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Pattern December, Make analogs relevant again

Tarheel1 said:
I'm waiting for the" super Arctic outbreak coming, but coming into the Rockies and Southern Plains first, then it'll slowly bleed east " :(
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Just going to bring this back up!
 
how does one arrive at a single temperature and call that number the global temperature? what is the margin of error? doesnt most of the factors involved in averaging to get a single temp CHANGE during the time it takes to do the calculation?? my point is simple and true we do NOT have the ability to claim a single temperature for the whole globe to within the hundredths of a degree being claimed.....
 
Webberweather53 said:
Don, the 1C drop in temperature was a global average you can't just assume the same drop occurred everywhere including in the SE US without actually looking at the data which shows otherwise.
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Eric,
After the Pinatubo eruption, there was another eruption from Mount Hudson in Chile. Both of the eruptions decreased the mean world temp. by 1°c over the TWO YEARS which would be into 1992-93. The winter of 1992-'93 had below normal temp. anomalies.
429b879278b55bc3edb763a4a774d4c4.jpg


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Webberweather53 said:
Probable-likely not a coincidence... It's arguable that we may have observed a +AO in the winters that followed anyway because the multidecadal bgd signaling was very unfavorable for a -AO in the early-mid 1990s, but there's little-no doubt that the Pinatubo eruption gave a massive boost to the very strong +AO regime that was observed in this time period. As aforementioned, not every winter was a bust/dud even with a strong +AO, but the comprehensive character of the winter storms that affected NC from 1990-95 definitely seemed to change with (aside from the March 1993 superstorm) a plethora of CAD/ice events relative to Miller As, as one would expect from the relationships between a +AO/+NAO - North Pacific blocking (-EPO/-WPO) couplet and the synoptic scale pattern that accompanies it over North America. (North Pacific block seeds troughs over south-central Canada and the northern tier w/ arctic and siberian air, big cold highs follow in their wake, and the NP blocking aids in forcing a ridge over or off the SE US coast which induces broad/moist southwesterly flow that overruns the cold domes that settle over the SE US in association w/ these cold highs leading to CAD.)
Significant ice storms were observed on December 27-28 1992, December 28-29 1993, February 10-11 1994, & February 1995. I recently analyzed the December 1993 event and the map is shown below

View attachment 1593
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Had a nice little snowstorm on December 22-23, 1993. It began in the late afternoon and continued throughout the night. I measured around three inches of snow. The neighborhood was absolutely beautiful that night with the falling snow and Christmas lights.
 
WeatherWatch said:
Eric,
After the Pinatubo eruption, there was another eruption from Mount Hudson in Chile. Both of the eruptions decreased the mean world temp. by 1°c over the TWO YEARS which would be into 1992-93. The winter of 1992-'93 had below normal temp. anomalies.
429b879278b55bc3edb763a4a774d4c4.jpg


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Don, for the umpteenth time, yes everyone already knows the global temperature fell after these volcanic eruptions by 1-2C, but that's not the topic of this discussion/argument. The temperature anomalies are skewed warmer in the US after major tropical eruptions because the tropical volcanic eruptions increase the strength of the wintertime polar vortex, but like I said in a previous post (which you apparently didn't read), a +AO/NAO doesnt automatically mean the winter will be warm, but if you attain a large sample size of events, the overall collective body of winters will end up being warmer... Showing a sample size of 2 winters here w/ a colder than normal US doesn't negate my initial argument that tropical volcanoes skew the probabilities for temps to be AN here...

Note the stronger than normal low-level vortex (as indicated by the -SPLAs over the arctic) in DJFM immediately following the top 5 strongest volcanic eruptions since 1880.
eluEltddUy.png
 
Eric said:
Had a nice little snowstorm on December 22-23, 1993. It began in the late afternoon and continued throughout the night. I measured around three inches of snow. The neighborhood was absolutely beautiful that night with the falling snow and Christmas lights.
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Yep it was a nice snowstorm that occurred right before Christmas Eve. Here's the snow accumulation map I constructed for the event...
December 22-24 1993 NC Snowmap.png
 
Webberweather53 said:
Yep it was a nice snowstorm that occurred right before Christmas Eve. Here's the snow accumulation map I constructed for the event...
View attachment 1613
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We got 2” of snow where I grew up in Eastman GA. That’s about 60 miles south of Macon. It was shocking because no one that day was calling for anything but rain that day.


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Webberweather53 said:
Don, for the umpteenth time, yes everyone already knows the global temperature fell after these volcanic eruptions by 1-2C, but that's not the topic of this discussion/argument. The temperature anomalies are skewed warmer in the US after major tropical eruptions because the tropical volcanic eruptions increase the strength of the wintertime polar vortex, but like I said in a previous post (which you apparently didn't read), a +AO/NAO doesnt automatically mean the winter will be warm, but if you attain a large sample size of events, the overall collective body of winters will end up being warmer... Showing a sample size of 2 winters here w/ a colder than normal US doesn't negate my initial argument that tropical volcanoes skew the probabilities for temps to be AN here...

Note the stronger than normal low-level vortex (as indicated by the -SPLAs over the arctic) in DJFM immediately following the top 5 strongest volcanic eruptions since 1880.
View attachment 1612
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Okay, carry on.

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whatalife said:
We got 2” of snow where I grew up in Eastman GA. That’s about 60 miles south of Macon. It was shocking because no one that day was calling for anything but rain that day.


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That's insane especially considering it never snows there period lol. Idk it's not as bad of a bust as November 2014 was when they called for rain mixed with snow showers no accumulation and u get 4 inches lmao (granted that forecast was hard af and the snow was more localized vs December 1993)
 
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In essence what he's saying is it's all connected in some way shape or form. More technically, momentum flux convergence associated with equatorward wave propagation peturbs the upper level winds and static stability of the tropics and subtropics and can serve as triggers for convective complexes that can sometimes serve as the impetus for a new MJO pulse as these convective centers grow upscale. Then of course the heat generated by these growing convective complexes can serve as an effective "wave source" that modulates the placement, intensity, longevity, & evolution of Rossby Wave Trains over the mid latitudes which then can impact the tropical convection thru cold surges, momentum deposition into the subtropics and tropics (among other things). There's definitely a lot of two way interaction that goes on behind the scences of the popular and classical one way MJO >>> extratropics view that's expressed in operational forecasting and blogosphere setting. Paul Roundys paper on tropical-extratropical interactions is a good place to start filling your head with these 2 way processes which are important to understanding the evolution and prediction of weather and climate variability ranging from scales of several days to a year or more...
http://www.atmos.albany.edu/facstaff/roundy/convection/Walich14.pdf
 
Lord have mercy; a day doing work and not being able to get on a computer, then to come here after hours and see all of this. Wonderful stuff; it'll be "old news" before perusing it all ... Thanks for the info everyone is providing, and special Kudos to Larry for his apparent Frosty the Snowman magic hat by starting this thread ... :p
 
Webberweather53 said:
View attachment 1614

In essence what he's saying is it's all connected in some way shape or form. More technically, momentum flux convergence associated with equatorward wave propagation peturbs the upper level winds and static stability of the tropics and subtropics and can serve as triggers for convective complexes that can sometimes serve as the impetus for a new MJO pulse as these convective centers grow upscale. Then of course the heat generated by these growing convective complexes can serve as an effective "wave source" that modulates the placement, intensity, longevity, & evolution of Rossby Wave Trains over the mid latitudes which then can impact the tropical convection thru cold surges, momentum deposition into the subtropics and tropics (among other things). There's definitely a lot of two way interaction that goes on behind the scences of the popular and classical one way MJO >>> extratropics view that's expressed in operational forecasting and blogosphere setting. Paul Roundys paper on tropical-extratropical interactions is a good place to start filling your head with these 2 way processes which are important to understanding the evolution and prediction of weather and climate variability ranging from scales of several days to a year or more...
http://www.atmos.albany.edu/facstaff/roundy/convection/Walich14.pdf
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Of course it's worth mentioning that the highest source of uncertainty and unpredictability in all this stems from latent heating in the tropical convective centers and warm conveyor belts of extratropical cyclones. It makes sense, as I'm sure many of you can attest to the predictability of even stereotypical afternoon cumulonimbus convection on a hot summers day, it's rarely known when, where, to what extent, and how large/intense said thunderstorm will become and often times even on days where little activity is expected a complex of storms can develop over your house and put a damper on your day. Similarly, while convection is a second order process on the synoptic-planetary scale, errors attributable to not accurately paramterizing convection and the heat associated with it (esp in the tropics) grows upscale quickly and is likely where most of the error in LR model forecasts ultimately stem from. Thus, it's not a bad idea to usually assume when a model busts even inside the short-medium range, (as was true in the January 2000 Carolina Crusher) a model's piss poor handling of convective heating is often a primary culprit.
 
Webberweather53 said:
Of course it's worth mentioning that the highest source of uncertainty and unpredictability in all this stems from latent heating in the tropical convective centers and warm conveyor belts of extratropical cyclones. It makes sense, as I'm sure many of you can attest to the predictability of even stereotypical afternoon cumulonimbus convection on a hot summers day, it's rarely known when, where, to what extent, and how large/intense said thunderstorm will become and often times even on days where little activity is expected a complex of storms can develop over your house and put a damper on your day. Similarly, while convection is a second order process on the synoptic-planetary scale, errors attributable to not accurately paramterizing convection and the heat associated with it (esp in the tropics) grows upscale quickly and is likely where most of the error in LR model forecasts ultimately stem from. Thus, it's not a bad idea to usually assume when a model busts even inside the short-medium range, (as was true in the January 2000 Carolina Crusher) a model's piss poor handling of convective heating is often a primary culprit.
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Webb,
The thunderstorm analogy is superb ...
Phil
 
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