2024-2025 La Nina

[Cobalt]

On 11/16/2024 at 10:35 AM, qg_omega said:

Record warmth looks likely to start December 

So close!! it's actually the coldest start in the East since at least 2010 ❤️❤️

[brooklynwx99]

2 minutes ago, Cobalt said:

So close!! it's actually the coldest start in the East since at least 2010 ❤️❤️

no changes

[donsutherland1]

So far, the ideas expressed last Sunday remain in good shape.

1. The first half of December continues to look cold with a weekly anomaly of 6°-10° below normal likely during that period. In fact, New York City could have its coldest December 1-10 period since 2002.

2. A significant lake effect snow event is underway. Several locations have seen excessive lake effect snow so far. Cassadaga, NY (31.6") and Mayville, NY (30.0") have the highest amounts so far. Buffalo has received a trace of snow, but as the lake effect snow bands move northward today, accumulating snow is likely there. Chicago (2.9"), Detroit (1.7"), and Toronto (0.2 cm) have all seen measurable snow. No measurable snow has fallen in Boston, New York City, or Philadelphia.

3. The potential for a colder than normal December has increased in parts of the eastern third of the U.S. Since 1980, all four cases where New York City had a mean temperature of 36.5° or below, wound up having a colder than normal December. The latest guidance shows New York City with a December 1-10 mean temperature near 32.5°.  The outcome farther west in such cties as Chicago, Detroit, and Indianapolis remains less certain and will depend on the timing of the pattern change. The farther east one is, the more likely that the month will come out with a colder anomaly.

4. The CFSv2 is pushing a warmup around mid-month. The November 29 12z ECMWF weeklies are holding it off for an additional week. As noted previously, the guidance has tended to rush the timing of pattern changes.

Four thoughts going forward:

1. The EPO is forecast to head toward neutral levels toward mid-month. The AO and PNA are also forecast to head toward neutral levels. Therefore, a pattern change seems likely, but probably with a lag that could favor the timing shown on the ECMWF weeklies.

2. Even as the pattern in the East is likely to be dry for much of the first week of December, a clipper system could bring some light snow or flurries to the northern Mid-Atlantic/southern New England areas  late Tuesday night and Wednesday. Boston might have a chance to pick up an inch of snow. Philadelphia and possibly New York City might only see some flurries.

3. Following the clipper, the coldest air so far this season will move into the eastern third of the U.S.

4. Out West, British Columbia could see a period of near record and record warmth develop for Tuesday through Thursday (December 3-5).

Overall, the exceptional warmth in BC and the cold in the East showed up quite well on the November 29 12z ECMWF Weeklies.

[TheClimateChanger]

1 hour ago, donsutherland1 said:

2. A significant lake effect snow event is underway. Several locations have seen excessive lake effect snow so far. Cassadaga, NY (31.6") and Mayville, NY (30.0") have the highest amounts so far. Buffalo has received a trace of snow, but as the lake effect snow bands move northward today, accumulating snow is likely there. Chicago (2.9"), Detroit (1.7"), and Toronto (0.2 cm) have all seen measurable snow. No measurable snow has fallen in Boston, New York City, or Philadelphia.

 

Highest amount [as of 7 pm yesterday] was 32.1" 2 miles ESE of North East, Pennsylvania, with another report of 30.2" from Girard, Pennsylvania shortly after 6 pm. No doubt well over three feet totals since that time.

[donsutherland1]

12 minutes ago, TheClimateChanger said:

Highest amount [as of 7 pm yesterday] was 32.1" 2 miles ESE of North East, Pennsylvania, with another report of 30.2" from Girard, Pennsylvania shortly after 6 pm. No doubt well over three feet totals since that time.

Thanks. I thought I had loaded the CLE local storm reports, but didn’t.

[George001]

3 hours ago, qg_omega said:

there goes the winter window

No, it’s just a relaxation period after 10 days of cold. How long the relaxation period lasts before the shift back to a colder pattern will be telling in terms of what direction this winter could be going.

[PhiEaglesfan712]

1 minute ago, George001 said:

No, it’s just a relaxation period

Yep, the pattern turns back to colder in February. As I said all along: cool December, very warm January, and cool February.

[MJO812]

Just now, PhiEaglesfan712 said:

Yep, the pattern turns back to colder in February. As I said all along: cool December, very warm January, and cool February.

Colder in January 

[PhiEaglesfan712]

25 minutes ago, MJO812 said:

Colder in January 

Possibly in late January, but most of the month is going to be warm. I don't see a 2010-11 or 2017-18 type winter.

[bluewave]

2 hours ago, George001 said:

No, it’s just a relaxation period after 10 days of cold. How long the relaxation period lasts before the shift back to a colder pattern will be telling in terms of what direction this winter could be going.

More like the start of December is a 10 day relaxation period from one of our warmest falls on record. It will feel much colder due to how warm it has been. But the cold departures will be modest compared to colder starts to December in the past. 
 

 

[TheClimateChanger]

3 hours ago, donsutherland1 said:

Thanks. I thought I had loaded the CLE local storm reports, but didn’t.

No problem, Don. Also, of note, the 22.6" officially recorded at ERI yesterday was just 2.2" shy of the entire seasonal total from last winter... which, incidentally, was the 4th lowest of record. The graphic below shows it as 6th; however, there is missing data for the winters of 1942-43 & 1943-44. If you cross-check the missing days from the climate reports using NCEI IPS, you'll see the seasonal total was over 48 inches in 1943-1944 and over 40 inches the preceding winter. The missing count for 1918-1919 & 1897-1898 appears just to correspond to months where no snow fell. No snowfall data was reported, which was interpreted as "missing" by the algorithm. And, of course, this ignores changes in snowfall measurement procedure which likely make the earlier data lower than it would otherwise be if the procedures were the same as today.

[MANDA]

1 hour ago, bluewave said:

More like the start of December is a 10 day relaxation period from one of our warmest falls on record. It will feel much colder due to how warm it has been. But the cold departures will be modest compared to colder starts to December in the past. 
 

 

A cold outbreak similar to some that occurred in the 70's and 80's would feel like the end of days compared to what we've seen in recent years with in and out modest cold shots.

[bluewave]

2 minutes ago, MANDA said:

A cold out break similar to some that occurred in the 70's and  80's would feel like the end of days.

Yeah, I grew during that much colder era. I can remember when NYC dipped into the single digits on 12-3-76. With the higher energy costs these days we are lucky we don’t get that kind of extended cold anymore.

[mitchnick]

3 minutes ago, bluewave said:

Yeah, I grew during that much colder era. I can remember when NYC dipped into the single digits on 12-3-76. With the higher energy costs these days we are lucky we don’t get that kind of extended cold anymore.

Coldest winter on record in the east will get you those numbers, but that was far from the norm. I walked 200' out onto the frozen Chesapeake Bay that winter in January, 1977 at Sandy Point State Park. The Chesapeake Bay never froze like that again.

[MJO812]

[bluewave]

7 minutes ago, mitchnick said:

Coldest winter on record in the east will get you those numbers, but that was far from the norm. I walked 200' out onto the frozen Chesapeake Bay that winter in January, 1977 at Sandy Point State Park. The Chesapeake Bay never froze like that again.

That winter was one for the ages. The early signs of the extreme cold began to become evident near the end of August. The last time NYC saw the December 1-10 average dip below freezing was 2002. 
 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

1	1926-12-10	26.2	0
-	1886-12-10	26.2	0
3	1876-12-10	26.4	0
4	1989-12-10	28.5	0
-	1871-12-10	28.5	0
5	1880-12-10	28.7	0
6	1882-12-10	29.1	0
7	1910-12-10	29.2	0
8	1976-12-10	29.3	0
9	1890-12-10	30.0	0
-	1869-12-10	30.0	0
10	1904-12-10	30.1	0
11	2002-12-10	30.6	0
-	1875-12-10	30.6	0
12	1958-12-10	30.9	0
13	1917-12-10	31.0	0
14	1906-12-10	31.3	0
15	1964-12-10	31.8	0

[snowman19]

Your hero says the east is going mild mid-December. Didn’t expect you to post his new tweet

[MANDA]

39 minutes ago, mitchnick said:

Coldest winter on record in the east will get you those numbers, but that was far from the norm. I walked 200' out onto the frozen Chesapeake Bay that winter in January, 1977 at Sandy Point State Park. The Chesapeake Bay never froze like that again.

Imagine if it did !

[mitchnick]

1 hour ago, MANDA said:

Imagine if it did !

Not interested.  I think BWI (mby at the time) had a lousy 12" or so that winter.

[uofmiami]

 

[MANDA]

2 hours ago, mitchnick said:

Not interested.  I think BWI (mby at the time) had a lousy 12" or so that winter.

Yea but it sure hung around for a long time.  Here in NJ I had a solid snow cover from early/mid December until around February 10th.  Don't recall my total but probably around 15" I think.  Nothing melted.  It was light to some moderate snowfall falling on existing snow cover.

[mitchnick]

6 minutes ago, MANDA said:

Yea but it sure hung around for a long time.  Here in NJ I had a solid snow cover from early/mid December until around February 10th.  Don't recall my total but probably around 15" I think.  Nothing melted.  It was light to some moderate snowfall falling on existing snow cover.

100% on that. The ground was snow covered almost all of January.  Then, February flipped warm mid month and March was around +5 at BWI. 

Maybe because I was younger in 76/77, but I found 93/94 to be even more brutal, though not as unrelenting as 76/77.

[michsnowfreak]

5 minutes ago, mitchnick said:

100% on that. The ground was snow covered almost all of January.  Then, February flipped warm mid month and March was around +5 at BWI. 

Maybe because I was younger in 76/77, but I found 93/94 to be even more brutal, though not as unrelenting as 76/77.

76-77 was certainly a brutal winter for cold, and I believe holds the record for longest stretch of below freezing temps. (It did warm up I'm March big time). Snowcover was good, but snowfall was nothing special, right around avg. 78-79 was another very cold winter though with snowfall actually below avg. 77-78 was definitely the harshest winter of the infamous trio, but doesn't hold a candle to 2013-14. Don't get me wrong, I would love to relive those winters for a few reasons, but from a snow perspective they were nothing special overall.

[BuffaloWeather]

Got about 3 feet today, great start to winter

[mitchnick]

This Pic of 11/25 SSTA forecast from updated Cansips is for Larry. 

 

[GaWx]

1 hour ago, mitchnick said:

This Pic of 11/25 SSTA forecast from updated Cansips is for Larry. 

 

Thanks, Mitch.

 This is the 4th run in a row showing a Modoki El Niño developing next summer fwiw. I’d also love to see the NW Pacific cool off.

[GaWx]

Latest AAM from CFS ensemble fwiw continues El Ninoish +AAM during the last half of Dec, something I like seeing as it may mean the SE ridge won’t become dominant anytime soon:

[bluewave]

The reason the modeling has been jumping around so much last few weeks is that this was the most volatile November for 500mb height changes since 1985 due to all the competing influences.

 

 

[snowman19]

@bluewave While we saw the La Niña struggle to develop all met fall, there is going to be marked strengthening and cooling this month. Full scale change with respect to ENSO/trade winds/SOI/MJO propagation and it’s going to result in a flip of the Rossby wave train we’ve been seeing up to this point:
 

[Terpeast]

All ensemble models show cold air reloading in W Canada while maintaining -EPO at the end of their runs, so any mid-month moderation may be short lived (a week, maybe 2).