Hilary Rainfall

The forecast has changed a bit since our last blog.  So I wanted to update you on those changes and their potential impact on our weather.

After a really hot night, the dry cold front is sweeping through the area today, dropping temperatures about 10 degrees.  But extremely dry air is also moving into the area.  This will do 2 things; today, extremely high fire danger as relative humidities will be less than 10% in many locations, and winds will be gusting to 30 mph.  This is not the day to mow those dry weeds.

Dry air also tends to allow temperatures to cool rapidly at night, as long as there is no wind or clouds.  That combination could yield some rather chilly temperatures Saturday morning.  It will be quite a contrast from last night.  Some locations (Springdale, Priest Lake, Deer Park) could actually dip into the upper 30s while most locations will be in the 40s.

Unfortunately, the much cooler temperatures next week aren't going to be quite as cool as hoped.  Think upper 80s instead of lower 80s.  The exception to this could be Tuesday, when Hillary comes knocking.  

Yes, the remnants of hurricane Hilary could impact our weather next Tuesday.  Previously in this blog it looked like Hilary would stay out at sea.  But now, the computer consensus is that Hilary will take a very unusual track into southern California.  Here's the official forecast from the Hurricane Center.  When was the last time you saw a hurricane track like this?  Never?

There are lots of computer forecasts of hurricane tracks.  Here's a collection of several of them from TropicalTidbits.  Now just because you see some of the tracks going into eastern Washington, don't think that we're going to get hit by a hurricane.  After traveling over that much land (from San Diego to Spokane), there won't be much left of Hilary.  

The main concern for Southern California won't be winds or storm surge as much as rain.  10" of rain in the desert mountains of southern California is not a good thing.

The computer forecasts of rain will vary of course.  Here's the European model forecast.  Lots of rain in the SoCal mountains and southern Sierra Nevada.  But this model would say that the bulk of the rain will move across southern Idaho and into western Montana, missing the Inland NW.

Let's zoom into the Northwest and look at the various ensemble forecasts.  First, we'll start with the Canadian models.  It gives some light rain to eastern Washington, but the bulk of the rain misses us to the south and east.

The European models are about the same, putting the Inland NW on the western fringe of the rainfall.

Lastly, the US models are in close agreement with the other models.    Looks like the central mountains of Idaho are going to get rather wet.

The current thinking is about a quarter of an inch of rain for northeast WA on Monday night and Tuesday.  But it wouldn't surprise me if we get less than that.