Cold Snap for the Weekend

Brad Leave a comment
Friday afternoon 850mb temperature forecast (RDPS)
Cooler weather is on the way for the weekend as a significant pool of Arctic air grazes Southern Manitoba.

Much cooler temperatures are on the way for the weekend – especially overnight lows – as a push of Arctic air slumps southwards behind the cold front that passed through Southern Manitoba last night. The result will be below normal daytime highs and some exceptionally cold nights for mid-March.

Friday
-2°C / -19°C
Mostly cloudy; slight chance of morning flurries

Saturday
-5°C / -12°C
Partly cloudy

Sunday
-2°C / -10°C
Increasing cloud

Today will be a mostly cloudy day with some sunny breaks this afternoon, however the main weather for the day will be the brisk northerly winds to 30–40km/h that pick up through the day. These winds will be ushering in significantly cooler air for this evening. Fortunately, temperatures will be able to recover a little bit today before the colder air pushes in with high temperatures reaching a slightly below-normal[1] –2°C. Unfortunately, the cold air slams into the Red River Valley tonight. Temperatures will drop to around –19°C overnight.

Saturday and Sunday look fairly quiet weather-wise. After a very cold start to the morning, temperatures on Saturday should climb to around –5°C under partly cloudy skies. This high will be around 6°C below normal. Temperatures will dip just below –10°C on Saturday night and then climb back up to –2°C or so on Sunday afternoon. Sunday looks to start fairly sunny but see increasing cloudiness through the day as a disturbance slips across southwestern Manitoba.

Seasonal Weather Returns Next Week

Seasonal highs anywhere from 0 to +4°C will return for the start of next week. Conditions look fairly dry, however early indications point to a system moving through Southern Manitoba mid-week that could bring some rain (or less likely, snow) to the area.

  1. Normal daytime highs for this time of year are around +1°C.  ↩

Shot of Cold Air Incoming

Brad Leave a comment

The mild, dry weather we’ve experienced over the past week and a half continues for a couple more days before a powerful cold front sweeps through Southern Manitoba on Thursday night, bringing much colder temperatures to the region. Fortunately, the cool-down is expected to be short-lived with temperatures returning to seasonal values by the end of the weekend.

Wednesday
7°C / -3°C
Mainly sunny

Thursday
8°C / -8°C
Partly cloudy

Friday
-4°C / -15°C
Mainly sunny & breezy

Today will be another beautiful day with a high near 7 or 8°C, light winds and just a bit of cloudiness. Temperatures will drop to around –3°C tonight with light southerlies and mainly clear skies. Tomorrow looks quite nice as well with partly cloudy skies and a high near 8°C. Unfortunately, a big change is swinging through on Thursday night.

A potent cold front will swing through Winnipeg & the Red River Valley overnight Thursday, bringing with it a chance for some flurries and much cooler air. Winds won’t be too bad through Thursday night, perhaps to around 20km/h or so. Expect a low somewhere in the –8 to –10°C range.

Much cooler weather will persist through Friday and Saturday. Friday will be quite an unpleasant day as northerlies strengthen through the day to around 30–40km/h by late afternoon. The temperature will only climb to around –4°C for a high which will make it the coldest day since March 6th when the mercury topped out at +0.8°C. Temperatures will plummet into the mid-minus teens on Friday night as those strong northerlies really tap into the colder Arctic air plunging southwards.

Cool, Dry Weekend Ahead

This coming weekend will be dry and generally cool as a ridge of Arctic high pressure dominates the weather over the Red River Valley. Saturday will see highs near –6°C or so while the high on Sunday manages to climb back up towards the 0°C mark.

Record Snow Pack Loss

As of Sunday (March 15th, 2015), Winnipeg’s snow pack officially fell to 0cm. This was thanks to a dramatic melt that took much of Southern Manitoba from snow-covered to bare ground in just a few days thanks to a surge of record-setting warm air.[1]

MODIS imagery revealing significant snow pack melt in Southern Manitoba
MODIS satellite imagery reveals the dramatic melting of the snow pack over much of Southern Manitoba in under a week.

A snow depth of 0cm on March 15th ties for the 3rd earliest snow melt on record since 1955, trailing 2012 by just one day:

Top 11 Earliest Snow Melts (1955 – Present)
Rank Date of 0cm Snow Depth Year(s)
1 February 28 2000
2 March 14 2012
3 March 15 1995, 2015
5 March 17 1981
6 March 18 1973, 2010
8 March 21 1994, 1999
10 March 26 1961, 1984

The early melt was icing on the cake for Winnipeggers wary of a repeat of the never-ending winter of 2013/14. The winter of 2014/15 was effectively 4 months long – from mid-November to mid-March – of which 2 months of it was unseasonably mild. Not bad at all.

  1. On Saturday March 14th, 9 communities in Manitoba set record highs: Winnipeg, Portage la Prairie, Gretna, Dauphin, Brandon, Melita, Pilot Mound, Pinawa, and Sprague.  ↩

Cooling Down a Bit

Scott Leave a comment

This week will see somewhat cooler conditions than what we experienced on the weekend, but temperatures will remain above-seasonal nonetheless.

Temperatures will be a bit cooler this week as cooler air floods in from the north
Temperatures will be a bit cooler this week as cooler air floods in from the north

Monday

Monday
3°C / -3°C
Mainly cloudy

Today will be mainly cloudy as extensive upper cloud moves through southern Manitoba. Some precipitation will pass to our south early in the day, potentially giving us a light shower or flurry. Temperatures will certainly be cooler than the record “heat” of Sunday, but with highs in the low single digits, conditions will still be above-seasonal. A chilly north wind will be responsible for ushering in these cooler conditions and also add a slight wind chill factor throughout the day.

Tuesday

Tuesday
2°C / -5°C
Mix of sun and cloud

Tuesday will be similar to Monday temperature-wise, but it should be a sunnier day. Skies will be a mix of sun and cloud with breezy north-west winds. A light shower or flurry will be possible due to some low-level instability developing, but any accumulations will be small.

Wednesday

Wednesday
4°C / -6°C
Mix of sun and cloud

Wednesday will once again see temperatures in the low single digits under a mixture of sun and cloud. There is a slight chance of a shower or flurry again, though the chance will be lower than on Tuesday. Winds will be light and from the south.

Long Range

The long range forecast suggests we should see generally above-seasonal conditions for the rest of the month. Now that our snow cover is gone the ground can effectively absorb solar radiation, converting it to sensible heat. As the ground dries out this process will become even more efficient. Our normal temperatures will gradually increase over the next few weeks, meaning that above-seasonal weather today will become more normal by month’s end. There is no sign of any significant precipitation in the forecast at this time, so flooding should remain minimal in the Red River Valley this spring.

Elsewhere in Weather News: March 14th, 2015

Matthieu

Powerful Cyclone Strikes Pacific Islands

The strongest Pacific cyclone of 2015, Pam, struck the small island nation of Vanuatu located in the South Pacific this past week and brought with it extreme conditions as it topped the cyclone scale at a category five storm.

[map autofit=”1″ disable_scrollwheel=”1″] [pin]Port Vila[/pin] [pin tooltip=”Where Pam formed”]-7.092716, 169.442139[/pin] [/map]

The cyclone developed about 1,000km northwest of Fiji last weekend as an area of thunderstorms organized under ideal conditions – sea surface temperatures were very high in the region, as high as 31°C, and shear was minimal. Pam continued to organize early this week. It struggled as it ingested some dry air into its core while heading towards Vanuatu but by Thursday morning it formed a large eyewall that was fairly symmetric. This meant that it had fought off the dry air and was intensifying rapidly. Peak strength was reached several hours before it reached the Vanuatu Islands, winds were sustained at 270km/h, gusting over 300km/h, and pressure bottomed out at extremely low values estimated by satellites to be around 890mb. Early Friday morning the storm’s eye passed very close to several of Vanuatu’s islands making it a worst case scenario situation. The islands were battered with 250km/h winds, storm surges of 6-8m and extremely heavy rainfall.

Typical buzz-saw appearance of a category five cyclone seen as Pam approached Vanuatu and was near peak strength. (Source: NOAA)
Typical buzz-saw appearance of a category five cyclone seen as Pam approached Vanuatu and was near peak strength. (Source: NOAA)

As of Friday evening rescue efforts were still underway while searchers made their way into remote regions that were completely isolated from the storm. Overall the infrastructure on the islands is not the best, with some houses simply made out of mud resulting in more damage than you’d typically see in a developed country. The largest city, Port Vila, was reported to be out of power and running water and had debris scattered across roads making travel difficult. There are unconfirmed reports of numerous deaths associated with this storm, but they have not been confirmed yet.

 

Damage seen on Friday evening (our time) as Pam was on its way out. (Source: UNICEF Pacific)
Damage seen on Friday evening (our time) as Pam was on its way out. (Source: UNICEF Pacific)

After Pam has finished its swipe through the Vanuatu islands, it is not expected have any other significant effect on any other island nations as it heads Poleward where it will weaken. The Pacific/Eastern Indian oceans have been extremely active this week, not only because of Pam, but there have been three other cyclones that were active at one time this week. Two of these made landfall on Australian soils (category three and category two), with minimal damage reported. With that said, there are no other areas of interest for possible formation of other cyclones as of Friday night.