Thunder was heard all around the Northwest on Saturday, together with many areas and not using a drop of rain.
Check out the lightning strike map for Saturday. Fairly a number of lightning strokes over the western slopes of the Cascades and Rockies….and quite a lot of boomers moved over southeast Washington.
Yesterday morning one might see the cumulus convection begin to pop up over the Cascades, and by early afternoon (2 PM for the Seattle Panocam proven beneath) there was pretty deep convection (the meteorological time period for cumulus clouds) with outstanding cirrus anvils.
I used to be taking a stroll with Steve Pool, the retired KOMO TV meteorologist about this time, and we had been admiring the large cumulus over the mountains.
The cumulonimbus producing the lightning had sufficient precipitation that the climate radar “lit up” over the area, one thing illustrated by the regional climate radar round 2 PM (see beneath). Lots of the showers fashioned initially over terrain after which drifted off.
For instance, a few of the convection over the Cascades drifted west throughout the afternoon, with one getting so far as Bellevue.
The cumulus convection was very obvious within the seen satellite tv for pc imagery, as illustrated by the picture round 2 PM (see beneath). I put in an arrow to point one of many cumulus cells.
How a lot rain fell throughout these showers? The reply is beneath (the rainfall for the complete day is proven). A lot of the Cascades and japanese Washington received some gentle rain (.01 to .1 inch), with a number of fortunate areas getting half an inch or extra. The showers will assist maintain the soil moisture up in japanese WA.
Now it’s possible you’ll ask: why did we get these showers and why had been the mountain slopes favored? Good query
There are two principal causes. The air over us yesterday was colder than regular (shock, shock), whereas the solar has develop into highly effective, strongly warming the floor.
The mix of heat air close to the floor and funky air aloft produces a big decline in temperature with peak (referred to as a lapse price)…..and enormous lapse charges foster ambiance convection, the place the ambiance begins to percolate.
An indication of the potential for instability is one thing referred to as Convective Out there Potential Power (CAPE), and as proven by the determine beneath, the values had been comparatively excessive for our area (as excessive as 500!)
And there was one thing else. An upper-level trough of low stress was over us (see the five hundred hPa–about 18,0000 ft–upper-level map beneath), and such options produce upward movement that encourages cumulus convection.
However why had been most of the thunderstorms initiated over the mountains? As a result of mountains present further upward movement that helps give the upward shifting air a soar begin!
In the present day the thunderstorms will probably be absent from the region–so take pleasure in.
And higher take pleasure in this weekend. Memorial Day weekend goes to be memorable…however NOT for good climate.
