The WxCafe™

Continuing On the Edge

Posted by Rufus La Lone on November 28, 2022

Monday November 28

We will continue on the edge for low elevation snow for the next several days. Time for that refill, Patron.

It’s always difficult to get snow at the surface in the PNW, mainly because we are so close to the Pacific, which holds temps up. The pool of cold air on the east of the Cascades will not be quite as cold as forecast several days ago, hindering our chance for west side snow. However, there will be periods between now & Sunday that may allow for cold air to be drawn west to mix with the marine moisture resulting in a snow/rain mix at the surface, and snow in the foothills.

Showers today will diminish before the next system moves in from the NW Tue & Wed. The mid-week storm will be rather strong, with a Low pressure center deepening to approx 980-984 mb when it is west of Vancouver Island. This will cause surface winds from the south to keep valley floors warm enough to hold off any valley snowfall. That said, depending on the position of that Low, colder air drawn in from the east could keep the air mass cold enough for snow/rain mix, or just snow at times, esp later Wed into Thu as that Low drift south off the coast of Oregon. You’re right: not a definitive forecast, because we remain On the Edge, indeed.

Another ‘repeat’ storm is modeled to follow nearly the identical path on Fri Dec 2. Yep, there will remain the threat for low elevation snowfall. Either way, it will be a very chilly, wet period as this week ends. Sat & Sunday are trending drier, with chilly air mass and a moderated east wind. Sunday night the next Low tracks just off the coast of BC and then right over OR. Rain at the surface, snow in the coast & Cascade ranges. North Puget Sound could see snow/rain mix, as the Fraser Outflow will turn on again, rushing colder, continental air into the region. Familiar pattern.

A classic wet, mountain-snowpack-building pattern will set up for 1st full week of December. A large pool of very cold air is charted to settle over the Gulf of Alaska during the week of Dec 5-9. By mid-to-late week, that colder air will drive wet systems into the PNW, for very low elevation snowfall. Too early to predict valley snow, but, if models verify, snow levels will be quite low (500-1,000 ft). This pattern will be quite different from the current one because the coldest air will arrive from the northwest, hence any chance for snow will not be predicated on an east wind. We’ll monitor this closely. California should get some precip out of this pattern, late week.

As the weekend of Dec 10,11 gets underway, an east wind may develop as High pressure, centered over the Continental Divide pushes air towards the PNW coast. Concurrently, a Low will be moving south off the coast, missing the PNW, contributing to a large pressure difference, which sets up the strong east winds. RAIN should return during the week of Dec 12-16, some of which may be moderate-to-heavy.

Well, that's the current long-range outlook. Change is inevitable, so keep that Mug of yours handy and step back into The WxCafé™️ on Friday for the latest revision.

“The right angle to approach a difficult problem is the try-angle."

-Rufus

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On the Edge for Snow

Posted by Rufus La Lone on November 25, 2022

Friday November 25

Thanksgiving weekend update. We’d like to keep this brief, but with the chance for SNOW coming, ‘yeah, right’. Around here, we affectionately refer to snow as “The White”. It is relatively rare for sea level snowfall around the region, so when there’s even a small chance for The White to occur, well, childlike excitement abounds; the forecast warrants a holiday Mug refill.

A weak system will present rain and showers across the PNW today, Black Friday (most of the precip will fall north of Salem). That will clear out, yielding a decent holiday weekend Saturday until after sunset. The next, stronger AND COLDER system will move onshore, from north-to-south, while most of us sleep overnight Sat. Windy. This system has the potential to complicate holiday TRAVEL back home if one is driving over Cascade passes. Rain will turn to showers on Sunday, with the air mass on the back side of this storm cold. In fact, don’t be surprised to see snow & rain mixed (if not all The White at times) later on Sunday, esp in the northern Puget Sound area. The warm ground, and diminishing moisture may limit accumulations, but it will be fun to watch.

Quite chilly Monday & Tuesday (highs 30s to low 40s west side). During this weekend storm, High pressure (>1040 mb) will begin to build over eastern Alaska, the Yukon (yes our fav place to peek for Arctic Events) and the Northwest Territories of Canada. In the Wed, Thu, Fri period, Nov 30 - Dec 2nd, we are anticipate the development of an “almost” modified Arctic Blast that will begin to shunt cold air out of the Fraser Gap, and eventually the Columbia River Gorge as another damp system tracks south along the coasts of BC, WA & OR. Net effect: rain could turn to snow/rain mix at the surface; all snow above just a few hundred feet. With the Low remaining off the coast (if verified), the colder air out of the Gaps will set up the snow or mixed pattern, esp overnight Thu. On Fri, another coastal Low will follow the same path as above, with a bit colder air already in place, a snow/rain mix is probable, or it could remain as all snow if conditions are just right. (We forecast an “almost” modified Arctic Blast because the bulk of the High pressure dome may skirt farther east, missing much of the region. We’ll know more in our next update on the 28th.)

Saturday Dec 3rd The White is possible in portions of western OR, as the Fri Low mentioned above tracks into CA, drawing in cold air support from east of the Cascades as the moisture arrives. Timing is everything. IF this pattern verifies, a couple inches of snow is possible south of Salem. By Sunday Dec 4, the moisture will be gone, the cold will be set in for a few days. East winds will cease. Morning fog possible.

The week of Dec 5-9 is trending chilly & DRY, with an east wind picking up again, esp out of the Columbia Gorge. Overall, though, temperatures will have moderated a bit, so not as cold as the weekend before. Plain ole’ rain may return by the weekend of Dec 10.

—> Final note: some model solutions dismiss the short-shots of moisture moving down the coasts, leaving the PNW mostly dry & frosty. Southerly breezes also remove the surface snow threat, so position of the various Lows discussed above, is critical for valley snow/rain mix. Either way, the coldest temps of the season are highly probable between now and Dec 6. Snow events often take on their own, unplanned, attributes. Be prepared.

Quip from the ’Net: “I always knock on the fridge door before opening — just in case there’s a salad dressing."

-Rufus

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A Bit of Both

Posted by Rufus La Lone on November 21, 2022

Monday November 21

The current long dry spell is nearing an end, although we do expect additional back-to-back days without rain in the near future. Hot java ready. Sip.

The next storm is on tap for tomorrow, Tuesday Nov 22. A quick shot of rain & wind moving in from north-to-south, heading to Vancouver Island around midnight, then pushing into NW WA by daybreak. The front should pack the strongest winds before noon Tue, esp for areas south of the Puget Sound into the Willamette Valley. This will not be a dangerous wind event, just rather blustery given the unusually calm, dry wx of late. By Wed, the event will be over, with clearing sky and dry conditions holding into early Fri. Yes, Thanksgiving Day will be DRY, with a gusty east wind out of the Columbia River Gorge for the Portland area (yep, no fog). Black Friday - a repeat play, with a relatively weak system moving in, north-to-south again so expect some precip mainly from Portland north; not too bad a day at all for much of western OR and east of the Cascades.

Post-Thanksgiving weekend, Nov 28 - Dec 2: pleasant, calm day on Saturday the 26th (maybe morning fog in the usual places), then another system moves in along the same path as the previous storms. This one will be weak in the PNW, but develop into a strong, news-maker storm for California Monday Nov 28th (then it makes big wind & snow in MT, WY). Around the PNW, temps will be chilly again, with frost overnight in most locations. Mixed model solutions for the last days of November. Some runs keeps the PNW damp, other on the dry, chilly side, with another system tracking into southern OR and CA mid-week. An E-NE outflow may develop out of the two Cascades Gaps - Fraser & Columbia - by late week. Again, other model charts suggest a stormy start for December (and week’s end), with a low elevation snow producer (above 1,000 ft) by Fri.

Let’s just hold off on a definitive early December forecast until after the big holiday. For now, we’ll Mug call to a rather dry, chilly start for the 12th month.

Our entire staff (me, myself & I) express thankfulness for family, friends & YOU - a Patron of The Weather Café®️- during this week of Thanksgiving. This is our 28th year ☕️.

“He who forgets the language of gratitude can never be on speaking terms with happiness."

-Rufus

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A Dry Thanksgiving?

Posted by Rufus La Lone on November 18, 2022

Friday November 18

Long-range outlook is trending away from a wet Thanksgiving. Interesting. Go ahead. Refill that Mug and return here for what could happen.

The current dry, chilly pattern around the PNW will continue through most of this weekend (some locations are teasing a record number of consecutive days with no rainfall for the month of November). A very dominant High pressure ridge, centered over the Continental Divide, has resulted in powerful east winds out of the Columbia Gorge and helped to block Pacific storms from entering the region. That is charting to weaken on Sunday. Therefore, for Patrons on Vancouver Island and in NW WA, a weak system could bring cloudiness & with showers late Sunday.

Thanksgiving week is now trending mostly dry! A weak system is likely to bring a gentle rain for western WA & NW OR overnight Monday into Tue. After that, we may end up with DRY weather on through Thanksgiving Day, with the east wind in the Columbia River Gorge & down the Cascade passes returning (not as strong as current event); the wind will help mitigate morning fog in valley areas. Black Friday is now looking rain-free.

STEADY precipitation should be back for multiple days starting Saturday night of the holiday weekend. A weak system will bring on a few showers Fri night, with a short break during daylight hours on Saturday. By Saturday night the 26th, rain will return. Sunday will be wet all day, with heavy rain charting for Mon & Tue.

Models are quite variable for the last day of November (Wed) and early December. Some solutions present very wet for all the region; others hold the rain over NW WA, missing much of OR. Either way, the first weekend of December is trending dry. We will mention that cumulative precipitation amounts may be quite substantial in the Nov 27 through Dec 1 period, esp for western WA & southern BC. Be prepared for localized flooding.

“Some people use language to express thought, some to conceal thought, and others instead of thought.”

-Rufus

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Unusual Dry Spell

Posted by Rufus La Lone on November 14, 2022

Monday November 14

The month is already half gone. So, too, is the rain for an unusually long period, given the time of year. Here is the dry outlook.

DRY. No rain is forecast between now and late Sunday evening, Nov 20. North Vancouver Island may get a shot of rain on the 19th, but that is iffy. Depending on your location, this could be one of the longest dry spells in the month of November in recent history. October was similar. By the week of Thanksgiving, the next rainy cycle should return.

For this week (Nov 14-18), east-NE winds will pick up considerably out of the Columbia River Gorge & Fraser River Gap; subsequently, temps will remain on the chilly side (fog on & off in the southern Willamette Valley). Subfreezing overnight lows in many locations out of the wind. The cold Yukon Dome of High pressure that we mentioned last time remains in play, however, the coldest “core” of that Dome will remain east of the Rockies. Still, the PNW will get another mini-shot of cold air east of the Cascades, which will, in turn, rush west through the Fraser & Columbia Gaps. Not a super cold event, just a few degrees cooler than the previous few days. Sat & Sunday Nov 19,20 will be dry & chilly.

Rain & Mountain Snow returns. Breezy & wet on Mon the 21st, as the first in a series of Pacific storms moves onshore. Models have varied considerably the past few days as to the strength of said storms, and in the precise timing. So, expect on/off rain & windy conditions to prevail from Nov 21 through the U.S. holiday weekend. Rain on Thanksgiving Day keeps appearing & disappearing on the charts. For now, plan for the possibility of wet should you be traveling on the big bird day. Black Friday is trending mixed like Thanksgiving Day - models are NOT consistent in their forecast for rain. There will be 2 more forecast updates here before the holiday.

Post-Thanksgiving - models continue to indicate stormy weather that weekend (Nov 26,27), with rain, wind and mountain snow on/off for those 2 days. Chilly l& damp to start the work/school week on the 28th.

“Science has been producing so many substitutes lately that it’s hard to remember what it was we needed in the first place."

-Rufus

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