GaWx

Per 12Z EPS fwiw, this (Gulf Miller A coming across over FL pen. and then offshore SE US with it cold enough to north) on the Euro op. is as one would expect currently only a very low probability scenario: I not surprisingly count only 3 of 50 members with something fairly close in track during a similar timeframe (members 16 and 34 have sig snow like op while member 32 has only very light snow): so only 6% of members. Member 43 track is inland and produces sig snow but further NW. If I count that it’s 4/8% of members. Also, member 34 actually has a second further SE tracking Miller A two days later that gives heavy snow to the SE coast similar to the very rare pre-Christmas Dec 1989 and early Jan 2018 historic heavy coastal snowstorms. As this period gets closer we’ll see how the various ensembles trend. I think this type of analysis is what was requested by @olafminesaw

This is day 10 on 12Z Euro with a weak Miller A Gulf low: so still in fantasyland/low statistical credibility period on an operational and thus mainly for entertainment showing a near best case scenario kind of thing (next run very likely won’t look similar):

New Euro Weeklies: 1. This week (12/2-8) coldest yet: just 6 days ago was mainly slightly AN 2. Following week (12/9-15) coldest yet: 4 days ago was mild 3. Week of 12/16-22 coldest yet (NN)

Makes sense: -Last time RDU got measurable Dec 1-15: 2018. -Only times since 2000 with 1”+ Dec 1-15: 2018, 2002

Note the change in the 3 day averaged 4 member CFS within just the last week: shows how blind it apparently (i.e., assuming they’re now on track) was just 2.5-3 wks out: As of one week ago for 11/30-12/6: Current for 11/30-12/6: In addition the subsequent fcast week, 12/7-13, has cooled almost as dramatically. However, the subsequent two weeks covering most of last half of Dec along with last 4 days of Dec have remained ~same (mainly mild) and the resulting in a near to slightly above normal Dec overall: NYC now at ~1991-2020 climo vs ~+2 as of a week ago: (Jan now coolest of DJF and Feb warmest) Will last 1/2 of Dec eventually cool off, too, or is this cold period going to end up being just in 1st half of Dec? Any educated guesses?

The 12Z EPS is about as cold as any through day 12 (Dec 4th). The rest of the run is a bit warmer than recent runs but is still cold overall along with reinforcing cold at the end (12/7).

The 12Z GEFS has a significant increase in the number of members with a tropical cyclone in the W Caribbean next week….interesting. Another TC or two this year would not be surprising with the still very warm W Caribbean and when looking back at the last 30 years or so.

12Z GEFS is about as cold run overall as any prior run through day 11. But days 12-16 remain to be seen. Also, fwiw, it has a significant increase in members with a tropical cyclone in the W Caribbean next week….interesting. Edit: 12Z GEFS isn’t the coldest days 12-16 but it is still cold overall thus making the total run another cold one. 12Z Euro: 15 day run is about as cold as any yet per my eyeballs with 4 Canadian highs including current one plunging down

Eric Webb discovered ABNA and that the -ABNA is driving the current/upcoming cold E US pattern. Anyone here knowledgeable about ABNA? It’s actually not a new index though we had previously never heard of it. Regardless, not having a daily forecast nor a monthly history of it makes it less useful to me though the DJF mean is shown on a graph in this Eric tweet:

Coldest lows of the season to date in this area with low 40s (41 at KSAV). Even colder expected tonight with the secondary push of cold air. Also, highs only in the 50s for today forecasted.

Thanks, Chuck. I just looked for the first time since yesterday. I see what you’re saying. But the latest GEFS/EPS are still pretty solidly cold dominated through day 16/15 in the E US with E US troughing. And trying to predict a few days later is full of danger as even predicting late week 2 isn’t so easy as we all know. Now are the full runs subtlety warmer than yesterday’s full runs while still quite cold? That’s very hard to determine without the actual HDD output, which I haven’t seen in awhile. Some of the 2M temperature change maps suggest that. And after a huge runup in NG to 13 month highs, that as you know could easily be all it takes for lots of profit-taking, especially if inventory is on the relative high side.

I just noticed that NG is currently down ~7% from yesterday. I don’t know why it is down sharply. Often that is a sign that the most recent EPS/GEFS runs are warmer than prior runs in the E US especially on days 8-16. But sometimes that can be due to other factors like lots of profit-taking after a huge runup that had actually occurred through yesterday. Also, yesterday had a weekly inventory report, which could have been bearish. I’ll see if I can find out. Admittedly I haven’t checked the latest EPS/GEFS. Anyone know if they’re as cold in the E 1/3 if the US as yesterday’s very cold runs?

Note the change for 12/2-8 on the Euro Weeklies in just 4 days: 11/17 run: 11/21 run:

Natural gas is now up a whopping 7% for the day and is at its highest since way back in Oct of 2023. To those who don’t know, NG price trends reflect well on the trend in EPS and GEFS forecasted E US temperatures, especially for days 10-16. When there’s a day with a significant drop (eventually it has to happen), that would tell me without looking at the ensembles that the colder ensemble E US trend very well may have stopped.

Lows in the area 43 (Hunter) and 45 (airport). Coldest overall of season to date. Even colder next 3 mornings is expected.

0Z GEFS and EPS at least appear to be the coldest runs yet for the E US! NG is once again at new highs (up 3%), highest since Jan.

0Z GFS has FIVE Canadian highs bring cold air down into the E US! That’s a relative rarity even for the GFS. NYC gets not just one but two measurable snowfalls fwiw.

0Z GFS has FIVE Canadian highs bring cold air down into the SE US! That’s a relative rarity even for the GFS. The NC mtns get 4 different NW flow accumulating events!

Very windy here this late evening. Hearing debris hit the roof. Dewpoints were near 60 just 3 hours ago and have fallen to 40 to upper 30s. This is a heck of a cold front!

Of the operationals over the last month, it looks like Euro 1st and UKMET 2nd at H5 (day 5). But look what’s in 3rd: CMC, which isn’t much behind UKMET! That tells me that if this month is representative of the longer term, the CMC may be the most improved op at H5 (at least at 120 hrs) over the last 10 years or so. In 4th is GFS. Bringing up the rear: the very unreliable CFS.

Being 160+ barely makes it officially hyperactive. Plus this might be raised in the post-season analyses.

I’ve been posting in the main La Niña forecasting thread. However, these posts have been addressing changes from run to run of overall US temperatures/heating degree days (especially E US) on EPS but also some GEFS runs as opposed to narrowed to SE US temperatures or winter storm threats. As a part of that I’ve been following natural gas mkt prices, which are often a good gauge of E US ensemble HDD forecasts in week 2. Example: today’s NG high was the highest since Jan! I also in there post about various indices and ENSO SSTa’s. Looking forward to the cooldowns!

NG is noting the overall colder GEFS/EPS so far today with it up a whopping 7%! Today’s high is the highest since way back in January!

With the 0Z EPS being significantly colder in the E US vs the 12Z run overall on days 7-15, NG is up to session highs. The coldest in late in the run (early Dec), when it is much BN with a hard freeze implied in much of the E US on 1-2 mornings. This cold is being driven by a solid -EPO/-WPO.

The 11/17 daily EPO of +233 (the latest daily available), which was the highest daily since way back on June 4, will probably end up being the highest for quite awhile. Models are unanimous in dropping it very sharply to at or near the lowest daily of 2024 on 11/21 or 11/22 (~-250)! The consensus then has it remaining negative the rest of Nov fwiw. When combining the low point and duration of this upcoming -EPO, it could end up the most impressive since way back in Oct of 2023! https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt