I have a question regarding SAILS scan strategy and if the lowest sweep is ever different than 0.5 degrees?
With the advent of sweeps less than 0.5 degree in operations for the USA NEXRAD network, we now see lower angles (even negative) at times. But all documentation I can find seems to be written prior to the lower elevation angles, with a couple explicitly saying that 0.5 is the lowest tilt angle possible.
So, if the site can/does scan at elevation lower than 0.5 degrees, and goes into SAILS strategy, will 0.5 degree be the lowest repeated scan? Or can the lower angle sweeps be the lowest repeated scan?
I opened a thread over on Twitter about this - here is a response from someone who just attended one of the training events at the RAC
“According to what I saw in RAC training that I did Saturday, it will be whatever the lowest elevation is for the volume coverage pattern. MRLE will then cover up to the lowest four. Since they did not specify specifically, I assume that that applies even with lower scans.”
https://x.com/ScottTGL1/status/1787543793694064819
Thanks Max. I think that last statement is what I’d love to have spelled out in docs: “Since they did not specify specifically, I assume that that applies even with lower scans.” But it’s nice to know it is feasible to have other angles.
Mike Istok at the NOAA ROC was nice enough to confirm that scans lower that 0.5 can be chosen as the base or 0.5 is the base depending on a local radar setting.
Currently the SAILS repeat scan will be the lower than 0.5 degree tilt. Site’s do have an option to disable the lower than 0.5 degree tilt, so then the SAILS tilt would be 0.5 degrees like all other sites. SCN 24-09 includes mention of this (https://www.weather.gov/media/notification/pdf_2023_24/scn24-09_nexrad_level_III_product_dissemination.pdf).
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