Clouds increase today, with a milder storm moving into the Northwest US. Rain and snow, and even freezing rain has moved into north Idaho, and we expect increasing and lowering clouds today, with snow showers developing later this afternoon and through overnight, continued through Monday morning. Roughly 1/2 foot of snow is expected to Bogus Basin, and a bit more further north and east. Snow levels are going to be a close call as they run near 6,000 feet under a southwest wind flow across the mountains, and a moisture tap from the subtropics.

Monday looks a bit colder and expect to see plenty of sunshine as we are between storms, and under high pressure ridging. By Monday night, we are seeing snow again. This storm moves in more from the west, with a strong pressure gradient and very strong winds expected on Tuesday. Snow levels will be a close call again, up near the base elevation around 6,000 feet. If the jet stream ends up a bit more south, our forecast snow will have to be doubled, from 2 to 4 to roughly 4 to 8 inches of snowfall on Tuesday. Snow ends Tuesday night, and by ...

Wednesday we see clouds clearing and cool temperatures, with fresh new snow to ski and board on Wednesday under now building high pressure ridging aloft and exiting low pressure/ moisture/ dynamics, and decreasing winds... By Thursday we are squarely under high pressure ridging aloft, with milder temperatures and less wind expected.

LONGER RANGE: Friday and through the weekend (21st - 23rd) we expect a couple of low pressure systems to move through with potential snowfall, looking mostly light at this point, but MORE snow nonetheless. The further north you are the better snowfall, is what it is looking like. Right now probably 1-2" of snow from each storm is the best bet, but of course we will monitor and update.Christmas Eve and Christmas Day a stronger and possibly juicier storm moves through the area with a better shot of heavier snow just in time for these days off. A couple of days later around the 27th-29th, another couple of storms may move through with a last blast of snow before a potential 2 week down time under high pressure ridging and dry/ milder conditions. By the 10th-15th of January we should be back into a regular storm cycle... CM

Fri, August 31st, 2018 (begun this article)
Wednesday September 19, 2018 (I finally finished it!)

MODOKI EL NINO = bad, REGULAR EL NINO = not always bad, WEAK EL NINO to ENSO Neutral = could be good (due also to other factors)! There are many possibilities with the last one (the one we think is coming) but we will nail it down for you! 

Southern Idaho, Sun Valley to Montana and Wyoming
FALL and WINTER SEASON FORECAST FROM SNOWFORECAST.COM!

...WHAT IS THE FORECAST?...
OCTOBER - (Near average snowfall and below average temperatures) Early season cold and October snows for the ski resorts, though best snow and coldest temperatures will be to the east of the divide and Wyoming/ southwest Montana (Big Sky and Jackson Hole), a bit drier for southern Idaho (Bogus Basin and Sun Valley), as storms drop in out of Canada for the most part, carrying the bulk of moisture and cold air to the east of the divide. There will be enough cold to test out any snowmaking equipment, even across southern Idaho, as cold air and moisture still manages to deliver some snow to Bogus Basin and Sun Valley at times. Early snows will linger for days at the resort elevations to help cool the soil for some good base building when we move into November... We also expect the usual transition season cut-off and closed low pressure systems to move in from the west and deliver some surprises (snow)... "Cut-off" means the low is cut off from and not being pushed around by, the storm steering flow (usually at 500mb).
NOVEMBER - (Near to just below average snowfall, and near to below average temperatures) Near average early season snow overall across the region (Montana and Wyoming will likely still do best) and mostly no snow level issues, with cold systems out of Canada clipping southern Idaho and hitting areas mainly east of the divide full force, as high pressure ridging offshore of the west coast allows storms to develop and move south from out of Canada, moving in with below average temperatures and possibly some extreme record cold. We expect some late November opening days on good bases mainly for Yellowstone-Jackson Hole, and some near to a bit below average base depths for Sun Valley and Bogus Basin, but pretty well preserved as colder than usual air helps to protect the snow...
DECEMBER - (Near average snowfall and near to below average temperatures through mid December, then dropping off to below average snowfall and near average temperatures in late December on some fair to good bases). Some good snowfall events through mid and maybe into late December, and near to below average temperatures should combine to be great for Christmas-New Year skiing/ boarding, then incoming storms start shifting to the south on a different storm  track, with lighter snows across the region as we move into the holidays, though there could still be some good moisture and snowfall from out of the southwest for especially for Bogus Basin and to a lesser extent Sun Vally.
JANUARY ONWARD, MORE COMING SOON - ? Stay tuned, but a brief synopsis: Dry for most of January with above average temperatures as high pressure ridging builds in, and the east coast gets hammered with cold and snow. Storms return in February with near average snowfall and temperatures for Bogus Basin and Sun Valley (a heavy snow is possible from storms on a more southern track), less than average snow for Big Sky, then March through the rest of the season looks near to warmer than average in temperature, with below average snows. April could produce some big storms and powder days to pass through the region, building the late season snowpack. More details are coming, and I will be naming resorts and forecasting long range snow totals. CM

...WHAT ARE THE FACTORS AND OPINIONS?...
Here are my August 31 observations: An El Nino that "wants" to happen, but meager warming to even some cooling in the key Nino regions (recent), and a mostly neutral status (currently) is not showing much hope for any El Nino pattern that may be classified as moderate or strong. In fact, I will say that we will not see a moderate or strong El Nino SST pattern this 2018-2019 season, and the NOAA forecasted weak El Nino is looking like a "maybe".
And, my September 15 observations: Latest guidance indicates that the El Nino SST anomaly will be weak, at best, in my opinion. Here is why: Cooler eastern Pacific waters (Nino 3.4 region)/ Subsurface waters heat content (180-100W Lat) has decreased/ and the current pattern is showing mostly a general cooling and not warming overall, though in the last 7 days, eastern Pacific surface waters off the coast of Ecuador (means "Equator") have warmed . Its mid September and this El Nino event should be a bit more evident. Its not. Even NOAA has backed off a bit with a 65% chance of El Nino formation, instead of the 70% they had called for early on in the summer when this anomaly looked more likely. For them to back off a bit like that indicates definite lost confidence, and this is not surprising, as I lost confidence in it occurring myself, back in July. Things work a bit slower in these large organizations, while us "loose cannons" (whatever in the hell that means) can blast off at will. Haha.


*An El Nino is still favored according to the above Climate Prediction Center chart*



*We have seen some areas of cooling in the Nino 1+2 and 3 regions, as this El Nino struggles to form. This is indicating cooling in the subsurface waters, which is a factor that is looked at for potential SST's*



*As of Sep 12, there is some warming going on again in the referenced "Nino 3" region, so overall there is a positive SST anomaly, but mostly less than +.5 (in yellow on the above chart), which is the threshold that needs to be met for 3 consecutive months before an actual El Nino pattern is recognized. For now we are in an "ENSO neutral" status.

SOLAR MINIMUM: In terms of sunspot activity, there is currently almost none, or even "none", zero, zilch, nada, many days. Decreased or zero sunspot activity also affects our weather patterns. The chart below shows how we are in a solar "grand minimum" right now:



Side note, look at the last minimum, in 07-08-09', when  the Inland Northwest had the most snow EVER recorded, back to back years, one with 170+ inches of snow in Coeur d'Alene, ID.

Also, we have seen some recent serious weather extremes this Summer of 2018, and have no reason to believe that we will not see similar extremes this fall and winter in North America:

From extreme heat in Europe, notably northern Europe:




To extreme snow and cold in August:

 NOAA: So to reiterate, NOAA (the National Oceanic and Atmospheric Administration) was forecasting a 60% likelihood for formation of an El Nino SST pattern this fall, and a 70% chance for the winter, 2018-2019, while now those forecasts are down to 50-55% and 65-70%, respectively. Large organizations like NOAA are not going to go backward on the forecast (decreased % chance), like this without very good reason, like, "its not happening like we thought it would guys"...

SNOWFORECAST.COM: At this point, a "weak" El Nino SST anomaly is the forecast from NOAA. I have believed since June that this would be a weak El Nino pattern that sets up, based on the afore-mentioned trend, but am now wondering if this El Nino will even show up at all. For those who desire to see some at least average rain and snowfall this winter, a weak El Nino or no El Nino may be best. If an El Nino, weak, does form, it is looking more likely to be the Modoki version, which on average, sucks (dry) all across the western US. Thankfully, as a weak factor (there are other factors), a weak El Nino of any kind will have a "weaker" influence on the weather patterns we see this fall and winter, THANKFULLY. We are also looking (currently) at a weakly negative PDO (Pacific Decadal Oscillation, more of a long term state of ocean water temps), which will not help in the El Nino department. Neutral to "very weak El Nino" is what we are forecasting as we move into fall and maybe through the winter, at best +.5 which is barely classified as an El Nino. As well, with the Grand Solar Minimum, expect the unexpected, and so far, that has proven true in many parts of the world. How will all of these factors; Weak El Nino, or even "ENSO Neutral" SST anomaly, neutral PDO, GSM (solar), and my own intuition, affect the Northwest US and Western Canada forecast? Just scroll back to the top to find out!

Feel free to share this, but please cite credit to snowforecast.com. Thank you! CM

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Some References:
COLD AND SNOW:  https://www.theweek.info/index.php?newsid=3760 (Salzburg, over 1 foot of snow in August!)
HEAT:  https://www.washingtonpost.com/news/capital-weather-gang/wp/2018/07/17/scorching-scandinavia-record-breaking-heat-hits-norway-finland-and-sweden (90+ degrees in Norway, all time record high temps!)
Great resource for current SST’s and anomalies:
https://www.tropicaltidbits.com/analysis/ocean/
International Research Institute:
https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-cpc_plume
Latest ENSO Discussion:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.php
Space Weather ("Solar Minimum"):
https://www.swpc.noaa.gov/products/solar-cycle-progression
NCEP model forecast SST anomalies (1 model forecasting La Nina):
http://www.cpc.ncep.noaa.gov/products/NMME/current/tmpsfc_Seas2.html
The ONE outlier model forecasting La Nina:
http://www.cpc.ncep.noaa.gov/products/NMME/current/images/NASA_GEOS5v2_ensemble_tmpsfc_season2.png
Loads of the latest SST charts from ESRL, knock yourself out:
https://www.esrl.noaa.gov/psd/map/clim/sst.shtml
Best anomaly chart (in my opinion):
https://www.esrl.noaa.gov/psd/map/images/sst/sst.anom.hov.gif

Detailed ENSO Discussion from NOAA:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
More info/ charts on Modoki El Nino:
http://www.jamstec.go.jp/frcgc/research/d1/iod/enmodoki_home_s.html.en
El Nino/ La Nina years/ ONI:
http://ggweather.com/enso/oni.htm
A GREAT resource for "no BS" historical ski season info:
http://bestsnow.net/
Latest PDO and history:
http://research.jisao.washington.edu/pdo/PDO.latest.txt
 

Mostly light additional snow, then a mostly sunny weekend, and  more snow next Tuesday and Wednesday (heavier)!

HOW ARE WE DOING (please contact chris@snowforecast.com or comment below)? Let us know please...

Light snow for most areas including Aspen, and  across southwest Colorado...

-The latest storm absolutely dumped RAIN and snow across southern California, is headed mainly along the Mexico border now, and taking a southern track... El Nino style, with a few" of snow across southwest Colorado to Aspen's mountains, under a moist southwest flow of moisture across the mountains, while most energy passes to the south

This coming weekend we expect a high pressure ridge to build in, with cooler air dragged into Colorado initially on Saturday, as the southern tracking low pressure system exits (northwest/ north flow of winds from the colder north), and sunshine pops through in the then drier air... Powder + sunshine, what Colorado is known for!

LONGER RANGE:
It looks like El Nino is not an official anomaly yet, as I expected in my September LR forecast (for Aspen and SW Colorado / For northern Colorado resorts) so we are in an ENSO Neutral phase, though in the latest update from NOAA, we are seeing warming waters, still a weak El Nino at best. This may explain the more southerly tracking storm systems we have seen, and will likely see in the coming weeks of December and January. CM

Next week, the 11th onward, we expect a couple of snow storms and some moderate to significant snow for western Colorado. Because these look like strong and cold systems (ask Niseko, Japan) with a good fetch of moisture across the Pacific, they are capable of good snowfall across all of western Colorado if the track is right (a bit more north). It looks like 2 storms total for next week, one Tuesday/ Wednesday and another late next week. CM

(NO CHANGE from the last LR update) : It is looking like we may see a busy time as we approach the Christmas and New Year holiday period, with some significant storms possibly lining up to affect all of the western US including Colorado... We expect to see a 7-14 day period of down time and mostly sunny skies following this series of storms, that may start around/ after Christmas. In January we see that down time to start the month (a week-ish), then storms should kick in again on a more regular basis, but possibly favoring northern resorts this time as the east coast gets hit hard and these systems brush mainly northern Colorado. More updates are coming. Do you have any ideas on what you want to see in our discussions? Please contact through the site! We do not charge for any of our info, and have been providing it all for free since 1998, "Predicting Sick Days since 1998"! CM