How can an inexperienced pilot tell if the weather is good enough for flying?

Question

When I look at weather in the morning of my flight, it looks good. However, the actual determination can be made later during the day closer to my flight time.

Being a student pilot, how can I efficiently make a decision about flight based on weather? Is there a particular way which can help me?

My flight is at 2PM. When I check weather at 8:30AM using this website I get the METAR for my closest airport as shown in these pictures:

There are a few details available. I want to know how can I make an informed decision at 8:30AM about my flight, instead of waiting until around noon time?

Answer 1

I'm a UK PPL of 14 years, I fly out of North Weald which is on the opposite side on London to Farnborough, so I'm well placed to give you some tips here. First, use the Met Office aviation portal for your planning, most of the services a PPL will use are free. Metars are useless for planning as they only say how the weather is right now, TAFs are good for planning, however they only get you so far as they show you the forecast for one location. The Met Office portal gives you access to the low level forecast charts and spot wind charts, these give the big picture for the whole UK and Europe, including fronts, and forecasts in specific zones. These are published 4 times a day and are good for about 18 hours each.

The weather in the south east of England is very hard to predict accurately, it's getting better as they throw more computing power at it but it's still a challenge. When I do my weather planning I look at the low level chart and spot winds, then I look at the TAFs throughout the area. Heathrow and Gatwick both have 24 hour TAFs, and Farnborough is snuggled between them I'd look at them both and assume the worst from each.

Read the TAFs and look at the briefing charts every day you can until you get a feel for it, experience will give you confidence.

Next set limits. In the SE of England there ain't much topography but you don't want to cruise below 800ft in most places, back before I got an instrument rating I typically set a limit of 1000 ft ceiling, anything below and I wouldn't fly except for circuits, and even than that's pushing it. Wind-wise you need to know your crosswind limit for your airplane and yourself. It doesn't matter if your airplane's rated for 20 knots if you can't hack it, so don't put yourself in a bad position.

Lastly, UK TAFs have a funny quirk. You'll often see PROB for probability in a TAF. The only 2 figures you'll ever see in a UK TAF are PROB 30 and PROB 40, the numbers are for percentage likelihood. PROB 30 means it's unlikely to happen, whereas PROB 40 means it probably will happen. In other words a 40% probability does not mean 40%, but about 60-70%, don't ask me why. So if you see PROB 40 consider it likely.

Answer 2

I am a private pilot with just VFR rating. I check many weather sites before I make a decision as to is it ok for me to fly or not. I call 800-WXbrief, which for US is a very good source, too.

I also have developed friendships with many instructors who have been flying to airports of my potential destinations for many years. I ask them about weather patterns on those itineraries and what to generally expect to happen if worse comes to worse.

I also call the tower of airports on my rout and ask them the weather or any noteworthy emerging situation. The flight following service which is available on demand will sometimes assign you a rout to help you stay in VFR till you reach your destination.

All that said, I have had a couple of times to cut short my flight and land to avoid an emerging convective front and call for a ride back home, or get a room in a hotel!

Answer 3

The METAR only gives you a small snapshot in time. They are only good for an hour. They are usually refreshed around 55 minutes past the hour. TAFs, on the other hand, cover a 24 to 30 hour period and they are published 6 times a day (0000, 0600, 1200, 1800). Routine TAFs are valid for 24-hours. SPECI is an aviation special weather report issued when there is significant deterioration or improvement in airport weather conditions, such as significant changes of surface winds, visibility, cloud base height and occurrence of severe weather. Now, lets go back to your wx search at 08:30. Well, looking at a METAR it is already 2.5 hours OLD. So, you should look again at the METAR @ 12:00 hrs. But, again you are 2.5 Hours old. The point being is when you are a PILOT you are ALWAYS looking at the wx. No one report is going to be good for any extended period of time. Even when you are flying you can contact Flight Watch (122.2) or listen over a VOR and get wx while you are in-route. ALWAYS - Get a WX report and a listing of any TFR's. Your instructor should be drilling into you the need to get a wx report and TFR's before every flight.
If you bust a TFR the first thing the FAA does is check when you received a wx report & TFR report. OK, so you got a current wx report. You did the flight to your destination airport. Great Flight! Did you look ahead? How is the wx going to be for the return flight? Flying does not start when you turn the key, it starts hours or days before and ends when you tie-down and close your flight plan.

Answer 4

One might consider reading books about aviation weather. Weather Flying by Robert Buck is timeless, and is good for VFR and IFR flight. All my primary and instrument students read it. I cannot remember any student complaining about having assigned reading in that book.

One way is to start by looking at the PROG charts about two days in advance and getting an idea as to what will be driving the WX for my intended flight(s). Then less than 24 hours before, one can start looking at TAFs. Before the evolution of phone WX apps, I used to record the TAFs for my route on a file card. That way the trends were visible. Hours before the flight, the METARs were recorded.

This way one has access to the trend in the WX. If the TAFs remain consistent and the METARs are in line with the TAFs, then at least there is a stable forecast. If the METARs are consistently getting worse than the TAFs, then the forecast is less stable and in an undesirable way.

In addition to watching the forecasts and how they are realized in observations for your intended route and nearby stations, there are other metrics. If one is a student pilot, doing solo pattern work, the instability of the air will influence the gusts and variability in the wind direction. Sailplane students may look at lift indices, such as K or LI, which are measures of air stability. Most airplane student pilots will look at gusts of surface winds, but often the gust reporting and forecasting only occurs after the gusts become a factor for students.

Looking at the winds aloft forecast will help one appreciate shear and instability at lower levels. Certainly if there is allot of differences at lower altitudes at or near where one is operating, a slight change against the forecast could yield difficult surface conditions.

Finally, there is a regional factor. Much of my instruction has been in the vicinity of the great lakes, and lake effect/enhancement can create localized changes, which are often not reflected in forecasts, but can be predicted by regional knowledge. Your instructor should help out here. In the US, areas with unique WX will often have seminars and other talks, where the local effects are discussed. This is more common in coastal, mountainous and similar areas (Great Lakes included).

One's friend is an understanding of the theory, knowledge of the specifics of the reporting products, and the regional tendencies. Integrating those aspects together will reduce your risk, not only of serious WX situations, but also help you better understand your likelihood of a successful flight or a wasted trip to the airport.