The gusty and dusty conditions of Tuesday will calm down as we go into the middle of the week. A cooler airmass logically following the cold front will settle into the Great Basin, dropping high temperatures in the valleys into the mid-50s Wednesday and Thursday, with a slight chance of a shower or two late Wednesday to early Thursday, mostly north of Interstate 80. After a brief warming Friday and Saturday, cooler temperatures will return for Sunday through Monday.

Courtesy University of Virginia

Courtesy University of Virginia

Nancy and Dave wrote in with the following question: “When highs and lows are displayed in the screen, they appear to always be the same size. Are they?  Do they differ in size with the intensity of the high or the low? How big is the diameter in miles? Do they ever measure them? Is there such a thing as a high high or a low high?”

Since a high and a low are only defined relative to the other, that’s kind of a hard question to answer. But in general terms, highs tend to be broader than lows (there are exceptions). The “size” or perhaps better put “strength” of a low and a high has to do with how low or high up in the atmosphere you have to go to reach the particular pressure surface, or how high or low the pressure is at the surface of the earth. That will take some explanation.

There are really two different ways that highs and lows are measured, depending on whether they are surface features or if they are higher up in the atmosphere. Tomorrow, I’ll tell you how each work.