Summer Arrives in Southern Manitoba

The heat is on the way to Southern Manitoba as warmer air finally spills eastwards bringing positively summer-like weather to the area.

There is astonishingly little to say about the coming few days. Temperatures will climb into the mid–20’s Friday, Saturday and Sunday with overnight lows near 11 or 12°C all 3 days. Winds will be fairly light with the slight possibility of some breezier conditions on Saturday afternoon, but even there it would only likely be 20–30km/h. No precipitation is expected, although there will be a slight chance of some showers on Saturday north of Winnipeg along a very weak cold front from Dauphin eastwards across the Interlake.

All in all it will be a perfect weekend to get outside either here in the city or head up to the cottage for a truncated mulligan of the May long weekend!

Uncertain Start to Next Week

The beginning of next week presents another interesting forecast challenge as yet another Colorado Low forms and pushes northwards into the Dakotas. Model forecasts currently diverge quite a bit, demonstrated easily by the current forecasted storm-total precipitation for Winnipeg produced by each one:

Forecast Storm-Total Precipitation for Monday’s Colorado Low
Model Storm-Total Rainfall (mm)
GDPS 16
NAEFS 8
GFS 0

In general, amounts increase to the south and east of Winnipeg in all the forecast scenarios. Why the big difference? The track of the Colorado Low will depend significantly on how it interacts with thunderstorm activity that develops through the Central Plains as it ejects northeastwards from Colorado. If the convection forms close to the upper-level low and has a significant amount of moisture wrap into it, it will strengthen more, tilting the entire upper-level trough and pulling the system further northwest. If the moisture from the convection pulls off to the east over the upper-level ridge, then the system will be a bit faster, weaker and further southeast.

At this point, there’s still far too much disagreement in the models to make much of a forecast. Overall, the GDPS – currently forecasting the highest amounts for Winnipeg & the RRV – tends to produce too much convection and over-develop lows. They’ve made significant improvements in the latest version of the GDPS, but it still tends to have that strong bias which results in slower systems further to the NW. I think the GFS solution of nothing at all to likely be missing the mark and not quite worth banking on.

That leaves us with the middle-of-the-road answer. Likely some rain on Monday, however not likely as much as advertised by some weather sources right now. We’ll certainly keep an eye on things as they develop and have some updates later in the weekend on how it looks like things are developing.

But for now, get out there and enjoy the hot & dry weather!

Nice Start to the Week, Then Some Rain

This week will start out very nice, with temperatures in the twenties. However, a strong low pressure system will move in toward the middle of the week, bringing more unsettled conditions.

Monday

Today will be a great day in southern Manitoba. Temperatures will be near the 20C mark with sunny skies and light winds. There isn’t much else to say, enjoy the weather!

Tuesday

Tuesday will be another very nice day as temperatures climb into the low twenties, once again under mainly sunny skies. Winds will be from the south-east at about 20 km/h.

Wednesday

Wednesday will remain warm, but more unsettled conditions will begin to take hold in southern Manitoba. An approaching low pressure system is expected to bring rain showers to southern Manitoba late in the day and into Wednesday night. This system may bring us more significant precipitation on Thursday, but it is too early to speculate on potential rainfall amounts.

Long Range

It looks like we’ll see cooler weather late this week into the weekend as a much cooler air mass gets pulled down from the north. This push of cool air will result from the departure of this week’s low pressure system. Long range models suggest we’ll return to above-seasonal conditions at some point next week.

Hot Weather Continues

The summer-like temperatures seen in Winnipeg over the past couple days will continue into the weekend with daytime highs 10°C above normal. A cold front will finally push through on Saturday evening, bringing an end to the exceptional warmth and ushering in a return to seasonal temperatures.

Today will be a gorgeous day in the Red River Valley with light winds and daytime highs near 25°C with a bit of a southwesterly wind. Expect a few clouds tonight with a low near 10°C.

Tomorrow will be a more interesting day as a more organized southerly flow develops over the Red River Valley ahead of an approaching low pressure system. Temperatures will climb to around 27°C while a meager amount of moisture pools through the Red River Valley ahead of an approaching trough. As the trough moves into the Red River Valley, it’s looking quite possible that we may see a few thunderstorms develop, however the chance is largely conditional.

Winnipeg Forecast Sounding for the afternoon of Saturday May 2, 2015
This forecast sounding valid Saturday afternoon for Winnipeg from the NAM model shows a deep layer of instability, adequate moisture and favorable shear for thunderstorm development.

Given the fairly low amount of moisture available, cloud bases would likely be very high; the forecast sounding indicates cloud bases near 10,000ft which would mean the biggest threat from the storms would be strong wind gusts. Some hail might be a threat further south in North Dakota, perhaps sneaking onto extreme southeastern Manitoba, but overall it looks more like we’ll see a few weak thunderstorms develop capable of producing some fairly gusty winds. The overall environment, save for the lack of moisture, looks quite favorable for the development of the storms, though. Winds will generally be out of the south to southwest at around 30 gusting 50km/h with a slight chance for some 50 gusting 70km/h winds in the afternoon.

Some cloud will linger overnight as temperatures dip to around 9°C with winds relatively light out of the west to northwest.

Sunday will bring a bit of cloudiness and slightly cooler temperatures with a daytime high of “only” 19°C. Winds could be gusty out of the northwest for a few hours beginning in the morning before settling down to 30 gusting 50km/h for the afternoon. Sunday night looks mainly clear with a low near 5°C.

Summer Warmth Arrives

Summer-like warmth has arrived for Winnipeg and the Red River Valley thanks to an upper-level ridge moving into the region that will spread warm air over Manitoba for the coming days. Some rain looks likely on Thursday evening as a “cool” front passes, but the other days through the second half of the week look beautiful with plenty of sun to go along with the warmer weather.

Today will be a mainly sunny day with a high near 21°C. Winds will remain fairly light through the day as well. With an overnight low near 8°C or so, the warmth should hang on into the evening making for a pleasant evening to be outside.

Thursday will bring a fair amount of cloud, however the sun will still poke out a few times through the day. Winds will be breezy out of the south, picking up to around 30–40km/h with gusts to 50–60km/h or so. Heading into the second half of the afternoon should really bring in the thicker cloud ahead of the approaching “cool” front. A band of showers will move in sometime between 6–9PM and last for a few hours as they move through.

RDSP 12hr. Precipitation Accumulation
The RDPS shows around 2mm of rain through much of southern Manitoba associated with the passage of a “cool” front on Thursday evening. Image above is total accumulations from Thursday evening at 7PM to Friday morning at 7AM.

Precipitation is expected to be fairly light, however, with total accumulations around 2mm, although if the odd convective cell gets going, some places may see closer to the 5mm mark. Winds will taper off with the passage of the front and temperatures will drop to around the 7°C mark with clearing skies overnight.

Friday will be another pleasant day with light winds, mainly sunny skies and a high near 21°C. Expect a low near 8°C on Friday night.