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Half Dome, Yosemite National Park

The Moon is Waxing Gibbous (75% of Full)


Re: Experienced with Yosemite Weather?

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Experienced with Yosemite Weather?
September 08, 2011 09:16AM
Maybe you can help flesh out this forecast for me?

Vogelsang Area:


What's your read? I take this as:

"Be lightning smart, be prepared for light rain lasting for brief periods (up to a couple hours or so off and on)"

Do you think this an accurate assessment for Friday and Saturday nights?
avatar Re: Experienced with Yosemite Weather?
September 08, 2011 01:09PM
This forecast looks slightly more ominous than that issued for the last weekend of July which turned out to be pretty gnarly. "Light rain lasting for brief periods" might be an optimistic interpretation. Thunderstorms move in cells. You might be in the clear and watch the storms smash into distant peaks, or the storms may smash right into you. I read "Chance of precipitation is 60%" as 60% of the area is going to get hit, possibly fairly hard.

That's based on my experience; a more educated assessment can be found here:

Forecast: The Owens Valley, Mammoth and Mono County
By: Dennis Mattinson, Weather & Atmospheric Forecaster
Sierra Wave Radio – TV – Online News

THURSDAY 08- SEPT-2011, 6:16 AM PDT

Warm high pressure finally gives way to a developing low pushing into Northern California today, then slowly into the Great Basin over the weekend. So a cooling trend is in order along with showers and thunderstorms through at least Monday of next week. Chances increase each day with a broad brush possibility of shower embedded thunderstorms through the period, particularly over higher terrain.

NOTE: For those hikers and backpackers in the Sierra this weekend. Be prepared for heavy downpours and lightning, between mid day Friday into late Saturday night. Nocturnal storms are a real possibility here. This is my best estimate for now.
avatar Re: Experienced with Yosemite Weather?
September 08, 2011 01:21PM
The percentages are too high. You need to be prepared to get smacked for hours on end.

I'd stay home and watch football. (o wait... that IS what I am going to do)

Seriously though... sometimes these forecasts end up with no rain and just some incredible cloud formations.
A couple weeks ago before I left it was something like 30% chance... and it never rained or anything...
and it was gorgeous... with this forecast.. I wouldn't be so optimistic.

Have fun

Chick-on is looking at you!
avatar Re: Experienced with Yosemite Weather?
September 08, 2011 04:23PM
I'm with the poultry. After spending that gnarly weekend in July in the mountains, and with this forecast being marginally worse, that means "stay home and watch football".
Re: Experienced with Yosemite Weather?
September 08, 2011 04:46PM
I read it as, "What a great weekend for a SAR conference! Where I'll be staying in a cabin at about 7,000 feet elevation!"

Some of the really high elevation forecasts are for snow. Be safe out there!
Re: Experienced with Yosemite Weather?
September 12, 2011 05:27PM
Thanks for the tips everyone.

Our group of eight hiked up to Vogelsang on Friday (rain gear at the ready) and hiked out on Sunday. We had distant thunder and a sprinkle or two on the way in but nothing major. Saturday was a beautiful morning that turned into a cloudy afternoon, rainy evening (hard for a bit) and clear night. Sunday ended up with pleasant hiking temps and some rain on the way out. Then, just after hopping in the car, all hell broke loose. Rain so thick my wipers couldn't keep up; turning to hail so thick my tires slipped; causing waterfalls across the road and a reasonable amount of rock fall on 120 with thick fog working to obscure the rocks until the last second. Slow going (people still tried to pass each other across the double yellow lines =/ ).

Pardon the low quality images. These were taken w/my iPhone.

Saturday morning:


Saturday afternoon:


Apparently pressure change makes marmots grumpy:


Edited 2 time(s). Last edit at 09/12/2011 05:34PM by Scogg.
avatar Re: Experienced with Yosemite Weather?
September 12, 2011 05:31PM
Excellent! Glad you made it back to your car in time. Thanks for the report.
avatar Re: Experienced with Yosemite Weather?
September 14, 2011 05:05PM
Was out from last Thurs-Monday; rained every day, and downpours in our area looked very localized (sometimes no rain on us, while we could see rain dumping on areas ~ 5 miles away).

On 9/7, prior to leaving, forecast was "slight chance of / scattered showers and thunderstorms" for all 5 days.

Thurs 9/8: start at Elizabeth Lake TH then XC to near Johnson Peak, where we got rained on from 6:00 - 7:00; clear skies after

Fri: XC (cross-country) & trail to Fletcher Lake, Vogelsang Pass, camp near Gallison Lake; rain ~ 4:00-5:00

Sat: same camp, hike to lake @11,500', heavy rain ~ 5:00-6:00; fabulous moonrise over Mt. Simmons after 7:00

Sun: down to Merced Lake, Echo Valley, camp at small lake at 7,500' along trail to Sunrise; rain 1:30 - 5:30; wet and NO fun

Mon: beautiful sunny all day, hike out to Sunrise TH, rain started 3:50 near Tenaya Lake, nasty pouring (while driving along Tioga Road) until 4:45
avatar Re: Experienced with Yosemite Weather?
September 14, 2011 08:59PM
I guess youz got some experience now.
smiling smiley

Dis bird wouldn't be a camping near Gallison with that weather a rollin in.
(although I guess it not supa diff. than 10500 which we've camped at
and had the same nice showers b4)

w/r to Johnson.
You may be interested in this:
(follow it down for a lovely set of first snow storm last year)
(and, of course, you didn't camp at that lake... that's not allowed... )
tongue sticking out smiley

Chick-on is looking at you!
Re: Experienced with Yosemite Weather?
September 15, 2011 08:53AM

Thurs 9/8: start at Elizabeth Lake TH then XC to near Johnson Peak, where we got rained on from 6:00 - 7:00; clear skies after

Hey, I walked to Elizabeth Lake on Thursday. Sprinkles on my way down, a bit of rain...maybe at about 4pm back at camp, then again while I was out trying to get sunset photos.

Was visiting my sister's campsite WED-THU-FRI. She and her husband were camped in the site that a month earlier, when I dropped off some hikers for the JMT, that I vowed that I wouldn't camp in. Then we show up Wed and she is in that site! (#17 next to the trail up to the backpacker's camp AND the campfire ring.) Noisy, but convenient for "a cup of coffee with the ranger" at the campfire circle.

Looks like one of the downpours of the past week did a number on the road to Parker Lake and exposed a lot of rocks on the steeper grades of that trail.
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