Could you explain this statement: “The 500-mb. Height is 590 dm and rising, so the warming-up persists.”
The 500-mb (millibar) height refers to the oint in the atmosphere at which the air pressure falls to 500 millibars–about 15.00 inches of mercury; the mean height for that is about 18,000 feet (about 5,500 meters or 550 dm–decameters.) If the height is greater, than it is hotter here because as air flows downward, it warms. Thus, 590 decameters is about 19,000 feet. This means upper air high pressure, downward-moving air (subsidence), and hot temperatures on the surface. During the intense heat of last Summer, the 500-mb. level was about 610 dm.
We use decameters instead of feet for the 500-millibar level because it is a smaller number, and the remainder of the world uses the metric system.