convention for wind direction in driving rain sum

[glass]

The Climate Analysis tab in WUFI Pro 5 provides a Driving Rain Sum [mm/a] for a given weather file. For the pre-installed North American weather files, is the wind direction given with the usual convention--the direction from which the wind is blowing? Or is it the opposite?

A number of cities in the Midwestern U.S. have a driving rain sum that is larger for East than for West, which seems counter-intuitive (weather generally moves from west to east).

Thank you,

Sam

[Thomas]

The usual convention should also apply for these files: the direction from which the wind is blowing.

Maybe the expectation that in the west-wind zone wind and rain always come from western directions is generalizing the situation too much. Here the question

Q: Which way does the wind blow most often in the USA? Is there a prevailing wind direction across the USA?

is answered this way:

A: Prevailing wind direction is defined as the wind direction most frequently observed at a location over a certain period. Although most of the USA lies in a region atmospheric circulation known as the prevailing westerlies, this applies generally to the middle and upper regions of the troposphere, the lowest layer of Earth's atmosphere.

The prevailing wind direction at the surface varies for different locations across the U.S., depending on local topography, season, and other factors. Prevailing winds in one part of a large metropolitan area may be different significantly from another. In New York City, for example, the wind blow blows most frequently from the northeast at LaGuardia airport, from the south at JFK, and from the northwest at Central Park.

Based on data from more than 300 National Weather Service reporting stations, the most common prevailing wind direction on an annual basis in the U.S. is from the south.

So it seems prevailing wind directions different from west are not unusual. A complicating factor might be that the prevailing wind direction at the moments of most intense rain may not always be identical with the overall most frequent wind direction.

Regards,
Thomas