National Weather Service United States Department of Commerce

Strong to Severe Thunderstorms in the East; Heat in the Central and Western U.S.

Strong to potentially severe thunderstorms with damaging wind gusts are forecast Thursday from parts of New England into the Mid Atlantic and Carolinas. Significant heat will expand across the West and Central Plains through Friday, potentially breaking daily high temperature records. Dangerous heat will then build into the Eastern U.S. this weekend through much of next week. 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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