The HRRR subhourly product has multiple values for wind. How do I get the one I want?

[blaylockbk]

Adapted from a question from an email

Looking at the sub-hourly product, I was expecting to get 4 timesteps for each variable at each hour, but some variables have 8 timesteps instead. What are these and how do I get the 4 that I want?

from herbie import Herbie

H = Herbie('2023-01-01', model='hrrr', product='subh', fxx=1)
H.inventory("VGRD:10 m")

This is particularly problematic because if you read this with xarray, it looks like there are double the data at each step

ds = H.xarray("VGRD:10 m")

Which looks like there are double values at each 15 minute interval.

import pandas as pd
pd.to_timedelta(ds.step)

[blaylockbk]

The solution is to craft your searchString to only get the data you want.

Here is a regex that gets both U and V winds for the instantaneous wind, excluding the grib messages with "ave".

H.inventory("^:[U|V]GRD:10 m(?!.*ave)")

And here is the opposite; the U and V winds for the 5-min averages at each 15-min interval.

H.inventory("^:[U|V]GRD:10 m.*ave")