CAPE

This upcoming period has consistently looked to feature a transient eastern trough with a ridge building right behind it on the means as the trough(temporarily) re-digs out west. The window is brief and pretty much centered on a wave forming along the boundary. Too soon to know if it will be weak, shredded, too warm,(insert other failure mode), etc, but the idea is still there on today's 12z GEFS.

At least I can say I have observed a few minutes of frozen in December, to go along with the few mins of flakes in November.

Sleeting in Easton.

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.