Salt Lake City Weather Assessment to Support Amateur Astronomy - Dashboard

Instructions Urls Last Verified and Updated 8-21-2025. K. Fisher fisherka@ipns.com

I. Weather Forecasting

II. Satellite Imagery

III. Moonrise-set and Sunrise-set, and Astronomical Twilight

IV. Deep and Shallow Sky

V. Air Quality - Pollution and Wildfire Affected Transparency

VI. Purpose and Background

A central nightly question for northern Utah amateur astronomers is "What is weather forecast tonight? How cloudy will it be?" The dashboard supports links primarily to authoritative government sources and reliable commercial sources to answer that question for northern Utah. Resources provided can be used to rapidly make screen clips to support nightly posts to northern Utah astronomy social media groups. This dashboard is duplicative of the many smart phone weather apps like Accuweather, The Weather Channel or Clear Outside. That is by design. I prefer to work from data closest to the original government source instead of information mediated by commercial providers. Additioanlly, general internet links are easier to gather weather data into a format suitable for social media posting.

VII. How to Use this SLC Weather Dashboard:

1. Under Section I:Weather Forecasting, click from left-to-right the first five buttons. Make screen captures as needed.
2. Under Section II:Satellite Imagery, click from left-to-right the first two buttons. Make screen captures as needed.
3. Section I, the last item, and Section III, Moonrise, Local Sidereal Time, reports the current UTC time and local Salt Lake City LST. This information is useful for annotating social media posts with date and times.
4. Sometimes for uncertain weather conditions, the National Short-term Forecast Maps under Section I, are useful to discuss the passage of front systems over multiple days.
5. The NWS CONUS Cloud Cover Animated Chart is useful for discussing the timing of cloud fronts.
6. The remaining sections and links provide additional useful information, e.g., during the summer time, wildfree smoke can compromise visibility but does not show up on traditional weather charts. Wildfire smoke is graphically forecast in Section V, Air Quality, resources.

VIII. Website Specific Notes:

1. Users should feel free to download local copies of this html file and to modify the same without this author's consent. To promote this process, this document is covered by a CC BY-SA 4.0 license.
2. GOES Satellite Animations: At night, use the sandwich filter.
3. Moon Phases: The Moon Phases display at TimeandDate dot com is used to identify those times during the calendar month in which the night sky is not washed out by moonlight - the "current dark sky window" - and those times of the month in which the night is compromised by bright moonlight - the "current bright sky window." Amateur astronomers typically do observing an imaging during a dark sky window. Planetary and lunar observing can be done during the bright sky window, although the advent of modern ultra-narrow band filters has enabled skilled amateurs to pursue DSO imaging without regard to the brightness of their local sky.
4. Utah Dept. of Transportation Webcamera System: This link goes to the UDOT Webcam portal. Use requires creating a login account and list of webcams. The use process to complicated and time-consuming, and is beyond scope of this dashboard. The UDOT webcam system can infrequently be used to verify the current cloud conditions in Utah's remote West Desert.
5. Heaven's Above: This satellite tracking website is best used as a mobile phone application. The website requires a login to particularize charts for a specific observing point.
6. NOAA HRRR Smoke Forecast Map: The HRRR Smoke Map has a maximum 48 hour look ahead. On the Vertically Integrated Smoke row, chose a look-ahead hour.
7. Skew-T Log P Plot - NWS SLC Upper Air Sounding: Skew-T Log P charts are a technical meteorological topic. On the reference map, click on Salt Lake City to display the Skew-T plot. If the graphical index chart of stations does not display, scroll down to the station list and to the Salt Lake Station "KSLC" row. Click and launch the current Salt Lake City Skew-T chart manually. Online search for "Skew-T Log P tutorial " for educational materials discussing this key type of meteorological chart. Sounding balloons (Radiosondes) are launched twice daily by the NWS at the Salt Lake City International Airport at 6 am MT and 6 pm MT. An easy way to study these complex weather balloon soundings is to download the Skew-T plot to your local disk. Then reupload the Skew-T sounding image to a GPT chat Large Large Model. Ask the chatGPT LLM to prepare a narrative evaluation, e.g., using a prompt such as, "From the uploaded Skew-T plot, please prepare a weather report narrative discussing the key features, readings, and notations in the figure." Three handy tables for interpreting Skew-T charts are in the Appendix. The first translates the millibars of pressure on the left-hand scale of the Skew-T plot into approximate feet above ground level. The second is a Celsius to Farhenheit conversion table. The x-axis of the Skew-T chart is expressed in temperature degrees Celsius. The third CAPE table defines Low, Medium, High and Very High levels of CAPE readings. CAPE measures the instability of the atmosphere. Higher CAPE values mean the atmosphere is more unstable and capable of producing stronger convection (e.g., thunderstorms, severe weather). Lower CAPE values indicate a relatively stable atmosphere with little potential for rapid convection of moist low altitude air to higher altitudes where they turn into thunderstorm producing cumulus clouds.
8. Skew-T Log P Plot - Nationwide Interpolated by Tropical Tidbits: Click anywhere on the nationwide CONUS map. Tropical Tidbits will generate a Skew-T Log P chart for that location from the surrounding NWS Radiosonde stations and the current GFS model run. There are a total of 92 U.S. Radiosonde stations in the United States.
9. Utah Division of Air Quality Pollutants: While the PurpleAir chart is a good summary for real-time particulant pollution measurements in the Salt Lake Valley, PurpleAir does not cover gaseous key summertime pollutants like NOx and Ozone. Because of this omission, the PurpleAIr chart can indicate good air particulate quality that is not healthy when gaseous pollutants are considered. The UDAQ air quality site provides this important additional pollutant information.
10. Federal Inciweb Wildfire Incident Reports: For large Utah wildfires managed by Federal wildfire response teams, daily incident reports are filed. This is the best real time data for large Utah wildfires on federal lands. Search by fire name.

IX. Acknowledgements:

1. College DuPage Meterology Department.
2. Danko, Attillia. Clear Sky Chart
3. Dept. of Geology, University of Utah (William Browning Building Webcams)
4. Heaven's Above
5. Jet Propulsion Laboratory
6. KSL News (Vortex Doplar Radar Forecast)
7. MesoWest
8. Netweather (Jet Stream Position)
9. NASA
10. NOAA-National Weather Service
11. Observatory Črni Vrh. (Comet Observation Database)
12. PurpleAir
13. Sky and Telescope
14. Time and Date (Weather Forecast, Sunrise Sunset, Moonrise Moonset, Extended Forecast, Planet Positions).
15. TropicalTidbits.com
16. United States Naval Observatory
17. University of Utah Geology Department (WBB Webcams)
18. Utah Dept. of Transportation
19. Utah Division of Air Quality.
20. Utah Wildfire.com (A consortium of Utah State and Federal Fire Agencies).
21. WeatherSpark
22. Wojczyński, Bartosz and PTMA (Transit Finder)

X. Revision History:

1. 2025-08-21. Added TropicalTibits nationwide interpolated Skew-T Log P charts. Added suggestion for using chatGPT to evaluate Skew-T plots. Added handy tables (millibars-altitude(feet) and C degs-F degs). Added Utah Div. of Air Quality Real Time Chart.
2. 2025-06-24. Added HRRR Smoke map link, Federal Inciweb Wildfire Incident Reports, and Skew-T Log P chart links.
3. 2025-06-02. Updated NOAA Satellite wildfire smoke map links.
4. 2025-05-20. Corrected link to South Rockies GEOS satellite image.
5. 2024-04-23. Updated url change for William Browning Building cameras.

XI. Appendix: