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Pattern December, Make analogs relevant again

Holy cow, there's a lot of wishing going on ... let's wait and see before there is a need for Jon to start dispensing heart meds ...
 
Tarheel1 said:
Yep, can get big storms during pattern changes, usually liquid though, as pattern changes to cold.
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The precip starts as a very cold rain, then changing to ZR/sleet then snow as the colder air progresses southward.

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pcbjr said:
Holy cow, there's a lot of wishing going on ... let's wait and see before there is a need for Jon to start dispensing heart meds ...
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Phil!!!! No one on this board would ever wishcast or would they


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whatalife said:
Phil!!!! No one on this board would ever wishcast or would they


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I never said "wishcast" ;); only "wishing" (wishing with fervor; and waiting here to see if the fervor is deserved or if it's the recipe for a board-wide Rx dispensary ... LOL) ... :confused:
 
pcbjr said:
I never said "wishcast" ;); only "wishing" (wishing with fervor; and waiting here to see if the fervor is deserved or if it's the recipe for a board-wide Rx dispensary ... LOL) ... :confused:
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I know...I just thought I’d throw that in for good measure


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pcbjr said:
I never said "wishcast" ;); only "wishing" (wishing with fervor; and waiting here to see if the fervor is deserved or if it's the recipe for a board-wide Rx dispensary ... LOL) ... :confused:
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Phil,
I'm about as confident as I can possibly be 10 days out for a change to much colder for much of the E and central US based on VERY consistent and near 100% agreement in the modeling moving it closer with practically each and every run. Model consensus like this for a change 10 days out for several days of runs is rarely stronger than this. The consistency of models predicting a strong -AO/-NAO/+PNA is a factor in the confidence.

The parts that can't be predicted well at this stage is how severe, if severe at all, the cold will get in the SE US, how long it will last, and whether or not a good portion (or any) of the SE US will get significant wintry precip associated with this colder pattern. However, QBO/ENSO/AO analogs combined with the look of the models tell me that a long and severe cold period is quite possible in Dec after the first week.

Predicting wintry precip is always very difficult thus far out especially. I hardly pay any attention to modeled storms this far out. The chance of at least light wintry precip at some point in at least some of the favored areas is high, however, based on the history of cold outbreaks like this. Of course, that could end up meaning just some of the mountains and nothing major but that's about the worst case scenario.
 
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whatalife said:
I know...I just thought I’d throw that in for good measure

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GaWx said:
Phil,
I'm about as confident as I can possibly be 10 days out for a change to much colder for much of the E and central US based on VERY consistent and near 100% agreement in the modeling moving it closer with practically each and every run. Model consensus like this for a change 10 days out for several days of runs is rarely stronger than this. The consistency of models predicting a strong -AO/-NAO/+PNA is a factor in the confidence.

The part that can't be predicted well at all is whether or not a good portion (or any) of the SE US will get significant wintry precip associated with this colder pattern. The chance of at least light wintry precip at some point in favored areas is high, however.
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Guys,
Please understand - I meant nothing negative. Just an observation about emotions.
All on board here. Heck, yours truly has been pushing and posting about a change to cold for weeks. I'll see something accumulate someday (maybe even this year again); but I've got no horse in this race (yet), and I'm really, really hoping that whatever happens in Gainesville this season, folks north of here get a good slam not once but 3, 4 or 5 times this winter.
My point was ... and is ... don't get hyped ... yet.
Wish I could do this vocally, since the thought probably does not come across well in this format. :oops:
Best!
Phil
 
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Exactly. Been burned too much in recent years to get hopes up on 300hr projections. I'm not diving into the deep end till we see something notable materialize in hr 192 or closer. Until then, I am hedging on dumpster fire December. At least then I won't be AS disappointed when nothing wintry happens.
 
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gfs_T2m_us_46.png
New gfs COLD!!! Nice blocking, and exciting times ahead
 
So the GFS is the only model showing this blockbuster potential pattern? Or because we are at the 11-15 day period on GFS , the Euro can't pick it up yet?
 
I’m starting to get excited about middle and late December with what everyone is posting. Would love to get some snow sometime next month or at least have something to track!
 
Webberweather53 said:
Euro ensemble is already advertising -3 to -6C 850 temp anomalies across the SE US & keep in mind this model has a warm bias (overall) in the extended range... Insanity.
View attachment 1590
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The worrisome part is, I think those colors/ anomalies for Thanksgiving and about a week later!?
 
Webberweather53 said:
Mount Agung rn... Hopefully the eruption is either too small or too late to substantially (negatively) impact the upcoming winter
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If it big enough to have a negative impact, hopefully it won't affect the first half much since we both are expecting a front loaded winter. And regardless, hopefully this will lead to at least some global cooling for the short term and stop the rising seas for now.
 
GaWx said:
No more dilly dallying, it is about time the December thread get created. In honor of, inspired by, and with permission from Mack, lover of analogs, here is the December thread and the first monthly I've ever done here. Model consensus is ecstatic about a pattern change starting around 12/7 to give the SE and much of the E US a dreamy cold (likely ending the nearly 2 year long warmer than normal months streak at KSAV) and potentially wintry pattern. QBO/ENSO/Nov AO analogs are suggesting a cold to possibly very cold December once past the first week. The top two Dec analogs I found were 1962 and 2000, with 2000 in first place.

Analogs have struggled in recent years as Mack loves to remind me and tease me about and for good reason. Now it is time for analogs to become relevant again. Let's do this!
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I can only offer this....the Moles came back last time with tattoos that say Sleet for a Week! I'm ready for some blocking gone crazy, and some cold air locked in with repeating shots of reinforcement :) We got a White Xmas, so a week of sleet seems doable :) Tony
 
dsaur said:
I can only offer this....the Moles came back last time with tattoos that say Sleet for a Week! I'm ready for some blocking gone crazy, and some cold air locked in with repeating shots of reinforcement :) We got a White Xmas, so a week of sleet seems doable :) Tony
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Tony,
If they only understood what you and I say ... :eek:
Best,
Phil

... assuming, of course, we do ourselves ... :p
 
pcbjr said:
Tony,
If they only understood what you and I say ... :eek:
Best,
Phil

... assuming, of course, we do ourselves ... :p
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Oh, it's ok, Phil, we don't know what we are saying either, lol. Climo says no, but analoges have a way of beating climo from time to time. I never even hope for much down here until after Xmas, but I was doing an art show every Nov. in Pensacola in the 80's, in late Nov, and inevitably a cold blast would come down thru Texas...... and one time I was in a pretty good sleet storm set up in down town Pensacola, lol. Ya takes yer pleasures where ye finds 'em :)
 
dsaur said:
I can only offer this....the Moles came back last time with tattoos that say Sleet for a Week! I'm ready for some blocking gone crazy, and some cold air locked in with repeating shots of reinforcement :) We got a White Xmas, so a week of sleet seems doable :) Tony
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Tony,
If it can sleet multiple inches in the ATL area during a moderate La Niña like occurred during Dec of 1917, then by golly it can do that all over again exactly 100 years later in a weak to moderate Niña.
 
Sometimes a shallow layer of bitter air sets up west of the spine of the Apps, and won't push over completely, and impulses will come down and feed in sleet for days and days all the way back into Texas from Memphis. We had a smaller version for a few days a couple of years ago, but one I remember many years back lasted at least a week, with zr and sleet, impulse after impulse. Piling up big time. I've always wanted to see such a set up with highs also moving down into cad position so both sides of the mountains are damming at the same time, with sleet from Sav to Galveston over and over until I don't care it I ever get to sled again, lol. And it's ok for the zr to mix in as long as it just coats the sleet base, and doesn't tear down all the phone poles making street sledding a dangerous proposition, having to dodge all the bouncing power lines, lol. Get a cut off back in the west spitting out impulses over and over, while shallow bitter air is reinforced with some cad in here. I've seen some stuff, and this is what I'd like to see next :)
 
GaWx said:
Tony,
If it can sleet multiple inches in the ATL area during a moderate La Niña like occurred during Dec of 1917, then by golly it can do that all over again exactly 100 years later in a weak to moderate Niña.
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It's rare, Larry, but what makes it rare is it does happen, lol. I am hoping for another great Sav call this year. Are you back there now?
 
dsaur said:
It's rare, Larry, but what makes it rare is it does happen, lol. I am hoping for another great Sav call this year. Are you back there now?
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Yes I am. So, just as the moles and you want your week of sleet (I love that the moles are so devoted to try to get you a weeklong sleet...that's fantastic), I want my near miracle. I tell
myself that if it can snow here multiple inches in cold neutral winters like 1989-90 and 1967-8, then by golly it can snow multiple inches in a weak to mod La Niña!
 
BHS1975 said:
Looks like a nice little mini torch around the 7th.


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Mini torch? There is no such thing. Yes, the temps will be above avg. but not significantly above avg. for most. It will warm some ahead of a cold front, but most places won't warm to 70/80° across the SE (except for the Gulf coast and FL.)

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Brent said:
I thought a volcanic eruption made the winter colder???

and the other seasons colder in general
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Nope, exactly the opposite. As I discussed on this forum a month or two ago, while the release of sulfuric aerosols into the stratosphere actually cools the troposphere, at and above the level where these aerosols are temporarily deposited in the stratosphere, it warms as incoming solar radiation and terrestrial radiation emitted from earth's surface are absorbed. If the volcanic eruption occurs in the tropics, this also means the tropical stratosphere warms in response and warms more significantly than the polar regions. The warming of the tropical stratosphere relative to the polar stratosphere steepens the meridional temperature gradient between the poles and the tropics which strengthens the mid latitude westerlies (due to thermal wind relation), the stronger westerlies imply the polar vortex (and thus northern annular mode) is more intense, and these anomalies propagate down into the troposphere over the course of the winter, enticing the tropospheric AO/NAO to become strongly positive, which significantly increases the probability for a warmer winter here in the east-central US. The impact of tropical volcanic eruptions on the polar vortex can linger for several years as stratospheric aerosols released by the eruption also liberate chlorine ions which destroy ozone in the tropical stratosphere. As this ozone is transported poleward via the Brewer-Dobson Circulation over the years that follow, less ozone reaches the polar stratosphere, which forces a net cooling of the polar stratosphere, which again steepens the meridional temperature gradient and thus increases the strength of the mid latitude westerly jet stream and attendant polar vortex in the longer term, indicative of a +AO/NAO.

From Robock (2000)...
http://climate.envsci.rutgers.edu/pdf/ROG2000.pdf
"The radiative and chemical effects of this aerosol cloud produce responses in the climate system. By scattering some solar radiation back to space, the aerosols cool the surface, but by absorbing both solar and terrestrial radiation, the aerosol layer heats the stratosphere. For a tropical eruption this heating is larger in the tropics than in the high latitudes, producing an enhanced pole-to-equator temperature gradient, especially in winter. In the Northern Hemisphere winter this enhanced gradient produces a stronger polar vortex, and this stronger jet stream produces a characteristic stationary wave pattern of tropospheric circulation, resulting in winter warming of Northern Hemisphere continents. This indirect advective effect on temperature is stronger than the radiative cooling effect that dominates at lower latitudes and in the summer."
 
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