WxUSAF

Did I look at soundings of a 360hr chart? Maybe.

I violently endorse the 18z gfs

^thats what I was saying several days (a week?) ago about storms trending south during anomalous blocking periods. Still think we’re a bridge too far for that event, but if I lived near Philly I certainly would be watching.

Good news is that the “pattern change”, such as it’s morphed into, seems locked in on all the ensemble systems and the Op runs are generally reflecting that as well if that makes a difference to you. Next week’s big cutter plus the Siberian PV initiate this. Even earlier, this late weekend storm also seems to play a part by blowing up offshore and helping rebuild the -NAO. After the cutter, we get a -EPO/-AO/-NAO combo, but it also comes with probably a -PNA. Ironically (??), this is very much like what the pattern was supposed to be circa thanksgiving weekend. But with the -EPO, we look to get some cross polar flow and rebuild the cold in Canada. That is an overrunning/southern slider type pattern, but it can be very productive. Don’t want a big wound up low still, which could cut. Also don’t want that -PNA to dig to Baja. But seems we are getting a pattern change finally.

It’s a ways out there and we’ve had this fools gold before, but I’m intrigued at the setup as next week’s cutter gets stuck under the block and slowly walks toward the 50/50 region.

@Ji will open the Winter 2023-24 thread soon

With the storm late weekend blowing up offshore into a big 50/50 low as @brooklynwx99 showed, suddenly our “torch” period is looking pretty chilly. The Friday-Thursday period looks BN actually right now with some notable CAD ahead of the big cutter that hopefully ushers in the pattern change.

About damn time a GFS op run shows a winter pattern when we expect one. I’m sure 18z will go back to hurricanes and SE ridges.

Late December sun angle is brutal. Hopefully any potential winter wx happens overnight.

Obvs

maybe time to step away from the computer for awhile?

As @Weather Will shows there, 18z GEFS maintains more or less a similar look to 12z but more emphasizing the -EPO vs +PNA. All 3 ensemble systems have the -EPO in place by D8. D8 has more or less been our can kick point so that’s encouraging. Deeper into the runs they all get a cross-polar flow look as the EPO ridge goes across the AO domain. That will recharge Canada with very cold air if it happens eventually.

Maybe maybe not. The EPS pattern shown by @DarkSharkWX is “good” not “great”. More -EPO than +PNA and the ridging in the NAO is not a true block. But still a -AO. I’d certainly take it.

Lol you were saying?

Wouldn’t shock me in the least Yes. GEFS still scours Canada free from most cold air, but that H5 look is light years better than it’s inverse. Yeah, I had to eyeball it as TT has no forecast trend plots for 250mb winds, but looked like a noticeable extension and strengthening after D7-8 on the 12z vs earlier runs.

Saw that! Bring it!

I’m on my phone so hard to post too many graphics but that forecast trend out west has totally flipped. It’s handling the Siberian PV a lot more like the eps. Seems to be all somewhat due to a much more extended Pac jet. Maybe due to an East Asian mountain torque event?

Lol just a few changes on the GEFS

^extrapolating a D13 KU there

These op GFS runs are just allergic to generating any legit cold air in North America and especially bringing any east of the Rockies. I miss the days of the always reliable D10+ blizzards.

Bingo

Follow up from above…if 1 runs trends are your thing (and we know they are!), 18z GEFS with more west coast ridging and moves the Siberian PV more into the Aleutians. Then it does it too much lol but one issue at a time .

Ok, so is Lucy going to kick the football again? Today's EPS was run out of JB's basement. That's worth some private time alone in a dark room right there. -AO/-NAO/-EPO/+PNA Yahtzee! But will it actually happen? GEFS continues to be far less enthused about west coast ridging. And the GEFS has led the way with the current can kick. What continues to concern me is that GEFS, already with a less impressive Pacific sector than the EPS continues to correct to a stronger -PNA. Look at all this blue on the west coast in this gif. This is the GEFS forecast trend continuing to trend toward -PNA and/or more +EPO at all time steps as we march forward in time. Past performance is not necessarily an indicator for future performance though and there continue to be reasons to think that at.some.point the Pacific will improve enough to put us in the game. So what can we look at to distinguish between the EPS and GEFS solutions? I think the big tropospheric PV over Siberia/Sea of Okhotsk is a big discriminator. Below is the D8 depiction for both systems. There *should* be notable skill at D8 to forecast the location of such major features at H5. The EPS wants to push this farther east toward Kamchatka and the Aleutians, which eventually produces the pants tent depiction above as it continues eastward. GEFS lags it far behind and keeps it more over the Arctic Ocean and eastern Siberia. Blue over Kamchatka above, orange over it below. By D11, EPS has troughing extending into the Aleutians and we have a pretty El Niño type NHEM pattern. GEFS is following to some degree (notice the blue over Kamchatka now at D11), but still different enough to have some big sensible wx differences downstream for us. The EPS continuing to show an El Niño-like pattern in the midst of a La Niña and with the GEFS continuing to push more troughing into the West Coast are two things to give us some caution. I certainly hope it happens obviously! Got to watch how that Siberian PV moves and wobbles over the next few days.

Lol this Harbaugh quote: “a bad idea in the sense it had no chance”