CAPE

Must be something hardcore to get the SE ridge hallucinations.

That has been a feature on op guidance but not much in the way of surface reflection. A bit better on the 12z op run today, so not surprising the 12z GEFS has a stronger signal for that time. Something to keep an eye on as this looks to usher in the initial push of colder air.

12z GEFS is a bit more robust with the trailing shortwave dropping south behind the 27th rain event. A little snow across the region on the mean verbatim.

12z GFS has the Jan 5-6 storm.

By early Jan the +10 to +15 temp anomalies across Canada are reduced to 0 to +3. -EPO/TPV combo cools our source region. With the advertised h5 pattern, cold air availability shouldn't be an issue for waves tracking to our south.

I just took a look at the 0z GEFS members and there appears to be 2 discrete threat windows- Jan 1-2 and Jan 4-6. Multiple members depict snow for the MA for one or both of those periods. A few are hits for the southern MA/SE around the 5th. A pretty decent signal overall for one or more events Jan 1-6, but the timing is a bit scattershot at this range. The GEPS mean looks a bit more bullish for frozen during this period, EPS a bit less. The advertised h5 pattern for around the 5th in particular looks quite favorable for a MA winter storm.

Ji doesn't know where he lives.

A -PNA means something entirely different in a Nina vs a Nino. With the prominent/extended equatorward shift in the Pac jet during a Nino, -PNA periods are inevitable, and not nearly the death knell they can often be during a Nina.

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.