Report

Space weather: solar flux 105, 10 below its 90-day average of 115. Maximum usable frequency 10 megahertz, measured by the Idaho Falls ionosonde via KC2G: long-distance paths open through 40 meters, 30 meters marginal, 20 meters and up closed. Critical frequency 3.4 megahertz, too low for NVIS right now. K index 3, active. No significant flares. Data from NOAA.

We're in the declining phase of Solar Cycle 25, which peaked in October 2024. Sunspots and solar flux are trending down toward the next minimum, expected around 2030.

Sun and moon, Pacific Daylight Time: sunrise 7:08 AM, sunset 6:48 PM, day length 11 hours 40 minutes. Moonrise 12:27 AM at 58 degrees, east northeast; moonset 3:40 PM at 299 degrees, west northwest. Last quarter moon, 41 percent lit. The Orionid meteor shower peaks Wednesday, October 21, a meteor scatter opportunity on 6 and 2 meters. Moonbounce: the moon peaks today at 8:07 AM, 76 degrees high and 3 percent closer than average, a good time to listen for EME signals on 2 meters and up.

Meteor scatter is best in the hours before dawn, when Earth's leading side sweeps up more meteors.

Amateur satellite passes for the next four hours. No passes above 30 degrees in the next four hours. Frequencies and live status at amsat.org/status. Pass predictions at n2yo.com.

Satellite tip: keep FM satellite contacts short, callsign and grid square, so everyone gets a turn.

DX activity, via the cluster network and hamqsl.com. None spotted by West Coast stations right now. No aurora or 6 meter E-skip.

Tropospheric ducting, from balloon soundings 8 hours ago: No ducting strong enough for amateur VHF or UHF bands over Oakland. K6EEG's experimental tropo forecast, based on NOAA atmospheric model data, for the next 12 hours. Bay Area coast, peaking around 3 AM: ducting expected on 70 centimeters, 85 percent; a chance of ducting on 2 meters, 45 percent. Southern California coast: ducting expected on 70 centimeters, 85 percent; a chance of ducting on 2 meters, 45 percent. Nothing toward Hawaii.

Events. The California QSO Party, now under way, California stations in demand. IARU Region 1UHF/Microwaves Contest, now under way. VHF-UHF FT8 Activity Contest, on Wednesday.

Club and community announcements. The SF Amateur Radio Club meets on the third Friday of each month, 7 PM at the Randall Museum. Visit sfarc.org for more details.

Many handhelds can receive NOAA Weather Radio. Program the local channels.

Current weather conditions at San Francisco International Airport: All values in SI units. Clear. Temperature 22 degrees Celsius. Dew point 13 degrees Celsius. Relative humidity 57 percent. Wind calm. Barometric pressure 1010 hectopascals, normal. Visibility 16 kilometers.

Know how long your backup power lasts. Test it under real load, not just with a meter.

National Weather Service forecast. Values converted to SI units. Tonight: Partly cloudy, with a low around 17 degrees Celsius. West southwest wind 0.0 to 1.3 meters per second. Sunday: Partly sunny. High near 29 degrees Celsius, with temperatures falling to around 25 degrees Celsius in the afternoon. West northwest wind 0.4 to 5.4 meters per second. Sunday Night: Mostly clear, with a low around 16 degrees Celsius. West southwest wind 0.0 to 4.0 meters per second.

Tide predictions for today at the San Francisco Embarcadero gauge. Low tide at 12:34 AM, minus 0.02 meters. High tide at 8:16 AM, 1.42 meters. Low tide at 12:48 PM, 1.00 meters. High tide at 6:32 PM, 1.72 meters.

Ocean and bay conditions. No marine advisories in effect. From the San Francisco buoy, 18 nautical miles west of the Golden Gate: significant wave height 1.1 meters, slight seas, dominant period 8 seconds, from the west northwest. Wind at the buoy 5 meters per second from the west northwest. Ocean water temperature 16 degrees Celsius. San Francisco Bay water temperature 20 degrees Celsius. Golden Gate currents: slack water at 3:01 AM, then maximum flood 1.0 meters per second at 5:40 AM, then slack water at 9:03 AM.

Air quality for field operations, from the Bay Area Air District's San Francisco Arkansas Street monitoring station. Fine particulate matter, PM2.5, is 14 micrograms per cubic meter, rated moderate. Ozone is 15 parts per billion. Nitrogen dioxide is 22 parts per billion. For more information visit the Bay Area Air District or openaq.org on the web.

Seismic awareness for emergency communicators: no Bay Area earthquakes of magnitude 2.5 or greater in the past 24 hours. Largest in California in the past 24 hours: magnitude 2.4, near Alum Rock. No earthquakes of magnitude 6 or greater worldwide. Seismic data from earthquake.usgs.gov.

Repeater sites can go off the air after a major earthquake. Program simplex frequencies and know your local simplex plan.