2025-2026 ENSO

[donsutherland1]

As previously noted regarding the February 15-28 period, what was fairly certain were:

1) Substantial warmup in the Plains States. 

2) Brief cool shot to the Southwest and then a return of warmer conditions. The cool shot likely won't be sufficient to preclude Phoenix from experiencing its warmest winter on record. 

The period has commenced with widespread above to much above normal readings in the Plains States. Phoenix is virtually certain to experience its warmest winter on record. Only one case saw in its period of record (1896-2025) saw a sufficiently cold February 15-28 that would miss the record. Nothing remotely close to that case is on the latest guidance.

 It was also noted that the Arctic Oscillation (AO) could hold the key to the overall outcome. The EPS and GEFS agree on the development of a WPO-, EPO+, PNA- pattern. During such patterns, conditions in the East tend to be much colder when the AO is negative than when it is positive. 

The latest AO forecast shows the AO returning to positive levels after a fairly short-lived dip to negative levels.

The most recent ECMWF weeklies show a brief return to cooler conditions in parts of the East during February 23-March 2, but a return to above normal temperatures afterward unlike prior runs. The weeklies also show most of the CONUS experiencing above normal temperatures to start March.

ECMWF Weeklies:

The CFSv2, which was been showing above normal temperatures on a consistent basis, shows a warmer than normal first week of March.

It's too soon to pronounce the end of Winter 2025-2026. There may yet be cold periods and snowfall, though the most severe cold is almost certainly behind us. But even if this latest guidance were to mark the end, many parts of the Northeast and Great Lakes Region had highlights that made this winter memorable, particularly sustained cold not seen for a decade or longer, long-lived snow cover, and from Philadelphia to Boston, a big snowstorm.

[Stormchaserchuck1]

Warm pattern setting up for the 1st week of March.. strong ensemble signal for long range

[EastonSN+]

2 hours ago, Stormchaserchuck1 said:

Warm pattern setting up for the 1st week of March.. strong ensemble signal for long range

The 2nd week of March SHOULD be a little interesting, although today's MJO forecast looks like its going into the COD. 

[EastonSN+]

Towards the end of the EPS run a LITTLE blocking looks like its forming by Greenland. This will likely be the key for as Don mentioned, an RNA is beneficial after mid Feb. with blocking.

[EastonSN+]

Pretty solid dip forming EOM. Not sure what the lag time is but could align with the 2nd week of March?

[GaWx]

1 hour ago, EastonSN+ said:

The 2nd week of March SHOULD be a little interesting, although today's MJO forecast looks like its going into the COD. 

 I just completed my study of La Niña March temperatures by MJO phase at Baltimore (as a geographically centered rep. of the E coast).

 Before I show Mar, here’s a review of what I found for Feb Niña by phase:

1: +2.1 (near Niña Feb climo)

2: +4.4 (2nd warmest)

3: -1.5 (coldest)

4: +3.3

5: +3.1

6: +5.5 (warmest)

7: +2.2 (near Nina Feb climo)

8: +0.7 (2nd coldest)

AVG: +2.5

Range: 7.0

—————

Now, here’s the just completed March Niña by phase:

1: +1.0 (near Niña Mar climo)

2: -0.1

3: +1.8

4: +0.3

5: +2.1 (2nd warmest)

6: +2.6 (warmest)

7: -1.7 (coldest)

8: -0.7 (2nd coldest)

AVG: +0.7

Range: 4.3

———————

So, how does March Niña compare to Feb Nina?

-phase 6 warmest on avg for both

-phase 7 coldest on avg for Mar vs phase 3 for Feb

-avg anomaly for Mar (+0.7) not as warm as that for Feb (+2.5), which is intuitive for La Nina

-Range of variation of averages by phase in Mar (4.3) not nearly as large as that of Feb (7.0), which is somewhat intuitive since temperature volatility tends to drop as we head into met. spring from the most volatile season, winter. This also may indicate  that MJO, itself, as a factor may not have quite as much of an influence in March as it does in winter

-It’s important to always keep in mind that these are just averages of a wide range for each individual case from MB to MA temp. anomalies. Thus, whereas averages are informative, they don’t tell us how any one case will actually turn out.

——————

Sources:

MJO phase for each day:

https://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt
 

Baltimore daily temperatures:

https://www.weather.gov/wrh/Climate?wfo=lwx

 

[donsutherland1]

The latest AO forecast is even more aggressive with the development of an AO+:

Given the other forecast teleconnections, this implies that the late February cold shot will likely be short-lived. Temperatures could return to near normal or above normal levels in the Great Lakes Region and Northeast in the closing days of the month.

[TheClimateChanger]

21 hours ago, donsutherland1 said:

As previously noted regarding the February 15-28 period, what was fairly certain were:

1) Substantial warmup in the Plains States. 

2) Brief cool shot to the Southwest and then a return of warmer conditions. The cool shot likely won't be sufficient to preclude Phoenix from experiencing its warmest winter on record. 

The period has commenced with widespread above to much above normal readings in the Plains States. Phoenix is virtually certain to experience its warmest winter on record. Only one case saw in its period of record (1896-2025) saw a sufficiently cold February 15-28 that would miss the record. Nothing remotely close to that case is on the latest guidance.

 It was also noted that the Arctic Oscillation (AO) could hold the key to the overall outcome. The EPS and GEFS agree on the development of a WPO-, EPO+, PNA- pattern. During such patterns, conditions in the East tend to be much colder when the AO is negative than when it is positive. 

The latest AO forecast shows the AO returning to positive levels after a fairly short-lived dip to negative levels.

The most recent ECMWF weeklies show a brief return to cooler conditions in parts of the East during February 23-March 2, but a return to above normal temperatures afterward unlike prior runs. The weeklies also show most of the CONUS experiencing above normal temperatures to start March.

ECMWF Weeklies:

The CFSv2, which was been showing above normal temperatures on a consistent basis, shows a warmer than normal first week of March.

It's too soon to pronounce the end of Winter 2025-2026. There may yet be cold periods and snowfall, though the most severe cold is almost certainly behind us. But even if this latest guidance were to mark the end, many parts of the Northeast and Great Lakes Region had highlights that made this winter memorable, particularly sustained cold not seen for a decade or longer, long-lived snow cover, and from Philadelphia to Boston, a big snowstorm.

Thanks for the update, Don. Going to be a close call as to whether we break the record for warmest winter in the CONUS, set just 2 years ago (2023-2024). Right now, I'm projecting this to finish as the second warmest on record, but it's not out of the question that we set a new record.

December-January averaged +2.25°F relative to 1991-2020 on NCEI's nClimDiv, and +2.71°F relative to 1991-2020 in the U.S. Climate Reference Network (all rural, non-adjusted) dataset. The record is +3.42°F in nClimDiv and +3.52° in U.S. CRN, from 2023-2024 (in each case). Second place is +2.73°F set in 2015-2016 for nClimDiv.

PRISM's analysis has us at +4.70°F for February for the first half of February. Obviously, this is an *unofficial* value. But that would place us at approx. +3.07°F if it held up through the end of the month (with averaging by month) or about +3.01°F (with averaging by day) in the official nClimDiv records. It would also place us around +3.37°F in USCRN (averaged by month) or 3.33°F (averaged by day). Although I would expect the (IMO, more accurate) USCRN anomaly to come in higher than PRISM's estimate. What's intriguing to me is it looks like there is room to run even higher in the second half of February with these projections. A final anomaly around +6°F (or a bit higher) would be sufficient to set a new record even in the official nClimDiv dataset. But like I said, right now, I'm conservatively projecting this to finish as second warmest on record. I do think we will set a new record for warmest AVERAGE MAX TEMP, however... unusually large diurnal ranges (i.e., somewhat cooler lows) are holding the means back a bit.

In terms of satellite TLT temperatures, this winter is pretty much guaranteed to be the warmest in the US48 band in the UAH analysis (with complete records back to the winter of 1978-1979). December & January were the warmest on record by a HUGE margin, so that one is pretty much already in the bag with another warm month.

[TheClimateChanger]

8 minutes ago, TheClimateChanger said:

Thanks for the update, Don. Going to be a close call as to whether we break the record for warmest winter in the CONUS, set just 2 years ago (2023-2024). Right now, I'm projecting this to finish as the second warmest on record, but it's not out of the question that we set a new record.

December-January averaged +2.25°F relative to 1991-2020 on NCEI's nClimDiv, and +2.71°F relative to 1991-2020 in the U.S. Climate Reference Network (all rural, non-adjusted) dataset. The record is +3.42°F in nClimDiv and +3.52° in U.S. CRN. Second place is +2.73°F set in 2015-2016 for nClimDiv.

PRISM's analysis has us at +4.70°F for February for the first half of February. Obviously, this is an *unofficial* value. But that would place us at approx. +3.07°F if it held up through the end of the month (with averaging by month) or about +3.01°F (with averaging by day) in the official nClimDiv records. It would also place us around +3.37°F in USCRN (averaged by month) or 3.33°F (averaged by day). Although I would expect the (IMO, more accurate) USCRN anomaly to come in higher than PRISM's estimate. What's intriguing to me is it looks like there is room to run even higher in the second half of February with these projections. A final anomaly around +6°F (or a bit higher) would be sufficient to set a new record even in the official nClimDiv dataset. But like I said, right now, I'm conservatively projecting this to finish as second warmest on record. I do think we will set a new record for warmest AVERAGE MAX TEMP, however... unusually large diurnal ranges (i.e., somewhat cooler lows) are holding the means back a bit.

In terms of satellite TLT temperatures, this winter is pretty much guaranteed to be the warmest in the US48 band in the UAH analysis (with complete records back to the winter of 1978-1979). December & January were the warmest on record by a HUGE margin, so that one is pretty much already in the bag with another warm month.

For further context, regarding high temps.

NCEI (nClimDiv) had us at +2.96°F for December & January, while PRISM has February at an unbelievable +6.12°F for the first half of the month. The record for DJF is +3.16°F, also from 2023-2024. So this is nearly guaranteed to be broken as well, unless the current forecast for the second half of the month is WAY off.

[EastonSN+]

29 minutes ago, donsutherland1 said:

The latest AO forecast is even more aggressive with the development of an AO+:

Given the other forecast teleconnections, this implies that the late February cold shot will likely be short-lived. Temperatures could return to near normal or above normal levels in the Great Lakes Region and Northeast in the closing days of the month.

Thanks Don.

Its far out there however the members are starting to drop at the end. This would align with the MJO heading to phase 7 and the dip in the zonal winds posted above.

This COULD make for a wild 2nd week of March.

[TheClimateChanger]

35 minutes ago, donsutherland1 said:

The latest AO forecast is even more aggressive with the development of an AO+:

Given the other forecast teleconnections, this implies that the late February cold shot will likely be short-lived. Temperatures could return to near normal or above normal levels in the Great Lakes Region and Northeast in the closing days of the month.

Certainly going to be difficult to see any sustained cold with that AO index.

[snowman19]

3 minutes ago, EastonSN+ said:

Thanks Don.

Its far out there however the members are starting to drop at the end. This would align with the MJO heading to phase 7 and the dip in the zonal winds posted above.

This COULD make for a wild 2nd week of March.

Not saying it can’t happen, but the models have been awful with showing the MJO propagating into phase 8 since late November only to have it fail. I guess all we can do is wait and see if it holds and is real this time 

[LakePaste25]

i’m fine with spring warmth. 40s feel like heaven here after that cold snap. obviously can’t really say i am done with snow here though because march can be quite wintery here in the great lakes. 

[EastonSN+]

2 minutes ago, snowman19 said:

Not saying it can’t happen, but the models have been awful with showing the MJO propagating into phase 8 since late November only to have it fail. I guess all we can do is wait and see if it holds and is real this time 

It did get to phase 8 twice, although for a couple days each. That being said, both phase7 periods ended up snowy for the NE.

What I am curious about is the large snowstorm the GFS, EURO AI and now the ICON are showing. The only favorable telecommunications are the RNA coupled with the negative AO, which is only SLIGHTLY negative. I would think this would lead to an inside track. Could the FAST flow be helpful here in pushthe storm east before it can gain too much latitude?

[EastonSN+]

3 minutes ago, LakePaste25 said:

i’m fine with spring warmth. 40s feel like heaven here after that cold snap. obviously can’t really say i am done with snow here though because march can be quite wintery here in the great lakes. 

I would rather get the cold phases out of the way in Feb and March so we can get warmth in April for a change. Spring has been awful here.

[GaWx]

13 minutes ago, snowman19 said:

Not saying it can’t happen, but the models have been awful with showing the MJO propagating into phase 8 since late November only to have it fail. I guess all we can do is wait and see if it holds and is real this time 

Actually, phase 7 has on average (using Baltimore as a representative) been the coldest phase in March (1.7 BN) following La Niña winters with phase 8 second coldest (0.7 BN). But regardless, those are just averages with wide variances and the MJO seeming to have less influence in March vs Feb. Also, the combo of the progged -PNA, +AO, and +NAO would strongly favor mild in early March.

[snowman19]

10 minutes ago, EastonSN+ said:

It did get to phase 8 twice, although for a couple days each. That being said, both phase7 periods ended up snowy for the NE.

What I am curious about is the large snowstorm the GFS, EURO AI and now the ICON are showing. The only favorable telecommunications are the RNA coupled with the negative AO, which is only SLIGHTLY negative. I would think this would lead to an inside track. Could the FAST flow be helpful here in pushthe storm east before it can gain too much latitude?

I don’t know what to make of Sun-Mon TBH. @bluewave did a write up on the pattern that’s going to be place at that point this morning over in the NYC forum

[GaWx]

23 minutes ago, snowman19 said:

Not saying it can’t happen, but the models have been awful with showing the MJO propagating into phase 8 since late November only to have it fail. I guess all we can do is wait and see if it holds and is real this time 

 

16 minutes ago, EastonSN+ said:

It did get to phase 8 twice, although for a couple days each. 

The official record has the following for phase 8 in Dec and Feb this winter:

Dec: 3-7, 15, 17-19. Was cold in E US overall.

Feb: 1-7 (coldest phase 8 in Feb La Niña recorded MJO history (per Baltimore), which goes back to 1975)

MJO phase each day:

https://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

 

Baltimore daily temperatures:

https://www.weather.gov/wrh/Climate?wfo=lwx

[LakePaste25]

49 minutes ago, EastonSN+ said:

I would rather get the cold phases out of the way in Feb and March so we can get warmth in April for a change. Spring has been awful here.

yeah i agree with this. i might have recency bias but getting a somewhat cold and snowy march here tends to correlate to a warm april, and the other way around:

2025: torch in march, cold rainy april

2024: very late season cold/snowy after mid march, record warm april

2023: SSW leading to cold and snowy march, a stretch of very nice weather (including 80+ days) in april

2022: little snow in march, cool and rainy april 

 

the all-timer was of course the historic march 2012 warmth which caused record earliest leaf-out, then lead to multiple freezes in april that damages a lot of plants and other crops. 

i’d be happy with a repeat of spring 2024, but that was a strong nino. 

[michsnowfreak]

3 hours ago, LakePaste25 said:

i’m fine with spring warmth. 40s feel like heaven here after that cold snap. obviously can’t really say i am done with snow here though because march can be quite wintery here in the great lakes. 

I just dont get into it. Been a great winter for the cold/snowcover crowd in the Great Lakes, so while most of the public is ready for a break, I hate the sun and melting snow. I am going to the U.P. later this week though.

[michsnowfreak]

3 hours ago, LakePaste25 said:

yeah i agree with this. i might have recency bias but getting a somewhat cold and snowy march here tends to correlate to a warm april, and the other way around:

2025: torch in march, cold rainy april

2024: very late season cold/snowy after mid march, record warm april

2023: SSW leading to cold and snowy march, a stretch of very nice weather (including 80+ days) in april

2022: little snow in march, cool and rainy april 

 

the all-timer was of course the historic march 2012 warmth which caused record earliest leaf-out, then lead to multiple freezes in april that damages a lot of plants and other crops. 

i’d be happy with a repeat of spring 2024, but that was a strong nino. 

There is definitely some merit to the Mar/Apr correlation of warm/cool or cool/warm. Its certainly not a guarantee. But in those few years where March is warm and nearly snowless, you can bet April will see accumulating snow. 

[MJO812]

MJO going into COD