2024-2025 La Nina

[Stormchaserchuck1]

45 minutes ago, michsnowfreak said:

That would be an unprecedentedly snowless December here for a La Nina. I don't buy it. As we say, seasonal models need to be taken with a grain of salt anyway, but a seasonal snowfall estimate? We have enough trouble with snow maps during nowcast time, much less an interpretation of snow maps for a season. 

The Euro did have 200% moisture in the Caribbean for ASO.. that's not verifying for sure. I have been impressed though at how we very rarely see a total disconnect from these modeled seasonal H5 patterns. 

[michsnowfreak]

1 hour ago, Stormchaserchuck1 said:

The Euro did have 200% moisture in the Caribbean for ASO.. that's not verifying for sure. I have been impressed though at how we very rarely see a total disconnect from these modeled seasonal H5 patterns. 

Yeah patterns are one thing. Temp estimates and especially snowfall estimates are another. Another thing with snowfall estimates. The models love their 10-1 ratios. We usually see quite a bit of powder, but ive never seen more pasty cement snow than in 2022-23. Detroit season total was 37.1", about 83% of normal, but if all the seasons snow fell at a consistent 10-1 ratio it would've been closer to 45-50", about 100-110% of avg. Just another example how not to get caught up in the finer details.

 

Two things I'm confident in:

Most confident: regardless of the kind of season it ends up, 1 month will be a wintry standout

A little less confident but likely: December will be snowy, very possibly the above mentioned standout month. 

[George001]

2 hours ago, michsnowfreak said:

That would be an unprecedentedly snowless December here for a La Nina. I don't buy it. As we say, seasonal models need to be taken with a grain of salt anyway, but a seasonal snowfall estimate? We have enough trouble with snow maps during nowcast time, much less an interpretation of snow maps for a season. 

I buy the general idea (a sharp gradient of AN snows north of that and BN snows south). However, a 500 mile shift in either direction for the location of the gradient would make a huge difference. 

[bluewave]

2 hours ago, Stormchaserchuck1 said:

The Euro did have 200% moisture in the Caribbean for ASO.. that's not verifying for sure. I have been impressed though at how we very rarely see a total disconnect from these modeled seasonal H5 patterns. 

It’s interesting how the Euro seasonal can have a great summer temperature forecast for the U.S. but miss on the hurricane forecast. My guess is that the seasonal forecasts can’t handle competing marine heatwave interactions with the base ENSO climate state. Same way the winter forecasts were way too cold and missed the record warmth last two winters. The model had the stock La Nina and El Nino composites but missed the much warmer MJO interactions. 
 

[snowman19]

6 hours ago, GaWx said:

Since 1979-80, there have been only 6 winters that had a -0.25- NAO:

1984-5: SS 20

1986-7: SS 6

1995-6: SS 12

2009-10: SS 21

2010-1: SS 33

2020-1: SS 14

 So, since 1979-80:

1. NAO winters dropped way down in frequency with only 6 (13%) of 45 following the 25 winters 1954-5 through 1978-9, which had 16 (64%). So, 1979-80 through 2023-4 winters had 1/5 the freq of -NAO winters the prior 25 had

2. All -NAO winters of the last 45 had SS 33 or lower. They averaged 18. 1900+ avg SS: 85. So, the 6 had SS that averaged only 1/5 of the 1900+ avg for all months.

3. Related, the 6 were all within about 2 yrs of min.

4. This graph shows the correlation well:

Great find

[GaWx]

19 minutes ago, snowman19 said:

Great find

 Thanks. It will be interesting to see if during 2028-31 we see the -NAO/near solar min pattern continuing. The last 4 mins back to the mid 1980s have had 1-2 -NAO winters as per that graph and that’s it. Only 1 in 7 of the last 45. So, if the next one waits til then it wouldn’t surprise me. Or will the pattern finally break and one slip in before the late 2020s? Will be fun to follow.

[susqushawn]

15 hours ago, bluewave said:

The PNA was weakly positive on the CPC site in January 2023.

https://origin.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.pna.monthly.b5001.current.ascii.table

 

2023   0.21

Bit of a tangent here ...The CPC methodology for calculating the PNA index may be subject to flaws.  This week ahead is a case in point.  It projects a +PNA despite an unmistakable trough modeled out west. 

It was pointed out to me that the CPC formula for + phase looks for above normal heights from Hawaii to the intermountain west, and below normal heights over the Alleutians and SE Conus. 

The week ahead is an anomaly as it does indeed have below normal heights in the SE but obviously not resultant from a west coast ridge, rather, a stagnant rex block.  I suspect that's the main anomaly "fooling" the formula into believing we have a notable +PNA, when from a sensible wx standpoint it's the complete opposite.  If this was winter the CPC projection would be under greater scrutiny.  That would be an exciting +PNA projection in DJF but sensibly it couldn't be farther from reality.

[snowman19]

@bluewave It appears we are going to see a strengthening of the already strongly negative PDO this month. Warming is continuing in the northwest PAC near Japan and the western Aleutians while there is rapid cooling in the GOA, the eastern part of the basin along the west coast and off Baja (-PMM) 

This is not screaming -WPO, -EPO, +PNA to me. 

Furthermore, we’re at the time of the year where the trade winds begin to collapse over the equatorial Indian Ocean as the Indian and Asian monsoons terminate, we are going to see SSTs warming up across the maritime continent and the eastern IO and additions cooling across ENSO. However, a potent WWB is forecast across the central and eastern part of the basin which will likely warm up the waters even more. Also, a prolonged EWB will park across the western basin and maritime continent which would fuel a -IOD.

-IOD/-ENSO is only going to enhance the background Niña circulation state and the Maritime Continent (MJO 4-5-6) convective forcing 

 

[bluewave]

4 hours ago, susqushawn said:

Bit of a tangent here ...The CPC methodology for calculating the PNA index may be subject to flaws.  This week ahead is a case in point.  It projects a +PNA despite an unmistakable trough modeled out west. 

It was pointed out to me that the CPC formula for + phase looks for above normal heights from Hawaii to the intermountain west, and below normal heights over the Alleutians and SE Conus. 

The week ahead is an anomaly as it does indeed have below normal heights in the SE but obviously not resultant from a west coast ridge, rather, a stagnant rex block.  I suspect that's the main anomaly "fooling" the formula into believing we have a notable +PNA, when from a sensible wx standpoint it's the complete opposite.  If this was winter the CPC projection would be under greater scrutiny.  That would be an exciting +PNA projection in DJF but sensibly it couldn't be farther from reality.

That’s just how the CPC calculates the PNA.  Most use the CPC since thats how people compare their seasonal PNA forecasts to what the CPC verified. The CPC method allows for a deep trough in the west and when heights are positive in Canada and calls that a +PNA. Usually if there is a ridge somewhere in SW Canada it’s considered a +PNA.

 

 

[snowman19]

@40/70 Benchmark I know you’re not considering ONI, but it looks like we are going to see some considerable warming with a WWB in the eastern to central ENSO regions. Region 1+2 is warming very quickly right now. That absolutely does not support an east-based event. Regions 3 and 3.4 are also going to see warming push in. I still feel like we may end up cold-neutral in the ONI sense, it’s very late for a substantial Niña event (SSTs) to take shape. Either way, this is going to be interesting to watch over the next 2 months 

[GaWx]

9 minutes ago, snowman19 said:

@40/70 Benchmark I know you’re not considering ONI, but it looks like we are going to see some considerable warming with a WWB in the eastern to central ENSO regions. Region 1+2 is warming very quickly right now. That absolutely does not support an east-based event. Regions 3 and 3.4 are also going to see warming push in. I still feel like we may end up cold-neutral in the ONI sense, it’s very late for a substantial Niña event (SSTs) to take shape. Either way, this is going to be interesting to watch over the next 2 months 

 There’s still plenty of time to drop a good amount per the latest models. CDAS 3.4, TAO buoys, and OHC have all been dropping to their coolest yet. OISST 3.4 has been lagging but I’m looking for it to resume cooling. SOI has been averaging positive overall although it has been negative the last few days.
I’m central based weak Niña (ONI based) and moderate Niña (RONI based) based on latest model runs.

[40/70 Benchmark]

3 hours ago, GaWx said:

 There’s still plenty of time to drop a good amount per the latest models. CDAS 3.4, TAO buoys, and OHC have all been dropping to their coolest yet. OISST 3.4 has been lagging but I’m looking for it to resume cooling. SOI has been averaging positive overall although it has been negative the last few days.
I’m central based weak Niña (ONI based) and moderate Niña (RONI based) based on latest model runs.

Ever since snowman concluded that cool neutral could result in an even warmer winter for the east he has been pushing that narrative lol

[40/70 Benchmark]

7 hours ago, snowman19 said:

@40/70 Benchmark I know you’re not considering ONI, but it looks like we are going to see some considerable warming with a WWB in the eastern to central ENSO regions. Region 1+2 is warming very quickly right now. That absolutely does not support an east-based event. Regions 3 and 3.4 are also going to see warming push in. I still feel like we may end up cold-neutral in the ONI sense, it’s very late for a substantial Niña event (SSTs) to take shape. Either way, this is going to be interesting to watch over the next 2 months 

I have never expected an east-based event....however, the weaker the ENSO, the less important EMI is....2000 and 2008 were both pretty far west. Obviously 2000 is way off with the extra tropical Pacific, but 2008 may not be an awful analog.

[Stormchaserchuck1]

9 hours ago, bluewave said:

That’s just how the CPC calculates the PNA.  Most use the CPC since thats how people compare their seasonal PNA forecasts to what the CPC verified. The CPC method allows for a deep trough in the west and when heights are positive in Canada and calls that a +PNA. Usually if there is a ridge somewhere in SW Canada it’s considered a +PNA.

 

 

No way should that be a +PNA.. not only that but it's >1, with one of the larger index readings in the last few months. '

Last Winter was also classified +PNA, when there was definitely an Aleutian ridge over their "blue" region. 

This messes me up, because I use their correlation composites, to run together different patterns +lag/lead times.. if they aren't classifying N. Pacific ridges right, it could give some silly and unwanted results. 

[michsnowfreak]

21 hours ago, George001 said:

I buy the general idea (a sharp gradient of AN snows north of that and BN snows south). However, a 500 mile shift in either direction for the location of the gradient would make a huge difference. 

I do too. It's the classic nina pattern, regardless of strength. I'm definitely feeling a much snowier winter here in the end (not without its frustrations course). If I'm wrong I'm wrong and I'll admit it. 

[snowman19]

13 hours ago, 40/70 Benchmark said:

Ever since snowman concluded that cool neutral could result in an even warmer winter for the east he has been pushing that narrative lol

Nice conspiracy theory Mark Margavage lol. It doesn’t frigging matter if it’s cold-neutral, the atmosphere is and has been in a strong Niña state. MAKES NO DIFFERENCE if the SSTs are cold-neutral. So no matter what the ENSO SSTs say it’s still going to behave like a La Niña with a strong -PDO. I can conclude that the SSTs are going to say that monkeys fly out of your butt and it’s still going to behave like a negative PDO Niña this winter. The twitter crowd can predict this being “east-based” all they want. Good luck to them with region 1+2 SSTs approaching an El Niño and region 3 warming up rapidly. Now, it looks like it’s going to be a CP/Central Pacific event. And good luck with the high Atlantic ACE fantasies, we’re now below normal. You’re going to be lucky to see the final ACE number for this season crack the low 100’s
 

[bluewave]

14 hours ago, Stormchaserchuck1 said:

No way should that be a +PNA.. not only that but it's >1, with one of the larger index readings in the last few months. '

Last Winter was also classified +PNA, when there was definitely an Aleutian ridge over their "blue" region. 

This messes me up, because I use their correlation composites, to run together different patterns +lag/lead times.. if they aren't classifying N. Pacific ridges right, it could give some silly and unwanted results. 

I thinks it's due to the higher heights near the Pacific Northwest and Vancouver in recent years compared to the older -PDO era. So we are getting a split -PNA vortex. One piece this week stays up in Alaska and another digs into California. The height rises in the middle register as a +PNA. In the older -PDO era we didn’t see this pattern much since the -PNA vortex was more consolidated. Could also be related to competing marine heatwaves changing the character of how we used to understand the teleconnections in the old days. As we have also seen changes in the North Atlantic with the AO and NAO not as in sync as they used to be. This was evident with the very strong winter -AOs during the 2020s and the NAO more neutral to even positive during those -AO intervals. As recently as 09-10 and 10-11 the -AO and -NAO were more evenly matched during stronger blocking intervals.

Split -PNA vortex this week

 

Weaker -PNA vortex in recent years with higher heights near PAC NW and Vancouver during La Ninas and -PDO

 

Stronger and more consolidated -PNA vortex in older era during La Ninas and -PDO

 

 

[qg_omega]

Very easy forecast for winter with MJO in 4 5 6 in the means for DJF, nothing else matters

[mitchnick]

Sun "may" have finally peaked looking at everything at this link.

https://solen.info/solar/index.html

[snowman19]

18 minutes ago, mitchnick said:

Sun "may" have finally peaked looking at everything at this link.
https://solen.info/solar/index.html

Going to have to wait awhile to actually confirm that but maybe…01-02 also peaked in August/September then slowly dropped through the end of March. That said, radio flux is still very high

 

 

 

[snowman19]

The never ending saga…

[PhiEaglesfan712]

20 hours ago, GaWx said:

 There’s still plenty of time to drop a good amount per the latest models. CDAS 3.4, TAO buoys, and OHC have all been dropping to their coolest yet. OISST 3.4 has been lagging but I’m looking for it to resume cooling. SOI has been averaging positive overall although it has been negative the last few days.
I’m central based weak Niña (ONI based) and moderate Niña (RONI based) based on latest model runs.

Does the MEI go strong la nina like 2021-22 and 2022-23, or does it stay moderate like 2020-21?

The MEI is running cooler than even the RONI. It had 2023-24 as a weak el nino, about the same as 2006-07. The only other strong el nino to not reach the +1.5 threshold was 2009-10, and that one got to +1.3 late in the season. Both aren't really traditional strong el nino years like the 1980s and 1990s (1982-83, 1986-88, 1991-92, and 1997-98 all reached +2 on the MEI).

[mitchnick]

9 minutes ago, snowman19 said:

The never ending saga…
 

He used the word "may" on 2 different levels. It was a useless post by Noll. Why even repost this?

[snowman19]

11 minutes ago, mitchnick said:

He used the word "may" on 2 different levels. It was a useless post by Noll. Why even repost this?

Why not? What’s wrong with keeping on eye on the strength of the PAC jet in the months ahead since it has consistently been a huge issue for the past 9 winters

[40/70 Benchmark]

25 minutes ago, PhiEaglesfan712 said:

Does the MEI go strong la nina like 2021-22 and 2022-23, or does it stay moderate like 2020-21?

The MEI is running cooler than even the RONI. It had 2023-24 as a weak el nino, about the same as 2006-07. The only other strong el nino to not reach the +1.5 threshold was 2009-10, and that one got to +1.3 late in the season. Both aren't really traditional strong el nino years like the 1980s and 1990s (1982-83, 1986-88, 1991-92, and 1997-98 all reached +2 on the MEI).

The MEI is probably going to register too low to be a viable proxy for intensity of thus La Niña event... just as it did with respect to El Niño, last year. RONI is probably the way to go....moderate.

[mitchnick]

1 hour ago, snowman19 said:

Why not? What’s wrong with keeping on eye on the strength of the PAC jet in the months ahead since it has consistently been a huge issue for the past 9 winters

A September 15th 10-day  forecast may be relevant to the coming winter when the original poster conditioned it on 2 levels? OK 

[bluewave]

7 hours ago, snowman19 said:

Why not? What’s wrong with keeping on eye on the strength of the PAC jet in the months ahead since it has consistently been a huge issue for the past 9 winters

Yeah, the last 9 winters had the strongest Pacific Jet east of Japan to the Aleutians on record back to 1950. It actually intensified more since 2019. These frequent jet extensions are a part of the reason why the winters have been so warm since 15-16 and less snowy back to 18-19 for places like NYC Metro.
 

 

 

 

 

 

 

[Typhoon Tip]

16 minutes ago, bluewave said:

Yeah, the last 9 winters had the strongest Pacific Jet east of Japan to the Aleutians on record back to 1950. 
 

 

 

 

 

i suggest if folks expanded/considered this research over the whole globe they may find mid latitude velocity anomalies elsewhere, as well.

[WestMichigan]

25 minutes ago, Typhoon Tip said:

i suggest if folks expanded/considered this research over the whole globe they may find mid latitude velocity anomalies elsewhere, as well.

Any reason why?

[Stormchaserchuck1]

12 hours ago, bluewave said:

I thinks it's due to the higher heights near the Pacific Northwest and Vancouver in recent years compared to the older -PDO era. So we are getting a split -PNA vortex. One piece this week stays up in Alaska and another digs into California. The height rises in the middle register as a +PNA. In the older -PDO era we didn’t see this pattern much since the -PNA vortex was more consolidated. Could also be related to competing marine heatwaves changing the character of how we used to understand the teleconnections in the old days. As we have also seen changes in the North Atlantic with the AO and NAO not as in sync as they used to be. This was evident with the very strong winter -AOs during the 2020s and the NAO more neutral to even positive during those -AO intervals. As recently as 09-10 and 10-11 the -AO and -NAO were more evenly matched during stronger blocking intervals.

I think it's because there is a trough over Alaska.. I've noticed over the years that they have weight on Alaska and Gulf of Alaska for PNA measurement