gordon.dewis.ca - Random musings from Gordon


Archive for the ‘Weather’

There will be snow. Lots of snow.

January 16, 2022 @ 22:07 By: gordon Category: Weather

It’s been a while since I blogged about anything of significance. The weather in Ottawa is going to be rather exciting over the next day or two.

TAF CYOW 170240Z 1703/1724 07010KT P6SM BKN140
FM170600 07012KT 1 1/2SM -SN OVC025
FM170800 06015KT 3/4SM -SN VV007
FM171300 06015G25KT 1/4SM +SN VV005 PROB40 1713/1716 1/8SM +SN
FM171600 01012KT 1SM -SN OVC008
FM172100 32012KT 2SM -SN OVC010

In simple terms, this TAF basically says that Ottawa is going to get snow. A lot of snow. Starting at about 01:00, or in about three hours’ time from now.

Looking at the various models, it looks like the peak is going to be between about 08:30 and 11:00, which is consistent with the bolded line above, which says that from 1300Z (08:00 Eastern) the wind will be 15 knots gusting to 25 knots from the east-northeast. The visibility is forecast to be about a quarter of a mile with a vertical viability of 500′ and heavy snow. And there’s a 40% probability between 1300Z and 1600Z (11:00 Eastern) that the visibility will drop to an eighth of a mile with heavy snow and blowing snow.

This model is predicting a 1-hour accumulation of 64.6 mm, or 6.5 cm, of snow at 9am Eastern.
This model measures precipitation in terms of rain, while snow is approximately 10 times as much. At 10am Eastern, it is predicting a 3-hour accumulation of 14.7 mm of rain, which is roughly 147 mm of snow or 14.7 cm of snow.

This doesn’t bode well for watching the Mercury transit on Monday

November 10, 2019 @ 00:46 By: gordon Category: Astronomy, Weather

While starting to prepare for observing the transit of Mercury on Monday, I took a look at the cloud cover forecast for Monday morning. It’s not terribly encouraging:

There is an intriguing hole in the Eastern Townships near Sherbrooke. That might be the place to be.

Maybe the forecast will change between now and then. (It could happen.)

Spring: Not coming to a city near you anytime soon.

April 08, 2019 @ 16:44 By: gordon Category: Weather

Spring just can’t seem to take hold this year. The forecast for the next 24 hours or so is quite bleak:

TAF AMD CYOW 081922Z 0819/0918 06005KT 5SM -FZRA BR OVC006 TEMPO 0819/0820 6SM BR

FM082000 06005KT 5SM -DZ BR OVC006 TEMPO 0820/0821 6SM BR FM082100 VRB03KT 5SM -DZ BR BKN006 OVC010 TEMPO 0821/0903 P6SM NSW OVC010

FM090300 03008KT 6SM BR SCT004 OVC010 TEMPO 0903/0908 4SM -DZ BR BKN004 OVC010 BECMG 0904/0906 07008KT

FM090800 10012G22KT P6SM -SN BKN008 OVC012 PROB30 0908/0912 3SM -FZDZ BR

FM091200 10015G25KT 4SM -FZRA -PL BR OVC008 PROB30 0912/0918 3/4SM -SN VV007


In other words, light freezing rain, which should be done by now, light drizzle, swirly gusty winds with snow starting overnight and then changing to light freezing rain and light ice pellets, a combination often known as sleet, with a 30% change of that turning into snow. You know, because we haven’t had enough snow this winter.

I’m seriously hating the weather.


October 17, 2018 @ 12:29 By: gordon Category: Weather

Well, it looks like the nice weather may be coming to an end. Or interrupted, to say the least:

TAF CYOW 171440Z 1715/1812 27018G28KT P6SM BKN040 BKN100 TEMPO 1715/1716 P6SM -SHRA 
FM172200 31012G22KT P6SM -SHSNRA BKN050 PROB30 1722/1801 2SM -SHSN 
FM180100 30015G25KT P6SM FEW060 

Loosely translated, this tells us that from 6pm to 9pm, we’re probably going to see precipitation that may not be entirely liquid. It’s not going to accumulate, but it that doesn’t change the fact that it probably won’t be purely rain.

I hope I’m wrong about this and that the only thing I’m going to need my windshield wipers for this evening will be rain.

First dragonboat practice of the season

May 28, 2018 @ 14:24 By: gordon Category: Dragonboats, Weather

This evening is the first practice of the season for my dragonboat team. Naturally, the weather is shaping up to be a bit exciting just before and just after our session:

TAF CYOW 281739Z 2818/2918 24007KT P6SM BKN020 TEMPO 2818/2820 BKN025
FM282000 26007KT P6SM BKN040 TEMPO 2820/2823 P6SM -SHRA PROB30
2820/2823 2SM TSRA BR BKN040CB
FM290200 26008KT P6SM -SHRA BKN050 PROB30 2902/2904 VRB20G30KT
FM290400 35010G20KT P6SM FEW050
FM290600 36008KT P6SM SKC
BECMG 2914/2916 06008KT

Basically, on either side of our practice (from 8pm to 9pm), the weather may include light rain showers and with a 30% probability of thunderstorms.

Figures, eh?

A weather non-rant

April 23, 2018 @ 12:01 By: gordon Category: Weather

This may just be the shorted TAF I’ve ever seen:

TAF CYOW 231439Z 2315/2412 22005KT P6SM FEW220

Basically, until 8pm this evening, light winds out of the southwest and a few clouds at 22000′.

A nice change from the other stuff we’ve had recently, eh?

Another apology to astronomers in this part of the world

January 10, 2018 @ 13:57 By: gordon Category: Astronomy, Weather

So, a couple of days ago I posted an apology to astronomers in this part of the world because I had cursed the weather by having ordered a new astronomy toy. Well, a couple of days ago, I ordered a tripod for my new toy and now the viewing conditions for the foreseeable future look like this:

The line of particular interest is the “Seeing” line. White and grey boxes are bad. And the “Transparency” line is pretty much solid white, so that sucks, too.

I think I’m done buying astronomy bits for a while, mostly because it appears there’s no point because I’ll never get to use them. That should cause the weather to clear up sometime by the end of the month.

Once again, my apologies to the astronomers in this part of the world. I’m sorry.

Hmm… I could use a dew heater. (Does anyone want to pay me to not buy a dew heater and thus not curse the weather further?)