raindancewx

Also, past nine years for snow. Substantial variation within seasons though. Once we started to see higher solar conditions around 2021, snow switched to ~incredible volume in the interior West in March again, which is a long-term signal I've noticed. March has more or less single-handily saved the Rio Grande water supply in 2021, 2022, 2023, and 2024 offsetting either failed monsoon moisture or poor moisture winters.

Heat in the old Mexican Highlands has now been fully destroyed, and then some. Highs will be in the mid-60s (5-10 below average if it verifies) there at approximately the same time frame places as far north as Boston could see mid-90s. June 2021 locally had both near-all time record warm highs and near-all time record cold-highs locally (103 and 67 respectively). A similar thing happened in June 2022 (101 and multiple days in the low 70s). This month has already seen several days hit 100 with another day only hitting 72. Both 2021/2022 had highs in the low 70s / upper 60s late June, which is actually super cold here (20-25 below average), while 100-103 is only 8-12 above average even in early June. We're not really in La Nina conditions for what it's worth. Nino 3.4 is still warm west of 140W. I read a paper a long time ago that said cold water by New Zealand is like a teleconnection for a wet/dry winter in the Southwest (NV, AZ, CA, UT - notably not New Mexico or Colorado) but it has to be cold there July-Sept to be reliable. Notably, July-Sept of 2018, 2019 were not cold by NZ and were not wet in the SW US. Years like 1997 and 2004 were much colder (though not frigid) as were other years like 2016/2022/2023 to a lesser extent. Also 2017, which was absurdly dry here, was quite warm too by NZ). The effect is diminished by NM/CO as a lot of our moisture is from storms getting stuck in the mountains for 1-3 days, not from extra storms or a better storm path per se. https://www.sciencedaily.com/releases/2018/06/180613101946.htm The New Zealand Index (NZI) teleconnection depends on a western Pacific ocean–atmosphere pathway. a Negative SST anomalies (blue shading) in the NZI region cascade in the northern hemisphere through a late summer interhemispheric atmospheric bridge and are maintained by air-sea coupling until the following winter. The SST anomalies affect the atmospheric pressure in the US west coast and strengthen the regional jet stream which brings more winter storms in the SWUS; b Late-summer positive SST anomalies (red shading) in the NZI region deflect the jet stream to the north, leading to dry conditions over the SWUS

Just for future visual reference: We remain very far behind the 2022-23 La Nina so far since we started from a warmer point last winter. The 2020-21 La Nina isn't super far off but we seem a bit ahead of it.

Nino 3.4 was 28.25C in May. The years coming off an El Nino winter that are with 0.2C of that (28.05-28.45C) are: 1958, 1969 - El Nino 2005, 2016 - La Nina conditions observed briefly 1980, 1983, 1987, 1998, 2019 are all following El Nino (ish) but either a bit too warm/cool or don't go to La Ninas. 1980, 1983, 1998, 2005, 2010, 2016 look ~correct as a blend for estimating the La Nina strength at the moment. 26.32 + 26.01 + 25.08 + 25.80 + 25.22 + 26.3 --> 25.78C in DJF Keep in mind, none of Dec-Feb periods in 3.4 have finished below 25.5C since 2010-11. The 2020-21 La Nina had an Oct-Dec with all three months colder than 25.5C, but it faded fast. I expect 25.8 - 26.2 for DJF, with a colder peak in Oct-Dec or Nov-Jan, but we'll see.

My forecasts actually seem to be getting more traction each year. I don't have a website, a Facebook, or anything like that. It's just one link posted here and on Twitter, but I get several thousand reads, or at least views now. I try not to post on here more than 1-3 times per day, as I consider it a waste of time in most respects. So I think the low interactions when I post my forecasts are more about me not posting too much than anything else. I could easily see the US (lower 48 anyway) average +3 to +10 for the winter, with a cold spot from Billings to San Francisco, but I really have no idea yet. It's too early. The global upper level pattern that matches with SSTs for JJA or JAS will be pretty telling. That combo almost always rolls forward correctly.

https://psl.noaa.gov/data/correlation/wp.data Looks like it already flipped? 2018 0.43 0.40 0.84 -0.67 -0.19 -0.44 -0.81 -1.38 -1.78 -1.14 -0.61 0.11 2019 1.05 2.09 0.88 -1.30 -0.63 -1.92 -0.27 -2.19 0.86 -0.81 -0.12 0.74 2020 0.69 1.46 1.29 -1.34 0.12 -1.25 -0.54 -0.21 -2.44 -1.18 0.72 0.99 2021 2.45 0.76 2.05 -0.12 0.18 -0.82 -0.44 -1.94 -0.65 1.74 -0.15 0.48 2022 -1.44 -0.39 0.58 0.31 -1.38 -1.66 -0.52 -0.41 1.82 1.04 0.34 -0.02 2023 1.99 2.50 0.65 -0.24 1.02 0.33 1.33 -0.37 1.34 -0.83 0.59 1.21 2024 0.67 1.56 0.97 0.73 -0.27 -99.90 -99.90 -99.90 -99.90 -99.90 -99.90 -99.90 CPC has monthly cross-correlations for all indices. No one ever bothers to look when I post this, but you can see what things tend to occur with WPO flips if you want to see if I'm crazy or not. https://psl.noaa.gov/data/correlation/table/ This thing called ESPI which measures how ideal a tropical precip pattern is for an ENSO event (El/La) seems to correlate most with the WPO tendency in the winter. Almost reads like it is looking at the interaction of the IOD and ENSO as the driver of the WPO. That actually makes a lot of sense to me since prior to the past 20 years most La Ninas had -WPO signatures and now they don't. But the Indian Ocean is warming faster than the other oceans and so you get different interactions than before. ESPI looks a bit like a poor man's MEI, so I doubt it would really much to analysis. https://psl.noaa.gov/enso/dashboard.html ENSO Precipitation Index. The index is based on rainfall anomalies in two rectangular areas, one in the eastern tropical Pacific (10°S-10°N, 160°E-100°W) and the other over the Maritime Continent (10°S-10°N, 90°E-150°E). The first step of the procedure involves moving a 10° by 50° block around each box; the minimum and maximum values of all possible blocks is obtained for each box and these are combined to estimate an El Niño precipitation index (EI) and a La Niña precipitation index (LI). The EI and LI are in turn combined to create the ESPI index. Finally, the ESPI index is normalized to have zero mean and unit standard deviation. Calculated at UMD.

https://x.com/Claudiashein I'm kind of tempted to ask Mexico's new president about seasonal forecasting models in Mexico or in general. It's a weird thing, thinking a politician could answer that or discuss that with a US president to improve our weather forecasting. The heat wave in MX seems tied to delayed monsoon onset as much as anything. Here is what AI had to say. It's pretty consistent with my own research. I've also found August/Sept tend to be wetter than July at statistically significant levels locally using a difference in proportions test at the 0.05 level with high v. low, July-June annualized solar activity. What kind of winter does the US tend to see following a delayed start to the monsoon in Mexico? Answer Based on the provided search results, a delayed start to the monsoon season in Mexico tends to be followed by a drier than normal winter across the southwestern United States, including states like New Mexico, Arizona, and parts of Texas. Here are the key points: There is an inverse relationship between winter precipitation in the southwestern U.S. and the strength/timing of the subsequent North American Monsoon. A wet winter is generally followed by a weaker/later monsoon (Me: we had a wet winter in 2023-24), while a dry winter precedes a stronger/earlier monsoon onset. If the monsoon gets a late start in Mexico, with precipitation increases delayed until late June or July, this tends to signal an early end to the monsoon rains in the U.S. Southwest as well. The monsoon moisture surge progresses northward from Mexico. A late monsoon onset in Mexico is often linked to cooler sea surface temperatures in the eastern Pacific (me - which we have), which can suppress the monsoon circulation and moisture transport. Warmer Gulf of Mexico temperatures (me - which we have) can enhance moisture flow into Mexico and the Southwest during an earlier monsoon onset. When the North American Monsoon starts late in Mexico, climate models project a decrease in monsoon rainfall over the southwestern U.S. in July and August, followed by an increase in September and October compared to normal. This suggests a delayed, shorter monsoon season. The delayed timing of the monsoon rains may be more impactful than the total precipitation amount. A late monsoon onset preceded by a dry winter would likely lead to an extended dry period in the fall across the Southwest before the arrival of winter precipitation. So in summary, when the monsoon rains are delayed in getting established over Mexico, it serves as an indicator that the upcoming winter is more likely to be drier than average across New Mexico, Arizona and surrounding states due to the inverse relationship between winter and monsoon precipitation in this region.

I find it a bit amusing that the severe heat wave in Mexico is breaking right as they elect their first female president, who happens to be a climate scientist (she's pretty bright - some of her papers are pretty interesting). The heat in some sense didn't really end though...it just moved. We're going to be near 100 locally at 5,300 feet above sea level. That's pretty common in June here but it doesn't typically happen until late June. Still doesn't look like much Atlantic hurricane activity is coming for a bit. I'm not completely sold on a hyperactive season just yet.

The joke is the precipitation for winter in the tropics doesn't really look like 4-5-6 this year on the Canadian. Which would imply a different state. But I doubt it knows what is happening yet. Will be curious to see what it looks like in a few days.

Last year had a big heat wave in Mexico too. But it was in June, which is rare overall, but more common in the stronger El Ninos. Global SSTs have 30-32C temps by Mexico and the Philippines right now. That's why I was thinking a couple big hurricanes may end that big high - the fuel is there if something can develop. If we get the effects of the Tonga eruption to decay while the aerosols from the new volcano circulate globally I actually could see air temps / SSTs cool off pretty quickly, with a pretty cold winter. I've mentioned a few times that I expect the WPO to flip - at least for a while. Part of why I expect that is how warm the water is by SE Asia. At some point, the persistent ridges down there are going to get destroyed by super typhoons, and then you'll likely see compensating high pressure by NE Asia to continue directing in storms to suck up the heat content there. When will it happen? Aug-Oct is my guess, which would favor some nice cool shots for the US in that time frame. We'll see though, I haven't done extensive research on this, it's just my gut.

The big heat wave over Mexico seems tied to a big high (at 500 mb) centered at like 21N / 95W. I think that's probably going to suppress hurricane activity away from the US Southeast for a while until something comes in to kill it. My guess is it will be destroyed from the West by the East Pacific hurricane season eventually - not sure though. The dome of heat in May 1998 was centered somewhat north and weaker. Huge area of +7F or hotter centered around 20N/98W

Just for kicks: +WPO La Nina: 1988-89, 1998-99, 2000-01, 2005-06, 2007-08, 2008-09, 2016-17, 2017-18, 2020-21, 2022-23 -WPO La Nina: 1950-51, 1954-55, 1955-56, 1956-57, 1964-65, 1970-71, 1971-72, 1973-74, 1974-75, 1975-76, 1983-84, 1984-85, 1995-96, 1999-00, 2010-11, 2011-12, 2021-22. -WPO & La Nina, recent progression +WPO, La Nina, recent progression January-February tends to be much hotter with the +WPO look in the East. Western typical La Nina cold is stronger with the WPO (+WPO is a strong Western cold signal for Feb-Apr centered on NV).

Old Mexico has been seeing a severe heat wave this month in the central/southern part of the country. Similar timing and magnitude May 1998. Part of why I've been saying that is a good match to global weather. A lot of the highland climates that have monthly highs peak out around ~80F over a 30 year period have had daily highs in the upper 80s and low 90s. This is directly tied to the absence of the monsoon that normally develops in April-May. I look at Pachuca as it is higher up than Mexico City. May is normally 78 / 52 (ish) for the high and low. This month has been 88 / 58 so far (+8). Still pretty tolerable for a place that is at 20N, but it is crazy warm for 8,000 feet above sea level. Temperatures on 90%-95% of days are between 30 and 90 in the highlands, so hitting 91 or 92 in Pachuca counts as a pretty major heat wave when it happens multiple times in a week or month. May to date looks like it is +7F or hotter for about the SE 1/3 of MX month to date. The monsoon seems to begin when high elevation sites in the SW US see higher daily/monthly temps than the high elevation sites of Central/Northern MX. Right now, we're still running about 10F colder than the highlands of Central MX - which is unusual and not a good sign for the monsoon. Normally, ABQ would be 80/50 in May with Pachuca 78/52 and the monsoon rapidly creeping north late month.

We should hit 90F here in a few days. That's a bit early, but close to the long-term average. Not really a cold/warm signal like in some of the recent La Nina emerging years, when Albuquerque hit 90F around May 5 or as late as June 5. I use solar activity the way I include all variables. I match on 7-10 factors that have occurred in the past that have predictive power in winter. I try to get the blend to match within 5% of what is supposed to happen. Not the individual years necessarily. One thing I've been testing recently is if there are any timing tendencies from solar conditions. It does seem like there is some tendency for which part of the country has front loaded or back loaded winters by solar trajectory (rising / waning sunspots). I do think we're likely to see the WPO go negative for at least some portion of the cold season this year, which would allow for at least some major cold shots in the East with any kind of meaningful NAO block. -WPO is actually a really strong cold signal for the US in the Plains in the Fall. Might be necessary just to knock that part of the US back into annual variation norms given how warm the past winter was.

This is the closest I've come so far to re-creating what the Canadian has for the winter. It's too cold in the Atlantic, but I'd give it a B+/A- as a match globally. It's not a particularly interesting winter, but it does seem to have some resemblance to how the Spring has gone. The La Nina will be coldest to the east though Sept/Oct before rapidly moving West if this is the right idea.