Confidence is sufficient for an upgrade to level 2-SLGT risk along the I-5 corridor in western OR/WA.
First Severe Thunderstorm Watch issued for this area in 10 years for March!
These severe storms are likely to be somewhat isolated, but they could occur even at lower elevations and have a high probability of generating large hail (>1 inch diameter) and strong wind gusts (~65+ mph). Given local terrain and topography influences, there is even a possibility of an isolated tornado.
Confidence is sufficient for an upgrade to level 2-SLGT risk for large hail, centered along the I-5 corridor in western OR/WA.
A rare and severe weather event is anticipated in the Pacific Northwest on March 26, 2025. Washington and Oregon are under a ‘slight risk’ for severe thunderstorms as part of this event, which the Storm Prediction Center has designated historically significant for the region.
Tornado and hail risk for Pac NW.
The event encompasses threats of large hail exceeding 2 inches, damaging winds reaching up to 60 mph, and a small but notable tornado risk. The potential for supercells which are uncommon in this area particularly along the I-5 corridor especially as early as March are being discussed. The conditions are anticipated to reach their peak intensity in the late afternoon and evening, potentially resulting in significant hail, wind damage, and isolated tornadoes.
A vigorous shortwave trough will approach the Pacific Northwest coast through the period. A pronounced mid-level jetlet, around 90-100 kts at 500 mb, should overspread the OR coast to west of the Cascades on Wednesday evening. Near record to record high temperatures are anticipated downstream amid a preceding highly amplified mid/upper ridge shifting east. This combined with well above-normal PW values should yield pockets of 500-1000 J/kg MLCAPE by Wednesday afternoon. Despite a meridional deep-layer wind profile, a few supercells will likely develop west of the Cascades as MLCIN wanes towards peak heating. With weak low-level shear, large hail should be the primary hazard. A storm or two might produce significant severe sizes of 2-2.5 inches before storms weaken over the Cascades.
The rainbow before the storm in the Pacific Northwest
Mamatus cloud + Rainbow before the storm enters the Pacific Northwest
