“Climate is what you expect, weather is what you get”
This is a phrase I always use to convey the difference between climate and weather. Unfortunately, it is oversimplified and paints climatologists as quite possibly the most boring and predictable people ever! More often than not, climate is not what you expect. June was a very interesting month across the region, though when looking at monthly summaries for a few stations (e.g., Spokane, WA, mean June 2013 temperature = “1981-2010 normal” or 0.0F departure from normal, 6/10 of an inch above normal) you might be inclined to yawn. A look at the daily high and low temperatures for the Spokane Airport presents a different story.
I highlighted four things that were noteworthy about last month that made seemingly boring numbers in climatological summaries of June seem like a roller coaster.
1. Hail storm
I tend to miss all of the good weather. By good I mean bad for most. While traveling to Bend, Oregon some rogue thunderstorm cells hit parts of the northern inland northwest. In typical hit or miss fashion, a report from one of our neighbors [who grew up in Nebraska and has enough convective credibility] reported dime-size hail an inch deep in Moscow and the best hail storm he’d seen in 15 years or so. My first reaction was, “oh no… how did I miss out of this?” Indeed the hailstones laid a beat-down on our newly planted garden, making swiss-cheese out of our lettuce and a strawberry smoothie out of our strawberry patch.
2. June gloom
Growing up in California, June gloom referred to the persistent marine layer that develops under high pressure and as a response to differential land-ocean heating. While June gloom may never catch on in the inland northwest, we did have a couple whopper days of gloom around the solstice. On the longest day of the year many locales in northern Idaho and northeastern WA saw diurnal temperature ranges that we might get during frontal systems in mid-winter. A couple of samples include: Spokane: 50/48; Pullman 52/47. The Coeur d’Alene airport had a temperature of 48F, dewpoints between 45-46 and over 16-hours with rainfall! That is hard to do, especially with all those hours of potential sunshine. Coincidentally the high temperature in Pullman of 52F was right on par with the climatological normal for the first day of spring.
3. R-A-I-N, how do you spell relief?
Through mid-June most of the region had seen little to no precipitation, furthering the moisture deficit and the mess that comes with it. A quasi-stationary trough off the WA/OR coast and wandering upper-level closed low brought a good slug of moisture to eastern WA/OR and the Idaho panhandle, as well as parts of northern California. This was part of the same large-scale regime that brought epic flooding to Alberta.
While many were not too pleased with the precipitation, it was quite a godsend from the perspective of some dryland wheat farmers given the scanty precipitation that has occurred over the previous five and a half months. While variable by location, there is a relationship between wheat yield and precipitation that is approximately 6 bushel/acre yield for every additional inch of spring rain. Some described this as the million dollar rain. One to 1.5 inches of precipitation over ~ 2 million acres @ $8/bushel, you do the math.
Another silver lining was the protracted wetting of precariously dry fuels across much of the region, bringing fuel moistures in northern half of the region closer to normal levels by the end of the month.While some spots received above normal precipitation for June, the regional as a whole is far below normal for the past half-year. The drought monitor now highlights the southern half of the region in some form of drought, with the most acute conditions in southwestern Montana.
4. Bit Warm
June ended with a historic heatwave that set several all-time temperature records in the southwestern US. As of this writing on July 1st, temperatures are close in 100F in Moscow-Pullman-Spokane corridor, and near 110F in Boise. The all-time record in Boise is 111F. Temperatures of 100F are extremely rare in the Moscow-Pullman area before mid-July. In fact, Moscow has only seen 100F twice in 120+ years before July 11th and Pullman has never seen triple digits before July 11th. Official records for the Moscow-Pullman area probably are a bit shy of 100F however. This warm air mass is part of a retrograding and amplifying long-wave pattern with the dome of the ridge parked right over SW Idaho (as seen by this model run from the University of Washington).
This air mass has been accompanied by usually moist air that has made temperatures feel even warmer. Dewpoint temperatures on the evening of 1 July included 76F and 70F at the Moscow-Pullman and Lewiston airports! According to some nifty analysis by the NWS Spokane office, these are close to the all time highest dewpoints seen at these sites. If this synoptic pattern happened to occur 3-weeks from now, we’d be talking about widespread all-time records broken. Fortunately, at least for areas that received precipitation in the last few weeks, there is some heating being lost to evaporation.