WeatherWatcher: 30 years ago in weather, December 18, 1990

 

Eight inches of snow in Shoreline, February 16, 2001
Photo by Carl Dinse

Thursday, December 18, 1990, 30 years ago, marks the day of an historic cold snap associated with likely the strongest convergence zone recorded in our region.

The King/Snohomish County line was near the center of this convergence zone and got hit the hardest. It was the beginning of a two week school winter break that started early and resulted in our first White Christmas in decades. (Although Sea-Tac recorded one inch of snow on the ground Christmas 1983, which by definition counts.)

Around eight inches of snow accumulated around the lunch time hour within a 30 minute window when the storm first hit. After the initial burst of heavy snow, relatively lighter snow fell off and on throughout the remainder of the afternoon and evening. Heavy snow had caused power outages by the late afternoon hours. 

We even had a rare thundersnow event around 4:15pm that night. North winds begin gusting up to 60mph shortly afterwards. Many school aged children were trapped at school, and people were stuck in gridlocked commutes home from work.

When the storm was over, we were in the single digits for lows and teens for high temperatures. Total snow accumulation on the ground was averaging between 12 and 14 inches in the Shoreline and Lake Forest Park area. I have the temperature numbers from Sea-Tac below but I can only imagine it must have been several degrees colder here in Shoreline than it was at the airport.

• 12-18-1990: High 36°F, Low 21°F
• 12-19-1990: High 22°F, Low: 17°F
• 12-20-1990: High 19°F, Low: 11°F
• 12-21-1990: High 18°F, Low: 8°F

It slowly warmed up from there with the first thaw starting on Christmas day with a high temperature of 34°F. But then, on December 28th, a second wave of arctic air moved in dropping the low back down to 14°F, with a high of 21°F. Things started moderating on December 30th, with most of the snow gone in time for school to resume from winter break.

High and low temperature graph compared to average December 1990

If you have any photos from that storm you'd like to share, or from any other history snow or wind storms of Shoreline's past, please send them our way at either editor@shorelineareanews.com or carl.dinse@shorelineweather.com

For our current forecast in December 2020, much warmer weather is expected, with highs near 50°F and lows in the lower to mid 40's. We have more gusty winds on the way Friday evening, about the same as Thursday morning's winds which gusted to around 36 mph. The current forecast is calling for gusts as strong as 40mph, but this isn't by any means a major wind storm. I'm not expecting much tree damage or anything beyond a stray local power outage.

After the wind, some warmer rains are expected this weekend. Some local rivers could reach flood stage with the rise of snow levels. An atmospheric river is expected to bring a soaking mild rain from Saturday afternoon through Monday. After we get through the rain Monday it looks like things will dry out a bit starting on Tuesday and lasting as far as Thursday. 

Cooler temperatures are expected to arrive by Thursday too, but it's too early to tell if that means anything serious or not. Right now it doesn't look like anything more than chilly nights and some rain showers in the extended forecasts.

For current weather conditions visit www.shorelineweather.com