Endless Heat - Update

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 weather system that will pass through our area on Wednesday.

Here's the weather map from today (Monday).  Strong hot high pressure dominates the Northwest US and western Canada.  There is some weak low pressure off the coast of California and Oregon.  This weak system will try to move over the high pressure ridge.  It won't have much success, but it could bring some high based thunderstorms and some sprinkles.

Most of the thunderstorm activity will stay over the Cascades and Blue Mountains (southeast Washington).  But there will be enough clouds that a stray strike or sprinkle is possible elsewhere.  The computers all say we'll still be in the 90s or low 100s on Wednesday despite the clouds and showers though.  Here's a forecast of lightning activity on Wednesday from the European model.

The hot high pressure ridge is strong, and will continue into the coming weekend.  However, there's a new contender low pressure system in the Gulf of Alaska, trying to land a knock-down punch to the ridge.  Here's the weather map for Saturday.  Triple digits for most locations.

The computers generally have good agreement that this new Pacific low will have some success knocking down the high pressure.  The biggest disagreement is on the timing.  Some say Monday.  Others say Tuesday.  Maybe even Wednesday.  If you look back at the first graphic in this blog, that's why those red boxes get so large on first part of next week.  Lots of disagreement on timing and how much cooling.  The consensus says that we'll break the string of 90F days by Wednesday of next week, but it could be as early as Monday.

The good news is that the computers generally agree that this will bring about a pattern change.  The high pressure isn't expected to redevelop over the western US by the end of July  (see the map below).  This should keep our temperatures in the 80s to finish out the month.  But that's a long way in the future, so I wouldn't be betting any money on that just yet.

Will there be any rain with that Pacific storm early next week?  The odds are very low (less than 10%), but they're not zero.  

One thing to note.  While Spokane's record for consecutive days of 90F or more is 15, the record at Deer Park is surprisingly 18.  So Deer Park would need to reach or exceed 90F until Tuesday 23 July in order to break their record.  Doable, but far from guaranteed.

By the way, if anyone noticed that strange cloud this morning, you might have realized that it was actually smoke from the Pioneer wildfire in the Cascades.  That fire did a lot of burning on Sunday.