Weather-guessing 2-3 weeks in advance?

[PJClark]

One of the (many) things I've not figured out is how to plan a trip, and be sure I'm really going to "go", more than the few days in advance that I can be sure of the weather.

I'll be the first to admit that my weather reading prowess when it comes to looking at the maps is...let us agree "crap".  :-)  Pilot Training was 35 years ago and even if I didn't sleep through most of the weather classes the brain cells must've got killed off in a bar somewhere long ago.

So any tips on how this is done successfully and consistently, I'd sure appreciate. Or I guess on the other hand if nobody can really plan much further in advance than the Forecast Discussion, that'd be good to know too: at least I won't feel quite as dumb!

thx

PJ

[Ragsf15e]

5 minutes ago, PJClark said:

One of the (many) things I've not figured out is how to plan a trip, and be sure I'm really going to "go", more than the few days in advance that I can be sure of the weather.

I'll be the first to admit that my weather reading prowess when it comes to looking at the maps is...let us agree "crap".  :-)  Pilot Training was 35 years ago and even if I didn't sleep through most of the weather classes the brain cells must've got killed off in a bar somewhere long ago.

So any tips on how this is done successfully and consistently, I'd sure appreciate. Or I guess on the other hand if nobody can really plan much further in advance than the Forecast Discussion, that'd be good to know too: at least I won't feel quite as dumb!

thx

PJ

I tend to plan no more than a day or two out in the winter.  Longer in the summer.  In a turbo, fiki airplane, extend the winter a few days.  Honestly, the weather guessers are no good past about 3 or 4 days, even for the big stuff.  But of course, now I’m gonna catch crap.

[carusoam]

What type of go/NoGo decision making are you doing?

IFR or VFR...

Avoiding clouds or avoiding ice...

Avoiding rain or avoiding thunderstorms...

We have a weather guy around here... he has a service that is awesome for IFR pilots that always want to know where ice and cloud tops are... and where unstable weather can be found...

If you can say things like skew log T in the right order... that weather service is good for you...

As far as weather guessing accuracy... it has gotten much better in the last few years it can go out a week in stable situations...

Even unstable predictions have gotten much better...  watch the hurricane modeling if you need an example...

What kind of weather are you trying to avoid?

weather prediction a week in advance is still pretty new, and not near 100% accurate...

I still use the old style prognostic charts delivered by my nav device called WingX...

Have you seen the windy app?

PP thoughts only, not a CFI...

Best regards,

-a-

[takair]

After years of fighting this issue, I have come to the conclusion, supported by perceived fact, that if I really want to use the plane to get somewhere on a specific day, the weather will likely be crap.  In an effort to beat this, I now don’t plan to use the airplane until almost the last moment.  I have cancelled fewer airplane trips this way.  I also hate driving places, so generally plan to go to fewer places.  Ironically, since starting this strategy, my flying hours seem to have gone up and I enjoy flying more!

[blaine beaven]

I fly between 80-120hrs a year, and most of it is to take me to work. Because I have to arrive at work at a specific time, I need to be airborne at a specific time. This is obviously a later time than I would have to depart at if I was driving.

Every morning that I wake up to fly, I wake up at the same time as if I had to drive and check the weather. If everything looks good, I go back to bed for a bit. If the weather is bad, I hop in the car.

The weather forecasters often can’t get it straight beyond a day... I always have a plan B. If you can predict the weather more than a week out, bottle that ability and sell me some.


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[Immelman]

2-3 weeks out all you have is statistics and seasonal averages.

You also have time to start studying the forecast discussions, wind aloft, and other long range forecasts (long range being 3-7 days) and see how those play out over the coming weeks.

You can decide whether you want to be somewhere on a specific itinerary (buy an airline ticket), or if not, to what degree of time slippage on either side of your target date/time is required to allow crap weather to pass should that happen when your trip comes if you still want to fly your Mooney. And with enough schedule flexibility you will be able to... its just a question of how much.

 

Edited January 11, 2020 by Immelman

[Niko182]

Book a refundable southwest ticket if need be.

[MIm20c]

1 hour ago, Niko182 said:

Book a refundable southwest ticket if need be.

I do this on every important trip or if someone needs to be picked up on a certain date. Get the southwest CC and you can easily cancel a day before the flight with no penalties. 

[Ibra]

4 hours ago, Immelman said:

2-3 weeks out all you have is statistics and seasonal averages.

Yes, only works as expected if doing the same trip in same date every year (I do London, UK to Nantes, France mid July), average temperature is accurate with small variations, surface pressure have bigger variations but surely in high side, that is still better than 2 weeks weather forcast model to make a call on the likelihood of you flight, forecast models do not use any historical data or seasonality adjustment, most will just run bunch of calculations on initial condition today with regular updates of the numbers against short term data...

 

Edited January 11, 2020 by Ibra

[0TreeLemur]

5 hours ago, Immelman said:

2-3 weeks out all you have is statistics and seasonal averages.

You also have time to start studying the forecast discussions, wind aloft, and other long range forecasts (long range being 3-7 days) and see how those play out over the coming weeks.

The skill of the current generation of weather models decays over time.   From one to three days they are generally decent at forecasting winds and clouds, and so-so with precip.    The current generation of models have some skill at predicting the location of precipitation only out to about 5 or 6 hours.  After that there is a large spread from one run to the next.

Weather forecasts from 4 to 7 days they are fair-to-middlin', with weaker events like popcorn convection being harder to predict than weather associated with strong cold fronts.  Current models can sometimes portray strong frontal systems like the one now affecting ArkLaTex up to Michigan up to about 10 days in advance with maybe a few hundred miles uncertainty in their location that far out.   Same thing with some deep lows that can get spun up, like hurricanes.  Beyond that, as @Immelman wrote, you gotta go with the climatology/probabilities.  

 

 

[PJClark]

Well thanks all.  I'm relieved to learn there's no magic I wasn't aware of.  Overnight I figured out that since I live in Ohio I can always look at a west coast METAR and figure my own weather will likely look like that in 3-4 days.  But beyond that there's literally nothin'.

 

[Austintatious]

Pro pilot here... you will become very frustrated if you try to plan 2-3 weeks out for go/no go decisions... We just arent that good... there are too many variables.  The only things we can predict that far out with any accuracy are seasonal patterns, including expected winds aloft  and approximate hurricane paths. 

For me, on a typical trip, I will look at weather no further than 1 week out just to get a feel for what MIGHT happen.  If weather is going to be a problem, I let everyone know.  At 2-3 days prior I make it clear in no uncertain terms that there may be delays. 

I have seen the situation change both ways... Good weather turn bad despite predictions and bad weather never come despite predictions.  I have gone to bed the night before a trip looking at 100% possibility of thunderstorms and the next morning when I woke up, the forecast had changed to clear skies.

 

One thing to keep in mind, all the weather services are getting the same info from the Log P skew T charts from the ballons that are released.  You can see the raw logs here  https://www.ospo.noaa.gov/Products/atmosphere/soundings/sfov/skewt/index.html

I mostly use the following apps:

Wunderground - typically start watching this a week out.

Windy - great for winds and precip

Storm radar-  Perfect for game day seeing where the storms are and where they are moving.  It has a great predictive feature that will continue the loop past the current time.  I have found it to be fairly accurate in that if once past the current time, the storms start to dissipate they will, or if it shows them getting worse (always does one or the other) then you can bank on wx being a factor.

I also use fore flight for official aviation weather purposes and also Arinc hazard alerting, although I have found it to be more annoying than relevant a lot of the time.

 

for me this has worked well and I have not been caught by any surprises.  The three apps give a great mental picture of what is going on in the BIG PICTURE.  The true aviation weather is better for seeing what is happening in a specific location.

Keep in mind that I fly a very capable aircraft.  There is really no en route weather that I cannot get over or around with minimal impact to the flight, so for me at the job, I am primarily concerned about departure and arrival location weather, winds aloft and weather at destination for the duration of the layover.  If I think storms or freezing weather are coming, hangar is essential.

When I get in my mooney, Enroute weather is much more important to pay attention to.  My wife knows that even though we have plans to go somewhere, weather can stop us and we might not know until the day of departure.

the most important thing is to be willing to scrap the flight.

 

 

[Bob - S50]

Don't forget the Farmers Almanac.

[FloridaMan]

I use the RadarUS+ app and love the 6 day pressure/precip map. While it isn't a full two weeks by a longshot, you get an idea of the forecast at your destination within a week and what you might expect enroute. 

[Skates97]

I start watching the forecast on the various sites when the 10-15 day is available (some sites predict/guess) further out. By the time I am a few days away I have a pretty good picture of what the weather is doing from watching how the forecast has or has not changed. It's served me well so far on many trips from SoCal to Utah, Northern California, Phoenix, and our coast to coast this past summer. 

I haven't ended up stuck anywhere, but I have made drives where it turned out I could have flown. Right now I'm in Salt Lake getting ready to drive back to SoCal. We had to be up here for my son-in-laws graduation last night, he just got his Masters Degree. The forecast for the past 10 days has said snow beginning last night and off and on through Wednesday. Even Thursday night it was still forecast for 1-3 inches Saturday with IFR conditions in the Salt Lake area beginning Friday about midnight with snow and carrying through Saturday. Friday was supposed to be, and was, a great day to have flown. Clear skies the whole drive here, but it was the getting back that concerned me.

Well, last night at 11pm it was still almost completely clear skies, and this morning it is still currently VFR conditions here and we could have easily gotten up and flown home this morning. However, I have to be back to work Monday and there wasn't the option to wait out weather, so we drove.

[Scott Dennstaedt, PhD]

On 1/10/2020 at 9:49 PM, PJClark said:

One of the (many) things I've not figured out is how to plan a trip, and be sure I'm really going to "go", more than the few days in advance that I can be sure of the weather.

I'll be the first to admit that my weather reading prowess when it comes to looking at the maps is...let us agree "crap".  :-)  Pilot Training was 35 years ago and even if I didn't sleep through most of the weather classes the brain cells must've got killed off in a bar somewhere long ago.

So any tips on how this is done successfully and consistently, I'd sure appreciate. Or I guess on the other hand if nobody can really plan much further in advance than the Forecast Discussion, that'd be good to know too: at least I won't feel quite as dumb!

thx

PJ

Hi PJ.  When I read the title of your post I thought there was a typo.  He probably meant days, not weeks.  ;-)  Well, if the title has been 2-3 hours in advance, that's a problem I can help with.  Two to three weeks?  No way.  At this far out you are hoping that you can count on knowing whether or not you'll need to pack an umbrella or carry sunscreen.  But I can't tell you how many times I've taken that umbrella and not needed it or never used the sunscreen or discovered that I should have packed more shorts.  

Rant on: I really do wish that pilots would acknowledge that forecasting IFR conditions, turbulence, icing, thunderstorms, etc. with any confidence is simply not possible more than a few days out.  You might as well flip a coin...it's more likely to give you the right answer.  About the best we can do beyond about three days is attempt to determine whether the surface temps will be above normal, below normal or somewhere in between.  Same with precipitation. Rant off:     

If you want to see some data that has even a remote chance of being correct, you will want to learn the words Climate Prediction Center.  See https://www.cpc.ncep.noaa.gov/products/predictions/WK34/ for the 3-4 week outlook.  Notice that under the precipitation forecast, it's experimental.  At that range we are still in the experimental phase.

Hope that helps.

Edited January 13, 2020 by Scott Dennstaedt

[aviatoreb]

7 minutes ago, Scott Dennstaedt said:

Hi PJ.  When I read the title of your post I thought there was a typo.  He probably meant days, not weeks.  ;-)  Well, if the title has been 2-3 hours in advance, I would have gladly been able to help. That's a problem I can help with.  Two to three weeks?  No way.  At this far out you are hoping that you can count on knowing whether or not you'll need to pack an umbrella or carry sunscreen.  But I can't tell you how many times I've taken that umbrella and not needed it or never used the sunscreen or discovered that I should have packed more shorts.  

Rant on: I really do wish that pilots would acknowledge that forecasting IFR conditions, turbulence, icing, thunderstorms, etc. with any confidence is simply not possible more than a few days out.  You might as well flip a coin...it's more likely to give you the right answer.  About the best we can do beyond about three days is attempt to determine whether the surface temps will be above normal, below normal or somewhere in between.  Same with precipitation. Rant off:     

If you want to see some data that has even a remote chance of being correct, you will want to learn the words Climate Prediction Center.  See https://www.cpc.ncep.noaa.gov/products/predictions/WK34/ for the 3-4 week outlook.  Notice that under the precipitation forecast, it's experimental.  At that range we are still in the experimental phase.

Hope that helps.

http://eaps4.mit.edu/research/Lorenz/Butterfly_1972.pdf

http://eaps4.mit.edu/research/Lorenz/publications.htm

http://www.stsci.edu/~lbradley/seminar/butterfly.html

 

[carusoam]

So PJ...

You have heard from pro-pilot...

You have heard from pro-weather guy...

You have heard from a bunch of PPs with IRs...

You got some info regarding math and math modeling from a pro-math guy...

Your homework, if you so wish, is take in as much as you can... review the apps the other people are using...

One of the best for flying in IMC is the one Scott D. has...

Do whatever it takes to stay out of thunderstorms and icing... 

There are a few threads for each of the recommendations, use the search to find them...

For fun... find the thread discussing supper cooled water droplets and how fast ice builds up... pics are included.

Does it get any better than this?!?!?!

Go MS!

PP thoughts only... not a weather guy, math guy, pro pilot guy, I didn’t even stay in a holiday in this year...

Best regards,

-a-

[PJClark]

@aviatoreb... yeah, I knew all that.  The post was dumb.  The right question  might better have been put as "how do you convince your passengers (ie, copilot, ie wife) that not knowing for sure that you're  going or not, until maybe the night before (or morning of!), Is OK?"

So much for gin-influenced MS posting!

[carusoam]

Better chance of gin-influencing the passenger... 

-a-

[aviatoreb]

44 minutes ago, PJClark said:

@aviatoreb... yeah, I knew all that.  The post was dumb.  The right question  might better have been put as "how do you convince your passengers (ie, copilot, ie wife) that not knowing for sure that you're  going or not, until maybe the night before (or morning of!), Is OK?"

So much for gin-influenced MS posting!

Maybe tell them you are on gin and you can't tell them right now until you sober up?

All my friends are used to my being a bit flakey with pinning down when I might show up.

I blow with the wind.  Sometimes it's sunny.  Sometimes it's nasty.  Usually there are nasty bits and in-between the nasty bits there are nice bits.  Just wait - or go early.  I blow with the wind.

[takair]

1 hour ago, PJClark said:

@aviatoreb... yeah, I knew all that.  The post was dumb.  The right question  might better have been put as "how do you convince your passengers (ie, copilot, ie wife) that not knowing for sure that you're  going or not, until maybe the night before (or morning of!), Is OK?"

So much for gin-influenced MS posting!

I think Anthony nailed it (gin or tonic of choice) I this is one of the biggest “discussions” my wife and I have regarding flying.  She likes to go when we planned on going but also has an influence on the weather gods (did I mention she’s not a fan of flying to begin with).

[Rick Junkin]

41 minutes ago, takair said:

I think Anthony nailed it (gin or tonic of choice) I this is one of the biggest “discussions” my wife and I have regarding flying.  She likes to go when we planned on going but also has an influence on the weather gods (did I mention she’s not a fan of flying to begin with).

Same here! My wife knows three aviation weather words: "thunderstorm", "icing" and "tailwind". If she hears the first two she picks an audio book for the car ride that we'll probably be taking. She hears the last one so infrequently I think she may have forgotten about it. Come to think about it, she hasn't forgotten, that the first question as we head to the airport - "Do we have a tailwind?". I try not to answer too quickly.

@PJClark, have you decided on a destination? Or is that what the long range weather guessing is helping to determine?

Hopefully I'll see you when you're here next week.

Cheers,
Rick

 

[PJClark]

@Junkman see if you can dredge up Dragon for a chat also.  Be good to see you both.

[Yetti]

windy.com has three different models you can compare.  The european model will give you about 10 days and has been pretty accurate for the gulf coast as to 3-5 days I decide to fly commercial vs. being fogged in.