H2Otown_WX Posted February 25, 2012 Share Posted February 25, 2012 I'm curious as to how the distance from a topographical feature (mainly a mountain or mountain chain) affects the magnitude of the typical effects caused by orographic lifting and sinking. For example, next week I have to forecast for Albuquerque, NM at the airport. I know that the airport is about 5300 feet in elevation. I know that they have plateaus or mountains that are relatively close to their east and north. They also have a chain of mountains to their west. This chain I noticed has elevations that are roughly 3000 feet higher than the airport. However, they are over 50 miles away. Does the fact that they are that far away negate the adiabatic compressional heating effect off a west wind or simply minimize it? I know the wording here isn't the greatest, hope someone can give me an explanation. Link to comment Share on other sites More sharing options...
Mallow Posted February 26, 2012 Share Posted February 26, 2012 Part of it depends on the stability of the atmosphere. But 50 miles will probably not be enough to cancel the leeward impacts. I'd imagine downsloping from the west could be relatively substantial, still. Link to comment Share on other sites More sharing options...
ohleary Posted February 26, 2012 Share Posted February 26, 2012 I'm curious as to how the distance from a topographical feature (mainly a mountain or mountain chain) affects the magnitude of the typical effects caused by orographic lifting and sinking. For example, next week I have to forecast for Albuquerque, NM at the airport. I know that the airport is about 5300 feet in elevation. I know that they have plateaus or mountains that are relatively close to their east and north. They also have a chain of mountains to their west. This chain I noticed has elevations that are roughly 3000 feet higher than the airport. However, they are over 50 miles away. Does the fact that they are that far away negate the adiabatic compressional heating effect off a west wind or simply minimize it? I know the wording here isn't the greatest, hope someone can give me an explanation. First, I'd guess you didn't mean west wind as there isn't much higher terrain to the west of ABQ. Second, looking at a topo map of the area, I'd guess any compressional heating effects would be minor with an easterly wind, with that range to the east...with a strong northerly wind possibly providing some moderate effects with the right stability in place. I've seen compressional heating affect areas hundreds of miles from the source...once in early spring strong westerly winds coming off the Rockies created an anomolously warm air mass that made it as far east as Iowa, where I lived. So ABQ is definitely close enough to feel the effect. Link to comment Share on other sites More sharing options...
Chinook Posted February 26, 2012 Share Posted February 26, 2012 I'm curious as to how the distance from a topographical feature (mainly a mountain or mountain chain) affects the magnitude of the typical effects caused by orographic lifting and sinking. For example, next week I have to forecast for Albuquerque, NM at the airport. I know that the airport is about 5300 feet in elevation. I know that they have plateaus or mountains that are relatively close to their east and north. They also have a chain of mountains to their west. This chain I noticed has elevations that are roughly 3000 feet higher than the airport. However, they are over 50 miles away. Does the fact that they are that far away negate the adiabatic compressional heating effect off a west wind or simply minimize it? I know the wording here isn't the greatest, hope someone can give me an explanation. An adiabatic layer or high-lapse rate dry layer lives above the whole Rockies region sometimes, and affects many cities. The sunshine also helps the atmosphere be dry adiabatic. Albuquerque is a weird place. It is just west of the Sandia mountain chain, but the continental divide is well west of it. So the Sandias protect it from easterly upslope events, such as arctic cold and snow on the high plains. In December, when all the cold and snow seemed to let loose on New Mexico, Albuquerque got 4.3" of snow but Roswell got 15.5". Albuquerque is one ridiculously snowless place. It gets 9.3" of snow per year. Link to comment Share on other sites More sharing options...
H2Otown_WX Posted February 26, 2012 Author Share Posted February 26, 2012 Part of it depends on the stability of the atmosphere. But 50 miles will probably not be enough to cancel the leeward impacts. I'd imagine downsloping from the west could be relatively substantial, still. Okay, thanks Mallow. The more unstable the more downsloping, correct? Or do I have that backwards? Link to comment Share on other sites More sharing options...
H2Otown_WX Posted February 26, 2012 Author Share Posted February 26, 2012 First, I'd guess you didn't mean west wind as there isn't much higher terrain to the west of ABQ. Second, looking at a topo map of the area, I'd guess any compressional heating effects would be minor with an easterly wind, with that range to the east...with a strong northerly wind possibly providing some moderate effects with the right stability in place. I've seen compressional heating affect areas hundreds of miles from the source...once in early spring strong westerly winds coming off the Rockies created an anomolously warm air mass that made it as far east as Iowa, where I lived. So ABQ is definitely close enough to feel the effect. Well, it's a little north of west. Do you see where Mt. Taylor is? That's the area I'm referring to, maybe you didn't look far enough west. Mt. Taylor looks like it is about 11,000 feet so I'd imagine it must have some effect. Wow, that must have been some super strong westerlies to get the effects that far east. Link to comment Share on other sites More sharing options...
H2Otown_WX Posted February 26, 2012 Author Share Posted February 26, 2012 An adiabatic layer or high-lapse rate dry layer lives above the whole Rockies region sometimes, and affects many cities. The sunshine also helps the atmosphere be dry adiabatic. Albuquerque is a weird place. It is just west of the Sandia mountain chain, but the continental divide is well west of it. So the Sandias protect it from easterly upslope events, such as arctic cold and snow on the high plains. In December, when all the cold and snow seemed to let loose on New Mexico, Albuquerque got 4.3" of snow but Roswell got 15.5". Albuquerque is one ridiculously snowless place. It gets 9.3" of snow per year. That answers my question to Mallow, thanks. I take it ABQ is a pretty dry place for the most part except maybe in an El Nino where it can get influence from the sub-tropical jet? Link to comment Share on other sites More sharing options...
Chinook Posted February 27, 2012 Share Posted February 27, 2012 Albuquerque is fairly dry because it's in between mountains. It gets only 9.5" of precipitation per year. It gets a bit less rain than the New Mexico high plains in the summer because the storms pop on the high terrain right east of the Sandias. Link to comment Share on other sites More sharing options...
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