Tuesday, October 8, 2019

The Professional Lowdown on Mountain Weather Sources: Benefits/Limitations and Application of Each

As a guide, I spend nearly every day of the year analyzing mountain weather. Throughout my experience, I learned about many different weather products that each have their place; but, like systems used in the mountains, require very specific application to be relevant. My guests often ask me about the pros/cons of each weather source I use; so, to answer to this demand, as well as your own, here’s a discussion of my favorite weather products. This post will focus on products specifically to planning your alpine climbing adventures. Enjoy!

Product Name: SpotWx (https://spotwx.com/)

SpotWx Forecast Options for Mt. Baker.
• Utilizes GPS point location for your forecast anywhere on Earth. Hence, forecast spatial scale and accuracy are quite good.
• One product offers many options for weather models depending on 1) how small of a spatial scale (i.e. area you want your forecast for) and 2) how long your temporal scale you want (i.e. how far in the future do you want your forecast for)
• Weather data presented in a meteogram format that is generally pretty easy to understand
• Pieces of data I’ve found most accurate: -cloud cover, -winds, -pressure

• Requires some expert-knowledge to know which weather model is good for what
• Doesn’t offer percent chance of precip like many other forecasts do (only offers precip. amount)
• Utilizes weather models rather than recorded data from a weather station
• Pieces of data I’ve found least accurate: -precip likelihood.


Generally this is my most used source when I’m alpine guiding in summer months on Mt. Baker, North Cascades, WA Pass, etc. It’s particularly powerful in these applications because of the spatial accuracy of the GPS point forecast, which can give me a specific forecast for a remote, mountainous region; but also because it offers both small-scale, short term forecasts and large-scale long- term forecasts. Hence using one website, I can fetch information on both exactly what is planning to happen tomorrow (with very good accuracy) and what is happening next week.

Product Name: Mountain Forecast (https://www.mountain-forecast.com/)

Screenshot of a Mountain Forecast Weather Forecast for Mt. Baker.
• Specific to a certain mountain
• One of the few forecasts that has FLs and weather at multiple elevation bands
• Generally a long-enough temporal scale to be useful (forecast goes out 6 days)

• Notoriously inaccurate at forecasting cloud cover
• Because it’s just a presentation of data, it’s unknown as to where the data is coming from
• Not all mountains you want to climb are represented in the database


Okay so this one’s probably not that new to people, but I’d like to highlight what pieces of data are best in an alpine-climbing context. I use this in tandem with SpotWx because SpotWx doesn’t give me data for multiple elevation bands on a single mountain. This one does, and this is its greatest asset. I use this for FLs and temperatures. I’ve found the cloud cover to be WAYY off on this product; but hey, that’s why I use it in tandem with SpotWx.

Product Name: Meteocentre (http://meteocentre.com/)

Example of a snapshot of the precipitation loop on Meteocentre.
• Great overall depiction of storms, major fronts, etc
• One website has data on forecasts, surface analyses, satellite imagery, radar, etc
• Utilizes multiple weather models and weather products, so once you gain experience with a specific model, can be quite dependable

• Whole website is in French, so need a browser with a translation function
• Requires some meteorology knowledge to interpret diagrams
• Depicts the overall weather situation, rather than specific data


Last but not least, I use this source to get a general idea of what kind of major weather system is happening in my area. Where Mountain Forecast and SpotWx lack is in the department of only showing weather model data, rather than the model itself. This is where Meteocentre shines. After selecting a model loop of your choice, you can view animations of the overall weather set-up for a large area (i.e. all of N. America, Europe, etc). This is useful to know if, or when a major storm is about to arrive, and whether you’ve got mostly H pressure (send it!) or L pressure (it’s about to get stormy).

That’s all for now! If you have any questions with any of these products’ uses, feel free to contact me at http://www.zackwentz.com/contact


Unknown said...

Super useful explanation for how to use a suite of weather prediction tools for trip planning, thanks Zack!

Mike said...

Here in the PNW we have the UW's Pacific Northwest Environmental Forecasts and Observations, full of useful tools such as the high res (down to 1 & 1/3 km) UW modeling products: https://a.atmos.washington.edu/mm5rt/ There are also ensembles of models so you can see how confident to be in the forecast from any particular model (ie. how big of a spread is there in the solutions?).

Anonymous said...

Mountain Forecast just takes weather data from the NOAA/NWS and massages it (as do most of the weather services). The massaged data is no more accurate than the NWS's data. That is my finding after using it since its inception in the Tetons. The NWS forecast is updated more often and has the ability to provide a point forecast at select elevations. Mountain-Forecast.com is another source for mountaineers but their track record is more mixed. As stated, SpotWx can't do elevations. None have "very good accuracy" in my opinion. You need to learn to read the weather if you plan on mountain adventures.