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joker
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PostWed Aug 07, 2019 10:52 am 
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Does anyone know of a forecast product or some such that would help me make an informed guess as to how high I'd need to go in order to get above the marine layer when it has penetrated as far as the Cascade crest?
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MtnGoat
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PostWed Aug 07, 2019 11:26 am 
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try looking for aviation weather forecasts, using terms like "winds aloft", they're interested in the same data for other reasons.

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hbb
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PostWed Aug 07, 2019 11:53 am 
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You can try checking PIREPS to see reported cloud top heights:

https://www.aviationweather.gov/airep

or here:

https://www.weather.gov/zse/PIREPClouds?id=SEA&hrs=11

The reports are sort of cryptic, you'll want to read this to figure out what to look for:

https://www.m0a.com/how-to-read-pireps/
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gb
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PostWed Aug 07, 2019 3:03 pm 
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You can start at the National Service Seattle and go to Aviation Weather Observations for various airports (scroll left) https://www.wrh.noaa.gov/sew/aviation_air.php

Secondly, you can use the various webcams for the ski areas and highways for current conditions.

Finally, for forecasts go the the U of W MM5 (I use 12km grids) and find the cloud cover forecasts - you can look at various levels of the atmosphere.

However, realize that depending on flow velocity and direction clouds approaching the mountains can be lifted considerably, so, for instance a 4000' cloud deck at Marblemount may rise to peak levels along the crests. This also depends on stability of the atmosphere at different forecast levels. There is some intuitive hint of this in the observed freezing level and lapse rates at different elevations (in mb). So, for instance if the observed data is close to the dew point at some particular elevation that would imply the elevations (very rough) of cloud layers and potentially the tops at a layer of strong stability.....Skew T Sounding Displays https://www.ospo.noaa.gov/Products/atmosphere/soundings/sfov/skewt/uil.html
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Jaberwock
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PostWed Aug 07, 2019 4:44 pm 
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I would just look at the current sat photo of WA and see where the clouds aren't. This link should always give you the current image:

https://atmos.uw.edu/cgi-bin/latest.cgi?vis1km+-notitle
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joker
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PostThu Aug 08, 2019 3:03 pm 
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Thanks much especially hbb and gb!!

Jaberwock - yeah I  love using  satellite images  for some sorts  of planning, but  in this  case I  actually want clouds, but I want to  know if and where I might have a shot of hiking up out of  them.
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Windstorm
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PostThu Aug 08, 2019 3:11 pm 
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joker wrote:
Jaberwock - yeah I  love using  satellite images  for some sorts  of planning, but  in this  case I  actually want clouds, but I want to  know if and where I might have a shot of hiking up out of  them.

Do the satellite images give enough detail that you could see individual mountains sticking up out of the clouds?
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joker
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PostThu Aug 08, 2019 3:13 pm 
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That's a good question. Not the  ones I've looked at but I wonder if there are images  I  could get that  level of  both visual  detail and geographical info from...
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nickmtn
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PostThu Aug 08, 2019 4:02 pm 
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Most Detailed Satelitte Image I Know Of

It is GOES 16 imagery
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Jaberwock
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PostThu Aug 08, 2019 4:30 pm 
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joker wrote:
Jaberwock - yeah I  love using  satellite images  for some sorts  of planning, but  in this  case I  actually want clouds, but I want to  know if and where I might have a shot of hiking up out of  them.

Totally.  So for this example, you can see the clouds are NOT covering the central Olympics but are covering all puget sound.  Can also be useful to figure out when the coast is fogged in.  The county lines in purple dash are useful for locating your hike.

https://atmos.uw.edu/cgi-bin/latest.cgi?vis1km+-notitle
Should note that this link won't show much at night since it's dark out... Have to wait until the sun is up to check this clouds. Think it's updated every 15 minutes or so.

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Stefan
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PostThu Aug 08, 2019 5:03 pm 
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Here you go:
0-3000 feet:  https://a.atmos.washington.edu/~ovens/wxloop.cgi?wrfd1_x_qclst+///3
3000-10000 feet: https://a.atmos.washington.edu/~ovens/wxloop.cgi?wrfd1_x_qcll+///3

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joker
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PostThu Aug 08, 2019 10:05 pm 
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Thanks Stefan!

And yeah, Jabberwock - this tells me where clouds are over the land but unless I'm missing something here not as much how high or low their tops are which is specifically what I'm trying to guess at (and they're also not a forecast). But super useful!!
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bk
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PostFri Aug 09, 2019 3:36 am 
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This question is also addressed somewhat in the Dec. 2017 post, Next Weeks Inversion Zones.

Also, in a different subject thread, gb mentions Skew T here in 2013: North Cascade Glacier Climate Project 2013 Field Season

(Learning how to read predicted cloud-tops off of Skew T's is still on my list somewhere....)
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Forum Index > Trail Talk > calling all weather nerds - ?how to predict top of marine layer  height?
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