Posts Tagged weather
Why you should be very leery of forecasts
Check out this blog by statistician William Briggs that gives the heads up on how Hurricane Predictors Admit They Can’t Predict Hurricanes. Years ago as a chemical engineer working on process development I would be encouraged by plant personnel to crank old data through a regression analysis to model the operation, thus avoiding any work on their part to run designed experiments. The joke was that we got very good at predicting what would happen last month.
In this case the issue is hurricanes. As Briggs explains, the top experts can fit past data very well (r = 0.79 for 50-year period the last half of 20th century). He refers to this as a ‘hindcast’. But, as the hurricane forecasters themselves admit, these models predict so poorly (r = 0.04) that you may as well just use an average — what I call the ‘mean’ model as a double meaning (ha ha) because it is so disappointing for the analyst.
What it boils down to is that any forecasts on hurricanes this early before the coming season will really just be a lot of hot air, despite impressive statistics from models fit to prior years. The same goes for long-term outlooks on other natural phenomena.
How hot? 103 under our shade tree!
According to my morning newspaper (St. Paul Pioneer Press), yesterday’s record temperature made it hotter hereabouts than a billy goat in a pepper patch, or the devil’s underwear (I hope he is not a tweeter like that New York Congressman), or two bears fighting in a forest fire (down in Arizona, I suppose). Even so, a vestige of the once 60-foot high pile of snow dump in downtown St. Paul remained intact. Perhaps it will disappear today. I hope so, because it will be back in the 60’s by Friday – colder than a basement toilet seat as Minnesotans like to say.
Winter not loosening its icy grip on Spring
I woke up to snow yesterday morning. It couldn’t quite cover the greening grass underneath, nor did it seem to discourage the budding bushes. Today the snow has disappeared and the near 40 degree F temperature seems mild with the power of April’s sun and the abatement of fierce northern winds. However, our Canadian neighbors are not faring quite as well, as evidenced by this very cool (literally and figuratively) photo from my sister – a resident of Calgary. Notice how the snow fingers feature icy nails — chilling!
When will Winter finally loosen up and let Spring spring free, eh? Maybe May…
First signs of Spring – premature return home by robins
As you can see from this photo taken Friday while cross-country skiing, Spring has not sprung in my neck of the woods. However, just overhead as I took this shot were several dozen robins perched in the birch. They were chattering a great deal – I imagine in complaint about which bird brain thought it was time to migrate back north.
A couple of years ago at this seasonal juncture I wrote about phenology – the study of timing for nature’s ways. For us in Minnesota the robins’ arrival is a sure sign of warmer weather around the corner.
Having just returned from a Spring break in Florida, I wondered how these southerners can detect seasonal changes. My searching on internet reveals little, other than this announcement of the first phenology workshop in Florida in 2009. The one sure sign of Spring for Floridians is the hordes of Minnesotans coming down for a break. They probably trump anything more subtle from Mother Nature.
Smooth sliding for 2011
Posted by mark in Uncategorized on January 1, 2011
Here’s hoping you enjoy smooth sliding in 2011 like I did recently outside my front door.
Happy New Year!
– Mark
PS. Kudos for my daughter Emily for this production.
The State of happiness
Posted by mark in Uncategorized, Wellness on December 20, 2009
Those of you American citizens who (like me) enjoy our unalienable pursuit of happiness should see where your home State ranks in this list presented by economists Andrew Oswald and Stephen Wu.
Our local newspaper headlined this report with the suggestion that we Minnesotans “try living in a sunnier State.” I have a hard time arguing with moving to Hawaii or Florida – both near the top the Oswald-Wu list. Louisiana (#1) is a good choice too, I think, despite the setback of Hurricane Katrina. I spent time there and in the neighboring State of Mississippi (#7) last March – a great time to get out of Minnesota (#26). However, I really do enjoy our winters here in the northernmost part of the lower 48. At this time of the year our sun sits nearly at its lowest point (Winter solstice being mid-day tomorrow), which makes any rays one can catch all the more dear.
This morning a little Canadian ‘clipper’ topped off our existing blanket of snow with another inch of sun-sparkled crystals. It was good to be outdoors walking the dog through our little “Sunwood” park of evergreens again after taking a little break on our daily strolls last week due to the bitter cold. Maybe it was just as well we stayed home because a cougar came through our neighborhood (called “Croixwood”) as evidenced by the huge paw print pictured here . The cougar was last sighted in Wisconsin. My guess is that this cat is headed for Florida. =^.^=
Coriolis effect continues to make the rounds despite efforts to flush it down the drain
Upon hearing a travel report from an acquaintance spending time this summer in Ecuador, I could not resist asking her to observe which way her sink and toilet drained. I’d heard that, due to the Coriolis effect, when you flush water in the northern hemisphere it swirls one way (clockwise), but below the equator it goes the opposite way.* Here is her enthusiastic report:
“Hi Mark, Yesterday I tested it – it´s true! We went to the Mitad del Mundo (Centre of the World), a big monument where the equator line is supposed to be. Unfortunately, they made a mistake when measuring, so the real equator line is a five minute walk away from the monument. By the real line they built a museum and there you can do funny experiments. For example, they put a sink on one side of the equator and let the water flush down, and then they move it to the other side and the water flushes the other way. On the line itself the water just goes straight down – no kidding! It was very interesting!”
I then had to do some research to see if this phenomenon could be independently verified. I hate to be a party pooper (ha, ha!), but, from what I read, in reality the Coriolis effect is so small that it’s easily overwhelmed the shape of the bowl and the other factors. Thus, most toilets flush in only one direction — clockwise or counterclockwise — regardless of location. This is explained very nicely by Alistair B. Fraser, Emeritus Professor of Meteorology Pennsylvania State University, in his white paper on Bad Coriolis.
In any case, it is fascinating to watch the last gallon of water from a hot bath twirl down the drain, so why not observe whether it exits clockwise or counter? I’ve never been south of the equator myself – the nearest I came was in Singapore. My hope is to do some personal validation on the Coriolis effect, or lack thereof. Why not?
*In a memorable episode (I thought it extremely funny) of the television cartoon The Simpsons (16th one in the 6th season), Bart, purporting to be an official with the “International Drainage Commission,” convinces an Australian boy to do a similar ‘down-under’ experiment. The results proved inconclusive, but very humorous. 🙂
Graupeling for words to describe nature’s emanations
Late Friday I took a call from a client in Hawaii. All day long here in Minnesota the weather forecasters had been harping about the dire prospects for over a foot of snow. The Hawaiian sounded skeptical when I told him of my positive view on these developments. Believe it or not, many of us Minnesotans enjoy the opportunity to ski, snowmobile and just revel in the contrast of winter with our other three seasons.
The first round of snow hit that evening. It was quite unusual – pelletized like Dippin Dots or IttiBitz ice cream, created by flash freezing the sugary dairy mix in liquid nitrogen. Something similar must have occurred naturally over my home town of Stillwater. The American Meteorology Society (AMS) describes this frozen phenomenon as graupel. Evidently it’s a cousin of hail, which we see in the summer-time when thunder storms become severe. This graupel was great for shoveling. I’ve got a low-tech, but amazingly effective, snow scooper, which just pushed it out the way and, with a quick twist, dumped it over. The pellets just poured right out.
That was only the first wave of the storm. Over the next 24 hours, another half-foot of snow fell. The neighbor across the street was really fired up about getting his snow blower running for the first time this year and promised to shovel my driveway after all was done with this winter storm. However, it took so long to start the disused engine, that I scooped him.
Getting back to Hawaii (a very attractive thought at the moment), I once visited their namesake “Big Island” and saw lots of lava from Kilauea. There I learned that Hawaiians differentiate flows as “aa” – rough, versus “pahoehoe” – smooth. (See details by volcanologist J. M. Rhodes.)
Having hand-shoveled snow for half a century, I can readily characterize their types. However, I must hand it to the Hawaiians for putting words to what Mother Nature puts in ones path. More snow is forecast later this week for Minnesota. I predict that this may precipitate many Minnesotans to have an “Aa, ha” and book an impromptu getaway to Hawaii or another warm State!
Weather to be or not to be, that is the question
Last night I got a panicked call from my host for a talk scheduled tomorrow night to a group of quality professionals and their student section at Purdue University. Predictions had just firmed up for a major winter storm that might dump up to a foot of snow in parts of Indiana. Which parts would get snow was hard to forecast, but it seemed likely to be rain south of Indianapolis – my flight destination, icy there and snowy to the north in Lafayette – home of Purdue. Thus, given I’d be driving through the middle of this wintry mess, my host’s bias toward canceling the meeting met with little resistance from me. At the moment, based on tonight’s weather reports, it appears that we made the right decision. However, I’ve seen plenty of dire weather predictions fizzle over the years, particularly for snow and/or ice, which often end up precipitating as relatively benign rain due to unexpected warmth.
North American winter storms can wreak havoc on a grand scale, for example, when ice builds up to a point where power lines come down over broad areas. However, hurricanes like Katrina really strike fear in the hearts of insurance underwriters. Richard Mullins of the “Tampa Tribune” reports* on the use of simulations for predicting the financial scale of disasters like this. According to him, some storm models sell for as much as $10 million! For that price, one would assume the results would be unbiased. However, non-profit and privately-funded researchers interviewed by Mullins agree that results from studies underwritten by insurance companies naturally fall to the high side, whereas ones done for the public interest tend to the low end. The range went from $2 billion to $12 billion for 2005’s Hurricane Wilma!
Things really get wacky when one tries to assess risks of buying a vacation property in Florida to escape the wretched winter weather of the northern USA, from Indiana on up. Where would one be safest in a beach home – a place like Jacksonville that’s experienced no category 4 hurricane in 150 years? Maybe they are ‘due’ for one. A contrarian might take an opposite tack – buy where the most recent horrific hurricane hit, such as the surprisingly robust Wilma that tracked in to Florida after clobbering Cancun.
My idea is to simply rent a haven in Florida during the winter – the season when there are no hurricanes. I would leave at the first sign of snow up north and not go back until it melted. I wonder if any fellow northerners have thought of this?
*“Calculating Disaster,” Sunday, 2/11/07
Nature’s dangerous forces — including cold temperatures
Sadly, tornados devastated central Florida this week, including a church designed to resist a category 4 hurricane. The twister that destroyed this building must have been a 3 on the Fujita scale based on my comparison of its wind speeds with that of the Saffir-Simpson categorization for hurricanes.
Scales like this are popular for devasting forces, such as the Richter for earthquakes and decibels for Rolling Stones (a joke). I’d like to contribute one of my own:Cold Force. My cold force (CF) scale begins at 40 degrees C (104 F) and increases by 1 for each decrease of 10 C. For example, today I experienced a temperature of 6 degrees F (-15 C), which translates to a CF over 5 on the Anderson scale. This measure is a useful predictor for the number of layers a person should wear to maintain body temperature. Notice all the clothes I wore today – not quite enough for prolonged exposure – take my word on that!
I experienced extreme heat, over 100 degrees F, last July at a Baltimore Oriole baseball game in their home field — Camden Yards. Since this correlates to 0 CF, one could comfortably go around in literally nothing, but I recommend at least a bathing suit. At 1 CF (30 C, 86 F), you might consider putting on a t-shirt. Next on the scale comes 20 C or 68 F, at which point (CF 2) a nylon windbreaker would be good – in other words a second layer.
Wind-chill becomes a factor below CF 3 (10 C, 50 F). The Mount Washington Observatory, “Home of the world’s worst weather,” provides the mathematical formula below their chart of temperature versus wind. They also provide a calculator for this purpose. According to Environment Canada , residents of Pelly Bay experienced a wind chill of -91 degrees C on January 28, 1989. That created a freezing force of 13 by my reckoning. However, it would be ridiculous to put on that many layers of clothes. Maybe that’s why last winter while vacationing in Miami during unseasonably cold weather – CF 2, a radio DJ derisively noted that anyone wanting to see Canadians need only drive by the beach. I was decked out in my bathing suit and driving there myself at the time!