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2024-2025 La Nina


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7 hours ago, raindancewx said:

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.

The phenomenon appears to be taking place elsewhere, too, around the 30N ( ~ ). 

India, suffering its greatest heat wave on record relative to date, is also ... prior to the onset of monsoon.

That said, Mexico nor India are delayed monsoon - typically begins in June.  It is the heat that is/has been premature.  There's a cause for that, which is disconnected from the monsoon circulation as a response to seasonal forcing. 

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1 hour ago, GaWx said:

 The NOAA PDO for May of 2024 comes in way down at -2.97, which compares to the May WCS PDO of -1.86. The last time the May PDO was lower than this was way back in 1950. 

https://www.ncei.noaa.gov/access/monitoring/pdo/

 That tells me that the last few days of NOAA PDOs have very likely been near -4. I’m educatedly guessing that the upcoming winter NOAA PDO will average -1.5 or lower based on the model progs and recent trends. The last 3 winters have been sub -1.5. Getting a sub -2 will be very tough based on there having been only four that low since 1853-4. But there have been 16 sub -1.5 and La Niña will help the chance for, say, a -1.5 to -1.75 winter. I’ll be surprised if it isn’t sub -1.

Given the rapidly developing Niña, the SST configuration in the PAC and the overall cycle, would not surprise me at all to see a strong to very strong -PDO winter

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5 hours ago, snowman19 said:

@40/70 Benchmark @GaWx Good info on QBO states during La Nina’s, also discusses solar. 
 

Link: http://blog.northgeorgiawx.com/weather-blog/ninas-qbos-and-our-winter-weather

 Interesting discussion he did in advance of the winter of 2017-8 for the SE saying a benign winter wasn’t a shoe-in for 2017-8 largely because of a combo of the Niña not being strong (turned out E based moderate based on RONI), a strong (and dropping) -QBO (at 30 mb), and a very weak sun. His suspicions turned out to be prophetic. Jan was very cold and Dec/Jan ended up quite wintry with three major winter storms. One of those was a once in a multidecadal SE coastal storm that gave even my rarely hit area the biggest hit since at least Dec of 1989.

 How do these and other anticipated factors for 2024-5 compare? It couldn’t be that much more opposite:

1. very likely rising +QBO vs falling strong -QBO in 2017-8 (30 mb)

https://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

 

2. likely stronger and more basin-wide Niña expected based on RONI vs E based moderate of 2017-18

RONI: lowest -1.25 in NDJ of 2017-18
https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt

Monthly SSTa showing it E based in 2017-18: https://www.cpc.ncep.noaa.gov/data/indices/ersst5.nino.mth.91-20.ascii

 

3. many more sunspots a near certainty with it progged near max (sunspots (well) over 100) vs only 8.5 in 2017-8

https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt

 

4. Strong -PDO progged vs neutral in 2017-8:

https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat
 

5. Warmer globe vs 2017-8: 2023 was significantly warmer than 2022/earlier years (record breaking) and 2024 hasn’t backed off yet

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18 hours ago, GaWx said:

 Interesting discussion he did in advance of the winter of 2017-8 for the SE saying a benign winter wasn’t a shoe-in for 2017-8 largely because of a combo of the Niña not being strong (turned out E based moderate based on RONI), a strong (and dropping) -QBO (at 30 mb), and a very weak sun. His suspicions turned out to be prophetic. Jan was very cold and Dec/Jan ended up quite wintry with three major winter storms. One of those was a once in a multidecadal SE coastal storm that gave even my rarely hit area the biggest hit since at least Dec of 1989.

 How do these and other anticipated factors for 2023-4 compare? It couldn’t be that much more opposite:

1. very likely rising +QBO vs falling strong -QBO in 2017-8 (30 mb)

https://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

 

2. likely stronger and more basin-wide Niña expected based on RONI vs E based moderate of 2017-18

RONI: lowest -1.25 in NDJ of 2017-18
https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt

Monthly SSTa showing it E based in 2017-18: https://www.cpc.ncep.noaa.gov/data/indices/ersst5.nino.mth.91-20.ascii

 

3. much stronger sun a near certainty with it progged near max (sunspots (well) over 100) vs only 8.5 in 2017-8

https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt

 

4. Strong -PDO progged vs neutral in 2017-8:

https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat
 

5. Warmer globe vs 2017-8: 2023 was significantly warmer than 2022/earlier years (record breaking) and 2024 hasn’t backed off yet

Agree on all points. The models are showing this Niña event rather quickly becoming “Modoki” as we head into winter. 16-17 was exclusively east-based, as you said. Solar, QBO, PDO, AGW….not even close. Just to add, we didn’t have the MJO stuck in phases 4-7 back then and the AMO wasn’t ridiculously positive as it is now, helping to feedback into the SE ridge and magnify it

 

edit: *17-18

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15 minutes ago, roardog said:

Are models really showing a Modoki Nina? I know the CFSv2 is essentially showing a basin wide Nina with coolest area around region 3.4 with region 4 barely in Nina territory. 1+2 is also cool.

Not necessarily Modoki but the models are showing at least basinwide, which would be in contrast to the E based Nina of 2017-8 and this was my point. I said “more basinwide”. The contrasts of this and the other 4 factors couldn’t be much bigger vs 2017-8. Also, @snowman19of course meant 2017-8 rather than the 2016-7 he has in his last post.

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17 minutes ago, GaWx said:

Not necessarily Modoki but the models are showing at least basinwide, which would be in contrast to the E based Nina of 2017-8 and this was my point. I said “more basinwide”. The contrasts of this and the other 4 factors couldn’t be much bigger vs 2017-8. Also, @snowman19of course meant 2017-8 rather than the 2016-7 he has in his last post.

Yes. 17-18*

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2 hours ago, GaWx said:

Not necessarily Modoki but the models are showing at least basinwide, which would be in contrast to the E based Nina of 2017-8 and this was my point. I said “more basinwide”. The contrasts of this and the other 4 factors couldn’t be much bigger vs 2017-8. Also, @snowman19of course meant 2017-8 rather than the 2016-7 he has in his last post.

The February, 2018 historic SSW and subsequent huge AO/NAO blocking in March fit the “script” of La Niña, -QBO, low solar being very favorable for SSWEs. The most unfavorable combo for SSWEs would be Niña/+QBO/high solar

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1 hour ago, 40/70 Benchmark said:

Would be congruent with his idea of a more -WPO next season.

I would think a -WPO would help drive cold air more to the east in Canada. Even if there’s a strong SE ridge, having some very cold air not too far away would help your area and mine. We were missing that in 22-23. 

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46 minutes ago, roardog said:

I would think a -WPO would help drive cold air more to the east in Canada. Even if there’s a strong SE ridge, having some very cold air not too far away would help your area and mine. We were missing that in 22-23. 

1. The winter of 2017-8 had a +WPO.

https://psl.noaa.gov/tmp/gcos_wgsp/data.73.21.103.151.156.12.50.31.txt

 

2. Is a -WPO being forecasted by the consensus of models (excluding Weatherbell CFS output, which is totally untrustworthy for reasons I’ve stated)?

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25 minutes ago, GaWx said:

1. The winter of 2017-8 had a +WPO.

https://psl.noaa.gov/tmp/gcos_wgsp/data.73.21.103.151.156.12.50.31.txt

 

2. Is a -WPO being forecasted by the consensus of models (excluding Weatherbell CFS output, which is totally untrustworthy for reasons I’ve stated)?

I think it was Raindance that first brought up the topic of how he thought next winter would feature more of a -WPO. Without trying to find that post, I can’t remember his reasoning but I know he’s had some great success with forecasting those indices. 

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On 5/28/2024 at 8:26 PM, raindancewx said:

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.

 

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30 minutes ago, FPizz said:

 

 Not picking on you or anyone in particular. When Raindance says warm E US winter, he’s sort of deemphasized. But when he says something that appears to possibly promote something other than a warm E US winter (even if it is just a snippet and even if he doesn’t outrightly say he’s expecting cold there), he becomes the must listen to guru by the E US cold winter lovers. Last winter, he was pretty much warm in the E until Mar. Thus he wasn’t getting too much attention before Mar. As Mar came, the attention increased because of Raindance’s chilly Mar since he did well with his warmth through Feb.

 I’m just having fun but y’all have to know this is pretty much true and that it’s due to bias resulting from desires for a cold winter. I’m also vulnerable due to the same desire. ;)

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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.

 

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3 hours ago, raindancewx said:

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

Raindance and others,

Per the above WPO data for 2018-24:

- All but one winter (2021-2) had +WPO

- All Marches had +WPO

- May had a lower WPO than preceding winter’s avg WPO in all cases except May after 2021-2

- All but one summer (2023) had a -WPO, the exact opposite of winter. This reminds me of the prevailing more negative NAO of recent summers vs winters.

- Every Dec rose vs prior August and all but one rose over 1.00

- So, considering all of the above, seasonal trends have been a major factor during this period. Keeping this in mind, is the flip to a -WPO in May (-0.27, the first -WPO month since Oct), itself, signifying anything different from the prevailing 2018-2023 pattern? Is this flip likely signifying much regarding the WPO for the next winter?

- Raindance, I read that your gut favors a -WPO Aug-Oct. But what does your gut say about next winter’s WPO?

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17 hours ago, roardog said:

I would think a -WPO would help drive cold air more to the east in Canada. Even if there’s a strong SE ridge, having some very cold air not too far away would help your area and mine. We were missing that in 22-23. 

Yes, this is a potential pathway for a decent (sneaky) season in the NE when it looks ostensibly very hostile yet again.

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15 hours ago, GaWx said:

 Not picking on you or anyone in particular. When Raindance says warm E US winter, he’s sort of deemphasized. But when he says something that appears to possibly promote something other than a warm E US winter (even if it is just a snippet and even if he doesn’t outrightly say he’s expecting cold there), he becomes the must listen to guru by the E US cold winter lovers. Last winter, he was pretty much warm in the E until Mar. Thus he wasn’t getting too much attention before Mar. As Mar came, the attention increased because of Raindance’s chilly Mar since he did well with his warmth through Feb.

 I’m just having fun but y’all have to know this is pretty much true and that it’s due to bias resulting from desires for a cold winter. I’m also vulnerable due to the same desire. ;)

I have no idea where this perception comes from. He is on a short list of "must reads" every season and there was plenty of talk that he had an unfavorable outlook yet again last fall. I'm not sure whether you have amnesia or what, but I along with some others had countless debates with him about how the forcing would not act like an east-based super el Nino....which was correct, but he was right that it would not matter.

I'm not sure on which planet his opinion was "deemphasized"....nor am I sure who forecasted a colder than average winter or one with above average snowfall?? I saw some forecasts that had near normal snowfall, incluyding my own, but none were particularly robust.

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16 hours ago, GaWx said:

1. The winter of 2017-8 had a +WPO.

https://psl.noaa.gov/tmp/gcos_wgsp/data.73.21.103.151.156.12.50.31.txt

 

2. Is a -WPO being forecasted by the consensus of models (excluding Weatherbell CFS output, which is totally untrustworthy for reasons I’ve stated)?

Sure, but it wasn't that extreme....and the rest of the extra tropical Pacific was not has hostile as it has been the past few years.

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27 minutes ago, mitchnick said:

If its weak in terms of ONI and moderate by RONI stadards, then that shouldn't be a death knell in and of itself....but if we can't get the waves out of the MC then nothing else really matters, anyway. I have learned that the hard way over the course of the past several years.

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On 6/5/2024 at 7:12 AM, bluewave said:

This goes to what I have been saying in earlier posts in this thread. The winter 13-14 and 14-15 Northeast Pacific blocking pattern has shifted to the summer. Some were expecting a repeat of those winters in 19-20 when the marine heatwave exceeded those levels during the summer. But the pattern weakened heading into the fall and winter allowing the MJO 4-7 and supercharged SPV to dominate during the 19-20 winter. 

https://www.nature.com/articles/s41467-020-15820-w

Summer 2019 observations show a rapid resurgence of the Blob-like warm sea surface temperature (SST) anomalies that produced devastating marine impacts in the Northeast Pacific during winter 2013/2014. Unlike the original Blob, Blob 2.0 peaked in the summer, a season when little is known about the physical drivers of such events

 

I'm not sure if it's a shift to summer because the Northeast Pacific blocking pattern was there in the summers of 2014 and 2015, maybe even late summer 2013. The onset was about the same for both seasons (2013 or 2014), it's just that the pattern never seems to be in place in the winter after 2015. The most amazing thing about this 10+ year Northeast Pacific summer blocking pattern is that the only summers here in the Eastern US that were below average were 2014 and 2023. Oddly enough, both of those years were pre-nino summers. 2016 and 2020, the post-nino summers, were well above average (only trailing 2022). Those three summers were among the warmest ever in many places in the Eastern US.

 

As for 2019-20, that was one of the weirdest years ever. There was a stubborn weak el nino that just refused to dissipate. It didn't until fully until the spring.

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Just FYI....what is equally reprehensible and inimical to the productive dialogue that fosters learning is assigning an emotional bias to every forecast effort that verifies too cold and/or snowy. That detracts just as much as any biased forecast in and of itself. Its not advisable to impugn the efforts of others like that when there is clearly defined logic and ratioanle for why the forecast did not work out. When we have a mammoth marine heat wave working in concert with the general background GW signal to produce an unprecedented magnitude of warmth spanning an entire decade that is going to cause most seasonal forecast efforts to exhibit a cold/snowy bias in the aggregate, is it not??

Raindance has been the best and even he would admit that he hasn't been quite warm enough. I'm not even sure @bluewave, who has had a great handle on this, expected this magnitude of warmth. I think we need to cut people some slack on the cold/snow bias crap.

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If its weak in terms of ONI and moderate by RONI stadards, then that shouldn't be a death knell in and of itself....but if we can't get the waves out of the MC then nothing else really matters, anyway. I have learned that the hard way over the course of the past several years.

The Euro is on its own and has had a warm bias, see last year. Given the real time observations and antecedent conditions we have right now, it’s all systems go for at least a moderate event. When you see tropical instability waves this well developed, it tells you a very significant Niña is on the way, despite what the Euro may be showing

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Just now, snowman19 said:


The Euro is on its own and has had a warm bias, see last year. Given the real time observations and antecedent conditions we have right now, it’s all systems go for at least a moderate event. When you see tropical instability waves this well developed, it tells you a very significant Niña is on the way, despite what the Euro may be showing

 

 

 

 

Yea, just speaking of that particular forecast in a theoretical sense. Not saying its going to be right, per se.

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28 minutes ago, PhiEaglesfan712 said:

I'm not sure if it's a shift to summer because the Northeast Pacific blocking pattern was there in the summers of 2014 and 2015, maybe even late summer 2013. The onset was about the same for both seasons (2013 or 2014), it's just that the pattern never seems to be in place in the winter after 2015. The most amazing thing about this 10+ year Northeast Pacific summer blocking pattern is that the only summers here in the Eastern US that were below average were 2014 and 2023. Oddly enough, both of those years were pre-nino summers. 2016 and 2020, the post-nino summers, were well above average (only trailing 2022). Those three summers were among the warmest ever in many places in the Eastern US.

 

As for 2019-20, that was one of the weirdest years ever. There was a stubborn weak el nino that just refused to dissipate. It didn't until fully until the spring.

19-20 was driven by the record ++IOD and also the strongly +AMO and to an extent by AGW. It lead to the SPV on roids and the severely positive NAO/AO that was unrelenting all winter long

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I don't know how anyone would be daring to assess anything less that hostile hot or inimical to winter ever again with the way CC's not only winning in that debate but flogging heads with its trophy.  LOL

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17 minutes ago, Typhoon Tip said:

I don't know how anyone would be daring to assess anything less that hostile hot or inimical to winter ever again with the way CC's not only winning in that debate but flogging heads with its trophy.  LOL

Overall you may be correct for the season, but most long range forecasters do monthly breakdowns.  The best ones that forecast the one correct cold month/period are those that separate themselves from the lazy ones that say warm 24/7 or cold 24/7.  Those who had the cold in January for the large area below won for temps this year. image.thumb.png.2b7212a5639688c1b980a8d70f2e4b19.png

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