I'll update this first post each day with the forecast (though I'll occasionally miss a day), both long and short term. As a general rule, up to 7 days is a pretty accurate forecast, beyond that it's educated guessing and largely dependent upon how well the models are doing at that moment, which is why I call it "voodooland." If you have any specific weather questions or comments, even if it's for an area other than WDW, please post and I'll answer throughout the thread. I'll also post weather tidbits every so often. Without further delay, let's get to the forecast:

Weather at WDW - Update Thursday pm, December 31, 2015

Welcome to the last post of 2015. And it looks pretty similar to what we've been facing.
Today will be around 83 with only a slight chance of a shower later on. Tomorrow should reach 80-82. A front will arrive late tomorrow and bring scattered showers. About a 60% chance you'll see one but fortunately the greatest rain threat looks to be late evening into early morning so minimal park impact. Saturday will be mostly cloudy with a high 62-64. Showers and thunderstorms are likely on Sunday, especially in the afternoon, with a high 57-59. The rain should clear before park opening on Monday and so Monday should warm to 62-64. Tuesday is dry with a high near 70 then a 50% chance of a thunderstorm on Wednesday with a high around 70 again. Thursday looks dry with a high 71-73.

Long range...Jan 8 looks dry but showers move in on the afternoon of Jan 9, clearing early on Jan 10. Trying to nail down exact timing is useless in voodooland, but at least if that scenario holds then the running times of the marathon weekend should be dry with the greatest rain threat afterwards. The high looks to be mid to upper 70s all 3 days with a temp in the upper 50s around the race start times. As long as it stays dry it should be very comfortable for running. Strong storms move in for Jan 11. Jan 12-16 looks dry with highs in the upper 60s to low 70s.

Travel Issues
No major issues for today or tomorrow.

Any of you who are nervous about flying, especially related to turbulence, go here and here to learn a lot about turbulence and other issues that sometimes cause anxiety when flying. Hopefully all of this will help you relax and enjoy the trip to WDW more!