GaWx

 It was about a week in advance when the models suddenly got colder for the period starting a few days before Thanksgiving. We’re now about a week before the progged big warmup in the E US. Just saying although I’m not saying that will likely happen again. But it’s good to stay grounded due to the inaccuracy of models more than a week out.

7 minutes ago, SouthboundYank said:

Got down to 29 again last evening in Myrtle Beach...and a 2nd morning of HEAVY frost, almost like snow! But temps rebounding nicely today compared to yesterday...we're up to 50 now with full sun and clear conditions.

It also got down to 29 at KSAV, which was a few degrees colder than the forecasted lower 30s. But it didn’t quite get down to the coldest yet this season, which is the incredible 28 of Nov 11th.

 Per yesterday’s Euro Weeklies, it’s overall looking to average mild from the Mid-Atlantic-OH Valley-lower Midwest south for most of the 4 week long period 12/22-1/18. Could it end up verifying well? Of course, especially the earliest portion, when statistically there’s more skill. Will it? Nobody could possibly know, obviously. Notwithstanding the poor performance for the 3 weeks from just before Thanksgiving through mid Dec, the Euro Weeklies have been just good enough at foretelling general trends that they shouldn’t be ignored by any means. But could they largely end up failing, especially for the Jan portion? Obviously they could.

2 hours ago, BooneWX said:

File this away as well: MJO always has and always will be a vastly overrated teleconnection. We’ll firmly be in 8 for these 70° days. 

1. No teleconnection even comes close to guaranteeing anything. Anyone who says it does is overrating it. But most have notable tendencies that make them helpful for forecasting. They’re useful tools, including the MJO, but they’re not crystal balls as the atmosphere is much too complicated for any one index to be reliable. I’d argue the MJO is about as good a tool as any of them, but like any tool it needs to be used correctly.

2. I recently did an analysis of 3+ day long Dec phase 8 at RDU and found a whopping 78% of them to have been colder than normal:

# of periods: MB 5 (22%), B 13 (57%), NN 0 (0%), A 2 (9%), MA 3 (13%)

 So, there have been nearly 4 times as many B/MB periods as A/MA periods at RDU for Dec phase 8 periods lasting at least 3 days.

3. Regardless, of what may come and in what phase, what about prior to that period? The period 12/3-16, most of which is forecasted to be in phase 8, is forecasted to end up with all colder than normal days at RDU and in much of the SE and to be at least in the top 5 cold for that period of the last 50 years! That would be 90 percentile cold.

4. I plan to average out the temperature anomalies for whatever days end up in phase 8 later this month.

3 hours ago, Met1985 said:

Heavy frost with a low I believe of 30 degrees here in North Charleston.  Not something you see often down in the low country. 

 Thanks. Our areas had a freezing fog advisory late last night, which I believe is quite rare:

309 AM EST WED DEC 10 2025  

..PATCHY FREEZING FOG THIS MORNING  

AREA OBSERVATIONS, SATELLITE IMAGERY, AND WEB CAMS INDICATE THAT  
PATCHY DENSE FOG IS IMPACTING PORTIONS OF SOUTHEAST GEORGIA AND  
SOUTHEAST SOUTH CAROLINA EARLY THIS MORNING. MOST OF THE PATCHY  
FOG IS SHALLOW, BUT IS PRODUCING VISIBILITIES OF A QUARTER OF A  
MILE OR LESS IN ISOLATED AREAS. MUCH OF THE FOG IS FORMING AS  
STEAM FOG NEAR WATERWAYS INCLUDING RIVERS, STREAMS, TIDAL CREEKS,  
AND MARSHES.  

TEMPERATURES ACROSS THE AREA HAVE FALLEN BELOW FREEZING AND INTO THE  
UPPER 20S IN MANY LOCATIONS. FREEZING FOG WILL OCCUR, EVEN  
PRODUCING LIGHT RIME ICE ON ELEVATED AND EXPOSED SURFACES. WHILE  
LOW VISIBILITIES COULD IMPACT TRAVEL, ESPECIALLY WHERE  
VISIBILITIES CHANGE SIGNIFICANTLY OVER SHORT DISTANCES, RIME ICE  
FROM FREEZING FOG IS NOT EXPECTED TO PRODUCE ANY IMPACT ON TRAVEL  
CONDITIONS.  

TEMPERATURES WILL RISE ABOVE FREEZING, AND ANY LINGERING FOG WILL  
DISSIPATE, BETWEEN 8 AND 9 AM THIS MORNING.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...  

IF DRIVING, SLOW DOWN AND LEAVE EXTRA DISTANCE AHEAD OF YOU IN  
CASE A SUDDEN STOP IS NEEDED.

 A half hour ago I finished walking at the park in 35 invigorating degrees. To sort of borrow a phrase from DT, yes, I was the only sick, twisted cold wx freak out there walking. But I was bundled up and had extra energy giving me an extra spring in my step. Winds were calm with clear skies allowing for Gainesville, FL-like ideal radiation. I could even see some cool looking steam fog over water. Dewpoints were only a couple of degrees lower.

 Today’s high was only 45, which is 20 below normal.

Today is the 9th day in a row of highs below 60 at SAV and below 50 at GSO, extending the record! Before this SAV had never even had this for Dec 1-7 going back to 1874. GSO had had a 7 day period one other time.

 Today’s Euro Weeklies for the 4 weeks Dec 22nd through Jan 18th continue to look bad (mild) especially in the SE and MidAtlantic. There’s no way to sugarcoat it. The hope is that they’re just pain wrong. But that’s just a hope:

12/22-28:

12/29-1/4:

1/5-11

1/12-18:

 There’s a college football thread for those who don’t know and are interested that could use more discussion like this:

After a big drop yesterday of 7%, natural gas prices are again sharply lower today (down 5% for a 2 day total of 12%) on warmer E US prospects for at least late this month. It’s very rare for NG to drop that much in early winter with cold looking to dominate for the foreseeable future, which as we know is not at all the case after about a week of intense E US cold per model consensus. Week one’s intense cold is already built into the price.

 It’s usually changes in prospects for week 2 into early week 3 that drive daily changes in NG prices. That’s because week one is normally already priced in and typically doesn’t jump around too much. And beyond early week 3 is usually too far out in fantasyland/too little forecasting skill that far out to have too much impact.

21 minutes ago, TheClimateChanger said:

 

1. Where’s “Star” located?

2. No index ever even comes close to guaranteeing anything. That’s nothing new to us.

3, However: The period Dec 3-17, which is prior to the days his maps are showing, is currently looking to end up much colder than normal in the majority of the E US, including a top 3-5 coldest of the last 50 years in many places. That would jibe well with phase 8’s cold E US tendency.

Per the quite fallible model consensus:

 The -WPO looks to easily be the strongest in Dec since 2013. Other strong -WPO (sub -1.00) Decembers: 2013, 2010, 2009, 2005, 1999, 1995, 1989, 1980, 1976, 1975, 1966, 1961, 1956, 1955, and 1954.

 So, Dec of 2025 has a good shot at making the top 20% strongest -WPOs.

 How was the subsequent Jan WPO for these 15?

Negative WPO Jan: 2011, 1996, 1981, 1977, 1976, 1962, 1957, and 1956 (8 of the 15)

Neutral WPO Jan: 2010, 2000, 1955

Positive WPO Jan: 2014, 2006, 1990, 1967

 So, these strong -WPO Decembers were somewhat biased toward -WPO Jan with twice as many -WPO Jans as +WPO Jans

 The current model consensus *fwiw* suggests there’s a good chance we don’t end up with a -EPO for Dec as a whole with a lean toward fairly neutral to potentially +EPO when averaged out. How often have there been strong -WPO Decs without a -EPO?

- -EPO Dec: 2013, 2009, 2005, 1989, 1980, 1976

- neutral EPO Dec: 2010, 1995, 1966, 1956, 1955

- +EPO Dec: 1999, 1975, 1961, 1954

 So, Dec EPO was pretty balanced for strong -WPO Decembers

Monthly WPO:

https://psl.noaa.gov/data/correlation/wp.data

2 minutes ago, Coach McGuirk said:

More common than you think.  We do get snowstorms in southeaster VA.  It's feast or famine.  Last year was 1 in, 2 in, 2 in, 8.5 inches.  The previous two years were nothing.  We average 8 in a year.  We could be zero or 20 inches.  Nor'easters can drop 8-12 inches on us. 

I forgot to mention that there’s a dedicated thread for today’s storm. For documentation purposes, you may also want to post your results in there:

 Today here I just got an invigorating walk in with low 40s and just enough breeze to give it a nice bite. Today’s high of only 51 (normal is 65) means that every day so far this month has had a high only in the 50s. We already had had the first time in recorded history (back to 1874) of no high reaching 60 for Dec 1-7. Now it’s also the first time for that for Dec 1-8 and tomorrow is going to make it the first time for Dec 1-9!

 Rainfall so far this month is over 2”, which is way above the normal of 0.75” for Dec 1-9. For the first time since at least Thursday we had no rain.

8 minutes ago, Coach McGuirk said:

Storm dying out, probably end up with 6 inches.  But 6 inches that came out of nowhere is fine with me. 

How often has your area received 6” or more from a single storm?

For the record regarding the main indices for today’s wintry event:

- The prior -PNA rose to the more favorable neutral PNA (-0.1)

- AO -1.9, one day after a short-term minimum of -2.2 was hit

- NAO -1.2, one day after a short-term minimum of -1.3 was hit

- MJO likely was inside the circle phase 8 (probably won’t know for sure for a couple of days)

- +EPO

- -WPO

55 minutes ago, snowman19 said:

As I’ve learned and I’m sure many others have…..They are going with persistence forecasting, which is really not advisable at all. When you do that, you are just assuming that a pattern is going to continue and models are all wrong and are just going to keep correcting to cold without any end or breaks. Persistence forecasting works until it doesn’t. Those guys are basically saying “yea, the models have been wrong so far and the pattern hasn’t broken yet, so we are just going to keep forecasting the status quo (cold) indefinitely, no matter what the forcing may do, no matter what in the long wave pattern changes and no matter what the models may show, we don’t care”. Not only unprofessional for mets, but a very bad idea and if it fails, you totally lose credibility and trust 

Good points. But if there were a clearly identified long time model bias,  adjusting for that would obviously make sense.

22 minutes ago, MJO812 said:

The questions are whether or not and, if so, how long these same model misses will continue. It isn’t black and white. Nobody knows including you and me.

Today’s Euro Weeklies for week 3+ are still lacking cold domination to return to most of the E US south of the N tier with a solid -PNA dominating through mid Jan along with no -NAO or -AO. If this verifies, it would likely be pretty mild in much of the E US and nothing like we’ve been experiencing the last 2 weeks. However, models the last 3 weeks have been too warm in the E US with too much SER and missing much of the -NAO and -AO. Also, Midwest snowcover is well above avg, there’s the potential lag effects from the 11/28/25 SSWE, and the MJO remains favorable for E US cold. Are the weeklies/models finally getting their act together or are they going to continue with the same errors? Opinions?

 A big reason the models have been much too warm in the E US are the horrible NAO/AO progs with this one from just 11 days ago having it go + just 1 week later:

11/28 AO prog for today: ~+1

Today’s AO verified way down at ~-2 (strong -AO) meaning a +3 miss:

There was a similar big miss for the NAO:

11/28 NAO prog for today slightly positive (~+0.2):

Today’s NAO verified way down at -1.2 (strong -NAO), meaning a +1.4 miss:

 OTOH: The natural gas market, which is down sharply (6%) currently feels the prospects for a warmer pattern Dec 16th and beyond have increased. Check out the 0Z EPS HDD, which is on left chart, as it shows HDD plunging from mainly AN through 12/14 to BN 12/16-21 along with a trajectory suggesting more BN HDD (meaning warmer than normal E US). We’ll have to see whether or not this will finally verify well as the EPS has been too warm for the last 3 weeks as it has continually been correcting colder as the periods get closer:

1 hour ago, stadiumwave said:

 

Go look at all -QBO La Nina's that had any early strat warming (not full blown SSW). January is the coldest month with thise analogs unlike the +QBO LA Nina's that basically all end winter early JAN. No way to know if it shakes out that way but it is interesting nonetheless. 

 Related to this is the -PNA Dec to +PNA Jan transitions for -ENSO that have been happening during the last 40 year period. That transition has been strongest when the Dec -PNA was strongest. Examples of cold Jans were during these winters: 1983-4, 1984-5, 2008-9, 2010-1, 2013-4, and 2021-2 where Jan was cold though not always colder than Dec.

3 hours ago, MJO812 said:

The models have been correcting colder so far this month after showing warmth in the long range. I believe it will continue as along as the WPO stays negative. 

Look at the gefs correcting in the bottom imaging.  This month will end up being a cold month. Now hopefully snow will eventually come with it for areas near the coast. 

Indeed, and look at the trend of just the last 3 GEFS for 12Z on 12/18: E trough deepening/W ridge strengthening. It’s important to keep watching these trends as the models in general have been much too warm in the E US since the runs starting 3 weeks ago though at some point this trend is likely to end at least temporarily:

3 hours ago, Spartman said:

Jonathan Wall apparently bringing up 2001-2002 regarding the Phase 8 MJO

https://x.com/_jwall/status/1997672498993762417

I’ll give him the benefit of the doubt and assume he’s not counting weak phase 8 (inside circle). But even so, these had outside the circle phase 8 in Dec since 2001:

2017: 

2009:

2007:

2002:

@mitchnick

5 hours ago, yotaman said:

Forecasted high 54, actual high 45. Clouds hung tight. Low was 31.

 There’s no question that the CAD wedge has been the big winner in the SE US so far this month.

 My area has had almost every day mainly cloudy, rain on most days, and every day 12/1-7 has had highs only in the 50s! That’s very hard to do on every day for a week in early Dec with normal highs 10 degrees warmer. As a matter of fact, it’s so hard that this is the first time on record that it has happened with records going all of the way back to 1874!

 Interestingly, the highs have ticked down each day this month: 59, 58, 55, 54, 53, 52, and 50.

 I see that GSO has had all highs only in the 40s Dec 1-7. I wonder if that’s ever on record happened there. Anyone know?

Edit: If that’s not enough, the forecast is calling for 2 more days of 50s highs, which will make it Dec 1-9! Same idea for GSO with 2 more sub 50 highs for Dec 8-9!

 Edit: I just checked GSO. Only once on record back to 1903 did they have not get out of the 40s Dec 1-7: 1910. However, they did get to 50+ on Dec 9th, So based on the forecast, Dec 1-9th, 2025 will be the first on record not having even one day get out of the 40s at GSO!

 Which are y’all going with for Saturday’s (12/13) low? 
 
 The GFS sticks out as much colder than the others at ATL with upper teens there, which tells me it’s likely too cold there. It has had a cold bias over snowcover in recent years (which is well above average in the Midwest). That’s probably a factor as I don’t know that that has been fixed.

6Z GFS: pipe busting cold with upper teens ATL/RDU: likely too cold

0Z Euro: slower with the cold and thus is much warmer on Sat AM with upper 30s: likely too warm though it has 20s the subsequent few days

0Z ICON: mid 20s RDU to upper 20s ATL: looks like a reasonable middle-ground

0Z CMC: coldest at RDU with mid teens (CMC has a well-known cold bias) though only down to mid 20s ATL

0Z UKMET: only down to low 30s though it has a warm bias/very likely too warm though it is headed for 20s on Sunday