It's officially Autumn, at least for meteorologists and weather/ski junkies.  While the astronomical start of Fall is the more well-known Autumn equinox (~ Sept 21), the more relevant calendar for our purposes is the meteorological one, in which Autumn starts on September 1.  So congratulations, we are 2 days into Fall (and that much closer to winter).

After a very cool and wet August for most of the area, we've dried out significantly over the past week.  Temps have for the most part been near average.  However, signs of the new season continue to emerge.  Today, we have a cold front moving through the state that is kicking up winds a bit this morning ahead of it.  Precipitation will stay well north of the area up in Montana and Southern Alberta, but cooler air will make it as far south as northern Utah.  Tomorrow's high temps should be a touch cooler than today's.   This weekend should be back to mostly calm conditions and it will feel a bit more like summer than Fall.  Currently the forecast looks tranquil for the next 7 days.  We could see another monsoonal moisture surge next week but it will likely mainly affect southern and eastern Utah.  Overall, we are just beginning the roller coaster ride we experience every Spring and Fall when the overall pattern is changing and we see dramatic changes from one day to the next.  Expect cold fronts to become stronger and more frequent over the next month or two.

Fall / Winter Outlook  - El Nino update: 

El Nino conditions, which started to develop in the Spring before taking a hiatus for most of the summer, are now starting to reappear.  The ONI value in the Nino 3.4 region is once again warming further above normal:

 

If you recall, El Nino conditions are defined as +0.5C or more above normal.  It looks like we are on our way back toward that threshold after briefly dropping below normal in late July.

The CFS model is currently forecasting the following precip anomalies for the Fall months (Sep-Oct-Nov):

 

What I take from this is that we will likely see occasional monsoonal moisture surges through the next month that might boost parts of Utah and the desert southwest slightly above normal in terms of precip, but in terms of winter-like storms, we should be near average.

By winter, El Nino should be stronger and things get a little more interesting:

 

This is much more typical of El Nino and exactly what the forecast has been all summer.  Northern Utah has about equal chances for above/below normal precip.  Southern Utah will be favored more and have a better chance for a good winter.

Again, all of this should be taken with a massive grain of salt as always.  There is cautious optimism for a good year.  Even an average year here is still 500" -- which is better than we've seen the last 3 seasons...

Evan | OpenSnow