CAPE

Chuck! +PNA

Oh its coming.

In the long range all 3 global means have a very serviceable Pacific look with the mean trough and cold directed more into the central US- and with the advertised look it would also be colder in the east. The differences are up top/on the Atlantic side. GEFS maintains a -NAO, EPS looks neutral to somewhat positive, and the CMC ens is somewhat in between, but has a colder look for the east overall. Maybe we lose the blocking for a time, but it has not done much good with the raging NPAC ridge. With improvements there, we should see more cold chances via a neutral PNA/ -EPO. eta- one other thing of note is the PV looks somewhat perturbed/elongated in the LR, and the indication of southward displaced TPV lobes can be seen on the mean. Not a bad look for getting cold air excursions further south.

The Euro ens tracks the New Years storm well NW, then has a trailing wave along the advancing cold front Jan 2-3 timeframe. Verbatim it would be cold chasing rain but still a week out so plenty of uncertainty, and we just cant know- although most of us probably have an intuitive feel for how it might play out.

Looking through the GEFS members, about half imply a more amplified storm that would probably track a bit too far N/W for much of our area(for frozen) but there are others that are less amped/flatter and colder, and there are a few that imply a second wave tracking further south on the 3rd.

My understanding is an extended jet places the exit region further east, which favors a ridge over the western US. This is more common during a Nino, while jet retraction places an anomalous ridge further west over the N Pac, and is associated with a Nina (Chuck's beloved -PNA!) Simple explanation. Cheers!

Too bad they didn't protect Trace McSorley, eh?

It's Complicated. Firstly a -PNA isn't always a bad thing. Jet extensions occur more in Nino, while retractions are favored in a Nina. A poleward shift is more likely in a Nina. MJO phase can have an impact, however. Don't quote me, but I think jet extensions in general are favored during MJO phases 7 and 8, so if we are in fact seeing an extension of the Pac jet (during a Nina) it is probably related to the MJO. What a surprise! I am sipping on my first bourbon after a couple glasses of wine with dinner.

The the last couple runs of the EPS in the LR is for you. +AO/NAO, and a neutral PNA.

The positive phase of the PNA is associated with an extension, and/or a poleward shift of the North Pacific jet.

GEFS, EPS, and CMC ens all have a wave riding along the boundary with cold air pressing in the Jan 2-3 timeframe. This has looked like a period of interest and guidance has been hinting for a few days, but more impressive in last night's runs. Looking at h5, the EPS and CMC ens have a somewhat deeper trough than the GEFS, implying a chance for a bigger storm.

The last 2 months have been a severely dull period weather-wise, outside of wind maybe. Our fave! Just had a legit(but brief) downpour and it seemed so bizarre. Honestly can't remember the last time that happened. 0.15" is already an overperformer lol. Forecast for tonight is a tenth or less, which is basically a broken record as any time there has been rain recently it's been insignificant.

https://forecast.weather.gov/MapClick.php?lon=-120.20927810878491&lat=39.32670071841457#.YceYY2jMKUk There was at least 10" still on the ground before this. I am prepared to travel most of Jan and Feb. Hopefully wont have to go too far, but we shall see.

The Ravens debacle of a season continues. Josh Johnson is the starting QB at Cincy, with Kenji Bahar as the backup.

Pummeled. Now this is a white Christmas. https://hdontap.com/index.php/video/stream/downtown-truckee-california

63 here. Actually enjoying today. Getting lots of stuff done outside. Much better doing it now than when its humid and 80 with bugs.

Outside of being stuck in a really crappy pattern like we have now, you gotta like the odds of seeing some snow during that period, climatologically speaking.

With the advertised setup, the most likely failure mode for us for the early Jan 'threat' appears to be suppression lol.

12z GEFS looks like the 0z EPS with weakening Pac ridge, -EPO, and shift in the mean trough eastward with time. Still a pretty respectable -NAO too.

Lots of white Christmas out west. https://hdontap.com/index.php/video/stream/downtown-truckee-california https://www.youtube.com/watch?v=DoUOrTJbIu4 Watch with a drink of choice and live vicariously.

Yeah I have noticed that as well. The GEFS has backed off some on weakening the trough north of Japan in recent runs. That seems key in getting the Pacific to be more favorable, with the MJO progressing into phase 8.

Latest EPS gives us the look we want. Weakens the EPAC ridge and shifts it eastward with +heights into the EPO domain.

The first period of interest imo is still centered on Jan 3. As advertised, a temporary reshuffle of the Aleutian ridge shears off a vortex lobe and sends it southeastward, relaxing the western US trough, bringing colder air east/south and flattening the SE ridge for a time. Our region should be on the colder side of the boundary and there will be a chance for a wave or 2 to track along it. Beyond that the trough digs in out west again, but some signs of favorable change again towards day 15.

I posted about the weakening Okhotsk vortex advertised on guidance this morning. It clearly plays a big role in sustaining a strong NPAC blocking ridge(wave breaking), so some weakening should occur if that trough dissipates. Seeing that in the ens means now, and in response the western US trough looks less 'diggy' and seems to broaden and expand eastward some with time. I am still not sure this is going to make a huge difference here without a shift in the tropical forcing further away from the MC. We really need the ridge to weaken a tad, shift east some, and ideally expand poleward into the EPO domain. It's a real pain in the ass. Seeing some slight improvement advertised on the means but difficult to say how meaningful/sustainable it ends up being wrt to sensible weather here. In addition the negative NAO is looking somewhat less impressive in the LR. It's a wait and see game as usual when we have a pretty shitty pattern in place.

The main piece of energy tracks way NW, and it becomes a weak strung out mess as it moves east. Best chance of seeing anything 'significant'- frozen or otherwise- would probably be in the western part of our region, and mostly further north. Might not see anything from the metros point east.