NoSnowATL
Member
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Pattern The Great December Dump
- Thread starter Rain Cold
- Start date
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The last 9 Decembers have been AN at KATL. However, the following Jans were AN only 4 of those 9 times with 2 of those times BN. If folks like Webb have reason to think Jan won't be mild, there's no reason to not believe that right now.
Also, consider these facts about KATL, which went from:
- a mild 48.1 in Dec of 2013 way down to a very cold 37.0 in Jan of 2014
- a mild 50.0 in Dec of 2014 down to a normal 43.1 in Jan of 2015
- the warmest on record Dec of 2015 57.6 way down to a normal 42.2 in Jan of 2016
- a slightly AN 46.8 in Dec of 2017 down to a cold 40.4 in Dec of 2018, which included a very cold first 18 days
So, 4 of the last 6 Decs cooled significantly from AN Decs to near normal or colder Jans.
Also, consider these facts about KATL, which went from:
- a mild 48.1 in Dec of 2013 way down to a very cold 37.0 in Jan of 2014
- a mild 50.0 in Dec of 2014 down to a normal 43.1 in Jan of 2015
- the warmest on record Dec of 2015 57.6 way down to a normal 42.2 in Jan of 2016
- a slightly AN 46.8 in Dec of 2017 down to a cold 40.4 in Dec of 2018, which included a very cold first 18 days
So, 4 of the last 6 Decs cooled significantly from AN Decs to near normal or colder Jans.
Where are you seeing the cold ? I see lots of warmth in FL.
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A near normal Jan in the SE that is wet could easily support a major winter storm...well, even if it weren't wet for that matter.
A near normal January is a pretty cold month and would be way colder than this month.
pcbjr
Member
Who cares ... LOL
If you look closely, that map has @pcbjr at only a 50% chance for a mild Jan. That is very far from a lock at a mild month there even per NOAA. I think Phil knows better.
pcbjr
Member
Not giving up on January ... not yet anyways ...
Mr. Golf
Member
Larry, you think because its a blip or is it picking up on the +AAM?
There's no reason for you to. Why would you now? You never expected a cold December in the first place.
I'm hoping it is the +AAM.
Mr. Golf
Member
I will always put more stock in the eps over gefs anyday right or wrong. Btw, where can i access AAM charts or forecasts?
Unfortunately, I don't know of any public links. For some reason, this one is super secret lol and only private services have this??
Mr. Golf
Member
You only get the AAM from maxar im assuming? I think weatherbell may have it. MYbe.
Joe's Index Shop has it. I've never heard much talk about it before this year, but it seems like it's pretty important.
I don't know what site this is, or how to get it, but I saw Webb and HM post this type of chart that has an AAM graph. If you can find the source of this, let me know.
Mr. Golf
Member
Rain, the only thing it pulled up is index for stock shareholder trading lol. I think the lack of coupling between the ocean and atmosphere isnt good. If you have a link, it would be appreciated.
Mr. Golf
Member
Figuratively speaking if the eps is correct about the AAM going positive, would it still take a while to reflect onto the models?
Webberweather53
Meteorologist
This is far from being the best pattern in the world but I think many of us will take it over raging warmth. EPS evolution in the 11-15 makes more sense than the GEFS showing a stationary SW US trough & is more consistent w/ what we've seen the last several weeks w/ SW US troughiness in the longer term means but these troughs eventually sliding east & evolving into bowling ball cut-off ULLs that run into seasonable air masses further east.
For most of us, our climo will continue to cool off another 3F or so & by this point in early January we'll be near peak climo temperature wise. It's the type of pattern that's generally capable of being just cold enough if the timing of the waves is right, to produce wintry weather for the I-40 corridor (OK/AR/TN/NC). Severe weather is also a legitimate possibility again depending on wave timing. Regardless, our active southern jet will remain so for the foreseeable future & arguably will become even more active in the coming weeks as the West Pac tropical forcing reasserts itself & superimposes onto the increasingly NINO base state.
On a scale of 0-10 in terms of favorability for wintry weather, this kind of pattern is roughly a 4-5 imo. If we can get a nice -EPO & big SE Canada vortex at some point down the road that will obviously increase dramatically towards at least an 8.5-9 because deeper & colder air masses will become more readily available in said pattern.
For most of us, our climo will continue to cool off another 3F or so & by this point in early January we'll be near peak climo temperature wise. It's the type of pattern that's generally capable of being just cold enough if the timing of the waves is right, to produce wintry weather for the I-40 corridor (OK/AR/TN/NC). Severe weather is also a legitimate possibility again depending on wave timing. Regardless, our active southern jet will remain so for the foreseeable future & arguably will become even more active in the coming weeks as the West Pac tropical forcing reasserts itself & superimposes onto the increasingly NINO base state.
On a scale of 0-10 in terms of favorability for wintry weather, this kind of pattern is roughly a 4-5 imo. If we can get a nice -EPO & big SE Canada vortex at some point down the road that will obviously increase dramatically towards at least an 8.5-9 because deeper & colder air masses will become more readily available in said pattern.
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Mr. Golf
Member
Webber, do you think models would trend better if this +AAM is realized? Or woukd it not make much difference? Just curious.
Webberweather53
Meteorologist
The curators of this data have basically locked it up except to a few select individuals. I know the individual who makes or provides said graph so I can ask for access if need be & provide an updated version of this.
Luckily, Ventrice has provided a similar graphic (although not the same because it only shows 250mb winds while the AAM graphic like the one above integrates through the entire troposphere). Very strong but equatorward displaced jet stream in the NH will be the name of the game going forward. Seeing -AAM/negative zonal wind (easterly) anomalies (in blue) near 60N is indicative of a pattern that's favorable for polar blocking (-AO/NAO), (obviously there's more that goes into polar blocking than that). Curious to see if we get some +AAM build-up in the tropics later though.
