Inland Northwest Hay Weather

The last week of July is (on average) the hottest week of the summer.  We are looking at 90s Mon-Thu this week, so this may be following the pattern.  The longest day of the year is June 20th, with 16 hours of daylight in Spokane.  By the end of July, we've already lost just over an hour of that.  Not that the length of day is the only factor of hot weather, but it obviously has an effect.  The days noticeably get shorter in August, losing about 3 minutes of sunshine each day. We were talking in the last blog about the potential for showers and thunderstorms this week.  As usual, things are becoming a bit clearer on timing and coverage.   Afternoon and evening thunderstorms will increase over the next few days over eastern Oregon, slowly creeping north each day. By Tuesday, the southern Washington Cascades could see an isolated storm.  Wednesday will see the potential for afternoon thunderstorms over most Washington mountains. Here’s the European ...

Our predicted rain event delivered very light rain to most folks, with a few pockets of rather heavy rain. Here’s the 2 day storm total rainfall detected by radar. Our temperatures have peaked today and will be trending down for the next couple of days before a longer hot spell kicks in next week. We should reach 95-100F by Tuesday or Wednesday.  The weather map below shows a hot ridge of high pressure over us, wedged between 2 cool low pressure centers.  But this pattern opens us up to minor little disturbances approaching us from the south or southwest, starting around Tuesday and continuing through the rest of the week.  Here’s the chances of rain for the next 10 days. Very low chances, but not zero.  The best chance will be Thursday or Friday.  This is a pretty typical pattern for what we call high-based thunderstorms. Those typically happen with a hot, dry atmosphere. The base of the storms are often more than 10,000 above the ground. As such, most of any r...

Computer forecasts are coming into better agreement on the potential for rain on Monday and/or Tuesday. This isn’t just a threat of some afternoon showers or thunderstorms. Rather, this will be a low pressure system that will develop right overhead.  Initially on Monday morning, the rain will move in from the southwest.  The best chance of rain will be in the afternoon and evening. We’ll probably stay in the 70s that day but some forecasts keep us in the 60s.  A second weather disturbance will move down from BC on Tuesday for a second chance of rain.  As for how much rain, here’s a few computer forecasts validated Monday through Wednesday morning, from the US, European, Canadian and UK models.  You can see differences, but they’re all fairly similar. Here’s the best average of all the computer forecasts.  You can see around 0.1” for Spokane, with more to the north and even some light amounts in the Basin.  But as you can see with some of the computer f...

In my blog back on 9 July (8 days ago) I mentioned that the European models were showing some low pressure in our area around the 19th of July. While not a perfect forecast, it does appear that we will have more low pressure than high pressure this weekend and the first half of next week.  Here’s the weather map for Saturday.   Strong high pressure in the Gulf of Alaska will allow low pressure to develop over southern BC. Another low will drop into our area on Monday. This will keep our temperatures in the 80s starting Saturday and through next Wednesday. What weather will we get besides cooler temperatures?  For starters, we’ll see some more wind on Friday and Saturday.  Nothing outrageous, with gusts to 20 mph.  But it will remove any chance of dew formation on Saturday (and possibly Sunday) morning, so don’t plan on any early morning baling. We’ll also see a threat of showers around Monday or Tuesday.  Still a low chance until the computers come to a bet...

  Just a quick update on the precipitation chances for Monday night and Tuesday.  Not a lot has changed in the overall forecast, but confidence has increased on a much cooler Tuesday. Here's the European model rainfall forecast for this period.  It keeps almost all of the rain in Pend Oreille county. The US model has pushed the rain a little farther south than its previous forecast. The UK model has backed off on it's crazy-wet forecast. The Canadian model is now the wettest forecast, but it is in the minority. Rainfall amounts should be light.  This isn't a great pattern for thunderstorms, but I would rule it out.  Our dew points and atmospheric moisture is pretty high right now so there is a chance of an isolated downpour, but again, this would mainly be north of Deer Park if at all. Wind is the other weather of note.  Monday will be a hot, blow-dryer day.  Temperatures will be in the 80s in central Washington, with 90s in the Basin and eastern WA, w...

In my last blog I said there was no rain in sight aside from some mountain showers near the BC and ID/MT border. I also mentioned that there would be a weak weather system on Monday or Tuesday that would bring us a bit of cooling after a hot weekend.  The computers are now thinking that the weak weather system could be a bit stronger than previously thought.  If true, this would mean more wind and a better chance of showers. But please understand, there is a LOT of uncertainty and disagreement on this forecast.  To show you what I mean, below is the temperature forecast for Deer Park. I’ve shown this graph before, but it’s been awhile. Basically, instead of predicting a single high or low temperature, it shows the range of possibilities. The bigger the box, the larger the range of possible temperatures.  See that big red box on Tuesday?  The range of the computer forecast high temperatures for Tuesday is from 70F to 101F. You won’t see that on any app or TV fore...