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
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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.

Elsewhere in Weather News: February 23rd, 2013

Matthieu Leave a comment

Major Snowstorm Hits US Plains

Another trough digging through the southern half of the US this past week, caused trouble for travellers and residents of the Great Plains. Moist air from the Gulf of Mexico made its way north into Kansas which fell as freezing rain and snow ahead of the warm front. In the warm sector a line of thunderstorms, some severe, formed along the trough line that plowed through part of Texas and Louisiana.

850mb analysis

850mb analysis of early Wednesday morning. Heavy snow was already falling at this time. Highest accumulations circled in pink. (Source: Twisterdata)

Highway conditions quickly deteriorated after snow started falling and 150km of I-70 had to be shut down in Kansas due to many vehicle accidents. This system also prompted the closure of schools, delayed flights at airports or even closed airports such as the Kansas City airport. This same trough is to be blamed for suspending play at the PGA in Marana, Arizona where an uncommon sight could be seen; snow – about 4cm of it, covered luscious greens with cacti nearby in the background.

Snow affecting PGA

PGA golfers leaving the course while it’s snowing. (Source: AP)

Snowfall rates of 3-5cm/h were not uncommon for several hours in Kansas and Nebraska and contributed to significant snow accumulations. Highest accumulations were just below the two foot mark (60cm) in south-central Kansas with a good part of Kansas receiving over 20cm of snowfall. Most of the Southern Plains residents welcome any type of precipitation at this time however due to a severe/extreme drought is currently in place through much of the Plains (as talked about in last week’s EIWN). Last Thursday’s storm should at least make for slight improvements in the short term drought index but for longer range improvements the Plains need to get out of a persisting dry pattern.

Recent model runs show another major snowstorm, with as much as another foot of snow, Sunday night into Monday for the US Plains.