Saturday, January 24, 2009

CoCoRaHS Affords Opportunity To Teach US Climate Like Never Before

It continues to be cool for much of the country with a few pockets of unsettled weather -- the cold is the main story, however, this weekend.

Let me take a minute here and get caught up on all your comments.

Fanghopper asked if the clippers have been more frequent than normal this year?

For those not in the Great Lakes, upper midwest or northeast -- clipper systems are weak cold fronts that move out of Canada and "clip" this region of the US.

They typically bring a reinforcing shot of cold air and squeeze out any available moisture in the form of a light, fluffy snow.

It does seem like there have been TONS of clippers this year but I just don't know enough about the climatology for your part of the country to know if this is above normal or not.

I'd venture to say it may be since the weather pattern this winter has been very persistent. (i.e. here in Denver we've been high and dry just about as long as you have been being hit with clipper after clipper)

John I sent a note up to CoCoRaHS central about your suggestion for expanding the training info.

I know there has been a lot of comments and debate over fog/freezing fog and if it is precipitation or not.

I misreported in a previous entry but for CoCoRaHS purposes, we ARE counting anything measured in your gauge from fog and freezing fog as precipitation. If possible, also make a comment about the fog just so users of the data know where the precipitation came from -- fog instead of passing showers for example.

I think now that CoCoRaHS is growing so large and is in so many states, with more than 5,000 pair of eyes making daily reports and comments each day about what is happening -- we are going to see more and more questions like this come up.

We are logging more data than any doppler radar scanning the skies could ever hope to record.

If you think about it, and if you look at a national plot of "first order" or "main" weather stations, talking about the main anchor locations for your state, there aren't that many for a country the size of the US.

It is a great representation BUT there are also many many gaps.

And when you add in all the secondary locations, such as on mountain passes or in smaller, remote towns -- which try to fill in these gaps -- there still aren't near as many as we would like to really study and learn the weather patterns of our country.

And here we have over 5,000 humans going out and making daily weather notes about the climate, observing things in some areas that quite possibly may have never been previously recorded -- certainly not to this extent.

I want to take this freezing fog issue for example -- it is not a new weather phenomena by any means.

But in the past, it was probably only observed at one or two locations during a widespread event across northeast Washington -- let's say both Spokane and Colville reported freezing fog and each station picked up 0.05" of moisture a day over a 5 day period -- they are 70 miles apart.

Big deal -- no one probably ever really thought that much about it before. It's fog and two places received a minimal amount of moisture. A total of a quarter-inch over a 5-day window.

Freezing fog is a very important issue for the transportation industry, but do we think of it as a valuable source of water?

Probably not.

Now with CoCoRaHS -- through the detailed reports filed by you the observer -- just pretend we saw a stagnant weather pattern set up with 5 days of freezing fog over a 100 square mile region of northeast Washington.

And pretend that in that 100 square mile region we have at least a dozen observers, but ideally many more.

When before, precipitation from fog in that same area was picked up only by just the 2 main reporting stations mentioned above, Spokane and Colville -- now we see at least a dozen reports over a several county area due to you.

It may spark all kinds of new studies and interest for someone like a graduate student to look at the question, can and does fog bring beneficial moisture to a region when it is widespread and persists over several days?

A quarter inch of moisture from a 5-day fog over a 100 square mile area would be HUGE if you look at it in terms of how many gallons of water it actually measured out to be!

Kind of a corney example and far-fetched possibly, but I did that intentionally just to show one of hundreds of examples of how 5,000 people taking simple precipitation data with a few comments makes a difference, and brings a meaning and a purpose you may not have thought about.

By the way, if that 100 square mile area did ever see a fairly uniform quarter-inch of moisture from freezing fog over a 5-day window, that would be equivalent to over 400 million gallons of water for the landscape to absorb.

A water company would LOVE to know that kind of data -- and I think it's pretty interesting to pretend that a prolonged fog event could deposit that much moisture if my pretend scenario actually did ever take place.

Here is a cool link that will help you see how I calculated the above water statistic.

My dream (and I am sure Nolan and Henry too) is to have enough money so we could support deeper employment with CoCoRaHS.

I'd love to sit down each day, read the comments and reports, and put together recaps, graphs, etc --- a climate "atlas" if you will -- of what we are seeing, observing, and learning about the climate of the United States.

Unfortunately I have too much debt like the rest of you and work 2 jobs to survive -- I do good to write this blog some days -- but I think one day we'll get there.

In the meantime, keep making your daily reports because every last bit of it is being archived and will be used down the road to learn more and more about the weather that impacts our daily lives.

And thank you for voting in the blog poll this week -- nearly 100 votes cast so far!!!

P.S. If there is something you are observing for your region that is of interest to you and you are one that would be inclined to study and analyze -- feel free to do so. I will be happy to help guide you as I am sure Nolan would be too.

It may be a section of your area that always seems to be wetter or drier. Maybe it's the precipitation from fog! Maybe something that needs a long period of data, perhaps up to 2 or 3 years?

The more we learn and document weather and weather patterns that become apparent thanks to CoCoRaHS and our growing network, the better we can demonstrate the value of our organization to potential sponsors.


  1. Sounds like a dream job for me, but for now, it's a hobby and passion. You can count on it, that I will keep observing and noting the patterns as they come and go. :)

    All the climate data from my corner of the Earth can be found HERE.

  2. .25" of freezing fog moisture is about 1.5% of Colville's annual precip (18 inches)! Measurement error is probably more, but that's still a suprising amount of moisture to me.

    Like you say, Chris, lots of little numbers make a lot of difference.

  3. As I recall, in northern California (way, way north) along the coast there are places that receive up to 100+ inches of precipitation per year, with at least 10 inches coming from fog!

    The redwood trees are particularly adapted to collecting the "fog drip."

  4. OSNW3, thanks for your link. Wow! I didn't realize how many different climate data sources were out there:
    Can someone tell me or point me to what all these station acronyms mean?
    And which one is CoCoRahs?

  5. You are right about specific areas having weather events and patterns that are of unique interest. During my career I worked at a place that was dubbed the windiest place in the U.S. We had the data to prove it too thanks to the NWS office in Lubbock, TX and their 24/7 wind speed and direction recording instrument that we monitored for them. The place is Guadalupe Mountains National Park, TX.

  6. Nancy, that is amazing! The time I spent on the central Oregon coast this Summer was an eye opener as far as the local climate is concerned.

    John, I suppose I should clarify, that not "all" but just my contribution of climate data is offered from that link. Every week I am finding new sites with climate data, mainly by links supplied by the Northern Wisconsin Weather blog.

    Bob, I had to google the Guadalupe Mountains National Park, TX. From the NPS site I was redirected to the NWS local forecast. WINDY. Thanks for the info.

  7. Thanks for your feedback about the clippers, although now I'm curious for some hard data on this.

    Just by way of additional information for others, I want to add that when he says a "shot of cold air" he's not kidding. The clipper systems bring some of the coldest temperatures of the winter--we've had a great deal of single digit and below zero temps--along with very dry air. The snow that comes with them often has a "fluff factor" of 20:1 which is more than twice as "fluffy" as our normal ratio, which is closer to 9:1 or 8:1.

    In my region in particular (Central NYS) the northwestern flow of air during clippers will activate some lake effect snow from Lake Ontario and the Finger Lakes. Again it is light, fluffy, and doesn't accumulate much, but generally we are south of the prevailing lake effect snowbelt by an hour's travel or more--except when the wind is right.

    Tagging onto the comments about specific patterns in specific areas, one thing I enjoy about reading the local CoCoRaHS data is seeing the variation among the 15+ spotters in this county. I live in a very small crossroads of a place, up in the foothills of the Allegheny Plateau, where our microclimate can be significantly different from that of valley-based Ithaca, 12 miles away and 1200 feet lower in elevation. The weather forecast is generally focused on Ithaca (generated in Binghamton, NY) but it can easily be 10 degrees colder and 2-3 times more snow up here than the forecast indicates for the rest of the area, due to the elevation and the orographic lift. Of course in the summer this means it is pleasantly cooler than the valley, with a nice breeze! I have lots of friends in the summer, but almost none in the winter. ;)

    When I signed up to be a spotter for the NWS (before NYS joined CoCoRaHS) they were thrilled to have me because they knew this phenomenon existed but had not really been documenting it systematically. My data over the past few years has shown my site to generally be the snowiest and coldest in the county.

    Thanks again for taking the time to discuss all the various comments and questions you get on here.

  8. Fanghopper-

    Thanks for reminding us Left Coasties that the first winter olympics in the US was in Lake Placid, not SLC, and you don't need big mountains for big snow!

    Stay warm..

  9. Chris, Thanks for mentioning the fog between Spokane and Colville. I live west and north of both and the fog persists past Coulee Dam, Wilbur and Almira. If it is true about the amount of precipitation received from the fog, we will be seeing the dam operators letting out much of the water that is in Lake Roosevelt. I live on the San Poil River and I have seen a rise in water levels recently.