CAPE

18z GFS trying to deliver the goods. Pretty similar to the 12z CMC.

Picked up 0.20" of rain today. Looks like a good soaking tomorrow night into Sunday. Maybe one inch plus.

It's a pattern with fleeting cold shots and challenges of timing a disturbance with a fresh batch of cold. A pattern i will gladly roll with given most of the alternatives, but also one I think has a much higher success rate in mid to late winter than early December. Hopefully it becomes a clipper-fest, rather than a cutter-fest.

Yeah its certainly possible we see some ridging hold on in the NAO space as the PNA/EPO ridge builds. That would potentially provide the anomalous cold we need in early Dec but also keep enough of a suppression mechanism in place to maybe allow a stronger shortwave to track underneath.

I think that was just part of the advertisement for the new complex and the available packages.

Can never be totally confident in anything, but I will give you a few reasons. The ensembles have been strongly hinting at the breakdown, and now we see it across ens guidance for several runs now. NA blocks have rarely come to fruition as advertised during winter in recent years. Even though they are lower skill and tend to be discounted(unless they show a "good" pattern), cannot completely dismiss that the seasonal/climate models have pretty unanimously been depicting HL -heights for December.

Yeah we lose the NA ridging, but this is an intriguing look. As Bob said, its a pattern that can be frustrating with cold shots tending to be more fleeting, and I would like this pattern a lot more in mid Jan than mid Dec, but I am not going to be picky given what we usually see in Dec. I like the idea of having a piece of the TPV in that location with the big EPO ridge.

Its pretty clear now that whatever NA blocking does develop, it will break down around the Dec 5th time-frame. So it makes some sense we will get our 12/5 snowstorm. After that the EPO will bring the big cold and hopefully a clipper type pattern, as anything amped will likely cut if the NAO goes positive as advertised.

Yeah for our general region that has been the case lately. Overall though, it seems pretty logical. This makes the most sense for us: Jan-Feb-March = Winter April = Spring May-June-July-August-September = Summer October-November-Dec = Fall

Yeah having an active pattern that rains on us a bunch can ultimately lead to timing it up with some cold air pressing. I don't mind seeing a few cutters either, as eventually we should get a cold push behind one and a trailing wave can ride the boundary and take a favorable track underneath. The Dec 5th deal looks like a virtual lock.

Looks like a decent soaker incoming after some light rain today.. Maybe an inch+. Been dry lately so no complaints other than I have a lot of outside stuff to get done.

In meteorology, every season is 3 full months. Makes much more sense than the sun angle deal.

Cutters wont stop happening because its winter. Met winter starts Dec 1. 6z GFS op run probably doesn't have the next 15 days nailed.

^Totally a gradient pattern look. Given climo, I would love that if I were in NE.

For anyone interested in today's edition of the weeklies - here are the 7 day height and temp anomalies a week or so beyond the end of the 0z EPS. Takes us out to mid Dec. Usual disclaimer..not a big fan of this tool in general, but that being said, I don't hate this look.

Yeah this is pretty close to the best possible setup/evolution to score a solid frozen event with a less than favorable Pac.

December threads started a third of the way into November will tend to have plenty of long range model discussion/speculation.

I am always 'cautious' when guidance advertises a NA block, for obvious reasons. Looks likely that there will be a period of blockiness at this point. Remains to be seen how long it persists. I haven't looked at the MJO forecasts for a couple days- last I looked it was forecast to move into the COD then perhaps emerge at a low amplitude, maybe in phase 1 or 2. The GEFS seems to be moving in the right direction overall in the LR on the Pac side and with heights building in the EPO region. Most recent runs of the EPS are showing some signs too. Time will tell. We just can't know.

I was looking at the ensemble runs and discussing what they are depicting for the first week in Dec. I try to keep the LR discussion in this thread, because that's what it is by definition lol. December is still 10 days away, and this has been an active thread for at least 10 days now. But yeah the op runs are useful for the early next week time frame.

The question is how long it lasts. It appears to break down pretty quickly on the EPS, while the GEFS at least keeps a neutral look towards the end of the run. Signs of some improvement on the Pac side and in the EPO domain, more so on the GEFS. Could be a warmish period ahead if/when the positive heights break down in the NA, and at the same time the Pac remains less favorable. Before that(should it occur), maybe there will be a chance or 2 at something the very end of Nov into the first few days of Dec with the favorable looks.

Might be time for me to change my profile pic to the Dec 2009 one. On second thought, I did that last year around this time..

Absolutely. But at the same time, there is clearly a correlation, in the same way we evaluate 500 mb heights and make reasonable assumptions about the mean temperature in the column below that point, as well as using it as a general (pretty accurate) indication of surface pressures and temps.

Ofc it's also important to realize that the AO and NAO phases are determined by surface pressure measurements(difference in pressures in the case of the NAO) in specific regions.

12z EPS has the AO and the NAO crossing neutral then heading into + territory around Dec 3-4th. GEFS strongly disagrees. This is obviously something to monitor considering the importance (particularly the AO) to a favorable pattern for cold and snow here. Also the weeklies/climate/seasonal guidance are almost unanimously insistent on a +AO/NAO as we move into December, so there is that. Personally I am not concerned at this point given the beating the PV has taken and is forecast to continue taking going forward.

UK weather here the past few days. Mostly cloudy, a bit of rain, temp range 37-45.