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Pattern January 2021 - Joyless January

How much have you had?
hahaha about as much as usual. But it's kind of luck of the draw. I know my night time lows have been below freezing more than most years but just haven't lined up a storm with that.
 
I see no way this can improve for those outside of the favored climo regions. Without some cold high pressure, we will continue to track marginal events that will end up being slop storms that yield illusions of grandeur and end in great disappointment. I can't wait to be proven wrong, but I highly doubt I will be.

Well, no, cold highs to the north usually give you CAD and there are more winter setups than CAD here in the Carolinas. Miller A cyclones rarely have cold highs in the right position or directly to the north.

If the sfc low intensifies, you end up w/ more precipitation & cold air advection on the backside & it's not gonna take much to make that happen.

There's plenty of cold air in the low-levels w/ 850s like these being progged, just not right at the sfc because the precip is too light on the model verbatim but we're still like 5-6 days out. More precip and a deeper sfc low to create an isallobaric effect w/ enhanced northerly low-level winds and you end up w/ legit storm over the piedmont.

This could certainly go to hell in a hand basket no doubt, but it's really not anywhere near as bad as you're leading people to believe.

1610469028457.png
 
Well, no, cold highs to the north usually give you CAD and there are more winter setups than CAD here in the Carolinas. Miller A cyclones rarely have cold highs in the right position or directly to the north.

If the sfc low intensifies, you end up w/ more precipitation & cold air advection on the backside & it's not gonna take much to make that happen.

There's plenty of cold air in the low-levels w/ 850s like these being progged, just not right at the sfc because the precip is too light on the model verbatim but we're still like 5-6 days out. More precip and a deeper sfc low to create an isallobaric effect w/ enhanced northerly low-level winds and you end up w/ legit storm over the piedmont.

This could certainly go to hell in a hand basket no doubt, but it's really not anywhere near as bad as you're leading people to believe.

View attachment 65202
exactly!
 
Oh yeah I totally forgot about the geostrophic & hydrostatic components of CAD.. yet I’m sitting here using froude numbers which are ground in the hydraulic principles ??‍♂️

I honestly never really thought about CADs being a subset of overrunning but it's 100% true actually. It's akin to saying every square (CAD) is a rectangle (overrunning), but rectangles (overrunning) aren't squares (CAD).
 
Well, no, cold highs to the north usually give you CAD and there are more winter setups than CAD here in the Carolinas. Miller A cyclones rarely have cold highs in the right position or directly to the north.

If the sfc low intensifies, you end up w/ more precipitation & cold air advection on the backside & it's not gonna take much to make that happen.

There's plenty of cold air in the low-levels w/ 850s like these being progged, just not right at the sfc because the precip is too light on the model verbatim but we're still like 5-6 days out. More precip and a deeper sfc low to create an isallobaric effect w/ enhanced northerly low-level winds and you end up w/ legit storm over the piedmont.

This could certainly go to hell in a hand basket no doubt, but it's really not anywhere near as bad as you're leading people to believe.

View attachment 65202
and of course, it seems as though moisture is always over performing right now... I think the rain we had overnight was supposed to be very light and I went out this morning to find .75 inch in my rain gauge
 
Here comes the freezer on the gfs
emoji102.png



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Here comes the freezer on the gfs


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Not buying yet. Sure it will get pushed back
 
Just came across a very interesting research that shows in GFS ensemble re-forecasts over the last 30 years that the worst forecasts and lowest predictability in the model tends to occur during major jet regime shifts (extension to retraction) and during the development and maintenance of high-latitude blocking in the N Pacific (-EPO/WPOs) & that this high-latitude blocking (-EPO/-WPO) are underforecast ~25% of the time.

Basically, we're fixing to encounter a period w/ very low predictability in the N Pacific in late January, and historically these blocks are often underestimated vs reality. Given this aforementioned information and that the GEFS is more aggressive w/ this -WPO/-EPO than the EPS, I'm tempted to lean towards the GEFS here but sometimes it can be overcooked beyond 300+ hrs.

Coupled w/ the increasing tendency for -NAO in the medium range, this ought to be fun to see what unfolds.

"The Development of the North Pacific Jet Phase Diagram as an Objective Tool to Monitor the State and Forecast Skill of the Upper-Tropospheric Flow Pattern"
https://journals.ametsoc.org/view/journals/wefo/34/1/waf-d-18-0106_1.xml

1610470204879.png
 
The last look is really not far from something significant at all. The problem is like has been talked about, the models are having such a hard time with all the energy flying around you see the wild swings that we see here. That’s why I really feel like we’re in a pattern that we could see a winter storm pop up only 2 days out.
 
Well, no, cold highs to the north usually give you CAD and there are more winter setups than CAD here in the Carolinas. Miller A cyclones rarely have cold highs in the right position or directly to the north.

If the sfc low intensifies, you end up w/ more precipitation & cold air advection on the backside & it's not gonna take much to make that happen.

There's plenty of cold air in the low-levels w/ 850s like these being progged, just not right at the sfc because the precip is too light on the model verbatim but we're still like 5-6 days out. More precip and a deeper sfc low to create an isallobaric effect w/ enhanced northerly low-level winds and you end up w/ legit storm over the piedmont.

This could certainly go to hell in a hand basket no doubt, but it's really not anywhere near as bad as you're leading people to believe.

View attachment 65202
I don't think we're as far apart as you may think. What I am saying is that for those of us outside of the more favored climo areas of the southeast, it is a mighty fine needle to thread without a parent high of any kind and it is much more likely to end up with a snowfall distribution like 12/18-12/19/2009. That one sucked like heck and many areas looked to be right on the line for days ahead of that one only to end in a few meaningless flakes considering areas just to the west got clobbered. Of course anything is possible with a lot of cold air aloft around, but it requires more help than if a parent high were in play. Anyway, I hope like heck I am wrong.

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