Nice Start to the Week

Brad Leave a comment

This week will start out fairly nice, with the exception of some showers on Monday.

A weather system will bring showers to Manitoba on Monday

Monday

Monday

Mainly cloudy a chance of showers, then clearing.
21°C / 10°C

Today will be a mixed day weather-wise. Showers are likely in the morning as a strong upper-level jet stream induces lift over the area. These showers are expected to taper off by this afternoon, with clearing skies thereafter. Once skies clear, temperatures should warm into the low twenties.

Tuesday and Wednesday

Tuesday and Wednesday look to be fairly similar days in Southern Manitoba. Both days should be mainy sunny with temperatures in the mid twenties. The wind should be fairly light, making conditions ideal.

Tuesday

Mainly Sunny
25°C / 13°C
Wednesday

Mainly Sunny
25°C / 12°C

Late Week

The late week forecast is unclear at this point. A strong longwave trough[1] will come onshore late in the week. This trough may generate a series of thunderstorm days across the Canadian Prairies and Northern US Plains. At this point the location and timing of storms is not known, but more details on this situation will be available as the week progresses.

  1. A longwave trough is a large-scale dip in the jet stream that is usually associated with strong weather systems and/or severe weather outbreaks.  ↩

Elsewhere in Weather News: June 8th, 2013

Matthieu Leave a comment

Severe Flooding in Europe

Major flooding has swept across central parts of Europe where Slovakia, Germany and the Czech Republic have all experienced crippling flooding this past week due to extreme rainfall. Amounts of 75mm were widespread across that part of the continent, and near the Alps, significantly higher amounts of precipitation were observed (some as snowfall at higher elevations). A few reports of 150-200cm of snow were recorded in Austria and Germany at high elevations.

Flooding

Severe flooding in Passau, Germany where the Danube easily overflowed its banks. (Source: AFP)

Rivers such as the Danube and Elbe have reached levels last attained 11 years ago and are threatening or have already breached sandbag dikes in some areas. Over 300,000 sandbags and counting have been prepared and put in place to prevent both rivers from overflowing their banks. The threat of a flood has forced residents out of their homes – as many as 40,000 people have been forced to move away from the nearby dikes and up to higher ground. The flooding upstream also has residents in Hungary, especially Budapest, worried as the Danube River has not crested yet but is expected to reach its peak later this weekend. Dikes there are expected to hold if the current crest projection is correct; it is believed the crest will be about a foot below maximum capacity.

Unfortunately 17 people have already lost their lives to the rapidly rising floodwaters and damage estimates top the 15 billion mark. Crop damage is widespread across Germany where over 250,000 hectares have been flooded out.

The forecast for central Europe calls for some rain on Sunday, associated with a trough but these showers will be nothing near as significant as what was experienced last week.

Mixed Weekend Ahead

Brad Leave a comment

The warm, mostly sunny weather of the past few days will give way to more unsettled conditions as a low pressure system anchors itself in Central Saskatchewan allowing a trough to sit over Southern Manitoba as a second low works it’s way across the Northern Plains of the United States. Showers will try to get going across Southern Manitoba but their coverage will be heavily limited by a lack of upper-level support over the region.

Today


24°C / 12°C
Sunny with cloudy periods. Chance of showers or a thunderstorm in the afternoon.

We’ll start off with some lingering clouds this morning with a chance of a few scattered showers as the remnants of a weak cold front wash out over the Red River Valley. We’ll then see a bit of short-lived clearing before skies cloud up this afternoon once we get warm enough to get some convection going. There will be enough instability around to produce a few afternoon showers or perhaps even a weak thunderstorm or two. Lifted Index values will be sitting at only –1 or –2°C which represents only marginal instability and CAPEs agree with values only around 500–750J/kg.

With little forcing in the area, the most favourable area for showers or thunderstorms will be near subtle convergence features; in our case, that will mean near either the western escarpment of the Red River Valley or any lake breeze convergence lines that form to the north and northwest of the city. At the moment it’s looking like the most potential for a thunderstorm sits west of Winnipeg in the Red River Valley, but there’s certainly a chance we may see an afternoon thunderstorm here in the city. Aside from the potential showers & thunderstorms, it will actually be a fairly pleasant day. Winds will be fairly light through the day and we’ll be climb to a high near 24°C. Skies will clear tonight as we head to a low of around 12°C.

Saturday & Sunday

Saturday

23°C / 12°C
Increasing cloudiness then a few showers or rain.
Sunday

24°C / 12·C
Mix of sun and clouds. Showers likely southwest of Winnipeg.

After a sunny start, skies will cloud over on Saturday as a trough connecting a low pressure system in central Saskatchewan and a low pressure system pushing into the Dakotas. There will some showers ahead of the trough line that will push through the Red River Valley in the afternoon. Rainfall amounts won’t be anything significant, but a localized 5–10mm can’t be ruled out. We’ll see a high near 23°C and an overnight low once again sitting near 12°C under clearing skies. Sunday will be a mix of sun and clouds with showers likely south and west of the Red River Valley. The high for the day will be around 24°C with an overnight low into Monday morning of about 12°C once again.

Pleasant End to the Week

Brad Leave a comment

A pleasant second half to the week is on the way with near-normal temperatures and lots of sunshine. Daytime highs will sit near 22°C through the rest of the week with overnight lows around 10 or 11°C. Winds will remain light through today and tomorrow then start to pick up to 20–30km/h out of the south by Friday afternoon. Not a whole lot to say other than it will be quite pleasant!

Wednesday

21°C / 10°C
Mainly sunny.
Thursday

22°C / 11°C
Sunny
Friday

22°C / 11°C
Mainly sunny.

The Weekend

Looking ahead to the weekend, it’s looking more and more likely it will be showery with with a risk of thunderstorms. An upper low is forecast to track across Southern Manitoba on Saturday supporting two lows: one that will track through the Interlake region tied closely to the upper low and a second low pressure system that will track through North Dakota tied to the associated frontal wave[1].

Lifted Index for Saturday Afternoon from the GFS

Lifted Index for Saturday Afternoon from the GFS.

At this point, strong instability is forecast through the Northern Plains of the United States with LI values (shown above) near –10°C showing some fairly significant instability. CAPE values south of the border are also forecast to climb into the 2500–3000J/kg range.

Further north, instability is forecast to be sitting over Southern Manitoba, although the weaker LIs of only of only around –2°C mean that we’ll need stronger forcing to get any significant storms going; with the frontal wave in the US I’m inclined to say that we’ll see more cloudy/showery weather than the potential for any significant storms. Rainfall amounts shouldn’t really come close to the last two systems, although convection in the United States is expected to feed moisture northwards into the upper low and it will spread it out into a band of showery rain again. As the system passes through, more showers are expected on the back side on Sunday.

That’s all still a long ways out, though. We’ll keep an eye out and be sure to give more details by week’s end.

  1. The frontal wave of a system is it’s associated warm & cold fronts.  ↩