Inland Northwest Hay Weather

As most of us know, summertime in the Western US is largely dry, while east of the Rockies it's rather wet and humid.  You can easily see this pattern in the normal rainfall for August. But there is one notable exception to this pattern in the map above.  That's in the desert Southwest.   Once the Four Corners high pressure has become established in the summer, moisture from the south (i.e. Mexico) is drawn up into Arizona and New Mexico, as well as Colorado and southern Utah.  Afternoon thunderstorms are a daily occurrence there at this time of year.  It's their wettest time of the year. Sometimes the moisture will make it farther north, into Burns, OR, Boise, ID and even Billings, MT.  But to get that moisture all the way up into the Inland Northwest is really tough.  Not only does it have to travel far to the north, it also has to move west, since Spokane is well west of Phoenix.  So Washington is the least likely western state to see...

We've gone through the month of July without a drop of rain (a few locations had a sprinkle).  But all of that appears to be coming to an end.  As I wrote in my last blog, there would be a chance of rain in the final days of July.  Now that it's close enough we have some details. First, we'll talk about moisture.  Currently, our atmosphere isn't bone dry.  We often look at a parameter called "precipitable water".  The name might imply it's how much precipitation you could get, but don't think of it that way.  It's just a measure of the amount of moisture that the atmosphere is currently holding.  If it's really low, then rainfall will typically be light, since there's not that much moisture in the atmosphere to form rain drops.  Here's our current precipitable water map.  Values in north and east Washington are generally around two thirds of an inch. As our storm approaches from the west, the southerly winds ahead of the storm will brin...

Well, our heat wave has finally ended.  Deer Park tied its consecutive string of 90+ degree days at 18.  But Spokane may keeping it going, now at 18 days and possibly 19 today and 20 by tomorrow.  Truly impressive.  But even more impressive is Omak, which had 16 consecutive days of triple digits , smashing their old record of 9 days set only 2 years ago.   Sunday was historic hot.  Fourth hottest day in Spokane history.  And no, this wasn't a local effect of the airport.  Every location in the metro area was hot. The dew point is dropping like a rock on this Tuesday afternoon.  That means a chilly night tonight.  Temperatures on Wednesday morning will be in the upper 40s, with mid 40s at the cold spots like Springdale and Priest Lake.  The low dew point will continue through the rest of this week, making dew tough to find, even with the cooler temperatures. Our heat-breaking low is actually coming in two phases.  The first...

When I first arrived in Spokane in the mid-1990s, the climate data at Spokane International showed that the airport averaged one 100F day each year.  But when you looked closer, you would see that only 14 of the 30 years from 1965-1984 had at least one triple-digit day.  In other words, if you're going to hit 100F once in a summer, it's likely you're going to hit it more than once.  Another way to put it is that it was wasn't easy  to hit 100F in Spokane. Recently, this has changed.  And this goes along with my blog a week ago about the recent trend towards hotter summers.  In the most recent 30 years (1995-2024), Spokane has hit 100F forty-two times, or an average of nearly 1.5 times per year.  Hitting triple digits in Spokane is getting to be more common.  In fact, the last summer we had where we didn't have triple digits was the pre-pandemic year of 2019.  We've never had a string of 5 consecutive years of triple digit summers, until now....

A week ago, we were only a few days into our current heat wave. And I wrote a blog entry about the upcoming week, noting that there was no strong relief in sight. The consecutive 90+ degree days would start to add up, and we could approach the record number of days for Spokane (15 is the record).  As of Monday, Spokane airport has reach 90F or greater for 11 straight days.  Does the forecast indicate we'll break the record? Here's a forecast temperature graphic I've shown before.  The red boxes are the forecast high temperature.  The bottom of the box is the forecast high temperature that 90% of the computers are forecasting that we'll at least reach.  You can see that the bottom of the boxes don't go below 90F for the next 6 days.  So 90% of the computer forecasts predict Spokane will have a string of 90+F high temperature for at least 17 consecutive days, which would break the record.. There are a couple of flies in the ointment.  The first is a weak...

I realize that it's risky to get overly excited about something during a streak.  Like calling for the firing of a coach during a losing streak.  But as we are well in the middle of a long stretch of hot and dry weather, it got me to wondering if there is any trend in our summer temperatures in the Inland Northwest. So the first thing I looked at was the average temperature at Spokane each summer.  I defined summer and June, July, and August, knowing that June is often a springtime month here.  But since we've also had some summer-like June's, I felt it was worth including in the search.   The reason for selecting Spokane is that its data goes all the way back to 1881.  However, there are some issues that I'll talk about in a minute. Here's the average summer temperature (high and low temperatures averaged together) for Spokane since 1881 (blue line).  The green line represents a smoothed trend of those yearly temperatures. The first thing to noti...

The record heat wave of 2021 in the Pacific Northwest brought to light an unusual aspect about our area: the lack of air conditioners.  Certainly, most new homes in the Northwest are now outfitted with A/C.  But a lot of older homes don't have the cooling comfort of A/C.  How is common is that in the US? A study back in 2020 by the Energy Information Agency determined the following facts: 89% of US homes have some form of Air Conditioning (central or window unit). Ignoring Alaska, the state of Washington had the lowest percentage of homes with A/C.  Only 53%.  That's probably higher now after the 2021 heat wave. Hawaii surprisingly only had 57% of homes with A/C. The rankings of the lowest percentage of A/C homes is as follows: Alaska - 7% Washington - 53% Hawaii - 57% Montana - 65% Vermont - 67% Maine - 70% Wyoming - 71% California - 72% Oregon - 76% New Hampshire - 78% Idaho - 81% The obvious pattern is that some of the states are located in the northeast, bu...