GaWx

6 hours ago, bluewave said:

 

I looked at the NYC snowfall for the 17 -ENSO winters for which Dec was cold and had snowfall of 6”+ (from @donsutherland1updated list):

Year (Dec)..Total Season..Jan+

1872….60.2….29.9

1874….56.4….46.3

1886….31.9….21.6

1893….39.2….30.9

1903….32.4….26.0

1909….27.2….17.4

1915….50.7….42.6

1916….50.7….36.2

1917….34.5….20.1

1922….60.4….51.4

1926….22.3….10.6

1933….52.0….36.6

1942….29.5….21.0

1944….27.1….20.4

1995….75.6….61.2

2000….35.0….21.6

2010….61.9….41.8

————————

Analysis:

-AVG of these Jan+: 31.5” vs 22.1” full 156 year record mean or 143% of mean for Jan+ (median was 29.9”)

-41% (7 of 17) had 35”+ for Jan+ vs only 12% of the other 139 (17 of 139)

-These 17, which are only 11% of the total 156 on record, had:

1. Highest Jan of the 156 on record (2011’s 36.0”) and 3 of top 5 Jans (2011, 1996, 1923)

2. 3rd highest Feb of the 156 (1934’s 27.9”)

3. 2nd highest Mar of the 156 (2016’s 25.5”)

4. Highest Apr of the 156 (1875’s 13.5”) and tie for 5th (1917’s 6.5”)

—————————

My NYC total 2025-6 snow prediction based on these stats:

 40” (most likely range 30-50”)

 This compares to 156 year and 35 year means of 28”.

6 hours ago, bluewave said:

The distribution of the snowfall this month between ISP, PHI, and BOS is not what we typically see when Islip has a snowy 10”+ December. This is the first time since 1988 that ISP has 10”+ in December and either Philly or Boston doesn’t have at least 10” also.

It’s why we may not be able to use the snowy December winter analogs that followed the other 10” December years on the list. This is due to the 10” at ISP being the first December with two 5”+ clippers that had narrower areas with heavy snow than benchmark coastal snowstorms that also affected Philly or Boston in the other snowy Decembers at Islip.

So it will be interesting to see how the rest of the winter plays out at all three locations. 

All 10”+ snowy Decembers at ISP and the Boston and Philly snowfall

2009…ISP…25.3”….BOS….15.2”….PHI….24.1”

2002…ISP….16.0”….BOS….11.1”……PHI….8.4”

2003…ISP….15.5”…..BOS….21.5”….PHI….6.0”

2010….ISP….14.9”…..BOS…..22.0”…PHI…12.7”

1995….ISP…..13.3”…..BOS…..12.6”….PHI….7.3”

2025….ISP…12.4”…..BOS…..2.3”……PHI….4.5”

1969….ISP….12.0”…..BOS……12.6”….PHI….7.5”

1975…..ISP….11.4”…..BOS…..19.3”……PHI….7.5”

1963…..ISP…..11.0”….BOS….17.7”…….PHI….8.0”

2000….ISP…..10.8”….BOS….4.5”….…PHI…..10.5”

2008….ISP…..10.4”….BOS….25.3”…..PHI…..0.4”

1988…..ISP…..10.4”….BOS….3.7”……PHI…..0.4”

 

 

 I looked at the NYC snowfall for the 17 -ENSO winters for which Dec was cold and had snowfall of 6”+ (from @donsutherland1updated list):

Year (Dec)..Total Season..Jan+

1872….60.2….29.9

1874….56.4….46.3

1886….31.9….21.6

1893….39.2….30.9

1903….32.4….26.0

1909….27.2….17.4

1915….50.7….42.6

1916….50.7….36.2

1917….34.5….20.1

1922….60.4….51.4

1926….22.3….10.6

1933….52.0….36.6

1942….29.5….21.0

1944….27.1….20.4

1995….75.6….61.2

2000….35.0….21.6

2010….61.9….41.8

————————

Analysis:

-AVG of these Jan+: 31.5” vs 22.1” full 156 year record mean or 143% of mean for Jan+ (median was 29.9”)

-41% (7 of 17) had 35”+ for Jan+ vs only 12% of the other 139 (17 of 139)

-These 17, which are only 11% of the total 156 on record, had:

1. Highest Jan of the 156 on record (2011’s 36.0”) and 3 of top 5 Jans (2011, 1996, 1923)

2. 3rd highest Feb of the 156 (1934’s 27.9”)

3. 2nd highest Mar of the 156 (2016’s 25.5”)

4. Highest Apr of the 156 (1875’s 13.5”) and tie for 5th (1917’s 6.5”)

—————————

My NYC total 2025-6 snow prediction based on these stats:

 40” (most likely range 30-50”)

 This compares to 156 year and 35 year means of 28”.

 Our area had a sweaty 80 high today.

51 minutes ago, BlizzardWx said:

It was 86 degrees at my place today. I hope we can get some payback later into January. EPS weeklies definitely looking more promising mid month. 

When you consider that both the EPS and GEFS have had a notable -PNA bias/notable warm bias from your area eastward and that all -ENSO -PNA Decs have transitioned to +PNA Jans, these consistently much better pattern maps for mid-Jan are quite encouraging. Just 5 days ago, the EW had this ugly -PNA for 1/12-18:

  I’ve been quite curious about what phases the MJO would be in during the heart of the widespread historic US warmth of late Dec, Dec 23-27. We needed to wait due to several days of reporting lag. Would any of it be in the typically chilly in the E 1/2 of the US phase 8? 

 Well, now we have the answer for the first 3 days, Dec 23-25: not surprisingly, none of those first 3 days were in phase 8. It turns out that Dec 23-4 were in very weak phase 7 while Dec 25 was in very weak phase 6, which I consider intuitive:

2025          12          23 -0.28945175      0.37228486               7  0.47157007      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          24 -0.12800699      0.45807526               7  0.47562456      Gottschalk10_method:_OLR_&_ACCESS_wind      
        2025          12          25  0.16766728      0.36077648               6  0.39783412      Gottschalk10_method:_OLR_&_ACCESS_wind

 Based on a combo of the above diagram and a related adjustment to the model prog consensus, I’m predicting that Dec 26th will be in very weak 4 and Dec 27th will be in either weak 3 or weak 2.

 Will we get back into phase 8 before the end of Dec? The GEFS, JMA, and CFS with my adjustments suggest likely not whereas the adjusted Euro suggests there’s a chance for at least one day of weak 8 then.

 Will we get back into phase 8 in early Jan? As of now there’s a moderate chance of mainly a weak 8, but that’s all I can say right now due to model disagreement and it being too far out for a confident prediction.

2 hours ago, donsutherland1 said:

1917 also had a mean temperature of 25.0° for December 

 

Corrected Table:

Note: The initial table was constructed from summing daily snowfall amounts. Not all daily amounts are in the NYC climate record. Thus, doing so understates the monthly figures. Here's the correct table using the monthly figures.

 For -ENSO (17 seasons):

1872 10.6

1874 14.5

1886 6.6

1893 9.4

1903 15.6

1909 11.1

1915 0.7

1916 5.8

1917 13.2

1922 24.5

1926 5.7

1933 0.1

1942 9.5

1944 12.3

1995 26.1

2000 8.3

2010 36.0

Mean/median: 12.4/10.6

 Interestingly, the lowest 2 Jans and highest 3 Jans were -ENSO.

 Today’s Euro Weeklies were better overall for E US, incl 1/12-18

Today H5:

Yesterday 2m:

Today 2m:

38 minutes ago, donsutherland1 said:

December 2025 will finish with a mean temperature below 35.0°C (coldest since 2010) and more than 6" of monthly snowfall. Below is how January fared in terms of snowfall following cold and snowy Decembers.

 Just looking at the 8 cases that were during -ENSO (16, 22, 26, 33, 42, 44, 95, 10), the Jan SN mean/median rises to 12.8”/9.9”.

17 minutes ago, TheClimateChanger said:

Like in Pittsburgh, Monday afternoon may be in the upper 20s but the high is likely to be near 60 degrees!

Thanks. However, when I did my estimates, I took into account that the 12/29 highs would be at midnight from there through OH/IN, ATL, to BRO, etc. I did the same for 12/28 highs in the Plains/upper MW and the 12/30 highs in the NE. If anything my 31 est. for 12/28-31 is slightly high. I est. 33, 26, 29, 33 for 12/28-31.

 For similar reasons, there were 11:59PM lows to take into account, which I did.

1 hour ago, TheClimateChanger said:

Either way, a VERY respectable anomaly. From a historical standpoint, this could wind up warmer than any December prior to 2015 if PRISM is close. Not sure what's going on with recent Decembers. 3 of the past 4 were even warmer. So from a historical standpoint, EXTREMELY impressive, but from the vantage point of recent years, pretty ho-hum national anomaly. It doesn't appear to be data error, because the USCRN network suggests recent Decembers were even warmer than given by the nClimDiv numbers.

 I see ~no chance for Dec ‘25 to come in warmer than Dec ‘39’s 37.7. Through the 27th (last widespread US warm day), MTD could rise to ~38.2. But 12/28-31 are progged to avg ~31. That would bring the full Dec back down to ~37.2.

1 hour ago, TheClimateChanger said:

Not too shabby. I think this might wind up warmer than any December prior to 2015.

 

 I see ~no chance for Dec ‘25 to come in warmer than Dec ‘39’s 37.7. Through the 27th (last widespread US warm day), MTD could rise to ~38.2. But 12/28-31 are progged to avg ~31. That would bring the full Dec back down to ~37.2.

-NYC now up to 7.2” snow this month, snowiest since Jan of ‘22. Thus, using stats @bluewaveand @donsutherland1got me informed about, I’m now forecasting a season total of 30” min., highest since at the very least 20-21.

-NYC headed to ~5 BN this month, coldest vs norm since Mar of ‘15!

La Guardia was at 4.1” as of 7AM. So, all NYC area official reports are now above 4”.

 Anyone see LaGuardia’s total? Other than that, I think every NYC official station got 4”+.

C Park was up to 0.49” liquid equiv as of 7AM. Was that that far off? How much liquid was forecasted?

Just now, wthrmn654 said:

Next central park update is at 1 am

They got an additional 0.20” of liquid equivalent 7-11PM. As of 7 PM, they had had only .01”.

 Today’s Euro Weeklies, which are overall fairly similar to yesterday, still have that new +PNA in the means for 1/12-18:

 This setup continues more strongly into the subsequent week, 1/19-25, than was seen yesterday:

13 minutes ago, wncsnow said:

There are some positive changes but its far from a slam dunk. The EPS is still not quite cold enough for most for the 4th-7th. The Op GFS looks terrible. The GEFS isnt there yet either. 

 

Things are looking up for Jan just as our buddy Buc-ee is doing:

 
Natural has us up 4% today. This is one of the reasons:

The 12Z GEFS has this at the end: more W coast ridging than prior runs along with a pronounced weakening of the Aleutian ridge:

 The result is an increasing hint on the GEFS of an Arctic high plunging down ~Jan 9th-11th along with a second one to follow:

The SW Canadian air that might be brought down then is very cold:

BAMwx video update from Michael Clark this morning:

1 hour ago, wncsnow said:

 

I don't see a January 2022 repeat next month. Maybe we get a week or 2 period but 2022 was cold for most of the month with multiple snows  in different parts of the state. 

 We’ll see. But keep in mind that:

-Jan 22 had +NAO/+AO

-This was the PNA forecast as of 4 years ago today through 1/9/22: it was for still -PNA as of 1/9/22. It turned out that 1/9/22 was the first +PNA day of a 38 straight day +PNA. So, GEFS 4 years ago was blind to its start even as late as today:

- Today’s GEFS PNA forecast is eerily similarly maintaining a -PNA: hmmmm

Also, keep in mind that GEFS (and all of the major ensembles) have had a strong -PNA bias over the last 90 days:

3 hours ago, michsnowfreak said:

It will be interesting to see how warm the conus ranking is this December, since it will have a large area of well below avg temps in the Great Lakes and northeast.

 Based on population weighted heating degree days, a good measure of energy usage, the Conus in Dec won’t be that warm at all! Pop weighted Dec temps are progged to come out to only ~1 F warmer than normal.

 My estimate is for Chicago to end up Dec 3 BN, Cinci 2.5 BN, Balt. 4.5 BN, Philly 4 BN, NYC 5 BN, and Boston 4.5 BN.  Even the upper SE (NC) should come in slightly BN and then ~+1.5 at ATL. SL should be right at normal. DFW should be ~5 AN, DEN ~11 AN, Phoenix 6.5 AN, LA 3 AN and Seattle 4.5 AN.

 Based strictly on geographic area though, my guess is that the Conus will come out to ~3 AN for Dec (~1 BN E 1/2 and ~7 AN W 1/2) or ~37 F.

 If it comes out to 3 AN, that wouldn’t be anywhere near the records of 2023 (~5.5 AN or 40.0), 2021 (~5 AN or ~39.3 F) 2015 (~4.5 AN or ~38.6 F), and 2024 (~4 AN or 38.3 F).

 So, I expect Dec of 2025 on an aerial basis to come out ~3 F colder than 2023, ~2 F colder than 2021, ~1.5 F colder than 2015, and ~1.0 F colder than 2024. Also, 1939 was ~37.7 F.
 

 So, I believe that on an aerial basis that Dec of 2025 will come out no warmer than 6th warmest Dec since 1895. Also, it’s possible that 1957 and even 2014 end up warmer than 2025 if I’m a little too warm with my 37 F guess by, say, a couple of tenths, possibly dropping 2025 down to as low as 8th warmest.

@TheClimateChanger

15 minutes ago, TheClimateChanger said:

I'm pretty sure Christmas 2025 easily eclipsed 2021 on an aerial-weighting, buoyed by much higher anomalies across the intermountain west. While sparsely populated, that's a large landmass and it was considerably warmer this year.

Thanks.
 Thus, we agree on aerial weighing. Do you agree that pop weighted would have been warmer in 2021?

 Which avg Conus Christmas highs were warmer, 2021 or 2025?

1. Based on geographic area, I’d say 2025. Why? Because most of the W 1/2 including most of the Plains states as well as MO and much of TX were warmer in addition to much of the SE. Much of the NE to Ohio Valley/Michigan to Virginias/KY and much of the Midsouth were cooler. Interestingly, NYC and Chicago were about the same.

2. In terms of population weighted highs (energy usage indicator), I think 2021 was net warmer because of the high population of the NE to Ohio Valley to Michigan being warmer.

2021 forecasted highs:

2025 3:20PM EST temps:

 78 was the high at SAV today. They’ve had 78, 78, and 75 the last 3 days. Torchy but no records, which are 81, 83, and 82. Most of their record highs in winter are in the low 80s as 70s aren’t at all uncommon. We still have 4 more days of mid to upper 70s to go before the bottom falls out. So, that would make 75ish+ 7 days in a row. 

 Good job by the models with the warmth for a change! This is the first period they’ve done well since the week prior to Thanksgiving. They saw this coming pretty far out.

 The best looking H5 map for cold potential for the E US in Jan on today’s Euro Weeklies is this one with a nice +PNA, which is for 1/12-18 (similar to yesterday):

Just 3 days ago it still had an ugly -PNA: so there’s been a big change for an ens mean for a week long period

Here’s today’s temp map for the same week (similar to yesterday): chilly but I fully expect this would turn much colder than this if the +PNA idea is right

Here’s what the same week’s map had just 3 days ago, which is consistent with that ugly H5 then: