638RS

638RS

Well Known Member
I?m thinking of making a long cross-country in late November / early December. Oregon to Texas? What do you use to guess the weather 3 ?5 weeks out? Are there any sites that do a reasonable job at long-range weather forecasting? Most weather sites go out 5 ?7 days at most. I understand anything longer is a SWAG but a best guess would be helpful.
 
Three Days

My personal opinion is anything beyond three days is a **** shoot. Weather forecasting is a lot better than it used to be, but 3-5 days if there are a bunch of high pressure systems around or moving towards your intended path.

Don
 
I heard the Government did a study on weather forecasters and determined that they were 90% correct - 10% of the time.:D
Go ahead and plan your trip. Then plan for deviations.
 
Good luck. Since you can probably make it south in one day all you have to do is look for a time a few days out when it looks fine.

Allow for weather delays and that is all you can do.

Your biggest problem may be getting out of Portland.
 
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I was going to suggest a pair of dice.

Two years ago I took mine from Seattle to Dallas for paint in late January, but lucked out with a major high pressure system across the entire west. I had nasty fog in Seattle and some really heavy frost in Oregon on day 2, but otherwise, a great trip. I'd plan your trip and hope for the best. At that time of year, not much else you can do, and it seems like from a precipation perspective, we tend to get most of the junk in November and December around here.

For web sources, wunderland.com and NOAA seem to be about the best for a weeks view.

http://www.weather.gov/forecasts/graphical/sectors/conusWeek.php#tabs
 
We had a National Weather Service Forecaster speak at our EAA chapter meeting a couple of years ago. He said that the NWS used to have a 7 day outlook product, and because the weather channel introduced a 10 day outlook, the NWS had to do so as well to look "competitive". No real accuracy in models that predict that far ahead, according to this forecaster.
 
638RS said:
I?m thinking of making a long cross-country in late November / early December. Oregon to Texas? What do you use to guess the weather 3 ?5 weeks out? Are there any sites that do a reasonable job at long-range weather forecasting? Most weather sites go out 5 ?7 days at most. I understand anything longer is a SWAG but a best guess would be helpful.
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Well, I think that what you are asking about is called 'climatology'.

And climatology is where, all of the weather data for a given area and a given time is averaged and it will enable one to accurately know what the weather will be provided that all the conditions are average.

And of course, since the weather is constantly changing, then the weather is rarely average.

Therefore, this tool is quite useful for broad, long-term planning but it does not provide the specific and detailed data that is needed for one particular flight.

I hope this helps!
 
About the only thing I can add: Supposedly this is a La Nina year. So a southernish route may be more likely to be successful.
 
I suspect you are only half joking

TX7A said:
The Old Farmer's Almanac is about as good as it gets. :D
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I suspect you are only half joking. It is actually good information as I'm sure you know. It is based on history and it is certainly good enough for gross flight/trip planning as opposed to seasonal assumptions. Also if you do weather history search on many cities you can get a good idea of how weather will be at the time you want to make the trip. If you do this for cities along your route you can develop a feel for the weather you can expect along your route. In flight planning you always have to include allowances for weather. Usually if you can allow sufficient margin in time and routes, you can plan and make the trip. If the weather is usually unfavorable on the date you want to make the trip the departure time and route margins have to be larger. Once the trip schedule gets down to seven days the Government Aviation Weather I find is very good. In addition to the large area charts I enter the cities along my route and get a good sense of what the experience is going to be. Finally, before the trip I call 1-800-WX-BRIEF and talk to a briefer for the current weather and TFRs. I can count on one hand the number of trips I have had to cancel because of weather in the past 30 years. One was to a race in South Carolina which I hated to miss - sometimes you have to just stay home because there is no way to get from point A to point B safely. I would never takeoff on a trip thinking that onboard weather depiction will allow me to thread my way through dangerous weather. If I cannot assure myself that there is a safe way to make the trip I do not go.

Bob Axsom
 
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