Coming after a warm summer and early fall, October was relatively torrid around here (as torrid as Seattle gets), with a number of stations enjoying their warmest October on record (such as Olympia). The minimum temperatures have been particularly high the past month (over the entire Northwest), with differences from climatology (the anomaly) the last 30 days being SIX TO TEN DEGREES ABOVE NORMAL. That is huge folks. Really. Leaf loss on trees has been noticeably delayed and my vegetable plants are still alive. I have gotten tired of tomatoes.
And the heavy precipitation in October and February/March has resulted in the total rainfall at Seattle Tacoma Airport so far this year (through the end of October) equalling our normal annual rainfall, around 37 inches (see plot, with blue being normal and red the observed precipitation).
So if it didn't rain a drop in November and December (our wettest months) we would STILL have a normal annual rainfall. The story is the same over much of the region.
A huge plume of moisture from the subtropics is now reaching our region, as shown by the latest infrared satellite photo and a model forecast of water vapor for 4 PM this afternoon (see below).
Rain will spread over the region this afternoon but the real heavy stuff will come later on Monday and Tuesday morning. Let me show you the latest forecasts for 24-h precipitation.
For the 24-h ending 4 AM Monday, the precipitation is mainly south of Everett, with Oregon getting the worst of it.
But the next 24-h (ending 4 AM Tuesday) is Washington's turn, with the Olympics and Cascades getting hammered with over 2 inches in places. Even eastern Washington gets wet.
The next day we are in postfrontal showers with continued (but lighter) precipitation over the western slopes of the Cascades.
You want snow in the mountains? Forget it. The air mass will be too warm, except for some of the very highest terrain in the north Cascades.
Want to play in the snow near the Columbia? No problem. Head to Columbia, SOUTH CAROLINA (see pic)
It will get quite windy Monday night. Take a look at the forecast for sustained winds (not gusts) for 10 PM that night. Very windy along the coast (sustained up to 35 knots) and over NW Washington (particularly the San Juans and northern Whidbey Is.). Windy enough over the Sound.
And talking about temperatures, here is the latest NOAA/NWS Climate Prediction Center 6-10 day temperature forecasts. WOW...huge warm anomaly forecast for the west. Yet very cold on the east coast.
The immediately cause of this contrasting pattern is clear: an amplification of the waviness of the jet stream over North America. Here is the forecast upper level (500 hPa) map for Friday at 4 AM--you can see what I mean. Ridge over the west and trough over the east.
Could this be caused by global warming? My reading of the literature suggests not.
Got to go....heading out for a run before the rain hits....
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