I am trying to model flight decisions (when/where to fly). Obviously an important factor is weather and I have found the very nice forecast archive that NOAA keeps.
Since I have no flying experience myself, I was hoping some forum participants could opine on:
how far in advance do people look (a day? a week?)
does you look at the average forecast for the day or for the particular time you were going to fly (the latter is only available 3 days out)?
what variables do you focus on: temperature, probability of precipitation, ceiling height, visibility, etc?
Essentially I am trying to figure out whether I should be focusing on the 3-day or 7-day forecasts. The former have additional variables and time-of-day forecasts, but are of course of shorter range.
The variable lists are available at:
3 day forecast: weather.gov/mdl/synop/metcard.php
7 day forecast: weather.gov/mdl/synop/mexcard.php
Any comments you have would be greatly appreciated
I was an FAA weather briefer, and after reading forecasts for years you realize the best any forecast can be beyond a couple of days is very general: Will it be VFR or not? Is there a chance of significant weather or not? And you go from there. Two days out is better data than three. One day in advance is getting close.
I doubt any pilot reading into the ETA forecasts (if they even know what it is) thinks the forecast for two o’clock in the afternoon three days from now (Sunday, as of this writing) is going to be exact. Its a pretty nice “guide”, but not something to really guarantee. And a seven day forecast is nice to read, but it is even less of a planning guide.
The best way to interpret these forecasts is with many different sources of information and charts, not just one. And the best way to interpret all these sources is to keep up with the weather every day. Today, for example, a big trof is cutting across the west. By Sunday and Monday, a cold front will form in the Mississippi River Valley and move east. You should know that information before you start reading the 3-7 day forecasts for the east coast.
how far in advance do people look (a day? a week?)
For me and long XC’s my planning started a week in advance using the basics of NWS.
3 days before I start using aviation websites up until the day of launch.
does you look at the average forecast for the day or for the particular time you were going to fly (the latter is only available 3 days out)?
3 days out, you can’t bother with time of day. They can’t forecast today with time much less three days out. So I use the “worse case” scenario in evaluation but no decision is made to go or not go until day of departure.
what variables do you focus on: temperature, probability of precipitation, ceiling height, visibility, etc?
All of the above. Since I fly a basic airplane below freezing temperature is critical in visible moisture (AKA clouds I may have to fly in). Being that I am instrument rated, rain is not a show stopper but thunderstorms or ice of any nature I just don’t fly. I’ve scrubbed flights on the same day of departure where a forecast of snow or thunderstorms without hesitation
The flying I do usually involves a friend saying, “come on lets go fly Tuesday” so it’s usually a couple days out. More than a day out, the most detailed I get is, it’s gonna be nice, it’s gonna be bad, or it could go either way, which in the spring/summer typically is the most common because the forecast (here at least) usually involves both nice and not so nice WX in the same day.
I usually give a more serious look 12-24 hours prior, but even then it’s with a grain of salt. I look at prog charts etc, but focus on the TAFs (Terminal Aerodrome Forecasts) for the airports I plan to use as well as those in between and nearby. I’ll also do an outlook breifing with FSS or DUATS. My experience has been that this info 12-24 hours out is still far from reliable and is only a guide to plan on where to go, or if we should even drive to the airport at all.
I’ll periodically check between this time and several hours before, but again the forecasts are still subject to change.
Before I leave the house I’ll usually give it a quick look, and 9 times out of 10 the forecast at that time contains at least a degraded expectation than what I’ve been seeing for the previous 24 hours. Usually this will include lower ceilings, more cloud cover, or precip that wasn’t in previous forecasts. If it looks like it’s doable, we’ll go to the airport and I’ll call FSS on the way to the airport, and/or I’ll check the WX including radar, TAFs METARs PIREPs etc.
It’s the forecasts in the last hour that, obviously, are the most reliable, and until then, I really don’t take much faith in the farther out forecasts.
I usually utilize the NOAA site aviationweather.gov for my info.
I also use DUATs, and FSS.
I’m mainly checking vis and ceilings, but of course precip and any hazardous weather, including the freezing level for icing conditions, winds that may dictate operations at a particular airport, etc. Temp is important for performance calculations so, all of the WX info is important for various reasons.
It depends on what you are flying and what kind of experience you have.
A couple of thoughts, in no particular order:
For us professionals flying high performance airplanes, as flyboy said, “why check the weather we are going anyway” is the standard saying. It may not literally be true but not far off the mark. It has to be bloody awful for us to not go. I check the weather just because the passengers are going to ask. Not so much with my company but flyboy sometimes only knows about a trip when he gets the call to “get to the airport now”.
Any forecast more than 48 hours before the flight is only good enough to tell me if I need to bring the swim trunks or the Alaska winter jacket.
On the other hand Allen and pfp217 don’t fly airplanes with the performance or equipment to handle much ice or to climb over the typical storm so they have to be a lot more religious in their preflight checks. Driving or calling Southwest enters into their equation so making the decision several days in advance may save them a bunch of money on airline tickets.
This probably doesn’t help you with a model but that’s my view.
I wish! I’m doing 50NM x-country’s etc. .although a big ocre 73 might be fun for a couple VOR approaches at the local airports !
Yeah John in Saudi and Flyboy bring up good points. I worked as an airline ops agent for many years and the crews would look at their weather for the pax info, and pretty much the idea of the probabilty of making it in right away, holding or possible diversion.
Another thing with the airlines and other charter, freight outfits is, their aircraft, though not all, is probably equipped with WX radar. Also they have dispatchers to keep in contact with that are keeping an eye on the big picture as well. That said, the dispatcher in his nice warm seat in front of a screen with a coffee at his side is a little more likely to go ahead and send em through that area than the crew that’s getting their !@#$# knocked around by the weather.
Wow: thanks for all of the responses! This is super helpful.
If I might roughly summarize what folks posted:
whether one flies or not in inclement whether depends on your training/experience and plane type
planning can start 7 days out, but 3 days or so is more typical. And from so far out from the flight, one looks mainly for extreme weather (since the forecasts are not very accurate)
one almost always checks weather pretty frequently starting 12-24 hours before the flight
time of day forecasts beyond a day out are not too useful
one needs to consider a wide range of weather indicators, and should look at the origin/destination airports (and perhaps ones in between as well)
Also a couple of particular responses:
pthomas745: thanks for the pointer to the prog charts. Since I am doing analysis at the airport-level I will not be able to use this, but it is a really nice reference.
Allen: thanks for going down the specific points I listed. Also appreciate the link to the other thread: lots of details (some of which went over my head) which helped me see what key factors people were looking at and how far off people plan.
pfp217: the detailed timeline was a real help. And as a non-flier, I did not know about DUATS (though I guess I will not be able use this since access seems to be restricted to registered pilots) or FSS (which seems to be primarily short range forecasts as described here, nws.noaa.gov/om/brochures/pilot.htm )
flyboy97222 and John: thanks for pointing out circumstances where weather forecasts do not matter too much
Again thanks to everyone for taking the time to comment. And if I misconstrued anyone’s points please let me know.
pfp217: the detailed timeline was a real help. And as a non-flier, I did not know about DUATS (though I guess I will not be able use this since access seems to be restricted to registered pilots) or FSS (which seems to be primarily short range forecasts as described here, nws.noaa.gov/om/brochures/pilot.htm )
I beleive that is correct about DUATs, once you have had a medical, you are considered a student pilot so that will allow you to access DUATS. BUT the info found at DUATS can be found at aviationweather.gov as well. It’s a little more labor intense, where , on DUATS you plug in route, planned altitude etc, and it will pull up all pertinent weather for your route of flight. W/ aviationweather.gov you get all the same weather info in plain or coded text, but you have to choose each type of weather product. For instance if I want to look up winds aloft, and then find out what the forecast is, I’d have to look the winds aloft up, and then look for the TAFs.
The reason I use DUATS really instead of aviation weather.gov is because I can get all of the Notices To Airmen. So aviationweather.gov is a good tool as an alternative to DUATS.
Greetings from Springfield by the way professor, despite what VT claimed a couple of years ago, we here at SPI ARE home of the Simpsons!
Oh and Prof Frink has calculated that there is a 32% probability that Springfield is in Illinois: Heisenberg uncertainty principle precludes a more specific statement.
