Elsewhere in Weather News: March 2nd, 2013

Matthieu Leave a comment

Strong Cyclone Affects Australia, Temperature Records Tallied

This past week a cyclone, Rusty, formed off the coast of north-western Australia and quickly spun into a strong cyclone by Australian standards. The cyclone made landfall as category one by Saffir Simpson Scale standards, (rated category 3 by Australian Bureau of Meterology) and even though it brought hurricane force winds, it affected an area of Australia that is sparsely populated. This meant that not much damage was caused by Rusty and only some overland flooding was reported as well as about a hundred houses without power. As Rusty moved inland, heavy rains and high wind gusts were the main concerns; over 450mm of rain fell and gusts of 150km/h were experienced around and south of the area where Rusty made landfall. Rusty’s quick strengthening off the north-western was aided by unusually warm waters – near 31°C and only about ten knots of shear present at the time.

Rusty Flooding

Flooding in an area just south of where Rusty made landfall. (Source: @Sturap)

This week the Australian Bureau of Meteorology also announced that the warmest summer on record (records since 1910) occurred this past summer. Australia’s average temperature surpassed the normal by 1.1°C and 95% of the country had above average temperatures this summer. Birdsville, Australia which typically has an average high temperature between 35°C and 38°C during summer had 31 consecutive days above 40°C. It has truly been an impressive summer 2012-2013 temperature-wise for Australia!

Average temperature anomalies

Average temperature anomalies for Australia summer 2012-2013. Much of Australia above average. (Souce: BoM)

In other news, another significant blizzard went through the Southern US Plains bringing more short-term drought relief to the area. Some areas in north-western Oklahoma and the Texas Panhandle received over 35cm of snow. Blizzard conditions were in place as strong winds and heavy snow fell along the deformation zone of the low pressure system. Almost all roads in the Texas Panhandle were impassable because of large snow drifts, residents were urged to stay home. Weather in the Southern Plains will be fairly calm this weekend and at the start of next week; no significant precipitation accumulation is expected.

Seasonal Weather Continues Through Weekend

Brad Leave a comment

Our streak of surprisingly seasonal weather will continue through the weekend as another push of Pacific air sweeps across the Southern Prairies.

850mb Temperatures Saturday Morning

850mb temperatures valid on Saturday morning. A warm front will be pushing across Southern Manitoba ushering in mild Pacific air and a very slight chance of a dusting of snow.
Friday

Mainly sunny.
-7°C / -14°C

We’ll see a mainly sunny day today as spend a final day under the effects of a weak ridge. Temperatures will climb to around –7°C, although depending where you are in Winnipeg, temperatures could climb locally to –5 or –4°C as more and more concrete is exposed.[1] Temperatures will dip down tonight to around –15°C before clouds begin to move in ahead of the approaching warm front.

Saturday and Sunday

Saturday

Mainly cloudy.
-3°C / -7°C
Saturday

Mainly cloudy.
-2°C / -7°C

Milder Pacific air will push into the Red River Valley this weekend warming temperatures up close to the 0°C mark. Both Saturday and Sunday will be mainly cloudy and other than a very slight chance on Saturday morning of a light dusting, no snow is expected. Temperatures will only drop to around –7 or –8°C both Saturday and Sunday night.

Next Week

Models seem to indicate a system diving southwards into North Dakota but differ on what to expect from it. Current indications are that no significant snowfall will be seen over Southern Manitoba, although the GEM-GLB is painting a swath of 20+cm through our region. We’ll keep a close eye on it as the weekend progresses. Even with the passage of this system, temperatures aren’t expected to drop more than a few degrees and we should continue to see daytime highs warmer than –10°C through the week.

  1. Concrete has a lower albedo than snow-covered ground. Albedo is a measure of reflectivity of a surface; because concrete’s albedo is lower, it reflects less sunlight and warms up more. This effect is very noticeable at this time of year over forested areas where temperatures can climb as much as 10°C higher than open, snow-covered areas adjacent to them.  ↩

Pleasant Weather Continues

Brad Leave a comment

The beautiful weather we’ve been having this week will continue in a slightly cooler fashion through the rest of the week as the benign weather pattern holds on.

500mb Winds valid 18Z Thursday

500mb heights and wind speeds valid at 18Z on Thursday. A slack flow will continue over Southern Manitoba through the rest of the week.
Wednesday

Mainly cloudy.
-3°C / -11°C

Today will be the least pleasant day of the bunch as a passing “cool” front moves through the Red River Valley. Winds will pick up this morning to 30km/h out of the north as we climb to a high of around –3°C. With mainly cloudy skies expected through the day today, it will feel a little cool out there. No snow is expected, but one certainly can’t rule out a few flakes, especially near the western escarpment of the RRV and over SW Manitoba. The clouds will begin to break up overnight as we drop to around –11°C.

Thursday and Friday

Thursday

Mix of sun and cloud.
-6°C / -15°C
Friday

Mainly sunny.
-6°C / -16°C

Thursday will see a mixed sky as a weak ridge of high pressure sits across Southern Manitoba. As we move into Friday this ridge will be able to slowly erode most of the cloud over the Red River Valley, although SW Manitoba will likely remain relatively cloudy over this same time. Other than Friday being sunnier, Thursday & Friday look to be near carbon-copies of each other with daytime highs near –6°C and overnight lows dipping to around –15°C. Winds should remain fairly light to the end of the work week.

It’s worth mentioning that with the sun beginning to get stronger, even at temperatures around –5°C the sun will be able to work at melting the snow. With a weak ridge over us and light winds, it’s fairly likely that some fog patches will develop through the Red River Valley during the nights. At this time, it doesn’t seem like they should be too extensive, but it’s certainly possible that they could be quite dense. Over the past few nights, fog has formed just south of the U.S. border and reduced visibilities to as low as 200–300m. Any fog that does form should burn off fairly quickly by mid-morning.

Mild and Settled

Brad Leave a comment

This week will start out mild, with little in the way of active weather.

image

NAM model predicted 500mb winds showing a slack flow through Southern Manitoba

A relatively stagnant flow will prevail over Manitoba for much of this week as the main storm track remains well to our south. This will give us seasonably mild temperatures and little if any precipitation.

Monday
image
Mainly sunny
-2°C / -16°C
Tuesday
image
Mainly sunny. Chance of flurries overnight.
-1°C / -8°C
Wednesday
image
Mainly cloudy. Chance of flurries.
-4°C / -18°C

Monday and Tuesday

Monday will be a pleasant day, with temperatures in the low minus single digits in most areas. There may be a few readings up near the zero degree mark in localized patches. There will be a light to moderate south wind through the day, but it won’t be particularly noticeable in most urbanized areas.

Tuesday will be almost identical to Monday, with temperatures once again generally around or just below zero. There may be patches of fog in Southern Manitoba again on Tuesday morning, but they will dissipate with daytime heating in the morning. The south wind from Monday will die off for the most part, making it a non-factor. A passing weather system may bring us some light snow on Tuesday night into Wednesday, but accumulations will be small.

Wednesday

As that system passes by on Wednesday morning, a weak cold front will go through, dropping temperatures slightly. This won’t prompt any kind of significant cool-down, but it will switch the wind to a slightly brisker northerly flow. Temperatures won’t change much however, with high temperatures in the low to mid minus single digits.

Long Range

In the longer range there is little to talk about. It appears we’ll cool down a bit towards week’s end, but otherwise models show no real trends over the next 7-10 days. No significant warm-ups are in the forecast, nor are there are major weather systems in the forecast. Unfortunately, this also means there is still no sign of spring…but at least there’s no sign of a nasty winter pattern returning either.