SEATTLE — Forecasters expected Saturday’s Pacific Northwest windstorm to be a severe weather event with damaging winds. And while many of us saw high winds and drenching rains, the storm did not pack the punch meteorologists expected.
Despite wind gusts on Washington coast 53 – 62mph and inland Puget Sound gusts 35 to nearly 50mph, many windstorm lovers felt let down and felled trees left homeowners down.
Where did the forecast of five hours of those wind gusts go?
Saturday’s windstorm had a forecast by the hour very similar to a hurricane. Forecast models gave solutions of a strong storm 14 days earlier, and every day following, a number of models changed minor details.
It’s the details that matter when making a windstorm forecast for Seattle. The center of low pressure must track over a specific area, either north of Puget Sound, or south of Puget Sound, to optimize the rush of air into the vacuous low.
Saturday morning near 8 a.m., a new issue of a weather model was released that forecast a path of low pressure farther west than previously shown.
Observations and monitoring the satellite over time led to indications that western Washington would receive a lesser impact.
Approximately 3 p.m. the center of low pressure moved over a buoy west of Grays Harbor. The information gathered from the buoy showed the storm was weaker and confirmed the track was farther west.
Without the center of low pressure crossing the Olympic mountains and over the San Juans, there wasn’t an intense pull of air to funnel through Puget Sound, in addition, the pressure was not as low as models had predicted.
The results were powerful wind gusts, but, not many, and the few gusts whipped through very fast instead of persisting for hours.
The National Weather Service Seattle office also explained how forecasting Pacific storms coming onshore to the west coast is difficult, covering thousands of miles of open ocean with six global forecast models all with differing projections.
And remember, this is good news! If the storm had taken its predicted path, we'd have severe storm damage and widespread power outages across the region.
Sunday: Rain in the morning will become rain showers through the afternoon, some showers will be heavy at times. A risk of a thunderstorm increases on the coast and for the south Sound, Tacoma to Olympia and Pe Ell, through the afternoon. Wind will remain breezy all day, south wind 15-25mph for most of us except for the coast and Strait of Juan de Fuca where gusts will continue up to 40mph. A thunderstorm may easily bring stronger wind gusts today.
Monday: Rain showers increase early, windy SW 15-30mph, closer to 5pm showers decrease. Highs in the mid to upper 50s. Tuesday scattered showers diminish late for a drier day Wednesday until evening rain returns.