Tag: Windy

A Windy Day to Mark Arrival of Warmer Air

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Winds will pick up today out of the south as warmer air finally begins to push it’s way into Southern Manitoba. By this afternoon, strong winds will be in place over the Red River Valley and temperatures will finally climb out of the single digits under an extensive cirrus cloud deck.

NAM Skew-T Log-P Digaram

NAM-based model Skew-T Log-P diagram for the central Red River Valley valid at 21Z this afternoon.

Winds will pick up by early this afternoon as a warm front pushes across Southern Manitoba. Sustained wind speeds will increase to 50-60km/h, with strong gusts on top of that; mostly around 70km/h, but the potential exists for gusts as high as 80-85km/h.

The picture above is a model-based skew-T log-P diagram which shows how temperature (red line) and moisture (green line) change with height in the atmosphere over a single location. Up the right-hand side of the chart are wind barbs, which represent the wind speed & direction at that height in knots. Each full tick mark is worth 10kt, a half tick mark is worth 5kt, and a filled triangle is worth 50kt. On the left hand side, the pressure is marked from 1000mb (the surface) to 100mb (about 16km off the surface). In the skew-t log-p diagram above, we can see a strong 20kt flow out of the south with an unstable layer from the surface to about 875mb. Within this unstable layer, near the inversion, winds increase to 45kt. Since it’s within mixing distance of the unstable layer, it’s entirely possible that those strong winds could be mixed down to the surface.

Temperatures will climb to about 10°C today, but with that strong wind it’s going to feel a little cool out there this afternoon. The winds will taper off this evening as things cool off, and then we’ll enter into a fairly pleasant weekend.

We’ll be under the influence of a weak low pressure system through the weekend, however unlike most systems, very little precipitation will occur near the system; instead most of the precipitation will be displaced northwards, into the high Interlake region, where frontogenetic forcing is stronger. What that means for us, fortunately, is that we’ll see relatively light winds through the weekend, a mix of sun and clouds and daytime highs in the low-to-mid teens. Overnight lows will be bumped up a little bit from the -3 to -5°C range to just at or above 0°C.

This weekend will be a pleasant break from the cold. Best to get out and enjoy it too; next week looks to bring multiple systems that could bring us some more rainy, windy weather.

Major Cool Down Begins

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A significant change in the weather is underway today as Arctic air blasts southwards, pushing out the pleasant, above normal temperatures we’ve had lately and replacing it with cloudy, cool, windy weather. I hope you enjoyed the last few days, because you probably won’t enjoy the next few.

850mb Temperatures from the GFS

850mb temperatures valid this morning from the GFS model. Warm and cold fronts are depicted.

A cold front, tied to a powerful low pressure system moving through central Manitoba, swept across the Red River Valley overnight, ushering out the warmer temperatures aloft that have given us pleasant temperatures the past few days. In it’s wake is a dramatically different pattern than we’ve seen lately.

Upper troughing will dominate the Prairies as a secondary low, currently spinning up over Montana/Wyoming tracks eastwards and pulls more cold air southwards. This will establish us into a much cooler pattern where cooler, Arctic air is entrenched over the region and it’s significantly harder for us to get those nice warm breaks.

Today we’ll see winds begin to pick up out of the north as temperatures climb to only around 13°C. We’ll get cloudier as the day goes on, and by the late afternoon into the evening some showers will push into the southern regions of the Red River Valley. Further north, we’ll see a chance of showers, however it will be more difficult for any organized precipitation to develop over the northern Red River Valley.

As the aforementioned US low tracks through South Dakota, winds will shift to the north-northeast over the RRV, which when combined with the cooler air being dragged southwards, will bring lake-effect showers into the central Red River Valley. Current model solutions hint that Winnipeg may be in the path of these, however, as usual, the exact wind direction will be crucial in determining where the showers will fall. Temperatures will drop to around +3°C tonight.

Thursday will be a cool day, with northerly winds persisting, cloudy skies and a high of only 7 or 8°C. Lake effect showers will persist in the lee of the lakes, and scattered showers will likely be found throughout the entire Red River Valley. Cold air continues to pour southwards and we’ll drop to near 0°C. Precipitation is…complicated for Thursday night. The GEM-GLB & GFS models are forecasting only around 5mm of rain for Thursday evening over SE Manitoba, including the Steinbach region. Other models, such as the NAM, have a much worse forecast. The NAM spins up the low over the states into a very powerful storm system, which taps into some Gulf moisture over the east-central States and lifts it northwest and slams it into a deformation zone oriented north-south over the Red River Valley. In this outcome, 1-2 inches of precipitation is forecast to fall, some as rain, however much of it as snow. Should we believe the NAM, it would result in many communities east of the Red River waking to find over a foot of snow on the ground! Ensemble forecasts suggest that this is an outlier; most solutions favour a quicker track to the low with less precipitation over the Red River Valley. We’ll keep a close eye on this as it develops, but you should be prepared for the potential for poor travelling conditions on Friday.

Things calm down on Friday as this system leaves the region and we’ll be left with cloudy skies and a high around 10°C. Things look to improve a little bit for the weekend (e.g. we may see the sun), but temperatures will remain locked in the high single digits to low teens as cold, arctic air remains entrenched over the region.

Two More Nice Days

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A couple more nice days are in store for the Red River Valley before a significant change in the weather occurs for the second half of the week.

850mb Temperatures valid Tuesday Morning

850mb temperatures valid Tuesday morning showing the baroclinic wave (warm and cold front) that will be tracking into Manitoba.

The Red River Valley will see a beautiful day today as temperatures climb to the 20C mark under sunny skies and light winds. A major low pressure system will begin to track across the Prairies on Tuesday, which will bring a major weather change to us, but not before we sneak one more nice day in. Temperatures will climb into the low 20’s on Tuesday with mainly sunny skies. Winds will increase out of the south to 40km/h with gusts near 60km/h in the morning, however they’ll let up in the afternoon as a weak trough passes through.

We’ll be under the influence of this major low pressure system for the second half of the week, which will bring cold, cloudy, very windy weather. We’ll have more details on what to expect bright and early on Wednesday morning. We’ll also have a complete summary of September’s weather within the next week. I hoped to have it ready for today, however circumstances have prevented me from being able to get it all together just yet.

Get out there and enjoy the nice weather while it lasts!

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.