Weather and mission planning ...

[Avocet]

I use a number of platforms for planning. Windy.com is my goto for wind information. Yesterday, I drove quite a distance for the perfect shoot, light, traffic (human), setting, mission planning all were perfect. However when I got there, I was socked in with fog. I flew a little in it (3-4 minutes) and realized the was shoot a bust unless I was prepared to wait and I also realized that this might be hardware harmful. What little footage I got was not great but I was able to make some lemonade out of the foggy lemons.

See it here.

METARs show temp/dewpoint but airport spacing is often too great to pinpoint conditions away from them and I'd llike to know what the best source for fog information might others be using?

Thanks ..

 

[The Editor]

I use a number of platforms for planning. Windy.com is my goto for wind information. Yesterday, I drove quite a distance for the perfect shoot, light, traffic (human), setting, mission planning all were perfect. However when I got there, I was socked in with fog. I flew a little in it (3-4 minutes) and realized the was shoot a bust unless I was prepared to wait and I also realized that this might be hardware harmful. What little footage I got was useless accordingly.

METARs show temp/dewpoint but airport spacing is often too great to pinpoint conditions away from them and I'd llike to know what the best source for fog information might others be using?

Thanks ..

METARS are better than TAFS obviously since they are observations rather than forecasts.
Other than temp/relative humidity/dew point via the METAR there isn't much else with accurate 'fog' specific information that I know of.

Will pop this one in certified pilots section as I can't imagine many hobbyists using/decoding METARS and TAFS.

 

[Avocet]

METARS are better than TAFS obviously since they are observations rather than forecasts.
Other than temp/relative humidity/dew point via the METAR there isn't much else with accurate 'fog' specific information that I know of.

Will pop this one in certified pilots section as I can't imagine many hobbyists using/decoding METARS and TAFS.

Thank you sir ... wasn't quite sure who the audience would be ...

 

[Steve@AerialImagesPro]

This is a good post and a good example of why these weather questions are on the certification tests (I assume in most countries, but definitely in the US). It's good to understand how weather works for this reason. Some people wonder why they need to know about weather to fly a drone because you can see the weather. And that's true to a certain extent. But this is a good example of why it's good to know. Also if you plan to fly when a t-storm is approaching, people don't realize the impact a good t-storm can have on the weather surrounding the t-storm.

I usually just use Weather Underground (or Weather.com) for the area I'm going to be in to get the forecast. I regularly have to drive 4 hrs away for a client and struggle with that. Pilot weather briefings give you 'observed' as The Editor stated which doesn't help you plan, and forecasted but those don't usually extend more than 24 hrs in advance because they know anything further out than that is too unreliable.

I try to pay attention to the forecasted Dew Point and Air Temp as that's what leads to fog. The closer the 2 are forecast to be, the more likely it is there will be fog. Fog occurs when dew point = air temp (or is very close to). Also look at forecasted ISO bars. The closer together the lines, the more likely it will be to be windy and even worse, shear in the area.

 

[Ralph thompson]

METAR/TAF data is the source for many third party sites. It is the most reliable data. In most countries there is a “plain language” selection for those unfamiliar with the meteorologist lingo. The Graphical FA provides a bigger picture. But in my experience, very local conditions are not picked up by any of the services. Specifically as it relates to winds & gusts, down drafts etc that can be very local and quite significant, say just above the tree tops or beyond the top of a building. There is a lot to be said for experience, caution and good judgement.

 

[Avocet]

METAR/TAF data is the source for many third party sites. It is the most reliable data. In most countries there is a “plain language” selection for those unfamiliar with the meteorologist lingo. The Graphical FA provides a bigger picture. But in my experience, very local conditions are not picked up by any of the services. Specifically as it relates to winds & gusts, down drafts etc that can be very local and quite significant, say just above the tree tops or beyond the top of a building. There is a lot to be said for experience, caution and good judgement.

Those weather attributes are usually handled with PIREPS and/or other comm centers distributed throughout the air traffic communication realm. Perhaps one day UAS pilots with have DROREPS or some such thing. Right now the ratio between UAV flights vs. Commercial or GA flights is barely measurable.

 

[Ralph thompson]

Like it DROREPS.
PIREPS are usually called in on Airways, higher altitudes with issues like clear air turbulence. It’s another kettle of fish for DROREPS to be called in, in a vast array of remote locations but like the idea. You heard it here first folks.

 

[SEAKdrones]

Skip to the last paragraph if you want to avoid the backgound.

As previously mentioned radiation fog, is formed when the air temperature drops to near the dew point temperature (e.g., 2 degrees C), causing the moisture in the air to condense into small, suspended water droplets – simply clouds at the surface. Often when cool/cold air overlies a warmer water body or moist surface, the winds are calm, or very light, fog will form.

For radiation fog, this occurs when the temperatures approach the daily minimum, typically in the early morning hours. The cooler air can be the result of overnight radiation cooling, a frontal passage, or overnight cold air drainage into valleys or over water bodies, among others.

It also is worthwhile to think about when the fog will “lift”, i.e., when you can expect the visibility to improve. And, is it is worthwhile to wait for your shot. Consider that the air is heated and cooled by contact with the earth’s surface. Cooling temperatures in the evening due to radiation cooling result in formation of an inversion near the surface, i.e., the air near the surface is cooler than is the air above. Cooler air is denser than the overlying air and thus wants to remain where it is (vertically) – not buoyant. However, as the sun rises and warms the surface the air becomes more buoyant and lifts, mixing with the overlying air and dissipating the fog. Also, when the inversion “breaks” there often is an increase in wind speed, which may be slight.

This is a simplistic explanation and there are other scenarios and conditions for fog formation (advection fog, ice fog, sea fog, etc.). But generally speaking I look for fog to form when there is (or forecast to be) a narrow temperature dew point spread of about 2 degrees C or less; light winds 2 meters/sec or less; and what is the location (e.g., near a water body, swamp, in a valley, etc.). I also crudely forecast when the fog will “break” (i.e., when the foggy air at the surface mixes with the “drier” air aloft) to determine when I should plan to shoot or if I should wait for a shot – as a rule of thumb 09:00 to 10:00 am. However, as with all weather forecasts – "it depends", e.g., season, frontal passages, and the vagaries of nature. This is hardly a rigorous explanation but I hope that it helps.