/blog/SteveGregory/comment.html?entrynum=270 (Not sure why, but Weather Underground links can sometimes land you half way down the page. Just scroll up).

Hi stuboy. Passo Tonale certainly looks an interesting resort and with glacier skiing too! Not one I'd heard of before but one of those little gems that are so worth visiting. (For anyone wondering - south of Bormio over the border from SE Switzerland). Nice selection of webcams. The weather forecast for the glacier at 3,016m look good for Mon through Weds next week with 60cm of snow possible and temps around -3c. The sun comes out but temps fall even further later next week to -7c as the trough impacting the UK introduces a cooler NW flow into the Italian Alps (according to today's GFS).

Unfortunately (for coldies) you are absolutely right PM. This mornings charts from ECM and GFS at Day 10 are similar and both look terrific. Bitter cold heading down towards us... ECM 17th Nov GFS P 17th But as the GFS P continues with this run, the incoming cold to the NE retreats and instead we have to look to the NW again: GFS P 23rd Nov But the 23rd is so far out in FI, and with such volatility in the Nth Hem, I think I'm convincing myself to look no further than the potential at Day 10 and not worry about later output!

Hi jules216, Nice pictures! It's good to see the Italian mountains are also in on this weeks snow! BW.

Extract from Accuweather's winter 2014/15 forecast, issued today: Europe Winter Forecast: 'Fantastic' Ski Season for Alps; More Tranquil in UK .....Another area that can expect more significant snowfall is the Alps, with the most impressive snowfall expected in the Swiss and Austrian Alps. "Ski conditions will be fantastic for the 2014-2015 ski season, especially when compared to last year," AccuWeather Meteorologist Tyler Roys. The first significant snowstorm of the year has already occurred across the Swiss and Austrian Alps. This winter, an active storm track and cold air will promote frequent big snow events for the Pyrenees, Alps and the mountains of the Balkan Peninsula. Let's hope they're right. Full forecast http://www.accuweather.com/en/weather-news/europe-winter-2014-2015-forecast-snow-cold/36777733

The forecast snowfall for this week looking even better than at the time of my opening post of the thread a couple of days ago. Today’s GFS 12z has the 850 hPa 0C isotherm on Wed 5th and Thur 6th Nov over the French and Swiss Alps and encroaching on the Tyrol region of Austria. As a consequence freezing levels are briefly lower so it's not just the glaciers resorts that will see snow. For example: Val Thorens - 1700m overnight on Wed rising to 1950 Thurs. Verbier - 1600m overnight on Wed rising to 1850 Thurs. St. Anton - 1700m early Thurs and rising to 2150m. Today’s model output: GFS for 6th Nov Euro4 for 6th Nov Euro4 showing 48 hour cumulative snowfall up to noon Thurs 7th. It's difficult to be precise with the scale used, but it looks like decent accumulations at height. Should be some lovely snowy webcams shots by this Thurs!

It’s November and for winter sports and mountain enthusiasts that means it’s time to start looking for early season snowfall and watching the advance of winter on resort webcams. In a good year, snowfall in November can start building the piste base for the coming season. Last year was mixed for the Alps; snow came late but reached impressive depths at height and for certain areas. There are a number of key indicators being discussed in other threads (SAI, OPI, e-QBO, etc.) that suggest the coming 2014/15 season could be a good one. Let’s hope so and let’s hope snow and great conditions are shared equally around all resorts this year!! And for those wondering, Julian (J10) has kindly given me the go-ahead to start this year’s thread. He will be joining us with his regular weather and conditions updates in due course. So, to kick things off, here’s the skiing reports from the last couple of days from some of the high level glacier resorts (courtesy of Ski Club of GB)… Austria - Hintertux (185cm) After recent snowfall their pistes are looking excellent and the off piste looks very appealing…. 15 lifts running and mostly sunny. Switzerland - … beautiful sunny skies… Zermatt (110cm) had recent 20cm snow reported… 12 lifts running and the pistes looking great. France - Tignes (30cm) enjoyed another sunny day… 6 lifts in operation for those out on the slopes… the pistes are currently in a good state. And the forecast? Well the weather is glorious across the Alps at the moment, but snow is forecast to set in by Tues 4th Nov and according to the Ski Club of GB (using old GFS I believe) falls could be impressive on French and Swiss glaciers over the next 9 days, but the snow doesn’t get further east into Austria: Saas Fee - 122cm forecast Tignes - 52cm forecast Stubai - 0cm forecast Kitzsteinhorn - 0cm forecast Today’s GFS (Parallel) does indicate heavy precipitation on the way for the French & Swiss Alps, particularly on Wed 5th Nov. And with the freezing level forecast around 2,300m it could indeed be a good fall of snow for Saas Fee and Tignes. (GFS(P) seems to take the snow further east into Austria too). GFS(P) 5th Nov: And finally, today’s webcam shot from the Kitzsteinhorn Glacier: Link for the Kitzsteinhorn 5 webcams: http://webtv.feratel.com/webtv/?bgcolor=707173&color1=ffffff&color3=ffffff&color4=ffffff&color5=8dc63f&design=960v2&c0=0&c2=0&lg=de&pg=01202657-CEC7-4FDB-8B07-9387A8707204&t=6&cURL=oPZknQQSLkNj9%2FAfvaLxSg%2BYOOMYo8OCR7UemOt7rbMQ1RnRsAkqTgCrv%2BmufDbYOAT0graxkN3SEGGcmzAdGWYhe2%2Fpv2RIqp%2B4nzd7bZxrwJfru8spvHU%2BFSu5mxCuR6GkiJH1NbSoGJToN8mi%2BSs2ZDTP2ClWbyscoMFOpX%2BcuLjM8PyAQ3d06qHIcnsJ

Well IMO it’s been a very enjoyable month of “OPI watching†and great that we have ended with a promising Index of -2.12 from today’s GFS 12z run. I guess most of us are now hoping that the OPI will deliver on the expectations. It’s certainly going to be a good test, but with so many other indicators (such as SAI and eQBO) pointing in the same direction, you sort of feel that this winter should deliver? Based on the 12z run here’s the Nth Hemisphere 500mb Geopot Height Anomalies for the 1st to 31st October 2014 compared with the Composite chart for the Top Ten most negative OPI years. 1st - 31st Oct 2014 Top Ten Composite To my eyes this October’s anomalies look even better than the Composite with the Polar heights stronger and the Vortex lobes weaker – but maybe that’s to be expected if we have a “better than average†Index this year? And the story shouldn’t stop here. If we look at today’s ECM and GFS Nth Hem profile out at 10th Nov the Vortex is still struggling to form with heights over the Pole and lobes scattered. The early signs for the winter ahead continue to look promising! ECM 10th Nov GFS 10th Nov

Latest model output continues to be very encouraging for months end. Of course they are FI charts and subject to chops and changes with the exact height profile come the day, but importantly all models are forecasting positive heights continuing to impact the Polar region. Model forecasts for 30th/31st Oct: GFS: GEM: ECM:

Absolutely agree LomondSnowstorm. Also, there's been a lot of points raised on here about the forecast element of the daily Index calculation. Whilst there are no doubt a number of areas where this could be improved, I personally enjoy the debate and model analysis around where the Index is heading. I view it as no different to looking at the "Snow & Ice in the Nth Hem" thread, where you can look at the actual and speculate about what the models indicate for the rest of the month. There would be little posting activity in most threads if we just waited until the "actual" had happened!! This thread has generated a huge amount of interest in what is often a month without too much interest in it as we wait for winter proper - just look at the fact we are on Page 29 in less than 3 weeks. So it's a thanks to Riccardo and team for creating this thread and letting us share in their trial output. I'm hoping that after the team have published their OPI paper for peer review and made any adjustments accordingly, the publication of the daily OPI during October becomes an annual feature that we can continue to follow and enjoy as part of the build up to winter.

Based on today's GFS 12z output, the run-in to the month end Index might be a nervous time. Comparing the GFS ensemble mean for tomorrow with the 31st Oct is like chalk and cheese and shows the heights have pretty much disappeared from the vicinity of the Pole by months end (although at least the most deterioration is between 27th and 31st Oct so possibly limiting impact on the Index). But as others have noted, compared to other models, today's GFS might be too progressive. GFS ensemble mean 19th Oct: 31st Oct:

Good post bobbydog! Moving on to some other posts tonight about ECM, at face value the model seems to be really struggling with the Nth Hemisphere profile at the moment. If you take the furthest ECM output available on the 27th Oct (which is also the outer day of the 10 forecast that will be incorporated in today's OPI calculation) and then compare it with the GFS and GEM output, you can see the ECM is out on its own with height placements, and as Captain Shortwave noted in the model thread, the high pressure over the UK "looks very overdone". Of course, at this stage we don't know who will actually be the closest on the day. But I guess we should be happy all 3 models still have heights near the Pole disrupting the vortex. ECM 27th Oct: GEM: GFS:

I've used the NOAA NCEP website to generate the 16 day mean 500mb geopotential heights anomaly for 1st Oct to 16th October. In many aspects it resembles the composite heights anomaly for the top ten most negative OPI years and (hopefully!) shows how the Nth Hemisphere heights profile so far this October has helped give us the current negative OPI. 1st - 16th Oct mean 500mb heights anomaly: Composite for top ten negative OPI years:

Hi MPG. The OPI calculations are far more complicated than just looking at the Nth Hemisphere heights for a 3 day period. I've shown that chart because it's an indicator of how the heights profile might be looking out at the end of the GFS 10 day forecast period that the OPI model includes in its' calculations. Bear in mind that the final OPI is based on "actuals" for the month, once it has finished (i.e. 31st Oct). So there shouldn't be any difference between ECM and GFS once you get to the months end, as either would give you the "actuals". Also, bear in mind the post from Interitus yesterday, that the inclination of the vortex against an imaginary line drawn between the two major oceans has more weight (certainly at this stage of the month) than the actual geopotential heights. Anyway, for now it's promising because we have a calculation based on 17 days actual results and another 10 days forecast added. The Index will be gradually firming up.

Yes bluearmy, a very encouraging Index of -3.36 from the GFS 0z run. Yesterday I posted the ECM/GFS 8-10 day Nth Hemisphere mean height anomaly from Weds 12z runs and the heights had disappeared from the Pole. I'm glad to say that last night's 12z output have the heights back again, as well as (to my eye) better positioning of anomalies in relation to the top ten -ve OPI composite chart. I have no idea what signal the GFS had picked up to drop the heights on Weds, then have them back on Thurs (bearing in mind this is a 3 day mean chart out at days 8 to 10). But a wise post from John Holmes yesterday saying not to worry, you shouldn't take just one run! Height Anomaly for 24th - 26th Oct: Edit: Meant to say GFS has heights back, ECM remains reluctant.

Oh dear! The ECM/GFS 8-10 Day Mean 500 Height Anomaly output from the 12z runs yesterday have lost the positive anomaly over the Pole out at 23rd-25th Oct. Both models showing this. I've been checking this chart since quite early in the month and this is the first output to lose the anomaly.

AccuWeather issued their US Winter Forecast today: US Winter Forecast: Cold, Snow to Seize Northeast; Wintry Blasts to Slick South Though parts of the Northeast and mid-Atlantic had a gradual introduction to fall, winter will arrive without delay. Cold air and high snow amounts will define the season. Farther south, ice storms and snow events will threaten the Tennessee Valley and parts of the southern Plains. Much of the South can prepare for a wet winter, with some severe weather encroaching on Florida. The northern Plains will be somewhat inconsistent with variable, back-and-forth temperatures and below-normal snowfall. Meanwhile, the drought will persist in the Northwest and northern California and ease slightly farther south. Full article: http://www.accuweather.com/en/weather-news/us-2014-2015-winter-forecast/35422753

Good to see the Index back on track! Given that we know what the Nth hemisphere 500hPa mean height anomalies looked like for the ten most negative OPI Octobers, and we know that the OPI calculation includes 10 forecast charts from GFS, then an encouraging indicator as to how the Index might progress will be to look at the GFS 8-10 day forecast height anomalies and compare with the Top Ten composite. So here's the latest comparison. First the composite for the most negative OPI Octobers (with thanks to BFTV for posting earlier in the thread). It's low heights for Russia, south of Greenland and south of the Aleutians, and positive heights over the Pole: Then yesterday’s 12z ECM/GFS 8-10 day mean height anomalies. (GFS on the right). There are a number of ticks in the box although some anomalies are slightly out of position. So good to see the heights maintained over the Pole and the Vortex still disturbed. It bodes well. But the unknown going forward is how any slight misplacement of anomalies and “wrong†inclination of vortex lobes will impact the Index calculations.

It struck me this evening that Super Typhoon Vongfong may be having an impact on the Nth Hemisphere profile forecast for the next 10 days and therefore included in the OPI model calculation. This is just an observation and may be nothing to do with yesterday's swing in the Index value, but if nothing else it's very interesting how a typhoon battering Japan seems to end up dragging the PV along in its' wake. I've marked up a few charts showing this: Vongyong enters the arena on 12th Oct: By the 15th engages with cold uppers By the 16th an active influence on the Nth Hemisphere cold pool and arguably already impacting the axis of the PV By the 19th it appears to me that Vongfong is saying to the PV "follow me".... So interesting in my view, with GFS suggesting from these forecast charts that Vongfong will have an impact on the axis of the PV over the 10 day forecast period, which is included in the OPI calculation.

That's how I see it too bobbydog. Well summed up!