CAPE

Yeah I'm always behind. WB lol.

Up next-

The evolution is generally similar to 12z. The low track is further NW- pretty obvious why comparing the upper levels between the 2 runs. Too far out to care much. Onward.

Until there is a persistent discrete threat, this is probably about as good as it gets at this range over a 5 or 7 day window. Problem is it can go right back to looking paltry the next run, and it really means nothing wrt the upcoming potential.

I knew you already did.

Those maps are what they are. Not worth much other than maybe a relative indicator between runs at this range. Supports the idea of an active period with cold in place.

I made reference to the Jan 6-10 period on my post this morning. That looks active on the 12z run as well. Yes those appear to be the 2 windows, give or take. A weenie might want to check the snow map for that period.

12z EPS is similar to 0z with the Miller B idea for the 6th and another wave after that. Again looks very active.

That dipole develops around the 4th this run and is initially too far south- suppresses the potential wave for that timeframe. Like where this is heading though.

As the pattern progresses/gets colder these aren't the typical kind of GLs lows that will kill our thermals. There is going to be a lot of NS vorticity in the flow between the western ridge and the TPV. They can be either constructive or destructive to our hopes and dreams. Timing will be key.

We got us a wave train on the 12z GFS lol.

This is just a week or so away.

Better interaction/a bit of phasing leads to a more robust shortwave for the 4th, pops a coastal low and we get a bit of snow. This could trend better going forward.

Yeah, we need more shitting up of the discussion threads.

lol You do this all the time. Your schtick, I know.

I got 1-3 so I didn't post lol.

Since it is our earliest shot at precip with some colder air in place, I took a peak at the 6z GEFS members for the Jan 3-5 window, and there are a half dozen or so that produce frozen precip. 3 significant- 2 for our area and one that misses south, and a few others that would be something minor. The rest are dry/offshore.

A minor event for Jan 3-4 is still a possibility, and would likely be our first chance of frozen coming out of the mild period. Ens means are still hinting, specifically the GEFS and CMC ens. Shortwave energy is there on the op runs, just a matter if a piece can sharpen up soon enough to get some precip going.

I know. He needs scolding once in awhile, as futile as it is.

If you really want to know stop looking at the surface. All you care about is seeing blue though, and whinging when you don't. It all happens upstairs. Relatively minor differences in timing/interactions between shortwaves can make a big difference in sensible weather for a given locale, and there are going to be differences between operational cycles at range because each iteration gets a fresh set of initial parameters to integrate/extrapolate, and the further out in time the model does that, the more likely there will be a different outcome at particular time/place than than the previous cycle.

Both the GEFS and EPS depict significant vorticity in the southern stream around the 8th- indication of a digging shortwave, which correlates to a surface low near the SE coast.

The 0z EPS has a Miller B signal for the 6th, and then another potential wave beyond that. Jan 6-10 looks very active on on the mean. A little too soon and don't have time to pore over the individual members for details, but this run definitely does not look dry.

Strong signal for an east coast storm on the 0z GEFS for the 8-9 window.

Big picture reminder- Of all the indices we track, historically a -AO, especially when combined with a -NAO, correlates to higher probability for cold and increased chances for snow for the DC area. All guidance forecasts -AO/NAO in addition to a neutral/+PNA and -EPO for early Jan. No guarantees as we always need some luck with timing, but this gives us a hell of a chance to achieve the desired outcome, entering prime time snow climo.

The 7-10 period is active on the GEFS. Looks like possibly 3 different events on the mean but some of that is differences with timing among members.