raindancewx

We seem to be entering the March 1973 part of the pattern now. After 10 feet of snow in California's high terrain in two days earlier this month, I suspect our mountains will get 1-3 feet in 1-2 days with this storm. I don't think it's the last one either. I would prefer to have a stout cold high in Wyoming trapping a flow of moisture from Puerto Penasco, but trapping a strong storm with a lot of moisture and some cold for a long duration under a high isn't half bad. If any of you still need your snow fix, our mountains will get pasted with this setup even though it's not as good as the Casper v. Penasco setup. I'm a little surprised this didn't happen in December or January, but these types of regimes tend to accompany the transition from East based to Modoki setups. If you look, the thunderstorm activity has kind of died in the East Pacific in recent days / weeks. It makes sense that it looks fairly cold in the East now. I would bite on this being a Modoki El Nino from now until it completely collapses into an East based La Nina in six weeks.

It looks like I had the right general idea for temperature and precipitation profiles seasonally, but not monthly. Warmth was more impressive than I expected too. But I had the warmest part of the US as MO to MN and east, and that verified. No one was expected to be cold overall, which verified, but coolest spots South and West. Dry spots in an ocean of above average moisture were generally placed correctly too. I'll do a more in-depth update on snow once the March snows settle down late March into April.

I've always found it a bit silly to look for a 500 mb profile in ENSO that is typical, and to complain that anything that doesn't match that profile is atypical. It's much more common for ENSO events to go to a temperature profile that matches the typical / atypical idea in comparison to the 500 mb profile. You essentially had the normal warm North / cool South look from this El Nino, regardless of how you got to it, plus maybe a bit more coolness for the Northwest with the -PDO. I'd be more willing to agree with your assessment if the subtropical jet had failed to be strong. But that actually is a direct physical response to ENSO, and it was there. The mid-lattitude stuff that people look for is essentially over fitting trend lines and history in a lot of ways.

Remember how I said there would be an incredibly powerful storm around March 1? Check out the blizzard over California the past two days. Welcome to March.

I doubt the models really have the orientation of SSTs right for next winter. It could definitely be very warm out here for 2024-25. But truth be told, a lot of the Modoki La Ninas are pretty good for snow out here. The Modoki El Ninos and Modoki La Nina both tend to see one of the dominant ENSO signs fail more often than the east-based events. The El Nino signs here are ~70% cold / ~70% wet, and the La Nina signs here are ~70% warm / ~70% wet. In Modoki El Ninos a lot of times the wet signal fails in winter (see: 1957-58, 2009-10, etc), and in Modoki La Ninas a lot times the warm signal fails (1974-75, 1984-85, 2000-01, 2020-21, 2022-23). One other thing that's lost is that La Nina tends to amplify the temperature differentials in the mid-latitudes by enhancing dry air. So here in the desert, with drier air and more sunshine, we tend to have very cold nights in a lot of -PDO/La Nina setups. In El Nino, moist air is abundant and the mid-latitudes have lower temperature differential v. the tropics, so we tend to have a lot of warm nights and cold highs. The caveat to that is that enhanced snow and snow cover duration offsets the warm nights. The 2022-23 La Nina had something like 112 nights with lows that were freezing or colder from Oct-May. That's a pretty severe winter by lows for us - even though the highs were not cold. Whether any of you believe me or not, there is a real tendency for the West to face incredible periods of severe cold in La Nina following years of low hurricane activity in the Atlantic. All of our record cold events, even in the Southwest are in La Nina. Look at February 2011, November 2000, January 1971, etc. La Nina climatology for the Southwest is persistent warmth, like 70 of 90 days that are +3 or more, with 20 or so days that are -5. The "harsh" La Ninas just have the 20, or 30 cold days at -10 or -20 v. means instead of -5. So you're really just trying to predict the harshness and duration of the brief cold periods.

Google is your friend. https://tropical.atmos.colostate.edu/Realtime/index.php?arch&loc=northatlantic

Canadian is a bit different from the CFS. The absence of heights by Japan is a major change from the winter and should come with some colder systems and/or late Nor'easters for the East Coast.

Google is your friend. https://psl.noaa.gov/data/correlation/wp.data

I'm not crazy for thinking the CFS has March 1973 right? I mean...that's an insane month for the West if it even comes to verifying. Top five for snow in the past 100 years I'd guess regionally. It does look like the North Pacific high pressure feature is off in terms of placement east/west, and maybe a touch north of 1973. But it really does look close to March 1973 to me. At this range, the CFS actually has skill for the next month too. It's done pretty well this winter actually.

Just for future reference - the area of the world that was coldest (v. local means) this winter was NE Russia. Looks very much like the WPO drove the winter pattern in Asia and North America as much as anything.

We're really starting to see the handiwork of the Super +WPO again. I've been telling people for six months here, the closer we get to March, the crazier the weather gets. You can see we're almost there. Plenty of heat in TX. https://twitter.com/MattHinesTX/status/1762276038665457919/photo/1 3-9 feet of snow for California in two days, starting Thursday.

I've actually found a lot more predictive 'events' with La Nina than El Nino over the years. A few examples: Early heat waves in the West (ABQ first 90F high, where 1 is May 1, 31 is May 31, etc) in La Nina are highly correlated to cold winters in the Rockies/West for La Nina. This is from my outlook for 2022-23. I've always assumed this worked because it meant a coherent MJO wave in phase 4-5-6-7 was showing up around 5/1. At a standard 45 day MJO lag (more dark arts, i.e. counting), that turns to 6/15, 7/30, 9/15, 10/30, 12/15, 1/30, 3/15 which indicates that 4-5-6-7 will show up several times in winter, when it is a cold signal here. MJO 5 is generally cold here early on (Nov-Jan). La Nina cold snaps in the West are also highly tied to ACE in the Atlantic - In the absence of cold snaps in the West, the cold either isn't anywhere in America, or it is going to the East. But really for the East, the high ACE thing is more of a good snow year indicator than a cold indicator.

I haven't quite given up on the time frame over the next few days that I outlined before. It looks bad now. But the models are rapidly changing locally. You already have a Blue Norther level cold front charging east, with St. Louis set to drop something like 65 degrees in 12 hours. NAM has snow around St. Louis after they hit 86. I doubt the solution further east is resolved well just yet. Each new run has some kind of fluky Southern snow, either Atlanta, Nashville, Little Rock, etc. I guess my premise is if someone that far south gets snow, someone in the Northeast will too - but we'll see.

February in the US looks like a pretty classic hot EPO & El Nino "east / east-central" temperature profile to me. Even the stupid little correlation break over Western Montana is there. The strongest correlation is for warmth in the North Central US. The lightest blues / lightest greens are not super relevant correlations. But they do paint a fairly accurate picture of what to expect. I find that in periods of rapidly changing ENSO conditions, the +/- WPO correlations tend to take over for US temperature profiles. The CFS has been trending to a classic +WPO look for March for temps. The WPO tends to send pretty powerful systems in the West, and they occasionally make it into the South with puddles of cold air. The cold generally gets to the Northeast last and in dire straights, and so that part of the country ends up warmest compared to means. It's dead on to the stronger +WPO looks. I've already looked, and there actually are several El Ninos that look like February 2024 with duller warmth that go to the projected March 2024 look. So it looks more or less right to me. I think people generally associate the WPO/EPO as kind of the same thing. But in reality, the EPO is rarely much of a signal for the West, that's how you know it is the West Pacific high/low orientation by the dateline driving the pattern.

Some of my dark arts (i.e. counting) methods are indicating that the fluky snowstorm in the South around 1/16 is going to show up again around 3/1. I'd imagine you guys will have a shot with that system and one other at least before your chances fully end in week two of March. GFS has snow as far south as central TN, just north of that 1/16 system which had snow to northern Mississippi on the latest run. I've seen signals for a pretty powerful system around 3/1 since October, so I do buy it. A lesser, but probably colder system around 3/9 too. We'll see if I'm right soon enough.

As a general rule, any storm in March or April that is cold enough, south enough and strong enough to bring snow to the valleys of New Mexico is likely to be quite prolific at tornado production. It's how the cold air mixes with the dry air and wet air over the state, and then how that blend mixes with much more humid / hot air to the East. Any air mass to the east in front of an orphaned cold system over the desert will warm dramatically. We should have some pretty powerful cold systems here. The April 29, 2017 tornado outbreak was instigated by a storm powerful enough to bring accumulating snow to the valley floors in NM - mid afternoon no less - after we had hit highs in the 70s/80 many times in Spring already.

The GFS earlier today had the look that I call the "legendary pattern" in the 2/29-3/2 period locally. Big cold high over Wyoming, with a potent low off Baja. Both got stuck for 2-3 days, and sent wave after wave of moisture with feet of snow for the high terrain locally. Its gone now, but that's what I've been looking for in March, it's the only way to get days of heavy snow here. The weeklies also had Nino 3.4 down to 28.0. Once we get to March, Nino 3.4 has a much warmer baseline. So by temperature, the basin is cooling quickly, even as it should be warming. The El Nino is ending pretty quickly. Subsurface is long dead too.

You guys are running +5F for Dec 1-Feb 16 in Baltimore. But your snow isn't near as bad as some of the winters with comparable warmth. I'd say you've actually been a bit lucky given the warmth. Those are your ten warmest Dec 1-Feb 16 periods, with snow following the dash. 1931-32 -1.6 1949-50 -0.5 1948-49 -14.7 2022-23 -0.2 1936-37 -11.1 2023-24 -9.1 2019-20 -1.8 1932-33 -25.4 2011-12 -1.8 2001-02 -2.3

CFS is trying to go to the 500 mb look I've been expecting for six months. It's maybe technically 2.5/3 on the features I want to see. It is trying for a +WPO, -/=NAO, with low heights across the southern US in between. It's sort of a diet, off-brand version of March 1973 at the moment. I suspect the area I put the L in will become more blue with time and push the yellow H closer to the south of Alaska. The heights by Japan have been there all winter, so not expecting that to change, in that sense it should remain a duller version of 1973.

I suspect the water vapor from the volcano is what drove a lot of the precipitable water though. I've also seen some papers recently saying that the hole in the ozone layer by Australia was likely damaged by the eruption based on observations that were taken immediately after. Anything that impacts heat/energy transfer unexpectedly is a big deal really. https://research.noaa.gov/2023/12/20/hunga-tonga-2022-eruption/ “Our measurements showed that stratospheric ozone concentrations decreased rapidly – by as much as 30% in air with the highest water vapor concentrations – in the immediate wake of the eruption,” said Stephanie Evan, a scientist from the Laboratoire de l’Atmosphère et des Cyclones in France and lead author of the other recent study, published in the journal Science. Evan and colleagues continued to measure ozone concentrations depleted by around 5% across the Indian and Pacific oceans two weeks following the eruption.

I've been a bit surprised this winter is going to be classified as a borderline Super El Nino. It really doesn't look anything like 1982-83, 1997-98, 2015-16 or even 1972-73 on the SST maps.

If you can imagine the US on a wheel, with the point centered on Kansas, the basic idea for next winter at this point would be to rotate all of the warm/average spots by 90 degrees clockwise, with the warmth thinning out.

Happy late February. Good old dark arts magic...i.e. counting the time between pattern changes. Still think an interesting period, even if it is brief, is coming nationally in March.

Minneapolis has been super warm this winter. If you roll forward their six warmest El Nino winters this is what you get. Pretty much what I imagine for a La Nina Modoki look, even without limiting the roll forward years to La Ninas. Still, that's a much colder winter than 2023-24.

What I've found over the years with La Ninas is that the higher activity is in the Atlantic, the fewer cold waves / moisture / general storminess you get in the Southwest. ACE does tend to favor heavier snow in the NE in La Ninas when high (see: 1995-96, 2005-06, 2010-11, 1933-34, etc). We're actually in pretty good shape now for moisture in a lot of the West. I could see next winter being almost barren of moisture in light of that. I think Elephant Butte Reservoir in NM, which is the subject of countless legal conflicts between CO, NM, TX, and MX may reach it's highest water level in 15-30 years with the run off this year, pending how March goes. For most of the last decade it hasn't even topped 20% of capacity which is the level that allows NM to store its water instead of sending it to TX. We're already well over 25%, with more snow-pack likely to build into at least March. I really think Elephant Butte, shown below has a shot at topping 600-700 thousand acre feet for the first time since 2004, approximately when the PDO flipped to negative. You can see though, the 2020-21 and 2021-22 were like the La Ninas in the 70s here - not particularly wet, but almost all moisture that fell was snow in the mountains and valleys feeding the Rio Grande, rather than rain.