Summary:

Moisture associated with another tropical system will move into the area late this week (Thursday-Friday).  Heavy rain is possible.

 

Details:

Remember last week when the remnants of Hurricane Norbert brought heavy rains to much of the area? Well it's a new week and we've got a new tropical system that will help push moisture into the area.  This system is named Odile.

There are, however, subtle differences between our scenario last week and the situation for this week.  Unlike Norbert, which weakened and moved inland, Odile is likely going to weaken and slowly turn west out to sea.  However, there will still be plenty of moisture associated with the system that will be dragged up into the area.  Like last week, we have a second, more fall-like low pressure system off the west coast that will help pull the moisture north into the region.  This is when forecasting becomes difficult.  If this east pacific low moves inland earlier than expected, it will quash the moisture and keep it from making its way far enough north for us to see a lot of rain.  Conversely, if the Low stays offshore for too long, there won't be enough flow to pull the moisture up to us.  But if this low is in the "sweet spot" at the right time.  It can not only pull moisture from Odile north into the region, but it will also add dynamics to the situation to generate more organized convection (thunderstorms) and heavy rain.  Right now... this last scenario is what models seem to be liking.  That means moisture will move into the area on Thursday and last at least through Friday.

Below is the EC's QPF thru next weekend:

 

Decent rainfall for most of western and central Utah, including the Wasatch.  Next, the GFS's qpf thru next weekend:

 

As you can see, the GFS is significantly more aggressive with even more widespread rain.  Either way, it looks like we'll have a good shot at precipitation.

As for precipitation type, this is warm origin storm so we won't have much cold air to work with.  There is some cooler air with the Low in the Eastern Pacific that will gradually work its way into the area.  Still... probably the only chance for snow will be on the highest peaks.

The second half of September is when the pattern really starts to change... So I'd expect for something interesting and more winter-like to develop in the models in the next week or two.  I'll keep you posted.

Evan | OpenSnow