imranipatel Posted July 6, 2014 Report Share Posted July 6, 2014 What is the science behind wind direction? What causes wind direction? Quote Link to comment Share on other sites More sharing options...
makatakam Posted July 6, 2014 Report Share Posted July 6, 2014 Rotation of the Earth on its axis and sunlight. Quote Link to comment Share on other sites More sharing options...
imranipatel Posted July 6, 2014 Author Report Share Posted July 6, 2014 Rotation of the Earth on its axis and sunlight.Rotation of earth on axis make sense. How does sunlight influence wind direction? Quote Link to comment Share on other sites More sharing options...
RobB Posted July 6, 2014 Report Share Posted July 6, 2014 On the coast, wind direction is away from where the heat is. During the day, the land heats up from the sun, and the wind heads off shore towards the cooler air over the water. It works in reverse when the water is warmer than the land. This is true when the air is otherwise still... if there's a storm brewing, the wind heads towards the center of the low pressure area. Quote Link to comment Share on other sites More sharing options...
Captainbob Posted July 8, 2014 Report Share Posted July 8, 2014 Actually, the land warms up from the sun during the day and the air over the land rises, creating a lower pressure. Cooler air, which is more dense, moves in to take the place of the rising air warmer air. So during the day you get a sea breeze, that is the cooler air over the sea, moving towards the land. At night, the land cools quicker, than the water, so the cooler air over the land blows towards the water, which results in a land breeze. Quote Link to comment Share on other sites More sharing options...
RobB Posted July 8, 2014 Report Share Posted July 8, 2014 Well, it probably works different here on the island, as we have 2 separate bodies of water and only a little land separating them. I guess it's a more complex dynamic, and my previous statement is only derived from local observation. So... what Bob said is probably more accurate at most shore locations. Quote Link to comment Share on other sites More sharing options...
Tmadz Posted July 8, 2014 Report Share Posted July 8, 2014 This is complicated. That's why the government uses supercomputers to model. Too many variables. Haven't you ever cursed the weatherman for being wrong? The weather and wind apps aren't good more than 36 hours out. Quote Link to comment Share on other sites More sharing options...
RobB Posted July 8, 2014 Report Share Posted July 8, 2014 I find that NOAA nails the forecast for us, probably better than 80% of the time. Wind speed & direction forecast is very good, too. http://www.weather.gov/ Just put in your ZIP code... I'd be interested to hear how well NOAA does in other parts of the country. 2 Quote Link to comment Share on other sites More sharing options...
Wayne Dowler Posted July 8, 2014 Report Share Posted July 8, 2014 Sorry, not worried about how, just about how much!! Look at leaves, flags flapping, stick stake with ribbon in air, hair on neck detection method, all tell me if there is enough to fly!! 1 Quote Link to comment Share on other sites More sharing options...
makatakam Posted July 9, 2014 Report Share Posted July 9, 2014 Google "wind map" (without the quotation marks) -- very interesting app. You can point and zoom for more detail in your area. Quote Link to comment Share on other sites More sharing options...
Reef Runner Posted July 10, 2014 Report Share Posted July 10, 2014 On the coast, wind direction is away from where the heat is. During the day, the land heats up from the sun, and the wind heads off shore towards the cooler air over the water. It works in reverse when the water is warmer than the land. This is true when the air is otherwise still... if there's a storm brewing, the wind heads towards the center of the low pressure area. Actually, the land warms up from the sun during the day and the air over the land rises, creating a lower pressure. Cooler air, which is more dense, moves in to take the place of the rising air warmer air. So during the day you get a sea breeze, that is the cooler air over the sea, moving towards the land. At night, the land cools quicker, than the water, so the cooler air over the land blows towards the water, which results in a land breeze. Gotta go with Rob on this one............. CB, it may be like that in theory (and even in Georgia), but on the North Carolina coast (the Outer Banks), the prevailing winds in the summer are out of the Southwest (blowing from the hot land to the water), and in the winter, they are out of the Northeast (blowing from the cold water to land). Now there are days here and there, that this may not be 100% true, due to other weather related factors, but overall, that's how it is, no matter what's warming or what's cooling. And no, I'm not a weatherman, or meteorologist, but as a rule of thumb, during the hot summer months, beach flying "S _ C K S" here in NC, because the wind is coming off of the land, bouncing over the cottages & dunes, and everything else, so it's bumpy. When it reverses, for whatever reason, and comes off of the water, it's smooth as a baby's butt........... Just thought I'd check that out, right now, so here's the current "skinny", from Nags Head, NC, via the Weather Channel ! Quote Link to comment Share on other sites More sharing options...
Captainbob Posted July 10, 2014 Report Share Posted July 10, 2014 On the coast, wind direction is away from where the heat is. During the day, the land heats up from the sun, and the wind heads off shore towards the cooler air over the water. It works in reverse when the water is warmer than the land. This is true when the air is otherwise still... if there's a storm brewing, the wind heads towards the center of the low pressure area. Actually, the land warms up from the sun during the day and the air over the land rises, creating a lower pressure. Cooler air, which is more dense, moves in to take the place of the rising air warmer air. So during the day you get a sea breeze, that is the cooler air over the sea, moving towards the land. At night, the land cools quicker, than the water, so the cooler air over the land blows towards the water, which results in a land breeze. Gotta go with Rob on this one............. CB, it may be like that in theory (and even in Georgia), but on the North Carolina coast (the Outer Banks), the prevailing winds in the summer are out of the Southwest (blowing from the hot land to the water), and in the winter, they are out of the Northeast (blowing from the cold water to land). Now there are days here and there, that this may not be 100% true, due to other weather related factors, but overall, that's how it is, no matter what's warming or what's cooling. And no, I'm not a weatherman, or meteorologist, but as a rule of thumb, during the hot summer months, beach flying "S _ C K S" here in NC, because the wind is coming off of the land, bouncing over the cottages & dunes, and everything else, so it's bumpy. When it reverses, for whatever reason, and comes off of the water, it's smooth as a baby's butt........... Just thought I'd check that out, right now, so here's the current "skinny", from Nags Head, NC, via the Weather Channel ! Nags Head.JPG Well the original question from the OP wanted to know the "science of wind direction". What I stated, was the scientific principle for wind directions regarding wind blowing from cooler areas to warmer ares, which is illustrated perfectly in land and sea breezes. I studied this when preparing for my written test for my pilots license years ago, and used it many times since. Prevailing winds have nothing to do with land and sea breezes. I lived right on the beach in Miami Florida for 10 years, and land and sea breezes were a fact of life. http://www.nc-climate.ncsu.edu/edu/k12/.breezes Quote Link to comment Share on other sites More sharing options...
RobB Posted July 11, 2014 Report Share Posted July 11, 2014 Well, you're probably right about the textbook science of what causes the wind. The area Nick is describing and where I live are similar land masses, on the coast, and we were just describing the actual observations in those areas. Whether it agrees with the textbook information available... well, I guess it doesn't. BTW, we haven't had a day yet in the last month that there wasn't an offshore breeze in the afternoon. I know, because that's when I'm looking to fly. Not the best wind to fly in, but better than nothing ! 1 Quote Link to comment Share on other sites More sharing options...
makatakam Posted July 11, 2014 Report Share Posted July 11, 2014 Well, you're probably right about the textbook science of what causes the wind. The area Nick is describing and where I live are similar land masses, on the coast, and we were just describing the actual observations in those areas. Whether it agrees with the textbook information available... well, I guess it doesn't. BTW, we haven't had a day yet in the last month that there wasn't an offshore breeze in the afternoon. I know, because that's when I'm looking to fly. Not the best wind to fly in, but better than nothing ! The indoor crowd prefers to fly in nothing! Quote Link to comment Share on other sites More sharing options...
Captainbob Posted July 11, 2014 Report Share Posted July 11, 2014 Well, you're probably right about the textbook science of what causes the wind. The area Nick is describing and where I live are similar land masses, on the coast, and we were just describing the actual observations in those areas. Whether it agrees with the textbook information available... well, I guess it doesn't. BTW, we haven't had a day yet in the last month that there wasn't an offshore breeze in the afternoon. I know, because that's when I'm looking to fly. Not the best wind to fly in, but better than nothing ! If you analyzed the temperature over the land versus the temp over the water, at any given time of the day which are called local winds, plus the large air masses ( global winds) that are moving due to the prevailing wind flow, the the wind direction at any given point could be predicted. That is what meteorologists and the computer models do, nothing more. Science is science, it doesn't change from day to day. The bottom line is cooler air is at a higher pressure, than warmer air, and air flows from high pressure to low pressure, always. The difference in air pressure causes the isobar lines, and the greater the difference, the closer the isobar lines are and the stronger the wind is. That's why pilots are so concerned about warm and cold fronts which are a predictor for stronger winds and or storm conditions. It is something we live with every time we plan a flight. http://www.theweatherprediction.com/kid_weather_questions/wind.html http://www.metoffice.gov.uk/learning/wind/what-causes-wind I also think you are confusing local winds such as land breeze and sea breezes, with prevailing winds. If you have a strong prevailing wind, which is like a strong ocean current, the sea and land breezes in comparison, are like a boat going with or against the ocean current. Say a prevailing wind is southwesterly, which it would be in the outer banks from June to July, and it is 13 knots, you would need quite a strong sea breeze generated by land-water temp differential, to buck that 13 knot wind, which is pretty unlikely. If the prevailing wind, was very low, say 2-4 knots, then the sea breeze would be noticed if it was strong enough to buck that 2-4 knot PW. In Miami, the prevailing wind strength was usually on the low side, so the land and sea breezes were very noticeable and observable. Quote Link to comment Share on other sites More sharing options...
Reef Runner Posted July 11, 2014 Report Share Posted July 11, 2014 Well, I'm headed to the coast next week, and I'd like to think that I could turn this dude around, and make it do right, but it "ain't" going to happen. It's July, it's Summer, it's hot as heck, and the wind is going to be blowing from the land, out towards the ocean. Crappy flying winds, at best, but as Rob mentioned, better that nothing. Works great for sitting on the beach, sipping a cool one, and watching SLK's 1 Quote Link to comment Share on other sites More sharing options...
RobB Posted July 11, 2014 Report Share Posted July 11, 2014 IDK, Nick, you might be in luck... with the 'Polar Vortex' coming back, that might be enough to flip the normal wind conditions for this time of year ! Of course, I'm looking at a nice 5-10mph onshore breeze this morning... from my window at work. 1 Quote Link to comment Share on other sites More sharing options...
Reef Runner Posted July 11, 2014 Report Share Posted July 11, 2014 IDK, Nick, you might be in luck... with the 'Polar Vortex' coming back, that might be enough to flip the normal wind conditions for this time of year ! Of course, I'm looking at a nice 5-10mph onshore breeze this morning... from my window at work. Well Rob, that's really cool. I hadn't seen that. Just Google'd, and read about it. So you're right, we may be in luck............... Quote Link to comment Share on other sites More sharing options...
Wayne Dowler Posted July 11, 2014 Report Share Posted July 11, 2014 Well, you're probably right about the textbook science of what causes the wind. The area Nick is describing and where I live are similar land masses, on the coast, and we were just describing the actual observations in those areas. Whether it agrees with the textbook information available... well, I guess it doesn't. BTW, we haven't had a day yet in the last month that there wasn't an offshore breeze in the afternoon. I know, because that's when I'm looking to fly. Not the best wind to fly in, but better than nothing ! The indoor crowd prefers to fly in nothing! Here, here!! We don't need no stinkin' winds!! Quote Link to comment Share on other sites More sharing options...
etully Posted July 12, 2014 Report Share Posted July 12, 2014 Brass tacks would start with the Coriolis effect driven by the sun heating air masses and the rotation of the earth. Then you get the jet stream, formation of high and lows, frontal weather, and local effects as mentioned above. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
makatakam Posted July 12, 2014 Report Share Posted July 12, 2014 Refer to post #2 as often as necessary. Quote Link to comment Share on other sites More sharing options...
Captainbob Posted July 12, 2014 Report Share Posted July 12, 2014 If you really want to study this topic, this is where most pilots get their info from for taking their written test. https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2011.pdf Quote Link to comment Share on other sites More sharing options...
Reef Runner Posted July 12, 2014 Report Share Posted July 12, 2014 I thought this was about kites (as in fun stuff) "ditto" on the.........."Refer to post #2 as often as necessary" Quote Link to comment Share on other sites More sharing options...
Captainbob Posted July 12, 2014 Report Share Posted July 12, 2014 I thought this was about kites (as in fun stuff) "ditto" on the.........."Refer to post #2 as often as necessary" "What is the science of wind direction?" hmmm Guess the OP's question was posted in the wrong forum. Quote Link to comment Share on other sites More sharing options...
Reef Runner Posted July 13, 2014 Report Share Posted July 13, 2014 I thought this was about kites (as in fun stuff) "ditto" on the.........."Refer to post #2 as often as necessary" "What is the science of wind direction?" hmmm Guess the OP's question was posted in the wrong forum. ? Again, I thought this was about kites and having fun ? Quote Link to comment Share on other sites More sharing options...
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