First Widespread Freeze!

Welcome to the coolest air of fall 2013.

If you spent any time outside you noticed the wind had an extra bite to it today, as that strong NW wind blew off of Georgia Strait up to 60 km/hr.

Dew points plummeted during the course of the day ushering in MUCH drier air and the cooler temperatures we're experiencing this very moment:

 Current temperatures as of 10 pm PST (6Z)  

Current temperatures as of 10 pm PST (6Z)

Notice the colder temperatures in the Fraser Valley and away from the warmer waters of the Georgia Strait.

Once the winds fully abate that's when temperatures will really fall, as the combination of clear skies, light winds, and an arctic air mass normally bring the coolest temperatures to our region. Even with this cool NW flow in place there's still a sharp temperature gradient (+5°C to -3°C) within 50 kilometers as seen my the temperatures above.

It's always tricky predicting overnight lows when there's a lingering breeze, because even a light breeze (5-10 km/hr), will be just enough to keep temperatures above freezing in a given location. I don't expect any fog during the first couple days of the cold snap, simply because the dew points are too low. This may change by the weekend.

Tomorrow, 3 or 4 degrees will be the high maximum temperature, so dress accordingly.

Over the next few days an upper ridge will strengthen and be the dominant force, so expect much of the same sunny, dry weather with cooler and frosty mornings.

Although temperatures will be below seasonal for the next few days, look for more seasonal temperatures by the weekend!

How unusual an abnormal is the strength of the ridge/high pressure systems that will be impacted our weather the next several days? The map below looks at climate normals between 1981-2010, with you units in standard deviations to determine the extent of the current high pressure anomaly:

SD High pressure.png

Vancouver: Two full standard deviations above normal for this time of year, and wouldn't be surprised if the barometric pressure plateaued at 1040 kPa at YVR

The real outlier will be southern Saskatchewan where the atmosphere will exert upwards of 1050 kPa of pressure on the surface (3 SD's above normal).

I know it seems like we experience vast changes and dips in surface pressure, but horizontal pressure gradients don't vary as much as you think if you perform a quick, trivial calculation.

The pressure inside Super Typhoon Haiyan (donate to relief efforts here) low pressure was estimated to bottom out at 890 kPa. Comparing that with our 'super high' over western Canada (1050 kPa) there's only a 160 kPa difference, or about a 16% between the two vastly different systems. Compare this in a 160 kPa difference in the vertical, which happens in about 1500 short meters.

This atmospheric blocking pattern, similar to the one we experienced in October isn't looking to be just short term feature, but rather a more pronounced and long term part of our weather for the foreseeable future.

It's looking more and more possible YVR will get at least a one week reprieve from the rain:

 Latest deterministic GFS model run 00Z November 20th (graphic by WeatherBELL)

Latest deterministic GFS model run 00Z November 20th (graphic by WeatherBELL)



Did you know?

One of the most ridiculous world record attempts has to go to the United Way's "Balloonfest '86." in Cleveland, Ohio. Their attempt was to set a world record by releasing 1.5 million balloons over the city, but some atmospheric indigestion (i.e. rain) pushed the balloons back to Earth in an abrupt fashion, causing mayhem.

Write-up by Dan Lewis:


But not all world record attempts go well. Some, even though good intentioned, go horribly wrong. Just ask the United Way, which learned this the hard way in 1986.

The charitable organization wanted to top the record for the most balloons released simultaneously -- a PR stunt, as many such world record challenges are. Called "Balloonfest '86," the plan was to release 1.5 million balloons over the city of Cleveland, Ohio. The release cost the United Way $500,000 and shut down the airport for half an hour. But otherwise, liftoff went fine. On September 27th of that year, 1.5 million balloons took to the sky in majestic fashion. Color filled the skies above Cleveland, and for a few moments, freckled the heavens as if a rainbow had burst into hundreds of thousands of space-bound dots. It looked like a huge success.

And then, disaster. Those 1.5 million balloons came back down to Earth -- and not so majestically. Shortly after the launch, the skies opened and it began to rain. According to the Cleveland Plain Dealer, the rains pushed the balloons back down and scattered them throughout the region. Some were pushed south, where a balloon allegedly scared a prized horse -- we know that because the horse owner sued the United Way for $100,00 (and eventually settled). Many more littered beaches on the north shore of Lake Erie, polluting the Ontario beachfronts. Much worse, though, were the thousands of balloons that actually landed on Lake Erie, as seen below. They may have led to a tragic result.

As it turned out, the day before the balloon launch, two fisherman went out to the lake and failed to make it back. Their boat was found anchored and otherwise fine on the lake, but the men were nowhere to be found. Per the Plain Dealer, the Coast Guard believed that the boat had capsized temporarily, tossing the pair from their vessel, hurling them into the water. The Coast Guard spent the next three days searching for them, but to no avail. And it's likely that the balloons which landed in the water obfuscated their view -- especially because from a distance, a bobbing head and a floating balloon look a lot a like. One of the men's widows sued the United Way (and others) for $3.2 million, and like, the horse owner, ultimately settled out of court.

The two men's bodies washed up on shore two weeks later