2024-2025 La Nina

[40/70 Benchmark]

13 hours ago, PhiEaglesfan712 said:

13-14 and 14-15 were more straightforward to me than 17-18. In 17-18, the record warm October threw me off. That one and a record warm February really skewed things.

 

Agree on 2017-2018, but 2014 was a bit more tricky in that it was entirely Pacific driven.....and I am willing to bet that most folks who went big expected a lot of NAO blocking, which includes myself.

[40/70 Benchmark]

17 hours ago, bluewave said:

The La Niña background state is so strong that it’s actually creating easterly shear in the Atlantic. This is why the models are quiet for late August instead of very active which we usually see during La Ninas. So we’ll have to wait until September for our next period of tropical development.

https://michaelrlowry.substack.com/p/the-bell-has-rung-so-why-are-forecast

Too much of a good thing?

 

As regular readers of this newsletter know, wind shear – the change in wind direction or speed with altitude – is one of the big hurdles to tropical development. Typically it’s the strong winds at upper levels (30,000-40,000 feet) which blow from west to east (known as upper-level westerlies) through the deep tropical Atlantic and the Main Development Region or MDR that create most of the wind shear issues.

So when upper-level winds in the tropical Atlantic turn more east-to-west (easterly winds) and against the west-to-east grain, it usually helps to reduce wind shear, which in turn favors hurricane development. This is especially true during La Niña years like we’re experiencing and when rising air settles in over Africa and the North Indian Ocean as it has recently – a big upper-level disturbance we track across the tropics called the Madden Julian Oscillation or MJO.

The combination of La Niña with the part of the MJO that usually reduces wind shear would normally suggest a conducive period for development. However, the upper-level winds have switched so far out of the east that they’re creating easterly wind shear issues across the Atlantic, an unusual problem not often seen in the basin.

 

It means that the MJO will need to move to a less conducive phase to bring back the seasonal upper-level westerlies and tamp down on easterly shear issues plaguing the basin right now. The easterly shear is also worsened by the low-level westerly winds from the northward displaced ITCZ we discussed earlier.

The MJO naturally propagates eastward across the globe and extended range models are already showing the easterly shear issues abating toward the end of the month.

So when will activity pick back up?

 

Putting all the pieces together, it should be another week or two before the current impediments clear out.

 

It’s possible our next spurt of activity is delayed until the beginning of September, but we should see the transition as August comes to a close late next week.

Traditionally 70% of tropical activity, including most hurricane formations, happens from September onward. Still a long way to go in the game, but for now we’ll soak up the unforeseen late August lull.

Yea, this is why I didn't entirely agree with notion that ENSO will not be a large factor this year....the entire hemisphere has been in a cold ENSO state for several years, which will allow it to be more influencial than implied by the ONI. We saw this in 2022. I feel like the point regarding less emphasis on ENSO was very valid last season with respect to the El Nino and certainly ENSO in general is not as prevalent a driver as it was 10-20 years ago.

[snowman19]

3 minutes ago, 40/70 Benchmark said:

Agree on 2017-2018, but 2014 was a bit more tricky in that it was entirely Pacific driven.....and I am willing to bet that most folks who went big expected a lot of NAO blocking, which includes myself.

2014 was obvious once the PDO went ++. You knew the +PNA/-EPO/-WPO was coming. 13-14, though technically -PDO, the configuration resembled +PDO and it was as textbook a +TNH pattern as you will ever see

[40/70 Benchmark]

21 hours ago, 40/70 Benchmark said:

Often the most difficult ones to predict end up being the ones perceived as being easy leading in because we are usually missing something. I think 2007-2008 and 2008-2009 are the pathways to better winter outcomes.

 

16 minutes ago, snowman19 said:

IMO the forecasts for 25-30 named storms are probably in peril

Any time you feel highly confident in racing to your laptop to convey seasonal throughts...pause, reflect and reconsider.

[40/70 Benchmark]

2 minutes ago, snowman19 said:

2014 was obvious once the PDO went ++. You knew the +PNA/-EPO/-WPO was coming. 13-14, though technically -PDO, the configuration resembled +PDO and it was as textbook a +TNH pattern as you will ever see

Not sure how early it was "obvious", but admittedly I only knew a fraction of the little that I know now, so....that was my first outlook attempt.

[40/70 Benchmark]

On 8/21/2024 at 6:47 AM, bluewave said:

This was one of the strongest La Niña 500 mb summer patterns that we have ever experienced. In our older climate, a La Niña summer 500 mb pattern featured a ridge near Japan and south of the Aleutians. The Atlantic usually had a ridge east of New England. These 3 ridges this summer were some of the strongest we have observed. If this had been the winter with such a strong ridge near the Aleutians and near the East Coast, then it would have been among the warmest on record. So this is telling is that unless we can get some version of mismatch like in January 2022, the winter is going to be very mild again. Probably have to wait until October for some clues to see how the October early MJO indicator evolves. 
 

 
If the winter ridges turn out as exaggerated as the summer, then it will be a very mild winter again. So we need a mismatch along the lines of Jan 2022 with the MJO 8 and more +PNA to counter it. Without pushback we end up with 22-23 warmth again.

Full disclosure.....gonna use this in my current blog piece.

Thanks.

[PhiEaglesfan712]

38 minutes ago, 40/70 Benchmark said:

Not sure how early it was "obvious", but admittedly I only knew a fraction of the little that I know now, so....that was my first outlook attempt.

If we're talking about 2013-14, then that one tipped its hand in July with the ridge building in the PNW. I mean, we got a big flip in the temperature pattern midway through the summer. The change in PDO pretty much sealed the deal.

If we're talking about 2014-15, well that was just a continuation of the +PDO/PNW ridge. JFM 2014 and 2015 were the coldest this side of 1980. Even the summer of 2014 was cooler than average (the coldest since 2010, though some places were cooler last summer). The PNW ridge finally subsided in spring 2015 (which is why we got a very warm May here, and a cold May in most of the West).

[40/70 Benchmark]

11 minutes ago, PhiEaglesfan712 said:

If we're talking about 2013-14, then that one tipped its hand in July with the ridge building in the PNW. I mean, we got a big flip in the temperature pattern midway through the summer. The change in PDO pretty much sealed the deal.

If we're talking about 2014-15, well that was just a continuation of the +PDO/PNW ridge. JFM 2014 and 2015 were the coldest this side of 1980. Even the summer of 2014 was cooler than average (the coldest since 2010, though some places were cooler last summer). The PNW ridge finally subsided in spring 2015 (which is why we got a very warm May here, and a cold May in most of the West).

I didn't really look at all of that back in 2013....I would just watch the models for snow in season and measure when it fell.

[PhiEaglesfan712]

The cold winters of 2014 and 2015: 

The rest of 2015 was warm, especially May, November, and December:

 

[bluewave]

8 hours ago, snowman19 said:

IMO the forecasts for 25-30 named storms are probably in peril

It looks this season will have 5 named storms by September 1st as the Atlantic experiences break in the action for late August. All the seasons that have made it to 19 or more named storms since 1995 had at least 7 named storms by September 1st and most 11 or more. But the concern going forward is how warm the Gulf Of Mexico is. Any tropical wave that makes it in there could rapidly intensify. It only takes one major hitting a populated area to have a big hurricane season regardless of total numbers or ACE. But actual land impacts for any given season are very challenging to forecast before the season starts.
 

19 or more named storms since 1995 and storm count by September 1st

2024…..5 projected named storms by September 1st

2023…..11 named storms by September 1st and 20 total named storms

2021…..12 named storms by September 1st and 21 total named storms

2020….14 named storms by September 1st and 30 total named storms

2012….12 named storms by September 1st and 19 total named storms 

2011….11 named storms by September 1st and 19 total named storms 

2010….7 named storms by September 1st and 19 total named storms 

2005….13 named storms by September 1st and 28 total named storms 

1995….12 named storms by September 1st and 19 total named storms 

 

 

 

 

[PhiEaglesfan712]

23 minutes ago, bluewave said:

It looks this season will have 5 named storms by September 1st as the Atlantic experiences break in the action for late August. All the seasons that have made it to 19 or more named storms since 1995 had at least 7 named storms by September 1st and most 11 or more. But the concern going forward is how warm the Gulf Of Mexico is. Any tropical wave that makes it in there could rapidly intensify. It only takes one major hitting a populated area to have a big hurricane season regardless of total numbers or ACE. But actual land impacts for any given season are very challenging to forecast before the season starts.
 

19 or more named storms since 1995 and storm count by September 1st

2024…..5 projected named storms by September 1st

2023…..11 named storms by September 1st and 20 total named storms

2021…..12 named storms by September 1st and 21 total named storms

2020….14 named storms by September 1st and 30 total named storms

2012….12 named storms by September 1st and 19 total named storms 

2011….11 named storms by September 1st and 19 total named storms 

2010….7 named storms by September 1st and 19 total named storms 

2005….13 named storms by September 1st and 28 total named storms 

1995….12 named storms by September 1st and 19 total named storms 

 

 

 

 

My top analog years:

1998: 4 named storms by Aug. 30 (14 total named storms)

2007: 5 named storms by Aug. 30 (15 total named storms)

[snowman19]

3 minutes ago, PhiEaglesfan712 said:

My top analog years:

1998: 4 named storms by Aug. 30 (14 total named storms)

2007: 5 named storms by Aug. 30 (15 total named storms)

One of my analogs, 01-02, had 17 tropical depressions, 15 named storms, 9 hurricanes, 4 major hurricanes, ACE of 110

[BlizzardWx]

So what do we know about the "Atlantic Nina". Does that even matter for us in winter? 

[PhiEaglesfan712]

Euro hinting at a cooler beginning, but a warm end, to September: 

[michsnowfreak]

50 minutes ago, PhiEaglesfan712 said:

Euro hinting at a cooler beginning, but a warm end, to September: 

It seems the weeklies have been warm in the extended range whether it ends up that way or not (this summer).

[BuffaloWeather]

50 minutes ago, michsnowfreak said:

It seems the weeklies have been warm in the extended range whether it ends up that way or not (this summer).

Every month this year has been above normal at Buffalo with an average departure per month of +4.4 degrees. That includes August which so far has been the "coldest" month of the year in relation to average with a 0.0 departure. That likely changes to a positive departure with the incoming warm spell.

[raindancewx]

2 hours ago, BlizzardWx said:

So what do we know about the "Atlantic Nina". Does that even matter for us in winter? 

I think we're moving into the cold AMO transition. If you subtract out the cold AMO years from the warm AMO years in La Nina, the three areas of biggest change are very warm/very cold east of Japan, very warm/very cool by West Africa, very warm/very cold by NE North America.

The cold AMO La Ninas tend to be snowier with severe (albeit brief) cold dumps into the SW US and Southern Plains. 

-PDO was roughly 1947-1976

-AMO was roughly 1964-1994

Some pretty severe and unusual cold-ENSO winters in the brief -PDO/-AMO period - ala 1964-65, 1966-67, 1967-68, 1970-71, 1971-72, 1973-74, 1974-75, 1975-76. La Nina has a reputation for dryness out here. That's largely true, but if the tropical Atlantic and tropical Pacific remain cold, I'd imagine the air over the deserts would get exceptionally dry to the point that someone out here would see a winter with sporadic near to record cold lows. January 1971 got to -17F ln Albuquerque in a January that isn't even that cold if you look at the records - that month was nuts.

[michsnowfreak]

1 hour ago, BuffaloWeather said:

Every month this year has been above normal at Buffalo with an average departure per month of +4.4 degrees. That includes August which so far has been the "coldest" month of the year in relation to average with a 0.0 departure. That likely changes to a positive departure with the incoming warm spell.

No doubt it's been a warm year. It was just an observation I had, locally, that for the 2nd summer in a row, we had a lot of fantasy range heat that never materialized.

[snowman19]

8 hours ago, raindancewx said:

I think we're moving into the cold AMO transition. If you subtract out the cold AMO years from the warm AMO years in La Nina, the three areas of biggest change are very warm/very cold east of Japan, very warm/very cool by West Africa, very warm/very cold by NE North America.

The cold AMO La Ninas tend to be snowier with severe (albeit brief) cold dumps into the SW US and Southern Plains. 

-PDO was roughly 1947-1976

-AMO was roughly 1964-1994

Some pretty severe and unusual cold-ENSO winters in the brief -PDO/-AMO period - ala 1964-65, 1966-67, 1967-68, 1970-71, 1971-72, 1973-74, 1974-75, 1975-76. La Nina has a reputation for dryness out here. That's largely true, but if the tropical Atlantic and tropical Pacific remain cold, I'd imagine the air over the deserts would get exceptionally dry to the point that someone out here would see a winter with sporadic near to record cold lows. January 1971 got to -17F ln Albuquerque in a January that isn't even that cold if you look at the records - that month was nuts.

This may be the very beginning stages of an eventual flip to a negative AMO. We won’t know for sure until next summer. The transition stage normally starts in the tropical Atlantic first, then moves north, throughout the rest of the Atlantic over time. As of now, the AMO remains strongly positive

[bluewave]

The Euro seasonal had a good summer forecast. The smaller cool spot was centered further north over the Midwest rather than down near Texas. This cooler in the middle and warmer near the coasts has been the summer temperature pattern since the 15-16 super El Niño.

 

[40/70 Benchmark]

On 8/21/2024 at 6:47 AM, bluewave said:

This was one of the strongest La Niña 500 mb summer patterns that we have ever experienced. In our older climate, a La Niña summer 500 mb pattern featured a ridge near Japan and south of the Aleutians. The Atlantic usually had a ridge east of New England. These 3 ridges this summer were some of the strongest we have observed. If this had been the winter with such a strong ridge near the Aleutians and near the East Coast, then it would have been among the warmest on record. So this is telling is that unless we can get some version of mismatch like in January 2022, the winter is going to be very mild again. Probably have to wait until October for some clues to see how the October early MJO indicator evolves. 
 

 
If the winter ridges turn out as exaggerated as the summer, then it will be a very mild winter again. So we need a mismatch along the lines of Jan 2022 with the MJO 8 and more +PNA to counter it. Without pushback we end up with 22-23 warmth again.

This is an absolutely lethal match to the MEI analogs....uncoincidentally.

[40/70 Benchmark]

16 minutes ago, bluewave said:

The Euro seasonal had a good summer forecast. The smaller cool spot was centered further north over the Midwest rather than down near Texas. This cooler in the middle and warmer near the coasts has been the summer temperature pattern since the 15-16 super El Niño.

 

I thought last summer was rather cool around here....

[FPizz]

20 minutes ago, bluewave said:

The Euro seasonal had a good summer forecast. The smaller cool spot was centered further north over the Midwest rather than down near Texas. This cooler in the middle and warmer near the coasts has been the summer temperature pattern since the 15-16 super El Niño.

 

How often is the Euro seasonal run?  I see that one above is from Jan 5th.  Was there one in Feb too for JJA and how did that do if it was run?

[mitchnick]

12 minutes ago, FPizz said:

How often is the Euro seasonal run?  I see that one above is from Jan 5th.  Was there one in Feb too for JJA and how did that do if it was run?

Monthly on the 5th.

Here's a link to all free monthly products. 

https://charts.ecmwf.int/?facets={"Product type"%3A[]%2C"Parameters"%3A[]%2C"Range"%3A["Long (Months)"]%2C"Type"%3A[]}

[40/70 Benchmark]

11 hours ago, raindancewx said:

I think we're moving into the cold AMO transition. If you subtract out the cold AMO years from the warm AMO years in La Nina, the three areas of biggest change are very warm/very cold east of Japan, very warm/very cool by West Africa, very warm/very cold by NE North America.

The cold AMO La Ninas tend to be snowier with severe (albeit brief) cold dumps into the SW US and Southern Plains. 

-PDO was roughly 1947-1976

-AMO was roughly 1964-1994

Some pretty severe and unusual cold-ENSO winters in the brief -PDO/-AMO period - ala 1964-65, 1966-67, 1967-68, 1970-71, 1971-72, 1973-74, 1974-75, 1975-76. La Nina has a reputation for dryness out here. That's largely true, but if the tropical Atlantic and tropical Pacific remain cold, I'd imagine the air over the deserts would get exceptionally dry to the point that someone out here would see a winter with sporadic near to record cold lows. January 1971 got to -17F ln Albuquerque in a January that isn't even that cold if you look at the records - that month was nuts.

I have really been warming up to the 1973-1974 analog..especially with respect to the Pacific.

[40/70 Benchmark]

@bluewave or anyone....Do you have the piece on the new Pacific pattern designations...ie. Alaskan trough, etc...?

[40/70 Benchmark]

Here is my early stab at the extra tropical Pacific....will be expanded upon in a more exhaustive segment this fall as part of the whole outlook.

https://easternmassweather.blogspot.com/2024/08/preliminary-assessment-of-extra.html

[40/70 Benchmark]

I feel like there have been some low key hints that raindance is going to be a bit more aggressive for the east than some may suspect.

[GaWx]

8 minutes ago, 40/70 Benchmark said:

I feel like there have been some low key hints that raindance is going to be a bit more aggressive for the east than some may suspect.

What do you mean by “a bit more aggressive”?

[40/70 Benchmark]

7 minutes ago, GaWx said:

What do you mean by “a bit more aggressive”?

Colder relative to what many susepect.