A Fairly Pleasant Weekend

Brad Leave a comment

Although temperatures will be a little below normal for foreseeable future, a fairly pleasant few days are on tap for Winnipeg. A ridge of high pressure over the central Prairies will work at clearing out the clouds giving us plenty of sun for Friday and Saturday while winds slowly diminish. A low passing through on Sunday will mark the return of potentially rainy weather.

Friday
19°C / 7°C
Sunny with afternoon clouds. Breezy.

Saturday
18°C / 7°C
Mainly sunny.

Sunday
18°C / 8°C
Cloudy periods with a chance of showers.

Significantly cooler air than seen over the past week is working its way across the Prairies into Southern Manitoba, dropping daytime highs from the the mid-to-high 20s to the high teens. Temperatures will remain roughly 5°C below normal for the next week as a much cooler pattern locks in; daytime highs aren’t expected to reach over 20°C until late into next week.

Today will bring some late morning/afternoon cloud with a breezy west-to-northwesterly wind at around 20-30km/h. Temperatures will reach around 18°C. Expect clearing skies tonight and a low of around 7°C.

Tomorrow will be very similar to today except with a little less cloud and lighter winds. High near 18°C once again and a low near 7°C again.

Showery Sunday?

A weak low pressure system is forecast across Southern Manitoba on Sunday, bringing a renewed chance of showery weather. At this point, it looks like little in the way of particularly active weather will occur; even a rumble of thunder looks out of the question.

Probability matched mean precipitation from the SREF model for Sunday morning.
Probability matched mean precipitation from the SREF model for Sunday morning.

In general, the system is expected to spread some light shower activity from west to east across Southern Manitoba through the morning hours, persisting into the afternoon. Overall amounts look to be low; in the image above, I’ve used a probability matched mean ensemble[1] which can better capture higher amounts embedded within the mean precipitation field, and it still only shows around 2-4mm for most areas.

There are some hints the system may pick up strength and produce 5-10mm over the woods from Pinawa down to Sprague, but it’s still a little too far out to say much reliably.

Sunday won’t be all showers and cloud, though with a good chance of a few sunny breaks through the day. Highs will be near 18°C once again with an overnight low around 8°C.

Heading into next week it looks as if the cooler temperatures will continue with a couple more chances for precipitation through the first half of the week.

  1. For those who are curious, this takes the ensemble mean value, but matches the rain rate distribution in the ensemble mean field to the complete ensemble. Can help prevent “smearing” of the precipitation field.  ↩

Sunshine Gives Way to Unsettled Weather

Brad Leave a comment

The beautiful summer weather will stick around for one more day before a large upper trough pushing across the Prairies spreads showers and generally unsettled weather into Southern Manitoba.

Forecast precipitation for Wednesday night from the RDPS.
Forecast precipitation for Wednesday night from the RDPS.

Today will be an almost ideal summer day across much of the Red River Valley. Sunny skies will gradually see increasing cloudiness through the afternoon hours, however before things cloud up temperatures will climb all the way up to around 27 or 28°C while light winds begin picking up in the afternoon to 20-30km/h.

Wednesday
27°C / 14°C
Increasing cloudiness in the afternoon.

The story will be a little different over southwest Manitoba today, where an incoming surface trough will combine with warm weather and moderate instability to produce mid-to-late afternoon thunderstorms. Around 1250J/kg of CAPE will combine with 25kt of bulk shear and a 25-30kt LLJ to support upscale growth from a few isolated thunderstorms to an eastward moving line by the evening. This line will weaken fairly quickly as it moves into the Red River Valley thanks to the loss of daytime heating and the storms moving away from their main support.

The overall threat of severe weather in southwest Manitoba is marginal. The main risks will be large hail, but that seems like a fairly off chance at best. A rogue wind gust can’t be ruled out either, but again, I don’t have particularly high expectations for severe weather. Were I the SPC, it would be a “See Text” sort of day.

This line will bring a chance of showers or thunderstorms to Winnipeg and the Red River Vally through the overnight hours. No severe weather is expected. Temperatures will drop down to around 15°C or so.

Thursday & Friday

Thursday
25°C / 10°C
Cloudy periods; slight chance of showers.
Friday
21°C / 8°C
A mix of sun and cloud.

Tomorrow will bring cloudy periods with a slight chance of showers through the day. The precipitation risk will increase towards evening as a second impulse digs the upper trough into Manitoba, leaving us with a chance of showers on Thursday night.

Cooler air will also start filtering in. Thursday’s high of 25°C will be replaced by cooler weather for the remainder of the week and weekend. The temperature will drop to around 10°C on Thursday night.

Things should push off to the east on Friday morning leaving behind some sunny skies, but skies look to become mixed midday. There may be a chance of seeing some rain on Friday afternoon, but guidance is very mixed right now as to whether or not a band of rain will push northeastwards out of North Dakota. At this point it seems more likely that things will stay dry than not. We’ll see highs across the Red River Valley top out around the 21°C mark. The overnight low on Friday night will drop into the high single digits.

The Weekend

The weekend across the Red River Valley is looking fairly nice, albeit a little cool. Saturday will see afternoon cloudiness bring a slight chance of late-day showers. Sunday looks fairly sunny, although cloud will likely increase in the evening ahead of another system forecast to push through the region on Monday. Highs will sit near the 20°C mark with overnight lows in the mid-to-high single digits.

State of the Climate: Meteorological Spring 2014

Julien Leave a comment
Meteorological Spring Stats and Rankings for Winnipeg
Category Spring 2014 Total or Average Rank (since 1872)
High Temp. 5.6°C Tied 19th Coldest
Mean Temp. -0.4°C Tied 20th Coldest
Low Temp. -6.2°C Tied 22nd Coldest
Rainfall 67.2 mm 59th Least Rainy
Snowfall 31.4 cm 59th Snowiest

Despite a seasonal May temperature-wise, the meteorological spring[1] of 2014 still averaged well below normal thanks to a frigid April and March. The spring averaged -0.4°C, 3.8°C below the 1981-2010 normal of 3.4°C. Thus this was the 9th coldest spring in the last century and tied for 20th coldest since 1872. In comparison, last spring in 2013 was a tad colder, averaging -0.6°C. It was just 2 years ago that we experienced our 2nd warmest spring on record. We’re sure paying for that now!

A Variety of Weather Conditions in May

Because I’ve already talked a lot of about March and April in 2014 – The Year so Far a few weeks ago, I’ll talk mainly about the month of May in this post.
May started out just like every other month since last fall: below normal. Things began warming up mid-month with our first 20°C of the year on May 10 when we reached 23.2°C. This marked the 18th latest first 20°C of the year since 1872 and the latest since 1996 when we did not reach 20°C until May 18. The 1981-2010 normal is April 20 and thus, we were a good 3 weeks behind schedule this year.

After some snow on May 14, mother nature had a dramatic mood swing in the 3rd week of May as July-like conditions arrived. Just 10 days after seeing snow, temperatures soared to a record 33.3°C on May 24, breaking the old record of 32.7°C in 1980. This also marked the first 30°C reading in May since 2007 and was the hottest May day since 1995. Temperatures soared again on May 29, reaching 32.7°C. With two days above 32°C, it was the most 32°C+ days in May since 1995 when there were also two.
With the warmer weather came thunderstorms. Winnipeg received its first thunderstorm of the season on May 20, the 8th latest start to the thunderstorm season since 1953. This follows the 2nd latest start last year. 1981-2010 normal first thunderstorm of the year is April 27.

In the end, May averaged 11.3°C which is pretty much bang on the normal of 11.4°C. However, at 0.1°C below this normal it is just enough to continue the streak of colder than normal months. May stands as the 8th consecutive colder than normal month, a streak which began last October. This ties for 7th longest below normal streak since 1872.

Top 12 Longest Streaks of Colder Than Normal Months Since 1872
Rank # of Consecutive Below Normal Months Timeframe
1 18 months Dec 1882-May 1884
2 14 months Jul 1884-Aug 1885
3 11 months Oct 1887-Aug 1888
4 9 months 1949/50, 2008/09 & 2012/13
7 8 months 6 occurrences (including 2014)

Thankfully, May ended a 5-month streak of months averaging over 3.5°C below normal, the longest streak of its kind since 1872. Prior to this year, the longest was just 3 months.
May this year also continued a now 2 decade-long trend of cool Mays. We have not had a top 35 warmest May in 23 years. The last time was in 1991 which featured a tie for 5th warmest May. Since then, 6 Mays were among the top 35 coldest.

The Year So Far

The monthly and accumulated year-to-date temperature deviation from the normal monthly average temperatures.
The monthly and accumulated year-to-date temperature deviation from the normal monthly average temperatures.

So far this year we have averaged -8.2°C (January to May), 4.2°C below normal and the 16th coldest first 5 months of the year since 1873. It is also the coldest since 1996 and the 5th coldest in the last century. This is little improvement from the 15th coldest first third of the year (January to April) we experienced.

  1. Meteorlogical spring lasts through the months March, April and May.  ↩

Normal Weather Through Early Week

Brad Leave a comment

The first part of this week will feature fairly typical early-June conditions, with temperatures in the low twenties and a chance of rain.

Areas along the International Border may see some rain on Monday
Areas along the International Border may see some rain on Monday

Monday

Monday
18°C / 9°C
Chance of Showers

Today will see a chance of showers over all of southern Manitoba. In areas near the International border, there may be more than showers, with periods of rain and perhaps even some embedded thunderstorms. Accumulations along the border should generally not exceed 15mm, but there could be locally higher amounts if any thunderstorms develop. In areas further north, such as Winnipeg, it should be a fairly uneventful day overall, with temperatures in the upper teens and a breezy north wind.

Tuesday and Wednesday

Tuesday
23°C / 10°C
Mainly Sunny
Wednesday
25°C / 13°C
Mainly Sunny

Tuesday and Wednesday look like uneventful days in southern Manitoba. Temperatures will be in the low to mid twenties with light winds and mainly sunny skies. There’s certainly nothing wrong with that!

Long Range

The long range forecast suggests we may see a risk of thunderstorms on Thursday, followed by cooler weather for late week into the weekend. We’ll likely rebound to seasonal or above-seasonal values at some point next week.