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Posted

I tend to use mountain-forecast.com but multiple times I have noticed different current conditions than what's being reported.

 

I'm assuming they just pull data from NOAA and extrapolate it to the different elevations?

 

I have searched around NOAA's archaic web site for weather stations at higher elevations near what ever mountain i'm going up but finding that station can be tricky sometimes. Sometimes there doesn't seem to be a close by station.

 

wunderground.com has a better UI and i'm assuming they are primarily pulling data from NOAA as well?

 

Any advice on how you get your forecast or your process would be awesome.

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Posted

You pretty much nailed the same system I use. I've generally observed that NOAA point forecasts tend to have a 'wet' bias (meaning they often forecast rain when actual conditions are dry) while mountain-forecast tends to have more of a 'dry' bias, occasionally missing storms. What different conditions have you observed when using mountain-forecast?

 

I believe that wunderground uses different weather stations, including more 'unofficial' stations run by enthusiasts. They also use additional models, whereas I think NOAA uses only one model(their own). This is all relayed second-hand, so weather experts feel free to correct me if I'm way off base. I've found wunderground to be really accurate for 'home' forecasts, but they lack the stations in the mountains to get really good predictions out there.

 

Also - when using NOAA, did you know you can just go to the map and click the location you want the forecast for? It will give you the forecast for the specific elevation you clicked on. For example, this forecast is for 5600' on Heliotrope Ridge. The current weather may not be accurate, but the forecast is for this specific location.

http://forecast.weather.gov/MapClick.php?lon=-121.87898407722952&lat=48.78110458486057#.VlymBb95Hhk

Posted

Pretty close to what I do as well. I have found that mountain-forecast is usually pretty close with temps and major events, but very off with amount of precip or with marginal days (basically if it is iffy it could be nasty or sunny). I have repeatedly found that the snowfall amounts forecasted are drastically lower than actual amounts. For me I double whatever their snowfall amounts are and it seems pretty close.

 

The other tool I like is the forecast discussion on NOAA. For example here is the forecast discussion for tstory's link (there is a link right under the map called "Forecast Discussion"). It is a much wider focus and talks about a whole region rather than local/specific location, but there is so much more information in there. It can seem a bit confusing to read but it really isn't that bad once you start to understand the basics. http://forecast.weather.gov/product.php?site=SEW&issuedby=SEW&product=AFD&format=CI&version=1&glossary=1

 

Also I would recommend reading this book. Anybody who spends a lot of time in the outdoors will benefit from being able to better understand weather. I learned a lot from this book and feel like it helps me understand forecasts as well as look at current conditions for changes. http://www.amazon.com/Mountain-Weather-Backcountry-Snowboarders-Mountaineers/dp/089886819X

 

Posted (edited)

NOAA has a bunch of models that they use (and blends), depending on the event.

 

That said, I typically use NOAA for the coarse story (fcst discussion mainly) and rough precip amounts and verify it with the UW WRF-GFS 4 km products: http://www.atmos.washington.edu/mm5rt/rt/gfsinit.d3.html

 

For short range (less than 48hr), you can step it down to the 1 1/3 km grid model outputs. Pretty amazing stuff.

 

The 1 hour precip and integrated column cloud water loops are especially helpful. Note that this site takes some study to understand fully, it isn't like the sites others have discussed above. And, it is much, much better. I've found the UW model to be the best for fine scale resolution of weather, hands down.

Edited by JasonG
Posted

Jason, how do you interpret the "column-integrated cloud water" loop? That one didn't make immediate and obvious sense. The Low/Mid/High cloud water loops seemed more intuitive, where I assume they are an indication of how cloudy the skies are going to be. If Low is green/blue your in a whiteout if not your in flat-light or better?

Posted

Good question. I was turned on to the column-integrated loop by a Cliff Mass blog entry several years ago. He says that the various modeled outputs for the different elevational bands aren't that accurate (maybe due to the forcing by terrain?) and to use the column integrated loop (at least that is how I remember reading the post).

 

In the column integrated loop, the gray is thin high or low clouds (i.e. won't mess with your climbing viz) and the white is thicker where you will likely be in a whiteout above treeline. Pair it with the 1 hour precip loops to see if you will be getting rained on by those clouds and you have what I've found to be the best weather predictor around. Especially less than 48 hours out. What I really like about this is that it gives timing of the weather (by looking at the time stamp) so you can see if you can squeeze something in or not. You don't get that with any other site I've found. You can see if clouds clear out fast or slow after a rain event as well, something that NOAA tends to be overly optimistic about.

Posted

wow, I had no idea this kind of information was out there.

 

tstory - Thanks for the book recommendation. I really have never gave much thought about reading up about weather besides the forecast that's given to me.

 

JasonG - Do you know of a blog post or write up somewhere that breaks down all of that information and some ways to use it? I'm not familiar with a lot of the terminology so I'm not even sure what some of information is.

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