Heavy rain and snow? Check.
Skiing before the holidays? Check.
Bring reservoirs to near normal levels? Check.
Threaten flooding on some local rivers? Check and check again!
The next few weeks are going to be an exciting meteorological ride, so buckle up.
A series of atmospheric rivers will make landfall over our region, resulting in bountiful precipitation, including snow in the mountains. Let me show you.
The next week will include three atmospheric rivers (water vapor transport is shown below...the key measure of atmospheric river activity)
A modest atmospheric river on Thursday,
A strong one next Monday.
Through Friday morning, a good wetting, with the mountains soaked by 3-5 inches. Just the start.
By Sunday morning, very large precipitation totals will have accumulated in the mountains, with some locations receiving 5-7 inches.
The above are forecasts from the UW modeling system, driven by the NOAA/NWS GFS model.
The European Center modeling system is doing the same thing, which gives us confidence that a major event is ahead. Below are the totals through next Monday morning. Mountains are hit very hard.
By next Friday, crazy high totals:
The rivers will rise rapidly, some to flood stage. Consider the situation for the Snoqualmie River near Carnation (below). The first two atmospheric rivers will bring the level up to flood stage (see below). The third, stronger river will cause substantial flooding (not shown below).
Snow in the mountains? Huge amounts will fall. Here is the forecast through mid-December by the European Center model. Yards of snow in some locations.
The ski season will begin. Our water resources will be greatly enhanced. Winter recreation will beckon.
Wait?! The times said we are in a horrible cough inducing nasty drought complete with forest fires and smoke and animal DYING of thirst pawing the empty river beds and DYING AG-gone-kneeee ag gon kneeeeeeee
ReplyDeleteWill the lower slopes get snow or rain?
ReplyDeleteWhat is the certainty level right now that this will be snow in the mountains? Seeing that much moisture ahead has me a little concerned that we might be seeing rain at skiing elevations.
ReplyDeleteYes, mostly rain except at the highest ski area elevations.
DeleteAccuweather 10 day forecast for Snoqualmie indicates limited snow with a boatload of rain. This seems inconsistent with the snow total charts shown. Do the UW/EU models indicate freezing level?
ReplyDeleteyesterdays UW GFS extended 850mb loop 0C isotherm location suggested more snow near-term in central WA cascades and points north until a significant cool down mid next week by fcst hr 240. Not great for OR and lower elevation WA areas until that happens.
ReplyDeleteEvery mountain forecast I see has mostly rain for the next week. Are you saying they are wrong? Or it will trend colder and snowier in the following week (outside the forecast range)?
ReplyDeleteThe 850mb loops show fluctuation in temps for western WA at the 850mb height in meters (roughly 4200-4600') until later next week starting 11-Dec when temps drop below 0C and continue to be cold. The same chart also shows winds at the 850mb elevation. This suggests higher elevations (crystal midway and above) will get some snow and rain between now and next thurs before it gets and stays cold and lower elevations (like snoqualmie) start seeing consistent snow. The freezing level chart provides useful graphics: https://a.atmos.washington.edu/~ovens/wxloop.old.cgi?wrfd2_x_fzlv+///3
DeleteMy question has to do with the wind (average and gust) that will accompany the atmospheric rivers. The combination of water then wind can be deadly for trees and even increase the probability of landslides. Can you please add a few wind plots to help quantify the excitement factor that these events will bring?
ReplyDeleteHi Cliff. Would you please add some snapshots of model predictions for winds? With all that moisture, trees are gonna come down at the touch of a breeze.
ReplyDeleteForewarned is fore armed. Thanks Cliff.
ReplyDeleteOn Friday I'll go to EBRG and fill the truck with gasoline ($3.80/g) and I already have aggressive tires. And I have ½ cord of firewood near my backdoor. Your plans are to ....?
ReplyDeleteNWS and most other forecasts for Stevens is a ton of rain, and a little snow here and there through next week. Seems early to predict this much snow when most models aren't calling for it.
ReplyDeleteAtmospheric rivers always give me Pineapple Express anxiety, some concern regarding how high freezing levels might go? Forecasts suggest somewhat mild temps, but is that not as much a worry with these systems?
ReplyDeleteAm I reading the last graphic right -- over 100 inches of snow in N Cascades!
ReplyDeleteIt will be interesting to take a look at the drought monitor at the end of the month to see if it drops us out of the "severe drought" that we've been in for over a year.
ReplyDeleteLets check back on this on December 10th. I don't think ski areas are going to be hit with snow. I see rain. I just do not see the snow at ski area elevations. I do see the forecast for snow at very high elevations....just not the ski area elevations.
ReplyDeleteCliff, what are the actual snow levels? The forecast for Stevens Pass is for mix rain/snow in the coming days and temps above 32 so it seems snow levels will remain high still. Is there any indication they will come down?
ReplyDeleteHonestly, some of y’all need to make better use of the maps Cliff is sharing. That Euro snow total forecast is clearly labeled as the totals through 12/17. Lots of time for things to trend colder.
ReplyDeleteAnd if the freezing level wasn’t forecast to drop — quite a bit — then that map wouldn’t show 3+ inches of snow for places like Tacoma and Olympia.
Actually, I’m surprised that nobody has pointed out yet: If that forecast verifies, *everybody* is gonna see snow. Oh noes, quick, go buy up all of the bread and milk!
Not going to happen.
DeleteAnother informative post as always, Professor Mass!
ReplyDeleteThe image of the European Center model you provided at the end of your post seems to suggest that the lowlands are going to see some potentially serious (although any lowland snow is noteworthy in these parts) snow in the next couple of weeks, especially from Seattle southward. Do the other models agree with this, and, if so, when should we be watching for this lowland snow?