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Weather: why does the temperature drop after sunrise?

Self-tutoring about weather: the tutor loves to bring you this post about a phenomenon that’s long confused him.

This morning, the temp was 6°C at 7am, but 4°C at 8am. The sun rose at 7:35am.

I’ve observed, so often, the temp dropping post sunrise. Yet, how can it make sense?

Finally, I read an explanation which is the best I’ve imagined. Mike Alger, a meteorologist in Reno, explains two key points:

  1. The thermometer’s position, typically, is several feet above ground. The temperature at ground level might be 5°C colder, since cold air falls.
  2. At sunrise, the ground starts to heat up, so the air touching it is stirred upwards. Reaching the thermometer, that colder air pulls the reading closer to the temp at ground. It takes the sun’s power to excite those cold air molecules so they bounce up to the thermometer’s level.

Mike observes that the drop in temp after sunrise is most likely on a clear, still morning. I agree. Here, we have dry nights that might turn out rather similar to conditions in Reno. His explanation is the best I can think of.

Thanks, Mike:)

Source:

mikealger.net

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.
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Weather: snow accumulation: mass of snow on the deck

The tutor mentions a consequence of the recent snow event.

Here, we’ve had an unusual amount of snow lately. I cleared off the deck two days ago to relieve it from the mass of snow on top. Then, from the night before until yesterday evening, we received about 18 inches (46cm) of fresh snow.

Last night I wondered again about the mass of snow on the deck, so I estimated it as follows:

deck area: 20’x10′ = 200sq. ft.

A foot is 30.5cm, so a square foot is 930cm2.

Therefore, the deck area is 200x930cm2 = 186050cm2.

The height of the snow is 46cm. I’ve heard 10cm of snow is equivalent to 1cm of rain.

Hence, the equivalent volume of water on the deck is 186050cm2x4.6cm = 855830cm3.

Perhaps surprisingly, 1000cm3 = 1 litre. It follows that the deck is holding 856 litres of water.

Furthermore, 1 litre of water has mass 1 kg: the mass of snow on the deck is 856kg, or about 1900 pounds.

So, after a heavy snowfall, the mass of snow on a structure can truly be significant.

Good luck with your snow clearing:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Geography: Ocean currents: why Canada’s east and west coasts have such different weather

The phenomenon of the mild winter of Victoria, BC, compared to the much colder one of Halifax, NS, has a reason….

Typically, spring blooms begin in Victoria, BC, in February. I’m a Maritimer, so I can tell you that a spring bloom in late March there would be welcome, but not typical. Why does spring arrive at Halifax so much later, when Halifax is significantly further south – 44°N, versus 48°N in the case of Victoria?

The answer is simple: a warm ocean current flows to Canada’s west (Pacific) coast, while a cold one flows to Canada’s east (Atlantic) coast.

The current flowing to the Pacific side begins around the Philippines as Kiro Siwo. Reaching this side of the ocean, it becomes the North Pacific Current, bringing tropical warmth to Canada’s west coast.

To Canada’s Atlantic coast, the Labrador Current brings cold water from around Greenland and the Arctic islands. Hence, the longer, colder winters there.

I’ll be talking more about ocean currents in future posts:)

Source:

Stanford, Quentin H., editor. Canadian Oxford School Atlas, 6th ed. Toronto: Oxford
   University Press.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Feb 2: Groundhog Day: early spring?

The tutor comments on a cross-quarter day.

In my post of Feb 6 last year, I defined and discussed cross-quarter days – those that mark mid-season, rather than start of season. The idea is that, to people serious about the seasons, the cross-quarter days may be just as meaningful as the junctions.

Today, of course, is a cross-quarter day – Groundhog Day. We are at mid-winter. According to npr.org, the groundhogs in both Canada and the US have predicted spring is soon to arrive.

From a more contemplative point of view, some important benefits of spring are apparent. The days are noticeably longer. When blue sky does emerge, you can suddenly have a really pleasant interlude of spring-like weather.

Someone who follows the cross-quarter days might focus more on the change during the season than the season itself. Winter’s evolution into spring is satisfying to observe.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Weather and Seasons: first day of spring, 2016, Campbell River

The tutor shares reflections about, from his point of view, the first day of spring, 2016, in Campbell River.

As many of my readers realize, I’m a Maritimer. The mild weather on Canada’s west coast continues to impress me, even after nearly 30 years living here.

As I mentioned in last year’s post about the first day of spring here, March 21 doesn’t aptly target it. The true change in warmth and sunshine is usually apparent much earlier. My definition for the first day of spring: It’s the first sunny day (in the new year) with high temp 10°C or above. By that definition, the first day of spring, 2016, in Campbell River, is today, January 28. Environment Canada reports the temp at 11°C, with sunny conditions. I’ve been outside; it’s true.

I’ve noticed a couple of signs of spring. Last week, downtown, daffodil shoots were a few inches up from the soil. This morning, as I opened the gate, a fly buzzed about in the sun. However, I wouldn’t have guessed that today would mark the change. Amid exams and other activities, this occasion is a very pleasant surprise.

I’ll be further discussing the evolving spring season in future posts:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Weather: difference between fog and mist

The tutor clarifies a distinction he has wondered about for decades.

Walking home this morning from dropping off the car, the air was cool and fresh. Hanging in it was water vapour which slightly dulled the landscape. I wondered: was that vapour mist, or fog?

Today I finally looked up the difference between mist and fog. The sources I checked agree: if the water vapour reduces visibility to less than 1 km, it’s fog. Otherwise, it’s mist. Therefore, mist is “lighter” than fog.

Now we know:)

Source:

National Geographic

weatheronline.co.uk

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Out in the backyard: the tutor reflects

The tutor comments on another Sunday afternoon out in the backyard.

We’ve been in a cold snap lately, with temperatures dropping -5°C to -8°C since perhaps last Monday. This afternoon I thought I’d get outside, breathe some fresh air, work a little off the burn pile, and reconnect with the yard.

A Greek friend of mine told me that, commonly in rural Greece, the orchard prunings are used to heat the homes through winter. With only a few trees in our yard, we don’t quite follow that tradition. However, the prunings, fallen branches, and cones (we have a 70-year-old Douglas fir in our yard) are adequate to feed a few backyard fires. With that in mind, I headed out today.

I got outside around 4pm to a cold, still, grey afternoon. The temp was probably around 1°C; water was dripping from the Douglas fir, even though we haven’t had rain for a week. I started the fire with some old phone book pages and cardboard, then turned to the ground for twigs and larger branches. I spent the next 25 minutes running around, grabbing up fuel, bringing it to the fire, then repeating the process. Finally the fire was strong enough to accept some larger rounds. I placed some half-burned wood from last fire on it, then turned to the burn pile. Afterward, I continued picking up twigs and branches from the yard, though at a more leisurely pace.

With the fire well established, I started adding cones from the Douglas fir. They burn slowly, but keep the fire stable once it’s strong. I’d say I put hundreds of cones in it.

I ran the fire for three hours; the last hour, cones were the dominant fuel. I’d guess the fire might have received about a pound of fuel every ten minutes. It was a good cleanup, but I wouldn’t be surprised if we could do the same again next month.

In a future post I’ll hopefully consider the heat output of the fire, given the fuel it received.

BTW: I saw one flying insect outside, even after a week of nighttime freezes. That’s the west coast for you!

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Today’s weather: rain w/ a few downpours

The tutor discusses the change in weather on BC’s south coast.

From early July until mid August, our summer has been uncommonly hot and dry. While we did receive one or two well-timed rains, the threat of forest fires has been unnerving.

I doubt the forest fire risk profile has officially changed at this moment, but we received heavy rain today. Looking at a weather map, I think I can see why.

The map shows us under a low pressure system, with a cold front also present. Although I’m not trained in weather, my simple explanation for the heavy rain is this: The low pressure system, which comprises warm, moisture-filled air (some of tropical origin) is colliding with the cold front. As the air in the low pressure system cools down, it can no longer hold so much moisture, so drops it as rain. The heavy rainfall results from the plunge in temperature as the low pressure system hits the cold front.

Over the next three days more rain is forecast:)

Source:

environment canada weather

theweathernetwork.com

cbc news

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Weather: rainfall on the North Island

The tutor discusses a topic of current concern.

Here on Canada’s west coast, we live in a rainforest. True, the rain comes mainly Oct. through April; the summer is often dry. However, our summers are not usually hot. We have the moderating Pacific Ocean, whose temp is always about 5°C, to the west.  Unlike Central Canada, for example, our air nearly always cools into the mid teens at night.  28°C is a hot day here; I’d claim that most of our summer days, the temp doesn’t climb above 26, with many in the low 20s.

This summer, according to the historical weather of the Comox Valley, provided by theweathernetwork.com, we haven’t had precipitation since June 24. At the same time, we’ve had a heat wave. Over the past week, smoke has been drifting into town from nearby forest fires. Surrounded by heat and smoke, I’d developed the beginning of siege mentality.

Over night, rain has come – more than I’d hoped for. It’s still falling lightly. We’ve been warned that it won’t be enough to end the forest fires, but will help the firefighting personnel. However, my sense of well-being has improved dramatically overnight.

Cheers: )

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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Lifestyle: the first weekend of yard work, 2015

The tutor discusses his commencement of yard work in 2015.

I hear that, on the eastern half of the continent, winter has been tough.  People have shown me pictures from the States, I think, of snow drifts as high as the front door.  I haven’t verified them; I never watch the news.  From what I’ve heard, though, this winter has been possibly even harsher than last year’s – in the East.

Here on the West Coast, we’ve had a different story:  this may be the warmest spring in ten years.  Back on January 25 (see my post about it here), we had, by my reckoning, our “first day of spring.” This past weekend, we had sun with highs in the double digits both days. The flies were buzzing and the birds were singing. I even got circled by a robust yellow jacket a few times.

True enough: unlike my comrades back East, I haven’t had to shovel the driveway lately. However, with spring weather comes yard work.

My wife and I built a new landscaping wall last November; from that, I had heaps of earth left on the lawn that needed clearing. We have enough bushes and trees so that there is pruning to do December through March. The front chip bed needed raking. The lawn needed liming. The old lawn mower needed starting….

I was out there Saturday and Sunday. Clearing the earth from the lawn, then moving it to other parts of the yard, took about six hours. The pruning didn’t take long, but the fire to burn the prunings took a couple of hours’ tending. The chip raking took around 45 minutes; the liming, around the same.

My lawn mower is an old Lawn-Boy from 1978. (I mention it in my post on horsepower and kilowatts.) At the start of the season it’s always a challenge to start; this year it took around 130 pulls of the cord. I’ve been told part of the problem is that I don’t put stabilizer in the gas in the fall. I don’t know for sure; I’ll have to research that for another post.

Anyhow, the mower always does start; indeed, it finally did in Saturday’s dusk, after 20 minutes of sweat. It hunted around for a couple of minutes to find its right RPM; from then, it ran like a top. I walked it around the back yard, doing a first pass over some strong patches of lawn so they don’t get away from me in the coming weeks.

Through twilight, I could see the kids’ TV on in their downstairs lounge. When I was a kid, the idea would have been that the kids should be mowing the lawn, while the adults relax. Did I feel that way? Not a chance. Part of being older is knowing that, outside on that early spring night, I was getting the better deal. Some day, they’ll be just where I was, and thankful to be there:)

To my cohorts on the West Coast: good luck with your spring cleanup:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.