Tag: Rain

Coldest Weather So Far This Season Arrives In Big Pattern Shift

Brad 1 Comment

An increasingly active storm track will bring a major winter storm through the Northern Plains of the U.S., drawing colder arctic air southwards cross the Prairies and ushering in the coldest temperatures seen so far in the fall of 2016.

Today will start with a weak system pushing through the Red River Valley, bringing with it a band of showers that will lift northeastwards across the region through the first half of the morning. After that moves through, we’ll be left with fairly cloudy skies as temperatures climb to a high near 9°C. Winds will pick up out of the southeast this morning to around 20-30 km/h, then taper off for the afternoon. Expect the winds to pick back up out of the northwest later in the evening with a slight chance of some very light rain showers or snow flurries overnight as a cold front moves through and temperatures dip down to the 0°C mark.

Thursday will bring mainly cloudy skies as a Colorado Low strengthens south of the border. Winds will be breezy out of the north to northwest at around 20-30 km/h and temperatures will climb to a high of about 3°C.

This history of forecast precipitation for Friday's Colorado Low shows how the GDPS model has developed consistency only in the last day and a half.
This history of forecast precipitation for Friday’s Colorado Low shows how the GDPS model has developed consistency only in the last day and a half.

Since last weekend, it’s been quite clear that a major winter storm was possible on Friday, and that much it got right. However, what at one point looked like a major blizzard for the Red River Valley has since turned into a moderate-strength winter storm for the Dakotas and Minnesota into Wisconsin. There’s a whole discussion on long-range model forecasts, but we’ll leave it at this: while it may get the general pattern right, don’t trust it on the details.

So what will we see instead of a blizzard? Cloudy skies and a stiff north wind likely at 40 gusting to 60 km/h. The southeastern portion of the province may get clipped with some snow from this system, but here in the Red River Valley, the system snow should miss us. There may, however, be a sneak attack from the north as cooler air surges southwards and lake-effect snow fires up over the lakes. Areas in the lee of the lakes may see some light to moderate snow flurries, however these will occur in fairly narrow strips and be highly dependent on the wind direction.

Temperatures will climb to only -1 or 0°C for a high. Expect the cloud and potential lake-effect snow to continue overnight as temperatures fall to a low near -4°C.

Long Range

The weekend looks cool with a continued chance for lake-effect snow through the day on Saturday. Cloud cover will be a mixed bag and highs will be near 0°C with lows near -6°C or so. If we get completely clear skies one night, then temperatures could plummet quite severely, though, so an overnight low below -10°C may be possible if the cloud manages to be scoured out of the Valley.

More Wet Weather on the Way

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More rain is in store early this week as a well-developed low pressure system pushes across southern Manitoba. Accumulations will be relatively small in the Red River Valley, but more significant to the north and west.

A strong low pressure system will bring rain to southern Manitoba today
A strong low pressure system will bring rain to southern Manitoba today

This Week

Rain will move into southern Manitoba today in association with a strong low pressure system coming out of Montana. Light rain will likely begin in the Red River Valley this morning, continuing into the afternoon. Models show a break in the rain during the evening hours, which might just provide a good window for trick-or-treating. Regardless of whether it’s raining or not, temperatures will be favourable for the youngsters to be outdoors, with temperatures hovering in the mid-single digits. Total rainfall of 2-5 mm is expected today, with another 2-5 mm tonight. Parts of western Manitoba and the Interlake can expect total accumulations ranging from 10 to 25 mm.

Today’s weather system will still be lingering over Manitoba on Tuesday, with some showers remaining possible through Tuesday morning. A drier flow should develop by Tuesday afternoon, signalling an end to the precipitation. Temperatures will remain relatively normal for late October, with high temperatures in the mid to upper single digits in southern Manitoba. Winds will be breezy out of the west at 20-30 km/h.

Nicer weather should arrive for Wednesday as a ridge of high pressure builds over the region. Mainly sunny skies and temperatures around or just below 10C are expected. Wednesday’s nice conditions should signal the beginning of a significant warm spell which should last into next week. Winds should be relatively light thanks to the surface ridge.

Long Range

Medium- to long-range models have been strongly hinting at a significant warm-up beginning mid to late this week. An anomalously strong upper ridge of high pressure is expected to build over Central North America, signalling a period of well-above seasonal conditions for Manitoba. Given that our normal high is 4C, we can easily expect temperatures of 10-15C. It is not impossible that we reach the upper teens once or twice when the “heat” peaks sometime over the weekend or next week. Models strongly suggest that this above-seasonal pattern will exist for most, if not all, of the first half of November.

An unusually strong upper-level ridge will build over Manitoba by next weekend
An unusually strong upper-level ridge will build over Manitoba by next weekend

Friday’s Disturbance Leads To Cooler Weekend

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Cooler, more seasonal temperatures will push into Winnipeg & the Red River Valley this weekend behind a low pressure system that will bring rain to portions of Southern Manitoba on Friday.

Today will bring a low pressure system, talked about in Wednesday’s forecast, through the province. In that post, we discussed how there was uncertainty in the track of the low, and that it seemed like much of the rain associated with it would fall across the Interlake. With the system imminent now, it’s become readily apparent that it will indeed primarily affect areas to the north of Winnipeg, at least for much of the day today.

Today will be a cloudy one across Winnipeg & the Red River Valley with light winds and temperatures climbing to a high near 12°C. Late this afternoon, winds will pick up out of the northwest to around 30 km/h, bringing with them a chance of some rain as a cold front sweeps southwards across the province. No significant accumulations are expected in Winnipeg, unlike the further north where 15-25 mm are possible along a west-east line running from Swan River eastwards across the Northern Interlake and Berens River.

With the gusty northerly winds and light showers tonight will come dropping temperatures. Lows should sit near 2°C tonight with winds tapering off towards Saturday morning. With the cooler temperatures and northwesterly winds, there may also be more persistent shower activity in the lee of Lakes Manitoba & Winnipeg as a result of weak lake-effect precipitation.

Light shower activity is expected across Southern Manitoba on Friday night.
Light shower activity is expected across Southern Manitoba on Friday night.

Saturday will be a mainly cloudy day with light winds and a much cooler, more seasonal high near 6°C. Expect continued cloud cover on Saturday night with lows near 1°C.

Sunday will start off cloudy but will likely bring an occasional sunny break in the afternoon. Temperatures will continue seasonal with a high near 8 or 9°C, but the wind will be more noticeable as it picks up out of the south to around 30 km/h once again. There’s a slight chance that it could end up even slightly windier than that, with sustained winds near 40 km/h, but at this point guidance suggests winds will be closer to the 30 km/h mark.

Expect a low on Sunday night near 5°C under partly cloudy skies.

Long Range

Guidance continues to be fairly consistent in a low pressure system moving through the province on Monday that will bring a soaking rain to much of Southern Manitoba. It’s a bit early for exact numbers, but general amounts 10-25 mm have been consistently produced by guidance over the past several days. After that system moves through, an upper ridge will build into the southern Prairies and…

NAEFS 8-14 Day Temperature Anomaly Forecast — Valid November 4, 2016 to November 11, 2016
NAEFS 8-14 Day Temperature Anomaly Forecast — Valid November 4, 2016 to November 11, 2016

Dry weather with an extremely high likelihood of above-seasonal temperatures will be on the way for Southern Manitoba, alongside much of North America, through the second half of next week. So hang tight, it looks like we have some beautiful November weather ahead!

Winnipeg’s seasonal daytime high is currently 6°C while the seasonal overnight low is -4°C.

Above-Average Temperatures Bring Wet Weather

Brad 1 Comment

Daytime highs will continue to be above the seasonal average of 6°C throughout the remainder of the work week, however it will come at a cost as a series of disturbances work across the region bringing multiple rounds of wet weather.

The first disturbance that will bring wet weather to Winnipeg is outside your window right now, as rain spread into the region overnight. The rain will taper off towards midday with a grand total of 5-10mm of accumulation likely for most areas.1 As the rain pushes off to the east, temperatures will climb to a high near 9°C under cloudy skies.

RDPS forecast rainfall totals for daytime hours on Wednesday.
RDPS forecast rainfall totals for daytime hours on Wednesday.

Tonight will bring some clearing to the Red River Valley, but the lack of any significant westerly flow to the winds will prevent us from seeing widespread elimination of the cloud, meaning skies will likely remain at least mixed over the region through the night. Temperatures will drop to a low near 4°C.

Thursday will leave the region in a slack flow with mixed to mainly cloudy skies. Temperatures will climb to a daytime high near 11°C in what will be a rather unremarkable day. The next disturbance will begin moving through the region on Thursday night, thickening up the cloud cover again as temperatures drop to a low near 6°C.

Friday is a bit of a wildcard at this point…at least for Winnipeg. A low pressure system tracking along the International Border will spread an area of rain to its north, however who exactly will see rain will be a bit of a challenged as the southern edge of the accumulations will see a rapid cutoff. Complicating things is relatively minimal model agreement:

Event Total Rainfall Forecasts for Winnipeg, MB – October 28, 2016
Model Event Rainfall (mm)
RDPS N/A
GFS 0.5
NAM 1.9
GDPS 3.9
PME 4.0
GEPS 8.8

So the range in precipitation amounts goes from the GFS’ low end forecast of 0.5mm, a situation where pretty much the entire area of rain falls north of the city, up to nearly 10mm from the global ensemble prediction system. It seems likely that the bulk of the rainfall with this system will fall north of Winnipeg, with the city seeing either some brief rain or more sporadic shower activity through the day.

The temperature should reach a high near 10°C while the overnight low drops to around 5°C under cloudy skies.

Long Range

The weekend is looking dry as seasonal air returns to the region with northerly winds on Saturday and southerly winds on Sunday. The chance for rain returns to the Red River Valley on Monday.

Winnipeg’s seasonal daytime high is currently 6°C while the seasonal overnight low is -3°C.

  1. A few locations along the western escarpment northwestwards into Parkland Manitoba may see total amounts in the 10-15mm range. ↩