Riddle me this Red Baron ...

[Xover]

.... below is a link to the LCC 7 day forecast table. My main question, among other little ones, is why on some days does "x" amount of precip yields say 4" of snow and on other days "x" amount of precip yields almost twice that amount?? does it have to do with dew points? temp at which precip comes? what?? give me a quick little weather lesson professor. thanx in advance

http://ifps.wrh.noaa.gov/cgi-bin/dwf...02&click.y=263

[Red Baron]

X- You've stumbled into the wild and weird world of "digital point forecasts". I went to a day-long conference about this a while ago, and it's pretty wild how they come up with that page.

What happens is, the weather service takes the output of their preferred computer models, and puts them into a giant, three dimensional grid, then lets you (the user) pick any point in that grid and get a forecast from it. For Alta, that means it knows the elevation (9440'), and longitude and latitude.

The forecast you are looking at there is not generated by a person, or quality checked at all; it's created by a computer when you poll the database by asking for the forecast. The coolest application of it for outdoors people, is that if you want to camp somewhere in the backcountry, you can get a specific forecast for the exact point in space where you will be.

That said, they are still tweaking the algebra that comes up with the precip and snow totals you see there...I'll check in with the NWS tomorrow and see what math they are using to come up with those numbers, but yes, it does invove temp, humidity, and precipitable water values, I'm just not sure in what configuration...

FYI, I use a different method of forecasting, which is why our forecasts and the ones the gov't issues don't always agree.

I go to the top of High Boy and roll a snowball down, and however many feet it gets, is how many inches of snow we'll get in the next week. It's simple, elegant, and environmentally friendly..