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Wintry January 3rd-6th, 2018 Winter Storm The ARCC/Xtreme Weather Special

Snowfan said:
gfs_mslp_pcpn_frzn_us_23.png

Late bloomer.
Click to expand...
Pure fantasy ...
 
There is no reason for this thing to come North, as it looks at H5 guys. The NW trend... no way no way. Webb explained it perfectly above.
 
Shawn said:
There is no reason for this thing to come North, as it looks at H5 guys. The NW trend... no way no way. Webb explained it perfectly above.
Click to expand...
That’s assuming H5 as depicted is correct . We’ve seen runs like the cmc and euro that allow for more digging . That pull things NW but would not be considered the NW trend . It would be a result of changes at H5 . Although I’m sure people will scream NW trend tonight at 00z if a model has a better run
 
For my area, I like where the 18Z GFS had the storm even though it was a little further away vs the 12Z. Whereas it backtracked a little from the 12Z, it was only a little backtrack and is still way better than the 0Z and 6Z. The pattern idea of big step forward (12Z), baby step backward (18Z), and big step forward (0Z or 6Z) is in play as a reasonable possibility imo considering the 12Z Euro and CMC and based on my many years of following model trends. Often after a big step in one direction like the 12Z, the next run is a temporary "breather" of sorts with a slight move back in the other direction (the 18Z in this case) before a resumption of the prior trend (perhaps tonight's 0Z?).

Opinions?
 
GaWx said:
For my area, I like where the 18Z GFS had the storm even though it was a little further away vs the 12Z. Whereas it backtracked a little from the 12Z, it was only a little backtrack and is still way better than the 0Z and 6Z. The pattern idea of big step forward (12Z), baby step backward (18Z), and big step forward (0Z or 6Z) is in play as a reasonable possibility imo considering the 12Z Euro and CMC and based on my many years of following model trends. Often after a big step in one direction like the 12Z, the next run is a temporary "breather" of sorts with a slight move back in the other direction (the 18Z in this case) before a resumption of the prior trend (perhaps tonight's 0Z?).

Opinions?
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I'll take that road right now. May lead to a cliff but it's better than the road I know leads to a cliff.
 
GaWx said:
For my area, I like where the 18Z GFS had the storm even though it was a little further away vs the 12Z. Whereas it backtracked a little from the 12Z, it was only a little backtrack and is still way better than the 0Z and 6Z. The pattern idea of big step forward (12Z), baby step backward (18Z), and big step forward (0Z or 6Z) is in play as a reasonable possibility imo considering the 12Z Euro and CMC and based on my many years of following model trends. Often after a big step in one direction like the 12Z, the next run is a temporary "breather" of sorts with a slight move back in the other direction (the 18Z in this case) before a resumption of the prior trend (perhaps tonight's 0Z?).

Opinions?
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Larry - That pretty well mirrors my thoughts (except my dadgum Chickasaw plum bloomed today ... which is a very bad sign down here (never seen it freeze after that happens))
 
The common denominator amongst every failed threat for wintry weather lately (& potentially this one too) is that aside from having a big vortex over SE Canada and New England, all of our potential events are associated with shortwaves that enter the contiguous US from the northern Rockies or Pacific Northwest and dive southeastward in the process, leading to a prolonged period of dry, west-northwest to northwesterly flow which leads to advection of cold, dry, descending air off the Rockies and Appalachians which suppresses the storm track and baroclinic zone well to the southeast. We can get the job done if we have a s/w that comes down the Rockies & Pacific NW, but we usually need to see shorter wavelengths and/or blocking upstream over the North Atlantic (-NAO) and/or north-central Canada to slow down the waves and give a chance for moist west-southwest to southwesterly flow to overrun the cold air that's obviously well entrenched atm. This doesn't mean the NAO is of upmost importance to get any wintry weather in general, but if we aren't receiving a steady supply of shortwaves in the southern stream, as we're often lacking in a NINA, we need a high-latitude blocking ridge there or else we're probably in trouble... If we can't get blocking in north-central Canada or Greenland, our only other primary option is we need a healthy shortwave to crash into California to really give us a chance for a board-wide overrunning event. You see, even with a big vortex over New England and SE Canada, plowing a healthy s/w into California and the four corners leads to moist west-southwest/southwesterly flow over the south-central plains anyway and allows deep tropical moisture from both the tropical east-central Pacific and Gulf of Mexico to overrun the low-level cold dome in the southern US, and gives us at least a legitimate fighting chance in a pattern like this. Huge upper level troughs plowing into California and the Four Corners regions often are associated with and herald a large-scale forthcoming pattern change and that may be what we need to trigger a storm here....

It's hard to pick out here (a testament to how pitiful this s/w was) but the shortwave that was associated with the December 28-29th threat (which ended up being a huge bust) entered the US thru the Pacific NW and Northern Rockies.
gfs_z500_vort_us_3.png

Shortwave associated with the New Years Day threat (which ended up busting), entered the US through the Pacific NW and Northern Rockies
gfs_z500_vort_us_11.png


Shortwave for the potential January 2-4 event enters the US thru the Northern Rockies in a few days. See the pattern here?
gfs_z500_vort_us_15.png
 
Well Webb's post is thorough and hard to deny and I almost jumped (again) but I read the Rah NWS and believe I'll hold off just yet... still too much to figure out for us, especially the Central/Eastern Carolina's

As seems to have been the case the past few weeks, the
models can`t seem to agree on how this system will evolve and what
the resulting weather over Central NC will be. Even small variations
in the amplitude and southern extent of the aforementioned wave
could result in very different weather forecast for the area. The EC
has been wetter over NC but has been more consistent from run-to-
run. On the other hand, the GFS has been drier, but has trended
toward the EC with the latest (12Z) run. The feature in question at
the surface is the low that develops over the Atlantic. How strong
it is and it`s proximity to the east coast of the US will determine
if/what weather we will see here. Again, the EC solution has the low
much closer to the NC coast while the GFS is farther out over the
Atlantic. Given such large differences the precipitation forecast
for this period is low confidence and high uncertainty. Have kept
the forecast dry, with precipitation chances below slight for now,
but would not be surprised to see an introduction of some wintry
precip in the southeast in the coming days if current trends
continue.
 
Webberweather53 said:
The common denominator amongst every failed threat for wintry weather lately (& potentially this one too) is that aside from having a big vortex over SE Canada and New England, all of our potential events are associated with shortwaves that enter the contiguous US from the northern Rockies or Pacific Northwest and dive southeastward in the process, leading to a prolonged period of dry, west-northwest to northwesterly flow which leads to advection of cold, dry, descending air off the Rockies and Appalachians which suppresses the storm track and baroclinic zone well to the southeast. We can get the job done if we have a s/w that comes down the Rockies & Pacific NW, but we usually need to see shorter wavelengths and/or blocking upstream over the North Atlantic (-NAO) and/or north-central Canada to slow down the waves and give a chance for moist west-southwest to southwesterly flow to overrun the cold air that's obviously well entrenched atm. This doesn't mean the NAO is of upmost importance to get any wintry weather in general, but if we aren't receiving a steady supply of shortwaves in the southern stream, as we're often lacking in a NINA, we need a high-latitude blocking ridge there or else we're probably in trouble... If we can't get blocking in north-central Canada or Greenland, our only other primary option is we need a healthy shortwave to crash into California to really give us a chance for a board-wide overrunning event. You see, even with a big vortex over New England and SE Canada, plowing a healthy s/w into California and the four corners leads to moist west-southwest/southwesterly flow over the south-central plains anyway and allows deep tropical moisture from both the tropical east-central Pacific and Gulf of Mexico to overrun the low-level cold dome in the southern US, and gives us at least a legitimate fighting chance in a pattern like this. Huge upper level troughs plowing into California and the Four Corners regions often are associated with and herald a large-scale forthcoming pattern change and that may be what we need to trigger a storm here....

It's hard to pick out here (a testament to how pitiful this s/w was) but the shortwave that was associated with the December 28-29th threat (which ended up being a huge bust) entered the US thru the Pacific NW and Northern Rockies.
View attachment 2389

Shortwave associated with the New Years Day threat (which ended up busting), entered the US through the Pacific NW and Northern Rockies
View attachment 2388


Shortwave for the potential January 2-4 event enters the US thru the Northern Rockies in a few days. See the pattern here?
View attachment 2387
Click to expand...

As a complimentary example to support the argument I'm putting forth here, look at the end of the GFS run, notice a big shortwave plows into south-central California and the Great Basin on January 8th. Not surprisingly a few days later, a big overrunning event breaks out east of the Rockies....
gfs_z500_vort_us_42.png
gfs_mslp_pcpn_frzn_us_45.png

Right on its heels, another s/w crashes into southern California, and once again, a few days later, wintry precipitation begins to break out over the southern plains
gfs_z500_vort_us_47.png
gfs_mslp_pcpn_frzn_us_50.png


Keep in mind, the point of this post is not to legitimize fantasyland GFS solutions, but rather provide a basis behind identifying a major ingredient we're currently missing and probably desperately need in this pattern that's necessary to catalyze a major overrunning event in the southern tier of the US. Equivalent to playing a competitive game of cards, while one move will work when you're dealt a particular hand to get you to win the game, when dealt a different set of cards, the same move/decision making may not work as effectively (or at all), and there's often another move or series of moves that will more likely lead you to win the game more quickly... Similarly, while shortwaves diving into the Pacific NW and Northern Rockies as well as California may have led to glory in the past when we were dealt w/ a pattern characterized by profound high-latitude North Atlantic blocking, the pattern we're currently dealt dictates that we have to rely more heavily on getting a wave into California and the four corners to produce the same result we want which is a lot of snow and ice...
 
Webberweather53 said:
The common denominator amongst every failed threat for wintry weather lately (& potentially this one too) is that aside from having a big vortex over SE Canada and New England, all of our potential events are associated with shortwaves that enter the contiguous US from the northern Rockies or Pacific Northwest and dive southeastward in the process, leading to a prolonged period of dry, west-northwest to northwesterly flow which leads to advection of cold, dry, descending air off the Rockies and Appalachians which suppresses the storm track and baroclinic zone well to the southeast. We can get the job done if we have a s/w that comes down the Rockies & Pacific NW, but we usually need to see shorter wavelengths and/or blocking upstream over the North Atlantic (-NAO) and/or north-central Canada to slow down the waves and give a chance for moist west-southwest to southwesterly flow to overrun the cold air that's obviously well entrenched atm. This doesn't mean the NAO is of upmost importance to get any wintry weather in general, but if we aren't receiving a steady supply of shortwaves in the southern stream, as we're often lacking in a NINA, we need a high-latitude blocking ridge there or else we're probably in trouble... If we can't get blocking in north-central Canada or Greenland, our only other primary option is we need a healthy shortwave to crash into California to really give us a chance for a board-wide overrunning event. You see, even with a big vortex over New England and SE Canada, plowing a healthy s/w into California and the four corners leads to moist west-southwest/southwesterly flow over the south-central plains anyway and allows deep tropical moisture from both the tropical east-central Pacific and Gulf of Mexico to overrun the low-level cold dome in the southern US, and gives us at least a legitimate fighting chance in a pattern like this. Huge upper level troughs plowing into California and the Four Corners regions often are associated with and herald a large-scale forthcoming pattern change and that may be what we need to trigger a storm here....

It's hard to pick out here (a testament to how pitiful this s/w was) but the shortwave that was associated with the December 28-29th threat (which ended up being a huge bust) entered the US thru the Pacific NW and Northern Rockies.
View attachment 2389

Shortwave associated with the New Years Day threat (which ended up busting), entered the US through the Pacific NW and Northern Rockies
View attachment 2388


Shortwave for the potential January 2-4 event enters the US thru the Northern Rockies in a few days. See the pattern here?
View attachment 2387
Click to expand...
You can’t explain it no better then that!!!!
 
Webberweather53 said:
As a complimentary example to support the argument I'm putting forth here, look at the end of the GFS run, notice a big shortwave plows into south-central California and the Great Basin on January 8th. Not surprisingly a few days later, a big overrunning event breaks out east of the Rockies....
View attachment 2391
View attachment 2390

Right on its heels, another s/w crashes into southern California, and once again, a few days later, wintry precipitation begins to break out over the southern plains
View attachment 2393
View attachment 2392


Keep in mind, the point of this post is not to legitimize fantasyland GFS solutions, but rather provide a basis behind identifying a major ingredient we're currently missing and probably desperately need in this pattern that's necessary to catalyze a major overrunning event in the southern tier of the US. Equivalent to playing a competitive game of cards, while one move will work when you're dealt a particular hand to get you to win the game, when dealt a different set of cards, the same move/decision making may not work as effectively (or at all), and there's often another move or series of moves that will more likely lead you to win the game more quickly... Similarly, while shortwaves diving into the Pacific NW and Northern Rockies as well as California may have led to glory in the past when we were dealt w/ a pattern characterized by profound high-latitude North Atlantic blocking, the pattern we're currently dealt dictates that we have to rely more heavily on getting a wave into California and the four corners to produce the same result we want which is a lot of snow and ice...
Click to expand...
OUTSTANDING!!!!!.. Plus what many "forget".. in general terms in weak La Nina winter seasons.. for us in the SE to get any significant winter events on average is almost pure "luck" so count your blessings!!!
 
Webber's explanation is what I look for when I come to a wx forum and spend half my day along with you guys hoping and praying for the big dog. It puts everything into perspective, to see a honest and educated analysis of what's really going on is what we need...outstanding commentary Webber!

Sent from my SM-N950U using Tapatalk
 
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