North America on the long term 24th March

Hello all, welcome to my final North America on the long term outlook for the season, and my final post for the Northern Hemisphere season. Today we take a last look at the models and drivers that matter in the long term to conclude the season, at least for me.

6-9 April

GFS shows a system moving across the PNW/BC region over the late hours of the 6th, staying over Coastal areas until the 8th, when the system heads further inland with moderate-heavy snowfall. EPS Control also shows a system over the PNW and BC area over the 6th and 7th, with moderate snowfall.

10-14 April

EC Monthly shows a system crossing the PNW/BC region with moderate snowfall in the late hours of the 10th, into the 11th. It continues into the interior, and then south to Colorado/Utah over the 12th and 13th as snow showers, before dissipating over the 14th.

15-19 April

EC Monthly shows a system again crossing the BC/PNW region with moderate-heavy snowfall in the early hours of the 15th, moving into the interior PNW over the 16th, before heading to Colorado over the 17th, turning to heavy snowfall over the 18th, before moving east on the 19th.

21-23 April

EC Monthly shows some snow showers in the Interior BC region on the 21st, moving south along the Rockies on the 22nd through MT/Idaho/WY, and then to Colorado on the 23rd.

Climate Drivers

GEFS Bias Corrected forecasts the AAM to stay positive for the rest of the month, and into the first week of April. This will assist the Pacific Jet in extending, which improves the chances of storms for the West Coast, and into the interior. CFS shows the AAM to stay neutral until April 10, when some of the ensemble members go for a positive AAM outlook into the later half of the month.

The EPS MJO forecast is for the MJO to go into Phase 7&8 by the start of April. This decreases chances of storms for the Western half of America, and improves them for the Eastern half. GEFS is similar, but shows a stronger MJO through Phases 7&8.

EC46 forecasts the AO to stay slightly positive through most of April, this improves chances of snowstorms for the Western States. CFS shows the AO as mostly neutral through April, until Mid May, when the AO is tipped to go negative.

To add to that, the Stratospheric Polar Vortex is still slowly weakening, providing a little bit, but not a lot of support for more storms and snowfall in the East, rather than the West.

To summarise, the models seem pretty average for this time of year, with a few storms in April for the PNW, and possibly into the Rockies. The drivers look good with the AAM and EC46 AO forecasts showing good snowfall chances for the West, and the Stratosphere and more importantly the MJO showing weaker snowfall chances for the West. Anyway that was the final forecast from me for the season. My season forecast earlier in the season went not so badly, with little snowfall falling in SoCal, NM and AZ, and with Colorado and Utah as relatively neutral(Tahoe until recently had a terrible season). And the PNW, more specifically the Interior PNW did the best. Thank you so much to all who read these musings, I really do appreciate all the support. Hopefully everyone had a great season, and is ready to do it all again next season! These posts will start back up again in October. Australian Long Range forecasts start later next month.

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 North American 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. I will see you all next season, until then, Stay Cool.

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