Yesterday, a low pressure center to our southeast rotated moist, easterly flow into our region with substantial upslope precipitation leading to National Weather Service flood watches along the eastern slopes of the southern WA Cascades and over the Blue Mountains of NW Oregon (see figure below).
Here are the 24 h precipitation totals for southern WA. Some locations near the Cascade crest received more than an inch, with many locations along the eastern slopes wetted by a half-inch.
With the system centered to the south, Oregon got even more rain, with some locations in the coastal mountains getting more than an inch.
Eastern slope rivers are surging from the combination of rainfall and snowmelt. The critical Yakima river reservoirs are near capacity and still rising (blue line below). Yakima agriculture should have plenty of water this summer.
As noted earlier, the cause of this wet bounty on the Cascade eastern slopes and Oregon has been a low center positioned ever southern Idaho. The 850 hPa (5000 ft) map below shows this feature clearly (wind barbs and temperatures at the level are also shown).
The slow-moving low will continue precipitation over eastern WA and Oregon for the next 24-h, as shown by the latest WRF model forecast below. Go north, if you want drier weather.
This week is going to be interesting. First, a weak ridge will develop over us, providing temporary improvement. But then a HUGEridge develops over the Pacific and a very deep low forms over our region (see upper level map for Friday at 8 AM). WOW.
This a cool, wet pattern for us. To show this, here is the 72h precipitation total ending 5AM Saturday. Even California gets a piece of this. You can expect the wildfire danger to be greatly reduced and all current fires should be controlled.
Public Service Announcement: WARNING TO HIKERS ON CHUCKANUT DRIVE south of Bellingham.
If you are hiking near the trailhead of the wonderful Oyster Dome hike on Chuckanut Drive (SR 11), be VERY careful. The State Patrol and their towing company buddies are towing lots of cars. So be very careful if you park there.