Our late fall and winter seasons have been wet
Coeur d’Alene and the rest of the Inland Empire have been receiving plenty of moisture during the November through March period, especially in recent years. However, despite having above-normal precipitation during the late fall and winter seasons, the late spring and summer months across much of the Northwest have been much drier than normal. As a result of the extreme dryness, the last two fire seasons across the region have been disastrous.
Cliff and I decided to see how our precipitation totals for November through March have compared to normal over the last 20 years. This time period is often a good indicator of moisture for the season, as more than half of our total seasonal precipitation — based on the averages — occurs within these five months. By using Cliff’s detailed information, we were able to see an interesting trend showing the five-month precipitation totals for Coeur d’Alene. I also put together a chart showing these figures and how they compared to normal.
According to long-term data, the average precipitation for November (3.07), December (3.90), January (3.77), February (2.17) and March (1.94) totals 14.85 inches. Our seasonal normal for Coeur d’Alene is 26.77 inches.
Starting from the 1998-99 season, the November through March rain and melted snowfall was higher with 21.10 inches. The following season, 1999-2000, was less, but still higher than average with 16.14 inches. Then, for the 2000-01 through the 2004-05 November through March season, moisture totals were below normal. The lowest was 8.67 inches during the 2000-01 time period. With the exception of two seasons, precipitation during this timeframe was above normal from 2005-06 through the 2018-19 season; with the exception of two years: 2009-10 with only 12.11 inches, and 2011-12 with a slightly-below-normal 14.54 inches.
Over the last 15 late fall and winter seasons, Coeur d’Alene has averaged 18.53 inches, which is 3.68 inches above normal. If we take out the 2009-10 season, the average figure climbs to 18.99 inches. Within the last 5 years beginning with 2014-15, the 5-month average is 20.12 inches, well above normal.
Cliff and I are still getting questions on whether the Inland Northwest will see the big snow year. We are currently locked a cycle or trend with plenty of moisture during the late fall and winter season, at least for now. This is one of the key ingredients for the big snow year that has been predicted for either the 2019-20 or the 2020-21 season, as close to 200 inches of snow could be measured in Coeur d’Alene with upwards of 700 inches in the higher mountains.
However, temperature also plays a big part. It needs be cold enough for these storms to bring us all snow rather than rain. There is currently very little sunspot activity, but we still have a weak El Nino, the warmer-than-normal sea-surface temperature event in the south-central Pacific Ocean. In order to get the big snows, there needs to be a La Nina, the cooler-than-normal sea-surface temperature event.
In 2007-08, there was a very strong La Nina and virtually no sunspot activity. Snowfall records were broken across much of the northern U.S. In Coeur d’Alene, we had a whopping 172.9 inches for the season.
During this wild cycle of “extremes,” as well as climate change, the wetter than normal November through March years will likely come to an end. Cliff and I believe that by the mid to late 2020s, a drier weather pattern will move into the Northwest. Moisture totals for November through March will likely be around 11 to 12 inches, rather than close to 15 inches. As is always the case, time will tell.
In terms of our near-term weather, April’s precipitation finished above normal with 3.07 inches. Early May is starting out mostly dry, but conditions should start turning wet around the full moon cycle of May 18. More showers and thunderstorms are expected in early June, but our weather should start turning drier than normal overall later in June.
Barring a surprise cold storm, we should be done with snow for the 2018-19 season. Thanks to a record-breaking February, our seasonal total will end up at 96.6 inches.
Looking farther out, July and August should be dry, but we don’t think it will be quite as dry as what we’ve seen over the last two years. Hopefully, this will translate to a less hazardous fire season across Coeur d’Alene and the rest of the Inland Northwest. The upcoming fall season looks wetter than normal.
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Contact Randy Mann at randy@longrangeweather.com