by Chris Scragg
Temperatures spiked into the low and mid 80s on Friday and broke several historical records in Western Washington. The highly welcomed weather ended as suddenly as it began and is transitioning into milder weather for the next few days.
A low pressure system is approaching the Northwest and will bring rain and wind. The National Weather Service in Seattle is also mentioning a slight chance of some thunder and lightning over the weekend and into early next week.
Springtime (typically mid-March) comes with the most unstable atmosphere during the year in our area! Instability in regards to the weather basically means that warm air rises like bubbles into colder air above, creating clouds and sometimes my favorite weather; storms!An unstable atmosphere is one of the main ingredients that when mixed with ample moisture (such as our frequent low pressure systems) and lift (such as our Puget Sound Convergence Zones), can and does produce exciting thunderstorms. Spring in the NW is a prime time for this because we experience a higher sun angle, which heats the surface more, as well as colder air in the mid levels of the atmosphere. Info. from Cliff Mass Weather Blog
The GFS weather model run by the University of Washington is showing a decent amount of instability (relative to our region) on Saturday, Sunday and Monday afternoons. The brighter the purple, the higher the “CAPE” (Convective Available Potential Energy).
However, here in the Northwest, long term thunderstorm forecasts are tricky to make. Thus, the most accurate period to forecast storms is on the day of the forecast with the High Resolution Rapid Refresh Models.
When widespread or severe thunderstorms threaten Western Washington, I will release video updates as well as live coverage on the PSWxG Live Stream to update you on where the storms are as well as their severity and danger.