High Sierra Topix

I'm heading up Ten Lakes trail the week of September 13 on my first-ever solo backpack, and am wondering how to figure what the weather will be.

For example, the 10-day weather.com forecast for 95389 (Tuolumne Meadows) for the first few days of that week is sunny with temps of 76/49, 77/48 and 77/51. Obviously, those numbers won't work up at 10,000 feet. But, I'm wondering if I can use that as a reliable gauge as to the relative weather/temps up the hill from the meadows ... say, at Ten Lakes.

Should I figure 20 or 25 degrees cooler, per se? And still sunny?

Or, is there a more-specific source of weather forecast information?

Thanks,

Dave

http://izotz.com/dweebreport/" onclick="window.open(this.href);return false;

http://www.usairnet.com/cgi-bin/Winds/A ... se=azimuth" onclick="window.open(this.href);return false;

Unfortunately the Dweebs real time weather reporting equipment is down. Maybe it will be up in the near future.

On the NOAA website you can click and zoom on a map and get a very very specific forecast.

I've seen it be wrong... but it's often quite accurate. Most other weather forecasters get their info from NOAA.

And weather isn't the only thing that affects temperatures... camping in a creek bottom automatically means you will be colder than if you camp a little higher, on duff, away from the water. Cold sinks and humidity and wind chill steal heat as well. Probably prepping for 10 degrees lower than forecasted would be safest - tho that doesn't always work, either.

Let's not forget our own dmatt (Dennis Mattinson) and his site at : http://www.easternsierraforecast.com" onclick="window.open(this.href);return false;

He had a pointer to it and other things weather at: viewtopic.php?f=9&t=4541&p=27269" onclick="window.open(this.href);return false;

I also look at CDEC weather stations near where i want to go beforehand. For example, they have one at the Tioga entry station at: http://cdec.water.ca.gov/cgi-progs/queryF?TES" onclick="window.open(this.href);return false;. I use this before i head up out of TM anywhere.

Granted, this CDEC data only tells me what it's like before i go, but, i tend to look at Dennis' report for the movement of high-pressure/low-pressure troughs moving in. It tells me about expected wind, moisture content, etc..

Thanks to all for the good weather forecasting tips. It gives me plenty to go on. Between all of them I should be able to interpolate what it will be like when and where I'm going.

That's a good point, too, to figure on 10 degrees colder to allow for local conditions.

Thanks,

Dave

http://www.wrh.noaa.gov/firewx/latitude ... lick.y=189" onclick="window.open(this.href);return false;

http://raws.wrh.noaa.gov/cgi-bin/roman/ ... rawsflag=2" onclick="window.open(this.href);return false;

The first is the forecast for the Yosemite high country.

The second is the real time weather obs for the various remote automatic weather stations scattered about the southern Sierra.

As mentioned above, there can be a great deal of variation in the vicinity of where you specifically camp -- even the microsite within your campsite.

All else being equal (i.e., setting aside the various factors folks have identified above), the rule of thumb is roughly -3.5 degrees per 1,000'.