GaWx

It’s as big as any I can recall. The size of the area in the 3rd shade of blue off the E coast is the most impressive I can recall. It isn’t easy to get that offshore as we know. Looking back in my saved maps, today’s EW map for 1/6-12, with it covering most of the E US in 3-6C/5.4-10.8F BN is THE coldest of any I have in the E US for the week still being 13 days out! The only other one I have that is comparable (slightly colder NE/slightly warmer SE) with most of the E US in 5.4-10.8F BN is closer in at 9 days out (11/23/24) preceding Dec 2-8: How well did this 9 days out map verify for 12/2-8/24? NYC (map: ~-5.5F): actual was -5.3F (so, very close) Wilmington, NC (map: ~-6F): actual was -10.9F (so, it wasn’t nearly cold enough) Savannah (map ~-5.5F): actual was -9.7 (so, it wasn’t nearly cold enough) If this verification were to happen to be an indication of what’s to come Jan 6-12, the SE (at the very least) would verify colder then what today’s map shows. Also, if the strong cold signal maintains itself, look for a portion of this going into the 4th shade of blue on a run within a few days. The 4th shade starts at -10.8F.

New Euro Weeklies: For Jan 6-12: H5 has the strongest negative anomalies yet with a whopping 13-14 BN at NYC with 536 dm for a full week! The PV is centered near 70N, 80W over far N Hudson Bay. The W ridge is a bit further east vs yesterday along W coast meaning stronger +PNA, thus bringing the center of the cold back to the E US like was the case before yesterday. The Aleutian low is the strongest yet. H5: 1/6-12 2m: 1/6-12 is as Mitch just said colder in the E US though it isn’t as cold W/NW of Chicago, where the center of the cold was yesterday. Today’s has the 3rd shade of cold covering most of the E US vs just a tiny area in the 3rd shade mainly in NC the last 4 days. The third shade is 3-6C BN or 5.4-10.8F BN averaged over a full week! The subsequent week, 1/12-18, is still cold/slightly colder SE vs yesterday though not as cold Midwest with like the prior week having the W ridge a bit further east along W coast. This run keeps a pretty stout +PNA much of Jan.

How about this earlier in the 12Z EPS (at 270)?This has E NC at 20 dm BN and NYC at only 532 dm, which is 17 dm BN! I’d say that’s ~equally impressive to the further out but not quite as cold 360 hour map posted above:

How about this earlier in the 12Z EPS (at 270)? This has E NC H5 at 20 dm BN!

The 12Z EPS 360 hour has about as negative H5 anomalies as I can recall on any run at 360 centered in the E US. NYC is at 534 dm, which is a whopping 14-15 dm BN! Keep in mind that that is a 50 member ensemble mean out 15 days, a very difficult modeled anomaly to have.

The 12Z EPS 360 hour has about as negative H5 anomalies as I can recall on any run at 360 centered in the E US. NYC is at 534 dm, which is a whopping 14-15 dm BN! Keep in mind that that is a 50 member ensemble mean out 15 days, a very difficult modeled anomaly to have:

OISST 3.4 ERSST/OISST anomalies dropped 0.40 C/0.47 C in 2008 from Nov to Dec. This could easily end up near a 0.5C drop for OISST which would be a new record Nov to Dec drop for La Niña back to 1950.

Compared to the 18 cold ENSO Jans since 1991: the mean of the last 12 runs of the 4 member CFS ensemble has the SE at the 3rd coldest Jan 7-13 for cold ENSO behind only 2011 and 1996 with an avg of ~4.5-5F BN: Just one week ago, this is how much warmer the 12 run CFS ens mean was: ~2F AN Getting a week to average 5F BN is not the least bit easy! Precip is ~normal, which is good because that is wetter than the majority of cold periods since cold is more often than not associated with BN precip in the SE. Also, Jan 7-13 normal precip is pretty significant, especially well inland. So, it appears that there would be a decent shot at wintry precip during this period if the last 12 CFS runs have the right idea (possible Gulf moisture):

It looks like 2” at Central Park in 2009 when it was measured that was left from a big snow 12/19-20 but it was melting rapidly due to rain falling and thus was gone by 12/26: https://www.weather.gov/wrh/Climate?wfo=okx

Every one of these 5 indicators is at the coldest of the season to date clearly indicative of a rapidly strengthening La Niña to near weak/moderate Niña border on the dailies and suggesting equivalent RONI dailies probably at least high end moderate to quite possibly bordering on strong. This means a Nov to Dec cooling likely one of the strongest back to 1950 though not near the 0.8 record shattering cooling suggested by many earlier CFS runs: OISST: -0.98 C CRW: -0.95 C CDAS: -1.43 C Buoys: coldest below -1.5 C near equator along entire Nino 3.4: OHC: 0.6 C plunge just since late Nov to -1.1 C

PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE NEW YORK NY 917 AM EST TUE DEC 24 2024 ..SNOWFALL REPORTS LOCATION AMOUNT TIME/DATE PROVIDER ..NEW JERSEY ..BERGEN COUNTY OAKLAND 1.0 IN 0800 AM 12/24 COCORAHS MONTVALE 1.8 ESE 0.8 IN 0800 AM 12/24 COCORAHS RIVER EDGE 0.5 IN 0840 AM 12/24 PUBLIC ..ESSEX COUNTY MONTCLAIR 0.5 IN 0800 AM 12/24 COCORAHS ..HUDSON COUNTY HARRISON 1.0 IN 0800 AM 12/24 COOP ..PASSAIC COUNTY WEST MILFORD 1.1 IN 0720 AM 12/24 COCORAHS ..UNION COUNTY NEW PROVIDENCE 0.6 IN 0730 AM 12/24 COCORAHS ..NEW YORK ..ORANGE COUNTY 0.8 N PORT JERVIS 2.5 IN 0700 AM 12/24 COOP PORT JERVIS 1.8 IN 0800 AM 12/24 COCORAHS 1 WNW MONROE 1.6 IN 0805 AM 12/24 PUBLIC ..PUTNAM COUNTY NELSONVILLE 0.3 S 1.4 IN 0715 AM 12/24 COCORAHS ..ROCKLAND COUNTY STONY POINT 0.5 IN 0700 AM 12/24 COCORAHS ..WESTCHESTER COUNTY CROTON-ON-HUDSON 1.3 IN 0850 AM 12/24 PUBLIC ARMONK 0.8 IN 0800 AM 12/24 COCORAHS SOUTH SALEM 0.5 IN 0755 AM 12/24 COCORAHS

So, are you saying Newark needs another 1.5” from this morning’s snow? I see that it had snow and only 1/2 mile visibility at 8AM. That sounds pretty significant if it had continued for awhile.

Chris, it appears NYC will get close to the 3” mark for snow in Dec that you follow during La Niña.

The bc GEFS and EPS continue to predict an MJO that would be weak left side of diagram for early Jan (see below). As mentioned, 7 of 8 similar cases during Jan for cold ENSO during last 50 years were concurrently cold dominated in the E US. Weak MJO (near or inside circle) has tended to be concurrently colder than strong for all phases in Jan after all cases were averaged. So, my hope would be for it to remain weak when later coming around on the right side: GEFS: EPS:

What a nasty late afternoon here with breezy drizzly and only 42.6 F now. CAD at its best/worst! This is easily the coldest afternoon of the season yet! I may not get a walk in. 10:45PM: Down to 41.1 with light rain. The cold has a real bite to it. 11:30PM 40.8 with light rain

Indeed, it is easily the coldest overall yet! Jan 6-12 is a whopping 5-7 F colder in the N Rockies to N Plains to Chicago vs yesterday as the strongest cold now aims to come into the US further west with the H5 ridge now a bit further offshore the W coast (stronger -EPO/weaker +PNA) and a further S piece of the TPV into N Hudson Bay. Temps in the NE are slightly colder and the SE is ~same as yesterday. Jan 13-19 is also significantly colder vs yesterday/easily coldest overall yet especially NE US to Midwest with the H5 ridge also a bit further offshore.

Wow, a rise of 0.4 more the last 2 days! NOAA equivalent daily is likely up to ~-1.64 vs a low of ~~-4 Oct 10!

The MJO forecasts toward weak left side are what make me think the recent GFS suite trend is mainly a head fake or temporary at worst and that the E US will likely be dominated by cold in much of Jan 1-20+. Also, a (near) record +PNA in Dec for cold ENSO is encouraging for Jan +PNA prospects as has been posted about. Fingers crossed I found 8 cases of weak left side MJO (similar to the images below) in cold ENSO in Jan with 7 of the 8 cases being concurrently cold dominated (posted in detail over the weekend): In addition, the early Jan progged -AO is on the side that supports E US cold.

The MJO forecasts are what make me think the recent GFS suite trend is mainly a head fake or temporary at worst and that the E US will likely be dominated by cold in much of Jan 1-20+. Fingers crossed. *Edit: Also the (near) record Dec +PNA for cold ENSO is encouraging for Jan +PNA prospects per analogs.

All commodity markets inherently have high levels of gambling. Not for the faint of heart! I’d say that market typically reacts to already existing model trends more than it predicts model trends. That’s why I like to mention its trends. This morning it reacted to what the last few models have shown. Even the latest EPS lost some HDDs.

The last few GFS suites especially have trended toward the initial cold in January coming down further west vs what was showing late last week through early yesterday. Hoping that would be temporary or better yet a head-fake. Interesting times in the forecasting discussion world!

I’m seeing what appears to be a trend toward the early Jan cold dumping more into the W US vs E US vs what was showing on runs late last week through early yesterday. Hoping that would be temporary and/or the trend is a head-fake. *Edit: This is especially the case on recent GFS/GEFS more than the others. Natural gas, which hit new highs on Fri, has been dropping back some the last few hours and most noticeably since 8AM EST. That market could be considering this recent trend, which would be bearish for NG demand if reflecting reality.

Today’s forecasted GEFS AO is getting quite low, sub -2 mean and still falling at the end. It averages ~-2 for Jan 1-5: Here are the 13 1950+ cold ENSO Jans with Jan 1-5 averaging sub -1.5 AO together with the full Jan avg temps anomaly (based on each respective 30 year climo period) at Baltimore (proxy for E US): 2021 -2.9 +2 2014 -1.5 -7 2011 -2.9 -4 2009 -1.7 -5 2008 -1.6 +1 2001 -2.6 -1 1997 -1.8 -1 1996 -2.0 -2 1985 -2.3 -4 1965 -2.4 -2 1963 -3.6 -4 1955 -2.6 -2 1951 -2.4 +3 AVG -2; 1 MBN (2014); 7 BN; 3 NN; 2 AN (2021, 1951) So, this fwiw implies a notably better chance for BN than AN for Jan 2025 at Baltimore (as a proxy for the E US) assuming todays GEFS AO forecast for Jan 1-5 will verify pretty well.

I don’t include Mar as part of winter. I’m talking met winter (DJF) since Mar normal temps are significantly higher (early met spring). I agree that many (though not me) just focus on snowfall and thus I agree with what you’re saying that many would think fail if cold but not snowy. But again not all think this way.

If the cold domination hangs on through Jan 15 and possibly as late as Jan 20, we’d be looking at the high likelihood that both Dec and Jan would end up averaging NN to BN in much of the E US, something you didn’t expect in advance per your posts. I certainly didn’t expect this then. So, even if Feb is mild (still quite possible as often is the case in La Niña…I favor it as of now), this winter is likely going to end up significantly colder than we had expected.