• Hello, please take a minute to check out our awesome content, contributed by the wonderful members of our community. We hope you'll add your own thoughts and opinions by making a free account!

Pattern December - Deal or No Deal?

For those who aren’t optimistic
about a drastically colder pattern change being likely in the first half of Jan, check this blog post I did 2 years ago on the various MJO phases’ correlation to the SE US temps in Jan of 1975-2014, which could be extended to apply to much of winter including late Dec:

https://blog.southernwx.com/2017/01...phase-inside-the-left-side-of-circle-coldest/

Concentrate on the diagram that shows that the warmest by far has been when the MJO was clearly outside the circle in phase 4 (+3) and especially outside the circle in phase 5 (+6). Now look at the current and forecasted MJO courtesy of the great site of @DaculaWeather as it shows we’re in strong phase 4 and are headed toward a long visit into strong phase 5 for the next 2 weeks or so:

http://www.daculaweather.com/4_mjo_phase_forecast.php#thumb


So, the upcoming warmth is about as well explained by the MJO as ever. This is textbook MJO related warmth! But the MJO will subsequently
move out of strong phase 5. Note on my blog diagram how much colder it has gotten as you leave outside the circle phase 5 to go anywhere including just into phase 6. Then look how much colder it has gotten on average, especially when it has rotated toward the weaker portion of the left side of the circle: -4 within weak phase 7 and -6 within weak phase 8 followed by a still cold -3 in weak phases 1-3! And remember that these are just averages as a good number of memorable extreme cold periods were included. When also considering we’re in a west based borderline weak/moderate Niño that followed La Niña and when considering past Euro seasonals (as well as the Pioneer lol), I feel confident we will be sitting pretty by no later than mid-Jan.
 
Last edited:
Storm5 said:
It’s that time of year when people go crazy and say things like maybe February it will turn around . It’s like clockwork every year


Sent from my iPhone using Tapatalk
Click to expand...
It's hilarious, isn't it? Forgetting that our forecasts aren't good enough to just think the next 6 weeks are a wash.

In other news, Christmas Day looks to be shaping up to be dry and seasonable across our area. And seasonable is a win.
 
Storm5 said:
It’s that time of year when people go crazy and say things like maybe February it will turn around . It’s like clockwork every year


Sent from my iPhone using Tapatalk
Click to expand...
Lol yep. Usually they are the ones who jump off the cliff 4 days from a snowstorm and climb up for the good runs and jump back down for the bad ones. We are still early into the season so worrying won't do any good especially if it's over a week or two away, since models will change.
 
deltadog03 said:
Correct me if I'm wrong, but the research that Webb, Larry and others, have presented on here suggested that typically nino winter's start off a blaze right? Heck I think December has been all good so far. Hell I call it a bonus??
Click to expand...

Typically with a weak-to-moderate Nino we have a cool Nov, warmish Dec and then cold Jan/Feb.
 
NoSnowATL said:
View attachment 9267View attachment 9267 More positive signals...
Click to expand...

Oh no he didn't...he just brought February 2004 legitimately into the discussion. Nobody better talk nuthin about my February 2004. I love the 2004. lol. It was a southern stream nino and yeah it was cold. If any year can do it I guess it would be this one. Hope so.
 
I don’t know about the actual pattern but going back and looking at the temps for here in December 2009 and it’s very similar, started out a bit cold, then got warmed up to around average. We know how that winter ended up for us in the Deep South.
 
Finally, here comes the much advertised unicorn...uhhh.....I mean strat. warming:

http://www.cpc.ncep.noaa.gov/produc...gif_files/time_pres_TEMP_ANOM_OND_NH_2018.png

Note the yellows (+4 to +8) on the far right. But the question is how much warmer it will suddenly get. For it to be comparable with past major warmings, it will need to warm well into the reds and preferably into the brown (+28 to +32) within a week or so and better yet into the not shown gray (over +32). Thank goodness we don't have to rely on this unreliable item for cold to return as we already have the weakish (west based) Nino, which will be helped once the MJO rotates out to the left. But who knows? Maybe if this turns out to be very strong it will help get the -AO to return in earnest next month.

PS: One thing I read is that this is more of a reliable cold inducer in Europe than here.

Hee is an example of a very strong SSW from Dec of 2003 on far right of this chart: http://www.cpc.ncep.noaa.gov/produc...gif_files/time_pres_TEMP_ANOM_ALL_NH_2003.gif
 
Last edited:
Maybe some light at the very end of the FV3 tunnel. It's a long tunnel, though. Hopefully, it holds.
 
deltadog03 said:
Correct me if I'm wrong, but the research that Webb, Larry and others, have presented on here suggested that typically nino winter's start off a blaze right? Heck I think December has been all good so far. Hell I call it a bonus??
Click to expand...

From Radiant this morning from a national standpoint:

"Warm Dec. 2nd Half Progressed Forward

The second half of December is shaping up to be an impressively warm one, with the current forecast of 408.4 GWHDDs for the Dec. 16-31 period ranking 8th-warmest since 1950. Whenever we see anomalous patterns such as this crop up in winter, the question often becomes whether such a pattern might carry on further through the season. Here we take a look at what the previous Top 15 warmest December 16-31 looked like pushed forward into the rest of winter. The composite of these fifteen years yields 1764 GWHDDs for the Jan-Feb period, colder than the 30-year normal (1731.2). Of these fifteen years, ten were above the 30-year normal for Jan-Feb including three in the Top 15 coldest (coldest is #5 1985), while five were below the 30-year normal including two of the Top 5 warmest (warmest is #4 2006). The smaller five-year subset of these years that featured a weak or moderate El Niño (2007, 1995, 2015, 1980, and 2003) yielded a higher 1818.8 GWHDD total for Jan-Feb, with four of the five yielding above normal GWHDDs. Among the weak/moderate El Niño cases, cold was most prevalent in February—the January composite for these years is 942.2 GWHDDs, warmer than the 30-year normal (952.1) while the February composite for these years is 876.6 GWHDDs, much colder than the 30-year normal (779.1) including four of the five ranking in the Top 12 coldest Februarys since 1950."
---------------------------------------------------

My comments: Remember that Feb has 3 fewer days than Jan. So, 876.6 HDD in Feb would be comparable to 971 HDD if it were 31 days long like Jan. So, you essentially have a 971 Feb vs 942 Jan, and Feb is normally about 90 HDD warmer than Jan. Also, keep in mind that the first 1/3 of Jan may still be warm in the E US meaning the last 2/3 would likely be cold to balance it out.
The maps Radiant showed have all of the cold centered in the E 1/3 of the US with a warm western 1/3. So, the E US cold anomalies are much stronger than the national #s suggest. When considering warmth likely carrying over into early Jan in the E US, essentially Radiant is saying be prepared for a good chance for the freezer to dominate in the SE US much of ~1/10-2/28. We'll see! I already stated that I like the chances assuming the MJO will rotate to the left side sometime in the first half of next month, especially if weak then.
 
Last edited:
RollTide18 said:
I don’t know about the actual pattern but going back and looking at the temps for here in December 2009 and it’s very similar, started out a bit cold, then got warmed up to around average. We know how that winter ended up for us in the Deep South.
Click to expand...
That was a great winter
 
That area of wintry weather for CAD areas is showing up on fv3 again. And that’s a strong 1040 high. Could trend colder


Sent from my iPhone using Tapatalk
 
GaWx said:
From Radiant this morning from a national standpoint:

"Warm Dec. 2nd Half Progressed Forward

The second half of December is shaping up to be an impressively warm one, with the current forecast of 408.4 GWHDDs for the Dec. 16-31 period ranking 8th-warmest since 1950. Whenever we see anomalous patterns such as this crop up in winter, the question often becomes whether such a pattern might carry on further through the season. Here we take a look at what the previous Top 15 warmest December 16-31 looked like pushed forward into the rest of winter. The composite of these fifteen years yields 1764 GWHDDs for the Jan-Feb period, colder than the 30-year normal (1731.2). Of these fifteen years, ten were above the 30-year normal for Jan-Feb including three in the Top 15 coldest (coldest is #5 1985), while five were below the 30-year normal including two of the Top 5 warmest (warmest is #4 2006). The smaller five-year subset of these years that featured a weak or moderate El Niño (2007, 1995, 2015, 1980, and 2003) yielded a higher 1818.8 GWHDD total for Jan-Feb, with four of the five yielding above normal GWHDDs. Among the weak/moderate El Niño cases, cold was most prevalent in February—the January composite for these years is 942.2 GWHDDs, warmer than the 30-year normal (952.1) while the February composite for these years is 876.6 GWHDDs, much colder than the 30-year normal (779.1) including four of the five ranking in the Top 12 coldest Februarys since 1950."
---------------------------------------------------

My comments: Remember that Feb has 3 fewer days than Jan. So, 876.6 HDD in Feb would be comparable to 971 HDD if it were 31 days long like Jan. So, you essentially have a 971 Feb vs 942 Jan, and Feb is normally about 90 HDD warmer than Jan. Also, keep in mind that the first 1/3 of Jan may still be warm in the E US meaning the last 2/3 would likely be cold to balance it out.
The maps Radiant showed have all of the cold centered in the E 1/3 of the US with a warm western 1/3. So, the E US cold anomalies are much stronger than the national #s suggest. When considering warmth likely carrying over into early Jan in the E US, essentially Radiant is saying be prepared for a good chance for the freezer to dominate in the SE US much of ~1/10-2/28. We'll see! I already stated that I like the chances assuming the MJO will rotate to the left side sometime in the first half of next month, especially if weak then.
Click to expand...

I'm going to take this Radiant piece further and look at KATL as a proxy for the SE:

So, they said the 5 wk to mod Nino warm 12/16-31 analogs for Jan-Feb are 1980, 1995, 2003, 2007, and 2015. Here are the Jan/Feb KATL anomalies during those 5 years (no blowtorches though some slightly warmer than normal Jans) along with MJO:

Jans:
1980 +1.6: MJO neutral
1995 +3.0: MJO unfavorable
2003 -3.3: MJO favorable.. coldest 8 F!
2007 +2.8: MJO unfavorable
2015 -0.2: MJO neutral

Febs;
1980 -5.3: MJO favorable....1.7" SN
1995 -0.8: MJO unfavorable
2003 -0.8: MJO neutral
2007 -1.9: MJO neutral
2015 -6.8: MJO favorable....lots of wintry in frigid 2nd half just N of ATL

So, what's the common denominator for cold and potentially wintry? A favorable MJO! By far, the 3 coldest months were the bolded ones with favorable MJO dominating while the warmest had unfavorable. Where exactly was the MJO for these 3 coldest months?

- Feb of 1980 (green line):
http://www.bom.gov.au/climate/mjo/graphics/archive/MJO_phase/198001.phase.90days.gif.small.gif

Note that the frigid and snowy part of the month was the first half, when the MJO was either inside or barely outside the circle in phases 7 and 8.


- Jan of 2003 (red line):
http://www.bom.gov.au/climate/mjo/graphics/archive/MJO_phase/200301.phase.90days.gif.small.gif

Note that the coldest part of the month was the 2nd half, when the MJO was inside or barely outside the left half of the circle.


- Feb of 2015 (green line):
http://www.bom.gov.au/climate/mjo/graphics/archive/MJO_phase/201501.phase.90days.gif.small.gif

Note that the coldest and wintriest part of the month was the 2nd half, when the MJO was mainly inside the left half of the circle.
 
Last edited:
ATLwxfan said:
Time for the January thread. I think it’s 4th and long and we are in punt formation.


Sent from my iPhone using Tapatalk
Click to expand...
I really don’t understand how we punt a month that never really produces much snow in the south anyways. Since we are using football terms, punting December is kind of like a team punting on 2nd down the whole game because they figure they won’t get any first downs anyways. Expecting a big snow in the south during December is kind of like expecting the bengals to have a wining record by December. Sure it could happen but you are going to be very disappointed most years.
 
olhausen said:
I really don’t understand how we punt a month that never really produces much snow in the south anyways. Since we are using football terms, punting December is kind of like a team punting on 2nd down the whole game because they figure they won’t get any first downs anyways. Expecting a big snow in the south during December is kind of like expecting the bengals to have a wining record by December. Sure it could happen but you are going to be very disappointed most years.
Click to expand...
For a month that supposedly is not great in the south, December sure has delivered the last 2 years. 2 historic December storms.
 
You must log in or register to reply here.
Back
Top