From bsvoboda at nrao.edu Thu Nov 6 19:15:17 2025 From: bsvoboda at nrao.edu (Brian Svoboda) Date: Thu, 6 Nov 2025 17:15:17 -0700 Subject: [evlatests] VLA site forecast graphics Message-ID: Dear colleagues, I am circulating some information related to the forecast graphics I have developed for near-term operational guidance on phase stability, cloud cover, and wind speed. I'm preparing a memo describing them in detail, but I think they can be useful in the meanwhile for, e.g., fixed date scheduling, tests requiring high-frequency, and supplemental use by the operators. Complementary figures for the VLBA are in progress. The latest figures can be retried from and are updated every hour at roughly ~35 min after the hour: /home/birdseye2/bsvoboda/atmosphere/site_forecast/plots/latest All figures us UTC time. Figures of interest (as PDF or PNG) are described below. - "summary" a (-1.5, +9.0) hour forecast of phase RMS, wind speed, and cloud cover. A strip of colors at the top indicates the band limit when considering the limits for phase, wind, and cloud cover. A relatively conservative threshold in cloud column density is used for the latter. Black shows measured values and forecasted in red. The phase RMS panel overplots the previous 12 forecasts in transparent red with the latest in dark red. The forecast wind speed is shown in red with gust potential as an upward shaded region. The dotted vertical magenta line shows the time that the forecast was generated. - "summary_long" a (-3.0, +72) hour forecast (i.e., 3 day) equivalent of the above. The primary differences are: (1) the phase model does not use the most recent measured API data so is less accurate in the nearest ~1-3 forecast hours, and (2) the cloud cover data is more crude using a limit of ~25% coverage at mid-level altitudes. Guidance on less than +12 hours should use the former figure. Note that the hour and date on the x-axis labels can look very similar. The calendar date is listed at UTC 0 hours and has a centered dot separating the day and month (e.g., "08?Nov"). - "cloud_combo" shows an areal view of ~50 km on a side centered on the VLA with, listed roughly in the order of severity, optical cloud cover in gray, cloud liquid column density in blue, and cloud precipitating liquid in red. Panels are shown in 15 min intervals. Please find examples attached. The cloud figure is from August 15 since there were no forecasted clouds today. Several other quantities are also plotted. Specific forecasts can also be found in a (UTC) "year/month/day/hour" structure rather than in "latest". For those interested, the data themselves are stored in a directory called "forecasts" instead of "plots" and follows a similar structure. Clear skies, Brian -- Brian E. Svoboda, PhD Associate Scientist National Radio Astronomy Observatory (NRAO) Office: DSOC 312 Office Phone: +1 (575) 835-7246 -------------- next part -------------- A non-text attachment was scrubbed... Name: cloud_combo.pdf Type: application/pdf Size: 361882 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: summary_long.pdf Type: application/pdf Size: 114784 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: summary.pdf Type: application/pdf Size: 55681 bytes Desc: not available URL: