Wednesday, June 17, 2015

The HRRR Has Arrived

I'm pleased to announce that forecasts from the 3-km High Resolution Rapid Refresh (HRRR) are now available on  Here's the 6-hour forecast valid at 0000 UTC (1800 MDT) this afternoon.  No showers or thunderstorms in the Salt Lake Valley.  Apply the sunblock liberally!

The HRRR is the highest-resolution operational model run by the National Weather Service.  Employing radar and other data assimilation wizardry, it produces 15-hour short-range forecasts every hour.  For now, I'm downloading a subset of HRRR output for the western United States and providing a couple of surface diagnostic loops, one that includes 10-meter winds and model-derived radar reflectivity, the other that includes 10-meter winds and 1-hour accumulated precipitation.  The loops on also include analysis frames going back into the past as knowledge of the past is always handy for predicting the future.

More information on the HRRR is available here.  It should be handy for ski forecasting this coming winter.


  1. Wow, I tuned into this at 2:30 PM (MT) and noticed that there is a small area of rain near West Yellowstone. See it up there?. So I go to the Old Faithful live web cam and sure enough it looks like it rained there.

    Does anyone know if it rained at Currie, NV at that time?

    1. The forecast above is for 6 PM tonight, not 2:30, so don't give the HRRR to much credit :-).

      Also, given how dry it is in the low levels, it's not uncommon for the HRRR to produce decent composite radar reflectivities, but little precip at the ground due to evaporation at low levels. There's a 1-h precip product on that might be a better choice for comparing with observations.

    2. Love it, I'm desperate for accurate hourly wind forecasts on Utah Lake that can pick up the local thermal winds. Anyway to pull out the hourly wind forecasts for a specific point?

    3. That seems like something that might be out there already. If not, it's something that would be nice to add, although I confess the to do list is really long.

    4. I have yet to find anything that can pick up the local thermal winds that does hourly forecasts. The local NWS in SLC runs a 4km WRF as I'm sure you know and they have several point forecasts around the state but it is not picking up the local canyon winds or thermal winds very well. If this is something you can pull out for one point over Utah Lake that could be posted to the web that would be great, I could even get the Utah Water Ski Club to pay you for your effort.

    5. Scott:

      I have it in my mind to do, but admittedly it could be a while. Pay won't speed up the process.