CAPE

A -PNA/-NAO combo is pretty common in some of our snowiest periods historically during a Nino.

Notice the tendency for low pressure off the Canadian Maritimes, and high pressure over the Great lakes. And ofc the southern stream loaded with shortwaves. These elements don't 'happen' by accident- this combo is generally what is favored in a Nino, and increases snow chances in the MA.

A bit different timing, but the potential is there on the EPS as well. Favorable h5 looks in a Nino.. just a matter of time. Hard not to be a little excited for the possibilities the first week of Jan. Unless ofc you are an agenda driven deb.

The 'Aleutian' low is still there-it is just shifted further NW in the LR. With the PAC jet forecast to retract, the exit region of the jet core is shifted westward, which influences the location of the lower(higher) h5 heights and surface pressure. The forecast PAC low position (below) reinforces the EPO ridge. When the Jet extends again the exit region of the jet core will be closer to the US west coast, favoring a PAC low positioned eastward over the Aleutians or closer to the GoA, and +PNA chances will increase. There are other factors ofc, but the NPAC jet is ever present and a major driver that influences the strength/position of features at 500 mb.

End of the GEFS run looks interesting. See it?

Yep. EPO ridge with an assist from the TPV lobes getting it done. Follow the flow.

Meanwhile the 12z GEFS has a better look in the NAO domain heading into January.

"Inferior model". Continue hand wringing over a single GFS op run with 'bad look' hundreds of hours out.

Another thing you love to see- with that amplified upper ridge there will be plenty of HP at the surface over central Canada, and the flow between the -EPO and the TPV provides a mechanism to inject Polar air into the pattern, so going forward those Highs will be legit as they press southward and meet disturbances in the flow across the southern US. Just need a little timing, as usual.

Everyone is tired of chasing h5 patterns, but we are now seeing persistent discrete threat windows on the ens means for something other than rain.

Pretty decent look in the NA with potential incoming on the 0z EPS.

The models hint at building heights in the NAO domain then back off, so we'll see. There will probably be transient -NAO periods via wave breaking with lows tracking NE over Atlantic Canada, but my guess is later in Jan there will be increased chances for a sustained block. Given the favorable look on the Pacific side, for now a neutral NAO should do the trick for more modest waves that track across the south.

Early January continues to look promising for shortwaves tracking to our south with colder air in place. Support on the GEFS for the GFS op idea around the 2nd. Hints of more waves in the southern stream beyond that.

Looking more EPS like. GEFS beginning to sniff the good stuff.

Not a good sign.

Thus why posting/seriously discussing such crap is useless. I'll stick to the general idea, meaning the overall h5 look. Some skill there. Those who want to weenie out over 45 day snow maps on extended tools can do so in the thread dedicated to it.

Zoom in. It's more like 6-10 across the area through early Feb. I had 20 inches here in January two years ago in a Nina.

It would potentially be a great pattern for confluence leading to surface HP over S Canada yes. Northerly flow, and waves tracking to our south. Nino 'Come to Papa' pattern.

I don't pay much attention to that stuff. I focus on a week to 10 days beyond EPS D15 at h5. Beyond that, too much uncertainty.

Latest weeklies with a more impressive -NAO heading into mid Jan, and not much else to say about that Pac look. Just damn. Cold air won't be a problem between the EPO ridge and TPV position.

The storm around the 28th looks like rain for the majority of the region, although there is a hint of a second piece of energy dropping in behind on some of the op and ens guidance, with colder air arriving. GFS op has been suggesting this. It looks very close on the heels of the preceding low, so probably not a high probability for surface development close enough to the coast. Something to keep an eye on. Behind that system somewhat colder air should be in place, and there are hints on the ens guidance of one or more weaker waves tracking to our south Jan 1-3 timeframe. Might be a chance or 2 there for an uncomplicated modest event with some frozen.

Impatience stage. Still a week to 10 days before frozen possibilities east of the mountains. Maps and more maps, over-interpretations and hallucinations.

A -NAO episode in early Jan would be a bonus imo. If we are going to see a sustained period of blocking in the NA, it will probably occur late Jan through Feb.

Chuck might be worried about the 'shrinking' Aleutian trough, but for most of the rest of us that is one hell of a nice look for early Jan on the Euro weeklies.

12z EPS D15, and the latest edition of the weeklies for the first week of Jan. Improvement in the NAO domain for early Jan.