Mussel Rock Weather Conditions Readme

DISCLAIMER: This website is beta. It is going to have bugs and bad data. Always use your personal judgement before flying.

How to use this website

This is NOT a site guide to flying at Mussel Rock. This is just a guide on how to correctly utilize this website. I made this site for my personal use. And for the record, I can't claim to be an expert on Mussel Rock flying conditions. I made this website, because I was trying to accumulate enough flight hours to complete my P3 rating, and I found the forecasts/data to generally not be reliable. And I would see on Telegram that other people were flying when conditions on wunderground looked unflyable. I live about 20 minutes away, so if conditions seem good it's easy enough to just hop in the car to check it out. But it also is a waste of time if conditions are unflyable/unsafe. I just want to maximize my effort, and I think this website works pretty well as a spot check before driving down.

So I generally read the whole page top to bottom before deciding to go. There is data from multiple sources, and individually they mostly have mediocre data quality. But if you combine and correlate the data, you can get much more value out of them. And if you don't look through all the data, you can easily miss out on a red flag such as rotor/fog/whitecaps/etc. and then waste a trip out to MR. I built this website, and even I've still wasted a few trips due to not looking at all the data.

KCADALYC1. This station is hosted at someone's house on Longview drive. I think that they also host the Mussel Rock webcams. I don't know the person, but I am very grateful for their data. This station is frequently in rotor when the wind has a South component. The easiest way to confirm that it's in rotor is to compare the wind speed with the station at Coyote. If Coyote is showing higher winds, then KCADALYC1 is probably in rotor. When it's in rotor, just ignore all the data from this station.

KCADALYC37. This station is at the Coyote launch. If you are standing on launch, and facing the water, it's just on your left. This station has had some past problems with solar power, it's battery, and wind direction sensor. Those issues seem like they are fixed now. I think this wind meter frequently under-reports data by approximately 1-2 mph. I like to launch from Coyote and Walker, so I pay a lot of attention to this meter.

KCAPACIF205. This station is at Sharp Park Beach. It's run by the same person who operates the Pacifica webcams( As of September 2020, this is a brand new station. I don't have any specific knowledge on how it might be effected by rotor. The elevation of the station is very low, so I would expect that it will under-report if there is any wind gradient. And also it's not on-site, so it's possible that conditions could be different between Mussel Rock and the Pacifica Pier. I believe that this could be really valuable data, but only time will tell.

KCASANFR69. This station is at Fort Funston. This station isn't at Mussel Rock, so it can be somewhat different. Most importantly it is higher than the other two stations. So if there is a wind gradient, it might show the wind as higher than the other two meters. This is important to avoid getting blown over the back. So if Fort Funston is reporting 20mph, and the others are reporting 12mph, you better be careful.

Mussel Rock webcams. The still image data might be stale. I couldn't find a programatic way to check the staleness of that data. But check for fog. It's possible that the fog could be low enough to show up on the webcams, but high enough to still be able to do some flying.

The Cheetah YouTube live stream is awesome. You can check fog levels down lower than the static webcams. And I've sometimes seen people flying Cheetah. If someone is already flying, it's on.

Fort Funston webcams. These are potentially useful for checking fog height, and a wind sock is in view as well. Sometimes you can see hanggliders staging, which can be a good indicator.

Pacifica Webcams. I only show the webcam pointed at the flag, but there are a few webcams at Pacifica. The ones on YouTube are really great video quality. The flag should act as another data point to confirm wind direction and speed. Remember the flag is closer to sea level, so it's possible to have light winds there, but stronger winds higher. The pier points directly West, so try to use that to determine the direction of the wind. This webcam also has enough detail to show whitecaps. Put it in full screen mode on YouTube to get the best view of potential whitecaps.

Fog chart. I think this is useful for seeing how thick the fog is. Some days it makes sense to do some parawaiting, and wait for the fog to clear. Some days it's not going to clear. This thing uses satellite data, and I don't think it can really tell clouds from low fog. Low fog is not flyable, but high fog might be fine.

Tide chart. The data for the tide chart actually refers to a NOAA station at the Golden Gate Bridge near Chrissy Field. So it's not exactly the same as Mussel Rock. But you get the big picture of approximately where the tide is at, and which way the tide is going to move with time. And I think that's what really matters. Also it's best to confirm these things visually on site, maybe the beach is getting pounded with giant waves and it's not a safe landing site.

NWS Forecast. I haven't really used this too much. Another developer added it in recently, but it could be useful.

Windy Forecast. I don't know how useful that thing is. But I use it to forecast how stable conditions will be. I don't compare the data from the sensors to Windy. I check if Windy thinks the wind will be consistent or if it thinks that winds will increase/decrease over the next few hours. In my experience Windy will over report gusts at MR.

Also follow the Telegram group for Pacifica. Nothing beats the knowledge from experienced local pilots onsite.