Death ridge .. please explain

[tom hanlon]

I would like to ask for a solid definition of the "death ridge" .

I got into weather from a storm chasers perspective so I am "synoptically ignorant". I tend to look at the micro or mesoscale on a two to three day time range. So when I sit here in ohio trying to plan a departure for the plains and I hear talk about "last years death ridge" . I wonder exactly what they mean.

I am assuming that they are talking about the polar wave pattern and a system where a ridge sets up somewhere over the US that prevents gulf moisture from reaching the plains.

What causes this ?

Does a high set up over the pacific or north pacific that blocks or prevents much movement in the overall wave pattern. Does a system set up over Hudson bay that blocks change. Does the bermuda high set up early ?

I am assuming that the change in the wave pattern from winter to summer is what allows for a dynamic weather pattern over the plains. Is the death ridge an early arrival of a typically summer-like wave pattern.

Thanks for helping out. I am so used to looking at specifics one or two days out that my knowledge of the big picture is pretty weak.

--
Tom Hanlon

 

[Adam Atkins]

Ridges lead to large scale subsidence (sinking motion) and warming in the mid-levels usually leading to large capping inversions. Weak wind fields are also associated near the ridge axis and southward, through the chase country. Moisture is prevalent because ageostrophic curvature convergence downstream of the ridge usually leads to a surface high and southerly surface flow across the plains. This goes to waste most of the time because high CAPE cannot be realized with such a strong lid and no large scale ascent to initiate thunderstorms. Last year there were more high CAPE cap busts than I've ever seen because of the blocking ridge patterns. There were dewpoint obs in the upper 70s and temps near 100 enticing chasers to head out and then get dissapointed by clear blue sky or benign boundary layer Cu.

On the other side of the pancake, west coast troughing is good for cyclonic vorticity advection, mid-level cooling, and large scale ascent, which is favorable for surface based convection. This year, we've had modest moisture and boundary layer temperatures, but abundant surface based convection and almost zero cap busts. Bottom line, ridging sucks, unless you live in Alberta, CA.

 

[Howard Robinson]

Ridges lead to large scale subsidence (sinking motion) and warming in the mid-levels usually leading to large capping inversions. Weak wind fields are also associated near the ridge axis and southward, through the chase country. Moisture is prevalent because ageostrophic curvature convergence downstream of the ridge usually leads to a surface high and southerly surface flow across the plains. This goes to waste most of the time because high CAPE cannot be realized with such a strong lid and no large scale ascent to initiate thunderstorms. Last year there were more high CAPE cap busts than I've ever seen because of the blocking ridge patterns. There were dewpoint obs in the upper 70s and temps near 100 enticing chasers to head out and then get dissapointed by clear blue sky or benign boundary layer Cu.

On the other side of the pancake, west coast troughing is good for cyclonic vorticity advection, mid-level cooling, and large scale ascent, which is favorable for surface based convection. This year, we've had modest moisture and boundary layer temperatures, but abundant surface based convection and almost zero cap busts. Bottom line, ridging sucks, unless you live in Alberta, CA.
[/b]

So that means that I may get some "treatment" for my SDS here in Saskatchewan???

 

[mikegeukes]

THE OMEGA BLOCK
METEOROLOGIST JEFF HABY
http://www.theweatherprediction.com/habyhints/144/

ATMOSPHERIC BLOCKING
METEOROLOGIST JEFF HABY
http://www.theweatherprediction.com/blocking/

Mike