2024-2025 La Nina

[GaWx]

The bc GEFS and EPS MJO forecasts are on two different planets for end of Dec/Jan 1st: forecasting battle of the titan ensembles

GEFS bc stalled in moderate phase 7 not far from phase 6/not favorable to cold as H5 shows:

EPS bc headed into left side of circle 7/8: more favorable to cold potential E US: note that H5 is going toward restrengthening +PNA

[Terpeast]

All we can glean from the above is that we'll be in mjo 7 by the end of the month. What happens after that is anyone's guess.

[TheClimateChanger]

14 hours ago, chubbs said:

You have to be careful using raw data from multiple station sites with different baseline temperatures; airport vs downtown for instance.  Per NOAA, who corrects for site differences, the past 10 winters in Cook county (2015-2024) were 4.6F warmer than 1895-1930 and the last 5 years (2020-2024) 5.8F warmer.

Independently, Madison,Wisconsin Lake freeze data going back to 1852 shows much shorter duration of ice cover now vs the 19'th century and the 1960s and 1970s don't stand out as cold decades. (Mendota and Monona Lakes below.)

https://climatology.nelson.wisc.edu/first-order-station-climate-data/madison-climate/lake-ice/history-of-ice-freezing-and-thawing-on-lake-monona/

You know what they say, there are lies, there are damn lies, and then there are statistics.

Here's how to manufacture a massive cooling trend from a trendless data. Move the station further and further away from the lake and present with no adjustment or even proper context. In fact, falsely claim the cooling should be even more pronounced if not for the ever-growing UHI effect.

Chicago "thread" [Mean winter temps from 1926-27 to 1993-94]

University of Chicago [Mean winter temps from 1926-27 to 1993-94]

We can see using a fixed site (in this case, the University of Chicago), the 1960s and 1970s were somewhat colder than the preceding decades, but not to the extent shown on the threaded record. By the 1980s and early 1990s, temperatures had recovered and were already exceeding many of the past decades. Overall, a flat trend over that interval with a cyclical cooling and warming superimposed on the trend. Much more in line with the NOAA values for Cook County.

[LakePaste25]

No indication that we are returning to a -PNA prior to mid-January. Everything looks on track to turn colder to start the New Year. 

[GaWx]

13 minutes ago, LakePaste25 said:

No indication that we are returning to a -PNA prior to mid-January. Everything looks on track to turn colder to start the New Year. 

Regarding colder to start new year, EPS/GEPS agree but last few GEFS don’t, which I feel are likely largely MJO related. We’ll see which is closer to being correct regarding MJO/Pacific:

[LakePaste25]

7 minutes ago, GaWx said:

Regarding colder to start new year, EPS/GEPS agree but last few GEFS don’t, which I feel are likely largely MJO related. We’ll see which is closer to bring correct regarding MJO/Pacific:

While it does delay the cold and prolong the jet extension against other guidance, it isn’t really showing any canonical -PNA Nina pattern. 

[PhiEaglesfan712]

7 minutes ago, LakePaste25 said:

While it does delay the cold and prolong the jet extension against other guidance, it isn’t really showing any canonical -PNA Nina pattern. 

Yeah, here are the subsequent Jan PNAs for non-Nino high PNA Dec, following warm Nov:

2021 +0.19 (Dec 2020: +1.58)

2006 +0.43 (Dec 2005: +1.38)

1986 +0.97 (Dec 1985: +1.39)

Based on these analogs, the PNA should be slightly positive (between 0 and 1). By the way, all of these years had warmer Januarys, and delayed cold until February.

[jconsor]

https://x.com/yconsor/status/1869457576339136768

[donsutherland1]

27 minutes ago, jconsor said:

https://x.com/yconsor/status/1869457576339136768

The "torch" will be in the vicinity of the Hudson and James Bays. The days 10-15 EFI does well in highlighting the risk. The Northeast and Great Lakes will probably be on the mild side of normal but widespread record-challenging warmth doesn't appear likely at this time in most of the CONUS. Wisconsin and Minnesota could see records challenged.

[bluewave]

16 minutes ago, donsutherland1 said:

The "torch" will be in the vicinity of the Hudson and James Bays. The days 10-15 EFI does well in highlighting the risk. The Northeast and Great Lakes will probably be on the mild side of normal but widespread record-challenging warmth doesn't appear likely at this time in most of the CONUS. Wisconsin and Minnesota could see records challenged.

Don, I believe that forecast would represent near the top 3 warmest last weeks of December  for the entire North American continent. The Hudson Bay Area would be ridiculously warm with the delayed freeze up from the marine heatwaves back in the summer and fall. My guess is that the North American snow cover extent would dip to near the lowest for late December. 
 

 

[donsutherland1]

2 minutes ago, bluewave said:

Don, I believe that forecast would represent near the top 3 warmest last weeks of December  for the entire North American continent. The Hudson Bay Area would be ridiculously warm with the delayed freeze up from the marine heatwaves back in the summer and fall. My guess is that the North American snow cover extent would dip to near the lowest for late December. 
 

 

I agree regarding the Continent. Yaakov's tweet referenced the Northeast.

[bluewave]

9 minutes ago, donsutherland1 said:

I agree regarding the Continent. Yaakov's tweet referenced the Northeast.

A very super El Niño look to the pattern close to close out the year. 

[MJO812]

25 minutes ago, bluewave said:

A very super El Niño look to the pattern close to close out the year. 

This warmup is due to the MJO going through  p6 . It shouldn't take long until we get back to a colder pattern. 

 

 

[bluewave]

27 minutes ago, MJO812 said:

This warmup is due to the MJO going through  p6 . It shouldn't take long until we get back to a colder pattern. 

 

 

The pattern coming up doesn’t equate to any one individual MJO phase. The forcing is split between the EPAC and WPAC. So it’s a bit like playing a chord with the forcing instead of an individual note. So the resultant pattern has features of several different MJO notes playing together.

 

[GaWx]

Today’s Euro Weeklies:

 Jan 6-12 back to about as cold as 2-3 days ago (a strong cold signal for still being 2.5-3.5 weeks out):

 H5 anomalies for that week are the most negative of any run. They stick out even more prominently on the world map with the coldest now being the 4th shade of blue (vs 3rd shade on prior runs and vs only 1st shade of blue for most negative in rest of world), which gets NYC down to 9 dm BN/541 dm (vs normal of 550 dm). That’s not easy to do in a warming world for a full week on a 100 member ensemble out 2.5-3.5 weeks:

 

If Jan 6-12 isn’t solidly cold in the E US, I’ll consider it a big bust of the Weeklies. There almost has to be some extremely cold members to achieve this cold of a mean.

[so_whats_happening]

8 minutes ago, GaWx said:

The bc GEFS and EPS MJO forecasts are on two different planets for end of Dec/Jan 1st: forecasting battle of the titan ensembles

GEFS bc stalled in moderate phase 7 not far from phase 6

EPS bc headed into left side of circle 7/8: more favorable to cold E US:

How it gets there not exact but surprisingly GEFS, ECMWF, and JMA all in rather good agreement. I do hope we don't have a high amplitude 7 and then quick to the COD becoming a weak 3/4 and repeating like we have had in recent years, that just leads to cold unleashing through the central plains. With the minor Westerly anomaly showing up into the new year this will start to look like a modoki La Nina with another warming of eastern 3 and 1+2 so it may throw us a bone if we can hold amplitude into 8/1 with that type of setup. 

My fingers are crossed! Of note the MJO has been crawling almost 2 weeks in phase 5 pretty solid phase 5 look in the northern hemisphere. As Bluewave has mentioned the jet extension is a bit more than we typically would see under this pattern thus you can see the shift of reality to what would typically occur.

 

[PhiEaglesfan712]

No "cold oval" for late January: 

Hopefully, this means a return to cold weather during the first week of February.

[snowman19]

No "cold oval" for late January: 
Hopefully, this means a return to cold weather during the first week of February.

IMO we go -PNA next month. The big La Niña push we’ve been seeing with the forcing/standing wave/MJO/trades/SOI is not going to be denied. And it’s taking on a very Modoki signature

[GaWx]

DT says central Pacific La Niña is more favorable for E US cold and snow than is E Pacific La Niña. I’m confused @snowman19?

 Here him say this during very short portion at 5:08-5:30:

 

[bluewave]

20 hours ago, LakePaste25 said:

No indication that we are returning to a -PNA prior to mid-January. Everything looks on track to turn colder to start the New Year. 

The issue is that the models are converging on a bootleg +PNA to at least start January with lower heights under the Canadian Ridge out West. Anytime we see lower heights in the Western US with a +PNA ridge in Canada it leaves room for storms to continue tracking to the Great Lakes. We get short term Southeast Ridge amplifications. The trough returns to the East after the storm has past. The EPS has been struggling the most showing too much of ridge beyond 10 days near EPAC and WNA. Same model bias since the beginning of December. 

New run

Old run

 

[snowman19]

24 minutes ago, GaWx said:

DT says central Pacific La Niña is more favorable for E US cold and snow than is E Pacific La Niña. I’m confused @snowman19?

 Here him say this during very short portion at 5:08-5:30:

 

I’m as confused as you

[michsnowfreak]

1 hour ago, PhiEaglesfan712 said:

No "cold oval" for late January: 

Hopefully, this means a return to cold weather during the first week of February.

Haha you are going to run you're warm January call til you can't . The wxbell surface temps for that exact same timeframe you posted that wxbell 500mb map is for near to slightly below normal temps in the Lakes and northeast. And its the dead of winter no less. Ie: not warm at all. That said, most consider the weeklies a big gamble past week 2. So week 6? Total crapshoot.

[LakePaste25]

24 minutes ago, bluewave said:

The issue is that the models are converging on a bootleg +PNA to at least start January with lower heights under the Canadian Ridge out West. Anytime we see lower heights in the Western US with a +PNA ridge in Canada it leaves room for storms to continue tracking to the Great Lakes. We get short term Southeast Ridge amplifications. The trough returns to the East after the storm has past. The EPS has been struggling the most showing too much of ridge beyond 10 days near EPAC and WNA. Same model bias since the beginning of December. 

New run

Old run

 

To me, that looks like a storm system from the GOA low breaks off as the block tries to retrograde westward. With blocking over the top, I don’t see cutting with that look verbatim  as it traverses through the plains. Now, if that look changes and energy gets buried in the southwest, then no block will stop that from cutting. We did this see frequently in 22-23. 

[michsnowfreak]

3 minutes ago, LakePaste25 said:

To me, that looks like a storm system from the GOA low breaks off as the block tries to retrograde westward. With blocking over the top, I don’t see cutting with that look verbatim  as it traverses through the plains. Now, if that look changes and energy gets buried in the southwest, then no block will stop that from cutting. We did this see frequently in 22-23. 

We saw a few good storms in SE MI thanks to that in 2022-23. We had the blizzard conditions and White Christmas that originally looked to be a big east coast storm. Then Jan 25 & Mar 3 were scenic paste jobs complete with thundersnow. 

[bluewave]

1 hour ago, LakePaste25 said:

To me, that looks like a storm system from the GOA low breaks off as the block tries to retrograde westward. With blocking over the top, I don’t see cutting with that look verbatim  as it traverses through the plains. Now, if that look changes and energy gets buried in the southwest, then no block will stop that from cutting. We did this see frequently in 22-23. 

We haven’t had a legit +PNA with widespread double digit snows since January 2022 around the NYC Metro OKX forecast zones. As you mentioned, many of the +PNA winter months had lower heights over the SW US leading to cutter or coastal hugger tracks which wound up too warm for a nice KU event. Mostly smaller snow events since then. The once common denominator has been the very fast Northern Stream Pacific Jet. So the +PNA ridges in Canada get undercut frequently.

This month the issue was the eastward drift due to the fast Pacific flow lowering heights from the west. Some localized areas from PA across to Central NJ were able to due well last February with the record jet streak snowband. But much of my area missed out on that event. The one positive for them was the record STJ was able to dominate over the NS due to such a strong El Niño. Both 22-23 and 23-24 were similarly both top 3 warmest around my area. But the STJ made the difference for a few spots while much of the area got very low snowfall totals both winters relative to the averages and rankings.

[LakePaste25]

47 minutes ago, bluewave said:

We haven’t had a legit +PNA with widespread double digit snows since January 2022 around the NYC Metro OKX forecast zones. As you mentioned, many of the +PNA winter months had lower heights over the SW US leading to cutter or coastal hugger tracks which wound up too warm for a nice KU event. Mostly smaller snow events since then. The once common denominator has been the very fast Northern Stream Pacific Jet. So the +PNA ridges in Canada get undercut frequently.

This month the issue was the eastward drift due to the fast Pacific flow lowering heights from the west. Some localized areas from PA across to Central NJ were able to due well last February with the record jet streak snowband. But much of my area missed out on that event. The one positive for them was the record STJ was able to dominate over the NS due to such a strong El Niño. Both 22-23 and 23-24 were similarly both top 3 warmest around my area. But the STJ made the difference for a few spots while much of the area got very low snowfall totals both winters relative to the averages and rankings.

I guess I should clarify - I am not saying it will be a snowy pattern for I-95 the first half of January. My call is that it will be cold. I’m not really able to discern whether it will be snowy, partly because I don’t live there and also, some of these events are tough to predict at medium range timescale. That said, I do think there is a risk of -PNA mid to late month. I’ve been saying that for a few days now. Whether that is a -PNA that digs to San Diego and we see a full SE ridge torch or it is more mellow, that remains to be seen at this point. I will cross that bridge when we get closer in time. 

[Allsnow]

3 hours ago, bluewave said:

The issue is that the models are converging on a bootleg +PNA to at least start January with lower heights under the Canadian Ridge out West. Anytime we see lower heights in the Western US with a +PNA ridge in Canada it leaves room for storms to continue tracking to the Great Lakes. We get short term Southeast Ridge amplifications. The trough returns to the East after the storm has past. The EPS has been struggling the most showing too much of ridge beyond 10 days near EPAC and WNA. Same model bias since the beginning of December. 

New run

Old run

 

Which might mean more of the same as Dec with cold/dry after cutters into the lakes. Never like seeing a trough in the sw as it has trended stronger over time every winter 

 

Makes sense with the mjo convection in different phases to start January. Going to need a clean pass in phase 8 to get anything on the east coast 

[brooklynwx99]

4 hours ago, snowman19 said:

IMO we go -PNA next month. The big La Niña push we’ve been seeing with the forcing/standing wave/MJO/trades/SOI is not going to be denied. And it’s taking on a very Modoki signature

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

lol this is a British Columbia weather weenie tweeting the CFS Control. if this was JB doing the same thing you'd lose it

[GaWx]

3 hours ago, snowman19 said:

I’m as confused as you

Somebody in disagreement with what DT responded with this in the comments below:

“Eastern based La Niña is better for cold and snow in the eastern U.S not a central based.”

[brooklynwx99]

also it wouldn't be shocking if the later weeks of the Euro Weeklies were just reverting to -ENSO climo. frankly, we haven't seen much of a canonical Nina pattern at all and aren't going to for the next two weeks at least. i don't see how one can resign to typical -ENSO climo into late Jan. sure, it'll likely get a bit warmer but a persistent SE ridge is not a given

they did the same exact thing last year reverting to +ENSO climo with an Aleutian low and -NAO that never really happened