December 2019 Weather Discussion for the PNW

[Cloud]

Day 11

 

Very close to arctic. 

[Gradient Keeper]

It would be really, really, really, REALLY nice to see the 6z GEFS show that the Op isn't a serious outlier.... At least for the cold/chilly troughs and yeah the improvements with the block Day 6-10.

[Gradient Keeper]

Very close to arctic. 

Yep. There are building heights over southern Alaska, but not quite enough amplification to drive the arctic front down into Bellingham southward. REAL close though.

[Cloud]

Yep. There are building heights over southern Alaska, but not quite enough amplification to drive the arctic front down into Bellingham southward. REAL close though.

It's an improvement within Day 10 but still skeptical, let see how this trend. 

At least it is trying to bring it back. Fingers crossed. 

[Gradient Keeper]

Check this out.

 

Day 7 past 20 runs (5 days of GFS Op runs)

Aside from poor run-to-run consistency with the overall 500mb pattern, the mean ridge position/positive anomaly remains near 160 W. That's impressive.

 

[Gradient Keeper]

It's an improvement within Day 10 but still skeptical, let see how this trend. 

At least it is trying to bring it back. Fingers crossed. 

I'm very skeptical because as I mentioned the 6z/GEFS lately has been good to very good, but the very next run we see the 12z GFS Op/GEFS bring us back to reality.

[Gradient Keeper]

Summary...An atmospheric river event impacting the PacificNorthwest today will bring locally heavy rainfall to portions ofwestern Washington. Hourly totals could reach as high as 0.5" attimes resulting in some localized flooding or runoff problems.Discussion...Current GOES-W imagery shows an impressive upperlevel low developing off the Alaska coast with a strong shortwavetrough being pushed toward the Pacific Northwest coast. Mostrecent blended TPW product shows a plume of higher moisture,characterized by values of 1 to 1.25", moving south/southeast fromthe British Columbia coast.As the upper level low develops and drops south, the shortwavetrough will move onshore and the latest forecast from the RAP showthe higher PWs impinging on the western Washington coast latertoday (after 15Z). With modest westerly inflow of 40 to near 50kts nearly orthogonal to the Olympics, the favorable orographiclift and higher moisture should break out moderate to locallyheavy rainfall for a prolonged period. Most of the hi-res and nearterm guidance also suggests potential for some instability rightalong the coast, with a few hundred J/kg of MUCAPE possible toenhance rainfall rates. The 00Z GFS shows IVT values in the600-800 range after 18Z today. All told, for the 12 hour periodending 21Z today, 2 to locally 4" of rain will be possible with aseveral hour period of hourly totals approaching 0.5" between 15and 21Z. The latest HREF probabilities indicate moderate to highchances of exceeding 0.5" in 1 hour, primarily on the westernfacing slopes of the Olympics. With this expected rainfall, somelocalized flooding or runoff problems develop.

[Gradient Keeper]

La-la land aka Clown Range living up to its name!

 

 

[SilverFallsAndrew]

Arctic Express

[Cloud]

La-la land aka Clown Range living up to its name!

 

 

 

 

A ridge like that could do some damage.... somewhere. 

Looks ridiculous. 

[Perturbed Member]

Pretty 06z run. Would be nice if the 06z GFS wasn't on crack for once though.

[Gradient Keeper]

Well, I wasn't expecting this. What are we to surmise and speculate about when the 6z GFS Op and GEFS show a very similar upstream pattern Day 13-16. There is a ridge merger leading to a block which then tilts and heights build into Alaska with good amplification. Downstream there are differences with the Southeast ridge. Nonetheless, to see this strong of a signal so far out with good agreement I can't remember the last time I saw this. Yeah. I thought you all might find it interesting.

 

6z GFS Op Day 13-16

 

6z GEFS Day 13-16

[Gradient Keeper]

6z GFS Analog Composite

 

Day 8-14. Best pattern and correlation score we've seen yet. Nice! December 1990!

 

[TigerWoodsLibido]

Let’s see what happens...

[TigerWoodsLibido]

Ensembles are good too.

[Jesse]

Ensembles are good too.

They’re ok. Probably a step back overall.

[Gradient Keeper]

They’re ok. Probably a step back overall.

Not long range 500mb pattern. Lining up with the Weeklies perfectly. I think the pattern becomes real interesting with Gulf of Alaska/Alaskan block in 6-10 days.

[SilverFallsAndrew]

They’re ok. Probably a step back overall.

 

Gonna downvote that negativity

[Jesse]

Gonna downvote that negativity

 

People seem to get negativity and realism mixed up a lot here. From both angles.

[Jesse]

Very close to arctic. 

 

Let's get Tim's two cents first. Not sure if we can trust ourselves to interpret this correctly given our raging biases.

[van city]

I didn't get my daily dose of EPS. Tim?

[TT-SEA]

I didn't get my daily dose of EPS. Tim?

 

Have not looked yet... just getting going here.   On it now.

[TT-SEA]

00Z EPS 10-15 day mean... better than the 12Z run yesterday.

 

 

[Kayla]

Pretty strong signal for a smoothed out mean 13 days out.

 

[Front Ranger]

This December is going to end up as the coldest +ENSO/neutral December at Fairbanks since 2003.

[MossMan]

.11” so far today, 5.10” for the month.

 

Currently 43 degrees.

[MossMan]

The daily fuzz is slightly less deep but still looking good!

[El_Nina]

Love this look- when the snow sticks to anything but the ground.

[Jesse]

Love this look- when the snow sticks to anything but the ground.

US26 at Keyes Summit_pid2550.jpeg

 

It's sticking to the ground on either side of the road.

[Gradient Keeper]

12z GFS Day 3

 

[El_Nina]

It's sticking to the ground on either side of the road.

It's sticking to the grass but the ground itself is still bare.

[Gradient Keeper]

Day 4

 

[FroYoBro]

The front Friday night/Saturday looks kinda fun. Big change in upper level temperature fairly quickly. 

 

Like Andrew said his location might be 50 Friday afternoon with heavy snow by Saturday morning. 

[Jesse]

[Gradient Keeper]

Day 5

 

[Jesse]

The front Friday night/Saturday looks kinda fun. Big change in upper level temperature fairly quickly. 

 

Like Andrew said his location might be 50 Friday afternoon with heavy snow by Saturday morning. 

 

Yeah, looking like an active winter pattern coming up at very least. I have been missing this sort of thing over the last few months.

[MossMan]

It’s actually Fall like out here! Wind is blowing at a good clip with a little rain...Winter must soon be coming.

[Gradient Keeper]

Day 6 meh

 

[Blizzard777]

Yeah, looking like an active winter pattern coming up at very least. I have been missing this sort of thing over the last few months.

I will enjoy this active patten as well! 

 

currently 47*

south wind around 4 mph

rained shadowed as well with a natural umbrella 

[Front Ranger]

Cooler/wetter in mid range, compared to 0z.