Third-driest July on record
Summer is doing a great job living up to its “hot and dry” reputation. Coeur d’Alene already has seen 25 days of 90-plus degree temperatures this season (four of those days at 100 degrees or warmer), and we still have plenty of warm days ahead. To put this in perspective, last summer ended with a total of 38 days at 90-plus degrees. The hottest consecutive summers occurred in 1967 and 1968, when a total of 81 days reached 90 degrees or warmer. Incidentally, the all-time hottest temperature for Coeur d’Alene occurred on this day back in 1961, when the mercury soared to 109.
The “dry” part of the season has been exceptional as well. With only .26 inches of rain recorded for July, the month will go on the record books as the third driest. Average rainfall is .96 inches. Our driest July can be found in 1967, when there was absolutely no rain for the entire month. August of that year did not fare much better, when only .04 inches of rainfall was recorded. The 2006 period of July-August came in second driest with only .12 inches total precipitation.
As you might imagine from watching the news, the Panhandle has not cornered the market on exceptionally hot and dry weather. The official numbers are in for our neighbors in Spokane, and July will go down in the record books as the second warmest in its recorded history. Globally, according to the National Climatic Data Center, the period of January through June 2007 was the second warmest in recorded history as well. Even the South Pole saw its warmest June ever. Hot and dry weather across the Western U.S. continues to fuel numerous wildfires, which as of Wednesday were most heavily concentrated in central Idaho and Western Montana.
Don’t expect much change from July’s dry weather in the August. Average precipitation is only 1.27 inches. We do occasionally get a small boost in wet weather as a result of the Southwestern monsoon.
The term monsoon is a word that is often thrown around this time of year when speaking of weather in the Southwestern U.S., but it is generally misunderstood. Most people equate the word monsoon with heavy rain. Though it is associated with increased rainfall in places like Arizona and New Mexico, the actual definition of a monsoon is any wind that reverses its direction seasonally. Arizona and New Mexico are on the northern fringe of what is called the “Mexican monsoon.” For most of the year, winds aloft over the Southwestern U.S. are west to northwest. On average, sometime during the first part of July, winds shift to a more southerly or southeasterly direction, helping to bring moisture in from the Pacific Ocean, the Gulf of California, and the Gulf of Mexico. This in combination with mountainous terrain, daytime heating, and upper-level weather disturbances that result in thunderstorms across the region.
During the monsoon or summer thunderstorm season, Arizona actually experiences more severe weather than any where else in the U.S. Dust storms or other windstorms, along with flash flooding, are frequent occurrences. In our neck of the woods, even while high pressure is dominating, some of the midlevel moisture from the Southwest occasionally works its way north under our summertime ridge and can result in widely scattered showers and thunderstorms across northeastern Oregon, central Idaho, and even up into the Spokane and Coeur d’Alene area. The monsoon season usually ends sometime in mid-September.
Fortunately for us, monsoon or not, we start to see a trend toward wetter weather by September with an average rainfall of just over 1.5 inches.