National Weather Service United States Department of Commerce

Severe Weather Threats Across the Plains; Dangerous Heat and Wildfire Concerns for the West; Watching the Tropics

Severe thunderstorms are expected across the Central Plains accompanied by damaging wind gusts and large hail. In addition, heavy rainfall may lead to instances of flash flooding from the Plains and mid-Atlantic regions. The heavy rainfall threat continues across Florida and across the northern Gulf as we monitor a tropical disturbance tracking westward. Critical fire weather for the Great Basin. Read More >

A Discussion on Water Vapor (Moisture)

QUESTION 3:

If the air temperature was 90 F with a relative humidity of 60 percent in the afternoon, would it feel more uncomfortable to a person than if it was 75 outside with a relative humidity of 100 percent in the morning?

ANSWER 3:

At 90 with a relative humidity of 60 percent, it would "feel" like 100 degrees outside; at 75 with a relative humidity of 100 percent, it would only "feel" like 80. Despite the much different relative humidity value, the absolute humidity or dewpoint would be about the SAME in both these cases (i.e., dewpoint of 75 degrees). This "feeling" that combines air temperature and moisture in the air is referred to as the "heat index." Please return to the text for further information.

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