Tag: Showers

Wet & Windy Weather On The Way

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Yesterday’s beautiful mid-October weather will be replaced in a hurry today and tomorrow, as a intense 985mb low pressure system brings unsettled weather into the Red River Valley with strong winds moving across the area as the low pushes eastwards.

RDPS 3hr. QPF for this afternoon.

3-hour accumulated precipitation for mid-afternoon from the RDPS. Precipitation will be oriented in a band NW-SE ahead of the main surface trough.

Cloudy skies will be dominant over the Red River Valley over the next couple days. While temperatures are fairly mild this morning, and of note is how high our dewpoint has climbed, we won’t gain too much temperature-wise through the day today. Showers will push into portions of the Red River Vally & SE Manitoba this morning, however it’s likely that precipitation will be sporadic for any one location through the day today with fairly minimal accumulations. Conditions don’t look too favourable for drizzle today; you generally want saturated low-levels of the atmosphere with a sharp contrast into dry air immediately above the cloud deck for drizzle generation. Today, we’ll actually have dryer low-levels with a fairly moist atmosphere above, so it’s more likely that any light precipitation would be somewhat-evaporated rain, not drizzle. Temperatures will climb to 12 or 13°C today.

A band of steady rain will begin to push into the Red River Valley this evening as an area of strong frontogenesis1 on the northwest side of the 850mb low orients itself over the region. The band of rain looks to be fairly narrow, and positioning of it will be very sensitive to the positioning of the 850mb low. All areas in the Red River Valley will see some periods of rain tonight, however any locations that end up under this sharp band of rain will likely see 5-10mm of rain. Amounts remain low, despite the strong forcing, as this system, while energetic, is relatively low in moisture. Precipitable water values look to be only in the 20-25mm range, instead of the closer to 40-50mm range we look for for higher-accumulation rainfall events.

Winds will pick up overnight into Thursday as the Red River Valley moves into a strong pressure gradient on Thursday. Winds will climb to 40-50km/h with gusts up to 60km/h. Showers will be widespread through the Valley as general “wraparound” precipitation moves in on the backside of this system. Total amounts for tomorrow will generally be 4-8mm across the Red River Valley. The rain and wind will taper off tomorrow night as the system moves off towards the Great Lakes. Temperatures will drop down to 6 or 7°C.

Friday will be a slow recovery day, as the clouds will begin to break up a bit through the day. With skies remaining fairly cloudy with only a few breaks for sunshine, temperatures will end up fairly steady through the day; likely only around 8°C. Looking ahead to the weekend, it looks to be a fairly seasonal weekend with a mix of sun and clouds and highs near the seasonal 10°C.

  1. From the AMS Glossary: In general, an increase in the horizontal gradient of an airmass property, principally density, and the development of the accompanying features of the wind field that typify a front. ↩

Decent Start to the Week

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The weather to start this week will be decent, with normal to above-normal temperatures expected. However, some change is in store closer to the middle of the week.

A strong low pressure system will move through Southern Manitoba this week

A strong low pressure system will move through Southern Manitoba this week, pulling down cooler air from the north

Monday will be a fairly good, albeit cloudy day. Temperatures will be in the low teens in the Red River Valley, with perhaps a couple of light showers in the afternoon. These showers are expected to develop ahead of a trough that will move through the Red River Valley during the day. Further west, in portions of south-western Manitoba, temperature should climb up around the 20C mark as sunnier conditions prevail. Tuesday looks to be the warmest day of the week, with highs close to 20C possible in the Red River Valley. Unfortunately that is where nice weather ends.

A powerful low pressure system will slide through Manitoba on Wednesday, bringing some rain and changing weather with it. Temperatures on Wednesday will remain near normal at around 10C with gusty west to north-westerly winds developing behind the low pressure system. On Thursday the system’s passage will be felt more noticeably as temperatures drop back down into the mid single digits and gusty north winds make for a chilly day.

There is some uncertainty in the forecast for late week into the weekend. Models currently suggest that another strong low pressure system may move through Manitoba, but the timing and strength of this system are not clear. This is what the end of the week will probably look like, but as we all know models like to change their solutions from time to time.

Slowly Improving Weather in Store

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The weather will slowly improve over the next couple days as some warm air begins to slowly push across the Prairies.

3hr. Cumulative Precipitation for late this afternoon

3hr. cumulative precipitation from the RDPS for late this afternoon.

Today will remain mostly cloudy across Southern Manitoba with two main features to pay attention to. The first feature is a low pressure system that will slide from Southern Saskatchewan into North Dakota, bringing with it a chance of showers through southwest Manitoba through the morning and into the early afternoon. The second feature will be a trough slumping southwards through the Interlake into the Whiteshell. The southern extent of this trough will move through the Red River Valley in the late afternoon and evening, and as it enters the area, a few scattered convective showers or flurries will develop along it and move through the region. Whether we see rain or snow will depend on the exact timing of the system and what the temperature is; either way, accumulations will fairly insignificant and the showers likely won’t be widespread. Daytime highs will be around 6°C this afternoon.

After these systems pass, we’ll see skies slowly clear out overnight as temperatures drop to around the -3°C mark. A ridge of high pressure begins working it’s way into Manitoba; skies will remain mainly sunny as temperatures slowly climb. Tomorrow we should see daytime highs around 9°C through the Red River Valley, and increasing up to around 11°C for Friday. We’ll see a mix of sun and clouds on Friday as a weak system brings some cloud through the Red River Valley as it passes through central Manitoba.

The weekend looks relatively average, with no indications so far that any significant precipitation events are in store for us over the next week.

Last Day of Summer Will Be Cold, Wet and Windy

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Far from the sunny skies and warm temperatures we’ve seen constantly over the last several months, today will be cold, wet and windy as a cold front blasts through the Red River Valley.

GEM-REG 850mb Temperatures

850mb temperatures from the GEM-REG model valid for this evening. A significant outbreak of cold air will occur over Southern Manitoba today.

A powerful cold front will push southwards through the Red River Valley today, beginning in areas north of Winnipeg early this morning, then pushing through Winnipeg mid-to-late morning and then pushing through the rest of the valley and southeast Manitoba by early this afternoon. There will be an area of showers that pushes through the central and eastern Red River Valley, with rain further east in the Whiteshell along and behind the cold front. Generally speaking, if you’ve seen showers in the past two days, you’ll likely see more today. Winnipeg will likely only see 1-2mm, however anywhere from 2-10mm are possible in the eastern Red River Valley to the Ontario border. In addition to the precipitation, strong winds will once again develop over the Red River Valley, with winds increasing out of the north to 40-50km/h with gusts to 60-70km/h immediately behind the cold front.

This system will be dragging the coldest temperatures aloft that we’ve seen this month; 850mb temperatures will drop to anywhere from -5 to -8°C. This will result in fairly significant low-to-mid-level instability, mainly through the Interlake and arcing southeastwards across the South Basin towards Sprague. This will have two main impacts:

  1. Today, associated with the passage of the cold front, there’s a chance for an isolated thundershower through the Central/Southern Interlake and the Dugald/Beausejour/Grand Beach region. They will not be very strong, however they may be able to produce small hail.
  2. As the winds at various heights in the atmosphere slowly line up, lake-effect streamers will develop this evening and overnight off of Lake Winnipeg. The location of the precipitation will be sensitive to the exact wind direction, however, in general, the regions that will be effected the most will be up in the Arborg area (from the North Basin), and then further south in the Dugald/Beausejour/Grand Beach region (from the South Basin). There will also likely be streamers in the Portage la Prairie region overnight from Lake Manitoba, however they’ll be weaker as a surface ridge approaches from the west overnight. There will only be a slight chance of isolated showers in the southern half of the Red River Valley overnight. Winnipeg will be nestled between the two bands of streamers to our west and east, however there’s a distinct chance that we could see the streamer from the South Basin move into the city overnight.

In addition to the streamers, the other significant weather tonight will be frost. Areas that clear out tonight, which will be most areas that aren’t in the lee of the lakes, will see frost with overnight lows in the -1 to -3°C range. There’s a chance that areas in SW Manitoba may see overnight lows dip as low as -5°C underneath the surface ridge.

For Saturday, here in the valley we’ll see clouds & showers from the lakes last until midday before things start to clear up in the afternoon. Temperatures will remain cool with highs only around 11°C. We’ll likely see a hard freeze tomorrow night with overnight lows in the -3 to -5°C range across most of Southern Manitoba.

On Sunday, we’ll finally see some warmer air make it’s way towards us. The models want to push temperatures as high as 18-19°C through the Red River Valley, however we often see cold air stick around a little longer than forecast. Winds are forecast to shift to the southwest, however it’s almost certain that if they don’t quite make it to SW and end up being southerly we’ll see daytime highs a few degrees cooler than that. We should see temperatures in the mid-to-upper teens last through much of next week with little significant weather on tap.