Can a area still have a high wind warning even with a weak pressure gradient but have strong thermals transferring strong low level winds ?
- oldprofLv 71 month ago
OK let's be clear...thermal lifting causes wind shears, which are vertical. These are the guys that make an airplane suddenly lurch upward or downward and cause you to spill that drink you just ordered and received. So high wind warnings are not going to come from thermal lifting.
High winds come from a strong pressure gradient. The horizontal winds result when the air literally falls from the high pressure peaks into the low pressure valleys. And the higher the discrepancy between the high and low pressure areas over a shorter distance the stronger the winds will be.
Think of the clump of air rolling from a summit of a high pressure mountain. The steeper the slope of that high pressure mountain, the faster that clump of air will accelerate and roll down the slope. That steep slope is the high pressure gradient.
If the slope is extended over a long range the gradient will be weaker than if it's covering a shorter range with the same pressure differential between the peak and the valley. And like a rock rolling down a mountain side the clump of air flowing down the longer weaker gradient will not pick up as much speed as it would if the slope were steeper.
Bottom line, a strong pressure gradient is needed for the high winds.