Western North America on the long term 8th Dec

Hello everybody, it’s the Snowy Hibbo back again for another update on the North America snow situation. Sorry for the big delay, but it’s time for another look into the drivers and the models.

17-23 Jan

GFS shows the jetstream bringing moisture into the PNW late on the 17th, before moderate-heavy snowfall spreads across the Western US mountains on the 18th. The first wave leaves the Western US on the 20th, not before dumping snow in the CO/UT Rockies and in the Four Corners region. More snow persists across the coastal ranges and the Rockies until around the 23rd, when the system starts to fall apart. EPS Control broadly agrees with this assessment, but contrasts with lesser snow totals, and little snow for NM and AZ.

25-29 Jan

Apart from some snow showers in parts of Colorado on the 24th afternoon, no major snowfalls until the 25th, as EC Monthly shows a trough ploughing into California, bringing heavy snow in the Sierra Nevada. This moves inland on the 27th, and then combines with a big low to form moderate-heavy snowfall across the Rockies from BC to New Mexico. This eases by the 29th into light snow showers. CFS shows a trough bringing heavy snowfall for the Sierra Nevada and the PNW, and the BC Coast from the 25th Jan to the 3rd of Jan. That’s a lot of snow for the PNW resorts. The Rockies largely misses out on CFS, except on the 28th, when some light-moderate snow showers come over CO/UT.

29-31 Jan

Another system ploughs into the West Coast on EC Monthly, showing heavy snowfall for the coastal ranges in the PNW and the Sierra Nevada on the 29th. The system moves inland on the 30th slowly, bringing moderate snowfall for the entire Rockies range. The system weakens on the 31st, bringing fading lighter snowfall to the Rockies. CFS shows a continued trough during this period, mainly bringing heavy snow to the PNW.

1-2 Feb

EC Monthly shows a system coming over the Coastal ranges on the 1st of Feb, bringing light snowfall there. It moves inland later on the 1st and into the 2nd, bringing moderate snowfall to the Inland PNW, CO and Northern UT. It is clear by the 3rd of Feb. CFS continues to show the West Coast trough, although during this period, it moves south towards California, bringing moderate-heavy snow in the Sierra Nevada, before weakening by the 3rd.

4-5 Feb

EC Monthly shows a quick moving trough, impacting the BC Rockies on the evening of the 3rd, coming down the Rockies into the Inland PNW, CO and UT later on the 4th. It brings moderate snowfall to these places over the respective days. CFS shows more snow for the West Coast, specifically the PNW and Tahoe during this period.

Climate DriversThe MJO is currently in Phase 2, and it is forecast to continue it’s cycle over to Phase 4. I am predicting that it will be in Phases 6/7 by Early Feb, which is more favourable for the Eastern US. That gives the next 20 days for the Western US to get lots of snow, while the drivers are in favour. EPS’s MJO forecast is below.

The GWO is currently in Phase 1. Changes in momentum, created by a MJO westerly wind burst, will result in a movement to GWO Phase 4, that will probably occur in Late Jan/Early Feb, to time with the MJO Phase 6/7 event. A Phase 4 GWO event is more favourable to the Eastern US, than the Western US snow wise, so again the next 10-20 days, while the AAM is lower, it would be a good time for snowfall.

The Stratosphere is still bland, with little change to the current cold and stable polar vortex. It is forecast to stay that way(below). This creates a positive influence for the Western US (more snowfall).

The Arctic Oscillation is forecasted by EPS(below) and GEFS to be negative, which is typically more favourable for the Eastern US.

So the drivers are looking not bad at all for the next 10-20 days in Western North America. I would personally love to be out there within that time period.

Thanks so much for reading. I hoped you enjoyed reading it.

Disclaimer: There is low skill asssociated with using long range model forecasts to find snow systems. All systems you see here will change, as the date gets closer and may not eventuate all together. I don’t give much accuracy to these forecasts, but you can give these a bit of your time and your dreams might come true 😉 I find the chase of these long range snow systems awesome, so come and join me! The climate driver forecasts tend to have a bit more skill than the model forecasts, but certainly don’t put all your money on them. However, climate drivers are an awesome tool to explain the weather around us.

Thanks again for reading this Japanese long range snow forecast, follow me on Twitter @longrangesnow and subscribe to my email list by clicking on the tab on the main header above.

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