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2024-2025 La Nina


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The latest CFSv2 forecast for November indicates that most of the CONUS will be warmer than normal.

image.png.b2ee345b60810b77a70152f37cb7c4dc.png

Thus, the question becomes what kind of winter would be likely to follow such a November. With the December 2024-February 2025 Relative ENSO Region 3.4 Index (RONI) likely to average -0.500 or below, it makes some sense to examine how CONUS  winters have fared in the past with winter values of -0.500 or below following widespread November warmth in the CONUS (1951-2010 baseline) since 1949-50.

image.png.aa3490a7a0a758c25f4b3f39eb78e18b.png

The Composite Temperature Anomalies for North America (1991-2020 baseline, as the larger period was not available) were as follows:

November:

image.png.8a2dfb05f67c23d2052b8325b0ff0471.png

December-February:

image.png.a329b4de1c7a2bd957efdedfbbfe999b.png

The most recent C3S Multi-Ensemble Forecast for December 2024-2025:

image.png.2f445a1715393740685625469d4567b6.png

It should be noted that even warm winters have often seen periods of cold. In cases, there have been some periods of severe cold.

Overall, the forecast winter anomalies are reasonably in line with those that have followed the kind of November that is forecast when the winter RONI averaged -0.500 or below.

 

 

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27 minutes ago, donsutherland1 said:

The latest CFSv2 forecast for November indicates that most of the CONUS will be warmer than normal.

image.png.b2ee345b60810b77a70152f37cb7c4dc.png

Thus, the question becomes what kind of winter would be likely to follow such a November. With the December 2024-February 2025 Relative ENSO Region 3.4 Index (RONI) likely to average -0.500 or below, it makes some sense to examine how CONUS  winters have fared in the past with winter values of -0.500 or below following widespread November warmth in the CONUS (1951-2010 baseline) since 1949-50.

image.png.aa3490a7a0a758c25f4b3f39eb78e18b.png

The Composite Temperature Anomalies for North America (1991-2020 baseline, as the larger period was not available) were as follows:

November:

image.png.8a2dfb05f67c23d2052b8325b0ff0471.png

December-February:

image.png.a329b4de1c7a2bd957efdedfbbfe999b.png

The most recent C3S Multi-Ensemble Forecast for December 2024-2025:

image.png.2f445a1715393740685625469d4567b6.png

It should be noted that even warm winters have often seen periods of cold. In cases, there have been some periods of severe cold.

Overall, the forecast winter anomalies are reasonably in line with those that have followed the kind of November that is forecast when the winter RONI averaged -0.500 or below.

 

 

Went over this before, but it's worth repeating. The Cfs2, as all other seasonal modeling, has December as a dumpster fire, which all have acknowledged.  The question is what about January and February, as the Dec-Feb average is and has been skewed by December's warmth. This can be seen on the monthly temps link below. I am going verbatim just as your post, and clearly January and February are not as bad is December, and never have been for that matter for the last month. Whether the Cfs2 and other modeling is accurate is whole different discussion. 

https://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/usT2me3Mon.html

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12 hours ago, mitchnick said:

Went over this before, but it's worth repeating. The Cfs2, as all other seasonal modeling, has December as a dumpster fire, which all have acknowledged.  The question is what about January and February, as the Dec-Feb average is and has been skewed by December's warmth. This can be seen on the monthly temps link below. I am going verbatim just as your post, and clearly January and February are not as bad is December, and never have been for that matter for the last month. Whether the Cfs2 and other modeling is accurate is whole different discussion. 

https://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/usT2me3Mon.html

On a month-to-month basis, it remains to be seen how things will ultimately fare. The CFSv2 now shows January as having the potential to have more widespread cold than February. Much can still change between now and the final forecasts. Overall, confidence that the winter as a whole will be mild (though I don't see it being as warm as the past two in the East) has increased. There will be some opportunities for cold and snow--more than the past two winters unless there are some big hostile changes.

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27 minutes ago, snowman19 said:

Typical Nina/-IOD forcing developing @Bluewave
 

The extreme +EPO pattern this month looks like a blend of influences. La Niña background forcing, marine heatwave east of Japan/-PDO, and some MJO. Notice how the MJO 6 composite is much weaker than the pattern we got. So the other influences are at work. Also notice how well defined the warm pool near Japan and the Cold SST pool near Alaska has become with the +EPO.


IMG_1666.gif.15455510e691af0a0b663f5ef7ce6769.gif

IMG_1662.png.dfff626eae51dd158cc266801adeacb5.pngIMG_1665.png.662b3000eddab061b758c61c85082d69.png

 

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2 minutes ago, 40/70 Benchmark said:

The month is going to be warm in the mean....no question. Just saying there could be a colder stretch in there if the MJO cooperates before it warms up again. 

It would be nice if the next mjo wave starts mid November in phase 4 and makes it to 8 and 1 by early-mid  December. 

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4 minutes ago, binbisso said:

It would be nice if the next mjo wave starts mid November in phase 4 and makes it to 8 and 1 by early-mid  December. 

Looks like it could try to sneak into the better phases at a low amplitude in November, but it would probaly need to be stronger to not get washed out by the baseline warm pool.

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23 minutes ago, binbisso said:

Will be interesting to see if this wave can go 8 thru 3. Hasn't really happened in late fall and winter the last few years. 

Euro says no 2nd image.

Gfs 1st image 

 

image.png

image.png

 

Fwiw, Cfs2 and and bias corrected Bomm get it thru 3.

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27 minutes ago, 40/70 Benchmark said:

I think November will have a really nice stretch.

I defintely should have been more measured with this statement. I can see how it could have a colder stetch, but we would need some breaks. Anway, its not like I was referring to an early east coast snowstorm or anything...don't want to be misleading.

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1 hour ago, binbisso said:

Will be interesting to see if this wave can go 8 thru 3. Hasn't really happened in late fall and winter the last few years. 

Euro says no 2nd image.

Gfs 1st image 

 

image.png

image.png

 

Either way, we should do another pass through 4-6 in December, before we take aim at the colder phases late Dec through mid-Jan, give or take a week or so. That will be the window of opportunity I’m watching for the MA.

The initial pass through 8-1-2 (weak or not) might yield some results for great lakes through interior NE, but just seasonal cool weather for the MA. 

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16 hours ago, mitchnick said:

Went over this before, but it's worth repeating. The Cfs2, as all other seasonal modeling, has December as a dumpster fire, which all have acknowledged.  The question is what about January and February, as the Dec-Feb average is and has been skewed by December's warmth. This can be seen on the monthly temps link below. I am going verbatim just as your post, and clearly January and February are not as bad is December, and never have been for that matter for the last month. Whether the Cfs2 and other modeling is accurate is whole different discussion. 

https://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/usT2me3Mon.html

Actually I wouldnt call December a dumpster fire. Your area looks 0.5-1C warmer than avg on the CFS for December.

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15 minutes ago, 40/70 Benchmark said:

Which is probably enough to constitute  a dumpser fire in the lower terrain of the mid atlantic during December as it relates to snowfall.

Yeah the lower terrain of the mid Atlantic needs a lot of help in December. Even my area December climo kinda sucks the first half of the month

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26 minutes ago, michsnowfreak said:

Actually I wouldnt call December a dumpster fire. Your area looks 0.5-1C warmer than avg on the CFS for December.

Cfs2 has been cooling the last  week, but I  assume it's too cool. If the trend continues, an updated forecast....err, guess may be needed. Lol

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Just now, George001 said:

Yeah the lower terrain of the mid Atlantic needs a lot of help in December. Even my area December climo kinda sucks the first half of the month

Northerly winds can get it done in a storm here since the air would come from inland New England. When we have any easterly component off the water it typically kills it unless somehow we have a cold enough preceding airmass. Water is too warm until late in the month. For the Boston area and SE New England same problem. 

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3 minutes ago, mitchnick said:

Cfs2 has been cooling the last  week, but I  assume it's too cool. If the trend continues, an updated forecast....err, guess may be needed. Lol

Eh...I have learned my lesson on that. In order to adjust too much colder, I'd need to see the whites of the weenie after having my ass handed to me by Bluewave's pee pee pool two years running.

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4 minutes ago, George001 said:

Yeah the lower terrain of the mid Atlantic needs a lot of help in December. Even my area December climo kinda sucks the first half of the month

It goes without saying that the 2nd half of December is better than the 1st half, climo-wise, just about anywhere. But I will say that every year is different. Last year we had snowy trick or treating and a bare Christmas lol. We have had years where the first half of December is a winter wonderland then no snow for Christmas. And, more recently, we have had years where December sucks overall but snowy weather arrives just in time for Christmas (2020, 2022).

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3 minutes ago, jm1220 said:

Northerly winds can get it done in a storm here since the air would come from inland New England. When we have any easterly component off the water it typically kills it unless somehow we have a cold enough preceding airmass. Water is too warm until late in the month. For the Boston area and SE New England same problem. 

NE wind often will often even kill me that early...need it like NNE.

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