The big weather story today is heavy rain and wind...but many of you are experiencing neither! How is that possible?
Here is the precipitation over the past 24h (ending 11 AM Sunday) at a collection of NW stations. Some folks to the east of the Olympics and Vancouver Island have gotten only a few hundredths of an inch, while the western slopes of the Cascades have received 2-3 inches (and will get more).
Why this profound rain shadow in central Puget Sound? The reason is that we have a strong trough embedded in northwesterly flow and the flow at crest level is westerly....producing a rain shadow to the lee (east) of the Olympics.
Here is the flow at 850 hPa (around 5000 ft and a good level to see what is approaching the mountains at crest level) at 8 AM. VERY strong winds from the west to northwest (the winds are proportional to the gradient of heights shown by the solid lines. The heights are like pressures on a surface chart. Winds are parallel to the lines). The air over us this morning is quite warm (denoted by red/orange colors in that chart)
Anyway, no issues for travel across the Cascades other than water ponding on the roadways and poor visibility.
As I mentioned before, the cold air is coming on Monday. The models are NOT producing major snowfall in the lowlands, but some of you will see some light white stuff. As the cold air pushes out of the Fraser River gap on Monday AM, there could be some light snow at its leading edge over NW Washington (see map of 3-h snow ending 10 AM).
The total predicted snowfall for the next 48-h is shown below. The mountains should do some business on Monday, but the lowlands are mainly snow free. Disappointing to kids.
Are you in venture capital/private equity and have an office in the Bay Area, or knows someone who does?
If so, I have a question for you. Please send me an email (cmass at uw.edu) ....thanks, cliff