Tag: Rain

Cool, Soggy Weather Slow to Leave

Brad 1 Comment

Although Winnipeg has seen most of the rain the city will receive during this unsettled period, the cool and soggy weather will remain in place for a couple days yet before improving for the latter half of the week.

Skies will remain mostly cloudy1 across the central and eastern Red River Valley today ahead of yet another disturbance that will lift northwards through the American Plains towards southern Manitoba. Under the cloud, there will be a continued chance for drizzle, particularly through the morning hours. The areas that may even see very heavy drizzle or showers will be south of Lake Winnipeg, where the warm lake waters will enhance the intensity of the precipitation. Temperatures will continue cool today with highs near 12°C with winds out of the north at 15-25 km/h. Skies will remain cloudy tonight with a continued chance for drizzle. Temperatures will drop to a low near 7°C while winds diminish to light.

Winnipeg NAM Forecast Sounding valid 12Z Monday September 25, 2017
Deep low-level moisture will help to sustain periods of drizzle until midday Monday.

Tuesday will bring more rain to southeastern Manitoba as another disturbance moves through Minnesota. While the rain moves through the southeastern corner of the province, portions of the Red River Valley will see a chance of rain, mainly due to uncertainty about how far west the rain will actually reach. Winds will remain light as temperatures head to a high near 12°C once again.

The rain will taper off by evening as the light winds shift to the west and temperatures drop to a low near 6°C. Skies will clear overnight.

Some models are keeping much of the rain east of the Red River Valley, while others pull westwards.

Wednesday will finally bring sunny conditions back to the region with clear skies in the morning giving way to partly cloudy skies in the afternoon. Temperatures will be quite a bit warmer with highs near 19 or 20°C and westerly winds of 10-20 km/h.

Temperatures will once again drop to a low near 6°C on Wednesday night with skies clouding up again. An upper-level disturbance will swing across the Red River Valley from west to east overnight, likely bringing another batch of rain to the region with 5-10 mm possible, although amounts will likely taper off quickly to the south of the line, likely leaving portions of the southern valley with no rain.

Long Range

The latter half of the week looks to return to more seasonal temperatures as northwesterly winds move back into the region behind Wednesday night’s disturbance and a large ridge of high pressure moves in. There may end up being a significant frost risk at some point later in the week, but we’ll have to just wait and see how cool things are able to get underneath the ridge of high pressure.

There’s some indication that more unsettled conditions will move back into the region on weekend or early next week as another upper-level trough digs over the American Rockies.

Winnipeg’s seasonal daytime high is currently 16°C while the seasonal overnight low is 4°C.

  1. Some sunshine will likely work into the western Red River Valley; if it manages to push further east, Winnipeg may end up seeing a bit more sun. ↩

Late-Season Thunderstorm Risk Returns to the Red River Valley

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A developing Colorado Low has brought very humid conditions to Manitoba’s doorstep, and a disturbance moving through the province today will tap into that moisture and spread showers and thunderstorms across the Red River Valley into the southeastern corner of the Province.

An upper-level disturbance moving through the province will bring a late-season thunderstorm risk to the Red River Valley with a small risk of severe storms. There’s a surprising amount of support for thunderstorms, largely due to the building humidity in Minnesota over the past few days. While the weather in Winnipeg is cool and dry, conditions have become positively balmy in Minnesota, where there are overnight lows in the 20s thanks to sticky dew points in the 20-22°C range.

A stationary front lies across northern Minnesota and far southeastern Manitoba this morning.

The dry air over the Red River Valley is separated from the muggy Minnesota conditions by a fairly strong frontal boundary running from Nebraska northeastwards through Minnesota and into northwestern Ontario. As an upper-level disturbance approaches today, that humid air will be lifted up over the front and into southern Manitoba. So while we won’t see particularly humid conditions here at ground-level, further up in the atmosphere will see significant moisture move in.

Before the weather gets busier this afternoon, temperatures will climb to a high near 18°C, but winds will be breezy, increasing out of the northeast to 30 gusting to 50 km/h.

By mid- to late-afternoon, things will likely begin firing up with widespread showers moving into the province from North Dakota. While showers and/or thunderstorms will be widespread over south-central and southeastern Manitoba, the severe thunderstorm threat will be confined to two regions. Within the Red River Valley, there will be a slight chance of an isolated severe thunderstorm or two, while southeastern Manitoba sees a higher chance of more widespread severe thunderstorm activity. The primary threats from today’s thunderstorms would be severe hail and/or wind.1

AWM Thunderstorm Outlook for September 22, 2017
AWM Thunderstorm Outlook for September 22, 2017

The rain and thunderstorms will move out of the region this evening. When all is said and done, most areas will have seen somewhere between 5-10 mm of rain, with amounts of 20-40 mm possible in areas that see more thunderstorm activity. Skies will remain fairly cloudy tonight as temperatures dip to a low near 10°C with winds diminishing to around 20 km/h.

Things calm down for Saturday as the region sees a lull between Friday’s disturbance and another system moving on for Sunday. Expect mostly cloudy skies, a high near 16°C, and winds out of the north at around 20 km/h. Skies will remain cloudy on Saturday night with a low near 10°C again.

GDPS 24hr. QPF valid 06Z Monday September 25, 2017
Some guidance suggests significant rainfall on Sunday

A Colorado Low will progress through the region on Sunday, bringing rainy conditions to much of Southern Manitoba. Unfortunately at this time, it’s not quite clear exactly how rainy things will be. Some guidance has this system a bit more progressive and tracking further eastwards, which would result in 5-15 mm of rain in the Red River Valley, but others — such as the GDPS shown above — are slower with the system and bring it further west. The slower solutions would result in higher rainfall amounts for the region, more likely in the 15-30 mm range with localized spots perhaps seeing 40 mm.

At this point, the lower rainfall solution seems most likely, but we’ll be keeping an eye on it. Otherwise, it will be a cool day with a high of just 12°C and more northerly winds around 30 km/h. Expect a cloudy low near 9°C on Sunday night.

Long Range

Cloudy and cool conditions are expected to persist into the beginning of next week, but Winnipeg will likely be done with any significant rainfall chances. By mid-week, it looks like things will clear out with temperatures returning to seasonal values. The more pleasant weather may continue through next weekend, which would be a nice change!

Winnipeg’s seasonal daytime high is currently 16°C while the seasonal overnight low is 4°C.

  1. EC³ considers hail with 20 mm diameter or larger and wind gusts in excess of 90 km/h to be severe. ↩

Warmer Weather Returns, But More Chances For Rain Ahead

Brad 1 Comment

Temperatures will rebound back above seasonal values today as southwesterly winds aloft bring warmer air back to the region, but another major low pressure system is heading into the Prairies that will spread rain across southern Manitoba on Tuesday.

Today will be a beautiful day in Winnipeg after a bit of a dreary weekend with plenty of sunshine and a high near 19°C. Winds will be light out of the south to southeast. Through the afternoon hours, a bit of cloud will move through the region, bringing mixed skies to Winnipeg and cloudier conditions to the southeast. Some areas may even see some light showers, but that looks like it will be more confined towards the Whiteshell and Sprague regions. Temperatures will then head to a low near 10°C tonight under a few clouds.

RDPS 2m Temperature Forecast valid 21Z Monday September 18, 2017
Daytime highs will sit in the upper teens across much of Southern Manitoba on Monday.

Tuesday will bring the arrival of the next significant low pressure system in Manitoba. Temperatures will continue to be relatively mild with highs near 19°C again, but winds will be breezy picking up out of the southeast to 30-40 km/h. Cloud will spread into the region early in the day, with rain blossoming1 mid-day over southwestern Manitoba and mid- to late-afternoon over the Red River Valley. The winds will then taper off in the evening, with the bulk of the rain pushing off east of the Red River around midnight. Temperatures will dip to a low near 11°C.

GDPS 24hr QPF Forecast valid 18Z Wednesday September 20, 2017
The GDPS suggests very high rainfall totals possible west of Winnipeg on Tuesday afternoon and evening, but the overall rainfall totals will likely fall into the 10-25mm range over the Red River Valley.

Wednesday will start off with a slight chance of a few lingering showers, but will then transition towards drying out and clearing as the day progresses. Temperatures will be mild with highs near 20°C again with a bit of a breeze out of the west to southwest at around 20-30 km/h. Expect a low near 11°C on Wednesday night under mainly clear skies.

Long Range

Thursday looks to be another nice day with above-seasonal highs near the 20°C mark, but then another major low pressure system will track into the Northern Plains Thursday night through Friday, bringing another chance for rain alongside brisk northeasterly winds and cooler temperatures. Once it passes by Sunday, it appears that Winnipeg will then see a more extended period of near- to below-seasonal temperatures.

Winnipeg’s seasonal daytime high is currently 17°C while the seasonal overnight low is 5°C.

  1. There may even be a chance of seeing some thunderstorms! ↩

Cool, Wet Weekend Ahead

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A distinct chill will be in the air over the next few days as unseasonably cool temperatures move into Winnipeg and the Red River Valley alongside the first substantial rainfall in months.

As mentioned on Wednesday, a low pressure system will begin working its way into Manitoba today, bringing what will likely be the largest rainfall event of 2017 [thus far] to the city. The biggest change between our forecast on Wednesday and what is expected to happen today is the timing: the system’s arrival will be slightly delayed, beginning in the afternoon rather than the morning.

So, today will start off fairly cloudy skies, although a few sunny breaks are possible between now and this afternoon. As the low pressure system lifts northwards out of Nebraska into the Dakotas, cloud will thicken up over the Red River Valley with rain beginning this afternoon. The rain will become more intense into the evening with even a small chance for a crack of thunder or two. The heaviest rain should move out around midnight, with some showers or drizzle left behind.

Temperatures will be cool; expect a high near 14°C, but quickly drop to around 10 or 11°C when the rain begins. Expect a low near 8°C tonight. The winds will also be rather unpleasant, picking up out of the north-northeast to around 40-50 km/h this afternoon. The winds will persist into the evening, then diminish to 30 gusting 50 km/h overnight.

By the time the bulk of the rain pulls out of the region, Winnipeg and the Red River Valley will likely see between 20 and 40 mm, with the potential for a bit more or a bit less locally depending where exactly any heavier or lighter bands of rain set up.

RDPS 24hr. QPF valid 18Z Saturday September 16, 2017
The RDPS is suggests as much as 50-60mm of rain may be possible from Friday afternoon to midday Saturday over the Red River Valley

Saturday will bring very cool weather to the Red River Valley with daytime highs likely not even reaching 10°C. Stuck between the Friday night’s disturbance and another one that will move through Saturday evening, skies will remain cloudy with a continued chance of showers or drizzle. Winds will continue out of the north-northeast at 30 gusting 50 km/h for the day, but then diminish to calm in the evening.

As the next disturbance rolls by on Saturday evening, it will likely produce another batch of showers or rain over the Red River Valley, but amounts will be considerably less, with under 5 mm expected for most of the Red River Valley. Temperatures will drop to a low near 7°C.

And for Sunday, some morning cloud with the potential for showers or drizzle will begin moving out midday, bringing mixed to sunny skies back to Winnipeg for the afternoon. Expect a high near 15°C with winds picking up out of the west-southwest to around 30 km/h.

Long Range

The beginning of next week will start off sunny with temperatures returning to near-seasonal values for Monday and Tuesday. By Wednesday, however, another series of disturbances roll through the region, bringing what looks like another fairly good chance for more rain through the latter half of the week.

Winnipeg’s seasonal daytime high is currently 18°C while the seasonal overnight low is 6.