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WTF? What the hell is that over South Dakota?


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I'll try to hold you over 'til the smart guys get here.

It's a cut-off Low; a low pressure system (notice the counter-clockwise rotation) that's not associated with any type of weather front.

Cya

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It's a "closed low". A cut-off low is a closed low that's isolated from the prevailing flow of weather patterns (i.e. it's "cut off" from the westerly flow of the jet stream). A closed low is merely a low pressure system that is completely bounded by a single isobar (i.e. you can draw a circle of constant air pressure around it - which you can see in this map: note the low over the Dakotas is completely surrounded by a circle - an isobar - whereas the one over northern Alabama isn't, which makes it a trough).

 

Which means it might be a cut-off low...but not necessarily. It's certainly a closed low, but I don't think there's enough info from either of these maps alone to tell for certain that it's a cut-off low. Frankly, as best I can tell (not very well), it's not a cutoff low.

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It's a "closed low".  A cut-off low is a closed low that's isolated from the prevailing flow of weather patterns (i.e. it's "cut off" from the westerly flow of the jet stream).  A closed low is merely a low pressure system that is completely bounded by a single isobar (i.e. you can draw a circle of constant air pressure around it - which you can see in this map: note the low over the Dakotas is completely surrounded by a circle - an isobar - whereas the one over northern Alabama isn't, which makes it a trough). 

 

Which means it might be a cut-off low...but not necessarily.  It's certainly a closed low, but I don't think there's enough info from either of these maps alone to tell for certain that it's a cut-off low.  Frankly, as best I can tell (not very well), it's not a cutoff low.

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Good explanation... My guess is that Stojan was looking at too many maps of hurricanes and was waiting for someone to say that the eye of the storm was located over Fargo... <_<;):w00t:

 

A closed low has several characteristics. Closed lows tend to be deep pressure systems with one or more height contours encircling them on the analysis charts at all levels in the troposphere. A closed low is occluded and vertically stacked. Because the low is closed, it does not generate much PVA and NVA. The vort max will be near the center of rotation. It is difficult to get a windflow that produces vorticity advection because the vorticity isopleths for the most part are parallel to the height contours. The weather associated with closed lows tends to be cloudy with showers in the vicinity of the low's center. Closed lows are often slow movers but can move quickly if they are embedded within the jet stream. Cloudy and rainy weather can persist with the slow movers. Thermal advection tends to be weak with closed lows since they are occluded. A special case of the closed low is the cut-off low. A cut-off low moves slowly since the jet stream winds aloft are displaced away from the low and are thus not able to move it along. Below is an example of a closed / cut-off low:

 

 

Cut-Off

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Good explanation... My guess is that Stojan was looking at too many maps of hurricanes and was waiting for someone to say that the eye of the storm was located over Fargo... <_<  ;):w00t: 

 

 

Cut-Off

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I heard Fargo was about due.....

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It's a "closed low".  A cut-off low is a closed low that's isolated from the prevailing flow of weather patterns (i.e. it's "cut off" from the westerly flow of the jet stream).  A closed low is merely a low pressure system that is completely bounded by a single isobar (i.e. you can draw a circle of constant air pressure around it - which you can see in this map: note the low over the Dakotas is completely surrounded by a circle - an isobar - whereas the one over northern Alabama isn't, which makes it a trough). 

 

Which means it might be a cut-off low...but not necessarily.  It's certainly a closed low, but I don't think there's enough info from either of these maps alone to tell for certain that it's a cut-off low.  Frankly, as best I can tell (not very well), it's not a cutoff low.

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The jet stream is dug south (a temp forecast map should show this) and that sit'n'spin sumbitch ain't movin.

It's a cut-off low.

Cya

 

P.S. Since a closed low is defined as a "deep" low pressure system, it can and often does have more than a single isobar around it.

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Amazing... As I read more... 59 inches of snow... 59! fell in the the BadLands.

 

Wow!

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Wow is right.

 

I know that SD has been very dry recently, but I doubt that is the way they wanted to end the drought.

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