Warm weather isn’t going away yet
September is turning into a banner month for those who like to keep summer weather around for as long as possible.
Spokane has seen five days so far with high temperatures of 89 degrees or warmer. Last Wednesday, Spokane’s high of 91 degrees missed the record by only two degrees. Can you believe that the average high temp this time of year is only 72 degrees? For the month so far, daily temperatures are averaging nearly four degrees above normal. Though this weekend’s weather brought us closer to “average” conditions, the medium range forecast models show another ridge building into the Northwest. It looks like temperatures will be back into the 80s – possibly warmer for the upcoming week.
Despite the beautiful late summer weather, it seems like everyone is focused on the upcoming cool season. If you couldn’t get your hands on a snow blower last year, should you be scurrying to land one now?
Let’s take the meteorology out of the equation first and just look at the law of averages. With the last two winters giving us back-to-back record to near-record snowfall, it makes sense that the pendulum should begin to swing in the other direction. Now, let’s add the current El Niño to the mix and look at the seasonal snowfall totals for Spokane during the past four El Niño winters:
2006-2007 – 34.0 inches
2004-2005 – 25.8 inches
2002-2003 – 21.2 inches
1997-1998 – 18.3 inches
The last three El Niño events were considered relatively “weak,” while the 1997-1998 El Niño was the strongest on record.
The strength of an El Niño is based on the sea surface temperature anomalies in the equatorial Pacific, i.e. the extent of the above normal ocean temperatures. The current El Niño is forecast to peak at “moderate” strength.
Now the lack of snowfall during the El Niño winters doesn’t necessarily mean those winters were dry, though that was the case quite noticeably in 2004-2005.
Low snowfall totals can result from below normal precipitation, above normal temperatures (in which the valleys would see more rain than snow), or a combination of both. In the case of average to wet weather with above normal temperatures, skiers and snowboarders can relish in a season that’s great for mountain recreation, while easy on the driveway snow shoveling!
In a nutshell, based on the current El Niño forecast, and the patterns of temperature and snowfall I’ve seen during previous El Niño winters across the Inland Northwest, it looks like we can expect below average snowfall in the valleys and above average temperatures this winter season.