Record Hot July, Rain Anyone?

If you are hoping for some rain, we have good news for you!  But before we get there, another heat wave is about to hit the Inland Northwest which isn't good news for the ongoing drought.

Here is the latest U.S. Drought Monitor released today, July 29th.  Exceptional drought (D4) was covering a large portion of Eastern Washington and north Idaho.

U.S Drought Monitor released July 29th, 2021

Much of this drought locally is from very dry weather over the past 6 months which has had significant agriculture impacts to spring wheat, barley, and hay.

Percent of normal precipitation past 6 months

Combining the dry weather with lightning so far this July has led to multiple wildfires across the region.  The maps below show total lightning this month through the 24th.

And here is satellite image from July 23rd showing smoke from multiple wildfires over the region.

Evening satellite - July 23rd, 2021 courtesy of UW

Making matters worse has been the hot July, with temperatures over most areas running 4 to 8 degrees above normal so far this month.

And another heat wave is likely as we close out the month of July.  On Friday many locations will reach the triple digits, with the heat peaking on Saturday with near record high temperatures for the day.   Here the forecast high temperatures for Saturday as of this writing

NWS Forecast High Temperature for Saturday, July 31st, 2021 issued 230 PM July 29th

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These temperatures will equate to many areas nearing, or exceeding their all time warmest July on record.  Here are some locations that have a good chance of the hottest July, with observed average temperatures for July 2021 so far shown.

Spokane Airport (GEG)

Bonners Ferry, ID

Lewiston, ID

Wenatchee Airport, WA

Omak, WA

Changes Ahead!

After all this talk of heat, fires, and drought, let's shift gears and talk about changes this weekend.  Some surfaces may look like this by Monday.

Yes, we have rain to talk about!  Models are pretty consistent in showing an increase in moisture moving up into our region.  This animation below (courtesy of College of DuPage) shows available moisture (also called precipitable water) and is NOT a rainfall forecast.  It's more of an indicator of available moisture for rain.

12z July 29th GFS run of Precipitable Water Standardized Anomaly valid July 29-Aug 3, 2021

Note that as values reach the blue and purple shadings on Sunday and Monday that it corresponds to the highest end of the legend at the bottom of the graphic.  This means there will be close to the highest amount of available moisture over our area as we can get for this time of year.

But the big question is will this lead to an abundance of rain and will there be thunderstorms?  We think most areas will get some rain, but amounts are uncertain.  This is due to the convective hit and miss nature of showers and thunderstorms.  Here is one ensemble forecast for rain totals for Coeur d'Alene, ID.

12z July 29th GEFS forecast of precipitation for Coeur d'Alene, ID through August 3rd, 2021

Note the large spread in possible rain amounts with the solid black line indicating the average values of near 0.25".  One solution gives as much as 1.50", while several show 0.20" or less.  

There will also be a chance for thunderstorms which could lead to new fires.  But the good news is that downpours should reduce the threat of new fires becoming large, and could help current fires with some much needed rain.

And there may be more rain for the middle to end of next week.  Here is the 6-10 day precipitation outlook from the Climate Prediction Center favoring increased odds of wetter than normal conditions.

Climate Prediction Center 6-10 day Precipitation Outlook valid Aug 4-8th, 2021

To summarize, hot temperatures to close out July will give some locations the hottest July on record.  Exceptional drought covers much of the region.  August will start on a different note, with an increasing chance for showers and thunderstorms.   With exceptional drought, don't expect this rain to even come close to ending the drought, but will at least bring a change in the weather and should help out the fire situation over the region.

How hot did it really get in Spokane on 29 June 2021?

After our historic heat wave of 2021, it's time to take a look back and answer the question of just how hot did it really get in Spokane on June 29th.  Unfortunately, the answer does get a little sticky.  First we need to look back in history, as well as look at the topography of Spokane.

Temperature measurements in Spokane started in 1881, and these were taken in downtown Spokane.  The Weather Bureau office moved out to Felts Field in 1941, and with it, the official temperature of Spokane moved as well.  Observations were still taken in downtown Spokane, they just were no longer official.  Six years later, the Weather Bureau moved again, from Felts Field to Geiger Field (which would later become Spokane International Airport) on the West Plains of Spokane.  The official observation for Spokane has been at the airport since 1947.

Moving the observation from downtown to Felts Field probably didn't have much of an effect on the temperature readings.  Both locations are at about the same elevation.  But in the 1940s, the area around Felts Field was more rural than downtown, so there may have been a little less "urban heat island" effect.  However, the move to the West Plains in 1947 was significant.  The elevation of downtown Spokane is about 1890' above sea level.  Felts Field is at the 1953 foot elevation.  But the Spokane International Airport is up at 2356 feet, an increase of nearly 500 feet.  Using the thumb rule of 5.5 degrees per 1000 feet, that results in a difference of about 2.5 to 3 degrees between the West Plains  and downtown. 

It's important to note that downtown Spokane is about the lowest elevation of the entire metro area.  57th Avenue on South Hill is at about 2360', which is the same elevation as the airport. Same goes for Five Mile.  Even I-90 at Stateline is at about 2100'.  So your location in the metro area has a big effect on your temperature, just from the standpoint of elevation.

Additionally, your surrounding environment also has an effect on your temperature.  If you're downtown with lots of concrete and asphalt, the temperature is probably a few degrees warmer than if you're near the river or at a golf course.

Late July of 1928 was extremely hot across the Inland Northwest.  Triple digits were common just about everywhere for several days.  For many locations, July 26th 1928 became the hottest day on record at the time.  Prior to this event, the hottest temperature on record at Spokane was 104F, set in 1898.  That mark was tied on July 24th and 25th of 1928, after a 102F on the 23rd.  On the 26th, temperatures peaked as Spokane hit the 108F mark.  Some other extreme readings on that day included:

• Omak  -  114F
• Ephrata  -  112F
• Lewiston  -  113F
• Orofino  -  114F
• Walla Walla  -  113F

The record of 108F for Spokane stood through for more than 3 decades of summers.  There were attempts, mind you.  The thermometer reached 106F in 1931 and 1934, and 105F in 1939.  Then in early August of 1961, extreme heat returned to the Inland Northwest.  This time the heat lasted only 3 days, but the extremes were more impressive.  Spokane once again touched 108F, tying its all-time record.  But recall that the weather observation moved up in elevation in 1947.  So which was the hottest day, 1928 or 1961?  Since downtown Spokane is typically a bit warmer than the airport, it's likely that 1961 was truly the hottest day.  And in fact, there was still a weather observation in downtown Spokane in 1961 and it reached 109F on 1961. This value was matched in Coeur d'Alene and St Maries.

Additionally, 1961 set the record for the hottest day in Washington state history, with a reading of 118F at Ice Harbor Dam (along the Snake River just east of Tri Cities).

So now we return to present day Spokane, and the 2021 historic heat wave.  We all know by now that Spokane Airport hit 109F, setting the all-time record for the city.  But was that truly the temperature that the citizens experienced?  After all, there's not many people who live at the Spokane Airport.  Thankfully, we now have a number of temperature measurements available to us to answer that question.

So while it was 109F on the West Plains, it was 113F at Felts Field.  So perhaps that should be the official temperature observation for Spokane during this heat wave?   Is that what most people experienced?  But then you notice that it there's quite a range of temperatures around the metro area.  It was 115F along I-90 in Spokane, but 108F near High Drive, and only 106F in Opportunity/Spokane Valley.  So perhaps the 109F at the Spokane Airport is a decent "middle of the road" temperature for the area.

For a bit broader view, several locations set their all-time high temperature record in the Inland Northwest on June 28th.

• Omak: 117F, old record 114F (26 Jul 1928)
• Wenatchee: 113F, old record 110F (18 Jul 1941)
• Bonners Ferry: 108F, old record 105F (11 Aug 2018)
• Chelan: 111F, old record 110F (29 Jun 2015)
• Davenport: 107F, old record 105F (26 Jul 1928)
• Mazama: 112F, old record 103F (1 Aug 2020)
• Northport: 113F, old record 110F (28 Jul 1934)
• Odessa: 115F, old record 112F (4 Aug 1961)
• Plain: 109F, old record 104F (27 Jul 1939)
• Priest River: 108F, old record 105F (10 Aug 2018)
• Republic: 109F, old record 108F (2 Jul 1924)
• Rosalia: 111F, old record 108F (27 Jul 1934)
• Sandpoint: 106F, old record 104F (24 Jul 1994)
• Wilbur: 110F, old record 110F (3 Jul 1922)

But not every location set all-time records.  Coeur d'Alene hit 108F for 2 consecutive days in this heat wave, but both fell short of their all-time record of 109F in 1961).  A similar story for Grand Coulee Dam.  Moscow and Pullman fell 4 degrees short of their 1961 record.  

Daytime high temperatures weren't the only records broken.  The nighttime temperatures were rather uncomfortable as well.  Spokane airport also set an all-time record for warmest low temperature.  It tied the record on the morning of the 29th, cooling only to 77F.  This equaled the record set back on 27 July 1928.  After topping out at 109F during that afternoon, the temperature was only able to cool to 78F by the morning of the 30th, setting the all-time record.

The all-time high temperature record for Washington of 118F may have been tied or even broken at a few different locations during this recent heat wave.  A climate extremes committee will review this in the coming months.