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HDF File Notes

Notes​

  1. The timestamps in HDF files provided by NOAA are in UTC.
  2. Flow data starts at Noon on the first day of a given HDF file.

Screenshots​

The HDF5 dataset is set up with with a matrix format as seen below. HDF5 table The columns are the indexes for the 4077 river stations. The Rows are the indexes for the Timesteps.

The Timesteps index can be viewed in a separate table.

HDF5 time table

Notes for HDF5 Table

Correspondence​

Email to/from Brian @ NOAA​

HEC_RAS HDF Date Time Values Question

Brian Astifan brian.astifan@noaa.gov

Jake -

I will have to dig a bit to confirm, but I'm virtually certain that the models (and output) are all in GMT (Zulu) time. Using standard time eliminates both DST and the Eastern/Central time zone issue.

The T[zero] - or initialization time - of each forecast should be at 12:00Z, which correlates to 7:00am Eastern / 6:00am Central in the winter and 8:00am/7:00am during daylight time.

Brian

Brian Astifan, P.E. | Development and Operations Hydrologist NOAA/National Weather Service | Ohio River Forecast Center Office: (937) 383-0528 x233 | Telework Cell: (440) 781-5436 Jacob S ​ Brian Astifan brian.astifan@noaa.gov, Melissa C, Sudhir K ​ Hi Brian,

Could you please verify the time zone information for the date time values in the HDF files? Specifically, do they switch between EDT and EST?

Thanks!

Jake Specht (he/him) Senior Software Director jacob@gqc.com | specht.jacob@epa.gov | www.gqc.com

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