Do you remember the Friendly Giant?  It was a popular children’s show in the 60s and 70s.  The camera would start on the giant’s boot and in a deep voice he would say “”look up, way up…and I’ll get rusty”.  Rusty was a rooster who lived in a bag, but I digress!  I guess I’m trying to say, you never know what you’ll see when you look up!  Our daytime sky is an ever changing palette.   If you can’t get outside to admire Mother Nature’s handy work, there’s always the wonderful network of web cameras.  Margaret Jeddry was having a look at the Nova Scotia cameras and noticed a very impressive cloud Sunday afternoon.  http://www.novascotiawebcams.com/south-shore/sambro-harbour.html

It’s a rather uncommon cloud that’s in the group known as the arcus clouds.   An arcus cloud is a low, horizontal cloud formation associated with the leading edge of thunderstorm outflow, or occasionally with a cold front even in the absence of thunderstorms. Roll clouds and shelf clouds are the two types of arcus clouds, slight variations in their generation and look being the difference.

From what I can see in the photo below, the cloud is a roll cloud rather than a shelf cloud.   A roll cloud is a low, horizontal, tube-shaped, and relatively rare type of arcus cloud. It differs from shelf clouds by being completely detached from the thunderstorm base or other cloud features.  Roll clouds usually appear to be "rolling" on an imaginary horizontal axis.

I shared the photo with a few coworkers and they immediately said, “I never see anything like that”.   To that I say “All you have to do is look up!”
 

Chief Meteorologist

Cindy Day 

Periods of Showers and Rain today.  Some of us will see peaks of sunshine here and there. Where there's sun, there are warmer temperatures.  Periods of rain expected, heavy at times for New Brunswick, again for tomorrow.  So far so good, the weekend forecast is looking warm and dry.

I hope everyone had a fabulous weekend.  The weather was pretty good, but it's really hard to please everyone!  I was out on the Dartmouth waterfront Saturday and someone came over to complain about the cold!  He wondered if I knew what the wind chill temperature might be... 

Wind chill is not something we use during the warmer seasons.  Of course there is still "wind chill" in the summer, however it is not considered a factor because it’s relatively warm, so the "chill" doesn't negatively affect the body.  The general basis for the wind chill is that the higher the wind speed and the lower the temperature the colder you will feel because the wind is wicking away the heat from the surface of your skin. The wind chill factor comes into effect when the temperature is equal to or less than 4 degrees Celsius and the wind is greater than 8 km/h.

When I speak with school children and try to explain the wind chill I usually use rubbing alcohol as an example.  When you moisten a cotton ball with rubbing alcohol and wipe in on the back of you hand, it almost immediately feels cooler. The cooling effect of evaporation: that's what wind chill is!  When the wind blows over your skin,  it raises the normal evaporation rate of your skin.  It is important to pay attention in grade 8 science.

PS: For more interesting tidbits, follow me on twitter @cindyweather

Chief Meteorologist

Cindy Day

I think Maritimers are the most weather savvy people in Canada.  Not only do you observe what’s going on around you, but you ask questions about it!  I had a grade 3 teacher who gave extra points to students who asked questions.  She used to say it was the best way to learn!

On Tuesday I got an email from Janet Ferguson & Real Morin.  They were curious about some very cool clouds they spotted on Saturday in East Gore NS.  They attached the photo below.

Now you have to admit those are very impressive. According to the email “they came out of no where all of a sudden and looked almost like grapes on the vine!”  The clouds in the photo are Mammatus clouds, also known as mammatocumulus.  The name ‘Mammatus’ is derived from the word ‘mamma’, which, in Latin, means breast or udder. As you can see in the photo, they’re clouds that drift in with pouches at the bottom.

These clouds are commonly associated with severe weather, such as violent thunderstorms and tornadoes.  Mammatus clouds are often seen after a tornado has passed. They’re usually opaque and that makes the entire area very dark and quite dramatic.  The lobes or pouches generally contain a mixture of ice and water.  In some cases, when these lumps contain a high quantity of ice crystals, it may result in hailstorms.  The pouches are a result of sinking of air, and when the air in that cloud is sinking, it usually means that the storm is weakening. 

That was the case in East Gore on Saturday.  There were no tornadoes in the vicinity, but a cold front was working its way across the province.   The front had been active with thunderstorms along its leading edge as it made its way across southern NB, but it was weakening as it approached East Gore.   Instead of producing thundershowers or even showers, the precipitation inside the clouds was evaporating.  Janet and Real mentioned that they didn’t get any rain only a fabulous sky to admire on a Saturday afternoon over East Gore.

A dramatic sky with little or no weather to show for it.

Chief Meteorologist

Cindy Day

Some of us got a break from the rain this morning, but there is more where that came from.  This afternoon, expect more rain, heavy at times with gusty southerly winds.  SW New Brunswick is under a Rainfall warning as well as the parts of the Fundy coast of Nova Scotia.  Les Suetes Wind warnings are in effect for Cape Breton as indicated by the shads of pink on the map below.

Well, we really haven’t had a lot of rain this month.  The first week is behind us and with the exception of Cape Breton Island most of us collected less than 2 mm of rain in the old rain gauge during that first week.

While we’re talking about precipitation, let’s have a look at snowfall why don’t we.  Why you ask?  Well, we haven’t had any this month but we often get some snow in May.   If you were around in 1972, you might remember a nasty spring snowstorm that rolled through on the 9^th and 10^th of May.  On this date 40 years ago, a rainmaker that had been working its way up the eastern seaboard moved into maritime waters.  A strong high pressure system parked over central New Brunswick fed cold air into the rainmaker, and voila, snow, lots of snow!   It didn’t snow in New Brunswick or Prince Edward Island, but it really piled up across Nova Scotia. 

By the time the system moved out on the 10^th, areas just outside of Halifax were reporting close to 45 cm of snow.   Snowfall amounts ranged from 15 to 20 cm in the Annapolis Valley and Sydney came in at a whopping 25 cm.  I thought that little trip down memory lane might make it easier to accept this wet, not white, weather!

Oh there’s more!  After doing a little research, I found that 1972 wasn’t a great year!  It’s the only year on record when all weather-reporting stations in Canada reported below normal temperatures for the year!   

Chief Meteorologist

Cindy Day

Finally some more sunshine.  The clouds have been fairly thick but at least for the better part of the day, most of us will see a lot of sun.  Another system is moving in from the west. Scattered showers are developing accross western New Brunswick.  These showers will move into Nova Scotia and PEI late today.  More rain for Wednesday.  Soak up the sun today! :)

 I hope you caught a glimpse of the super moon over the weekend!  It was quite spectacular! Last week I got an email from Michael Pelley. He wanted to know why he sees the full moon across the street from his house, but the other phases are visible from his backyard.  

The Moon appears in a different spot in the sky every day, because it moves in space every day. The Moon takes 28 days to revolve around the Earth, so moves 1/28 of the way around the Earth every 24 hours. After 28 days it arrives back at the point in its orbit where it started, and is back in the same place in the sky.   The moon slowly moves from west to east along the ecliptic; each day the moon will shift about 12 degrees east if observed at the same time of day.
A cool thing about the moon is that it is in synchronous rotation: it rotates on its axis in about the same time it takes to orbit the Earth. This means that it nearly always keeps the same face turned towards the Earth.  The side of the Moon that faces Earth is called the near side, and the opposite side the far side. The far side is often called the "dark side," but in fact, it is illuminated as often as the near side: once per lunar day, during the new Moon phase we observe on Earth when the near side is dark.

Chief Meteorologist

Cindy Day

This weekend, backyard astronomers will be treated to something quite special: a full moon.  Now you’re probably thinking what’s so special about that; we have 12 sometimes 13 full moons every year.  Yes, that’s right, but not like this one!

This weekend’s full moon will be the biggest and brightest of the year!  The Moon will be at perigee, the closest point to earth in its orbit.  It will lie about 354,000 km away; that’s 48,000 km closer than when it is at apogee. Apogee occurs when the moon is at its farthest point from earth in its orbit.  This year the moon's perigee coincides with its full phase. 

The official time of the full perigeean moon is 35 minutes after midnight Saturday night.  If “parigeean moon” doesn’t roll off your tongue, the full moon in May is called the Full Flower Moon or the Full Corn Planting Moon.

Oh and if that wasn’t enough, Mother Nature has an added treat for early risers.  This weekend, Earth is entering a stream of debris from Halley's Comet, source of the annual eta Aquarid meteor shower. Because the shower's radiant is located below the celestial equator, southern hemisphere observers are favored, but even northerners will be able to see at least a few flecks of Halley-dust disintegrating in the atmosphere when the shower peaks this weekend.  The best time to look is during the hours before sunrise on Sunday, May 6th.  Bright moonlight will cap the meteor rate at about 30 per hour.

Happy Sky Watching

Chief Meteorologist

Cindy Day

I think I speak on behalf of all gardeners when I ask “are we there yet?”.  After what always seems like a long winter, gardeners count down the days to the average frost free date for their area.

Of course there are no guarantees, but the dates below are calculated by taking into account more than 30 years of data.  

It’s still important to keep an eye on the sky.  Clear skies allow temperatures to fall back quite quickly and without a breeze, or a mixing wind, there could be pockets of frost well after your “last frost” date.  Grandma would never put out her delicate plants before the full moon in May.  This month's full moon is on Sunday.  If you can't wait until then, cover up your petunias and hope for the best J

Chief Meteorologist

Cindy Day