Category: Forecasts

Showers With A Chance of Thunderstorms Tonight & Friday

Brad Leave a comment

Showers and isolated thunderstorms will push into the Red River Valley tonight, signalling the start of the next major low pressure system to move across the prairies.

A low moving NE out of Eastern Montana has spread rain into much of Southern Saskatchewan through the day today, and is posed to bring more rain into Southern Manitoba.  Thunderstorms have initiated along a warm front draped W-E across North Dakota and will move northwards, supported by a 40-50kt southerly 850 jet and large scale ascent with a strong southerly flow aloft overriding the warm front.

Winnipeg should see rain beginning late this evening into the overnight period and through much of the day tomorrow as the precipitation will continue to blossom coming out of the United States.  All in all, most of the Red River valley should see 20-30mm of rain by the time the rain lets up on Friday evening, with local amounts possibly reaching 50mm underneath a few of those isolated thunderstorms, should they manage to develop.

This is, unfortunately, not good news to many of the Farmers in the RRV, who have had to battle saturated grounds through much of the latter half of the summer.  This is also bad news for the RRV in general, as we continue to have the soil re-saturated as we approach the winter freeze.  Should a long stretch of dry weather not occur, this wet fall could lead right back into a wet spring due to overland flooding.

It’d Be A Shame to Let the Puddles Dry Up

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Don’t put your umbrella away yet; our wet start to September isn’t going to be going away any time soon…

I wish I had better news to share, especially for our farmers outside The Perimiter©, but more wet weather is in store as the cool and unsettled weather continues.  At least the mosquitoes won’t be much of a problem, right?

The first thing to note is the incoming surface ridge that will be moving across Southern Manitoba tonight and tomorrow.  Cool air combined with clear skies will drop our overnight lows down to 3-4°C in the city, with temperatures a degree or two colder outside the city.

Cool daytime highs trying to reach 20°C should persist through the weekend.  To begin next week, it appears as if another low pressure system will track through North Dakota, with a warm front draped across the state close to the international border.  I have decided to go with the NAEFS (North American Ensemble Forecast System) solution, as individual models have been varying their solutions a bit for this system:

This shows the probability of 10mm of precipitation or more through 00Z Sept 6 to 00Z Sept 8.  Current indications are that areas close to the border should expect rain through this period, with NAEFS indicating a 70-80% chance of >10mm of rain.  The probability decreases as you head north, but even for Winnipeg the probability of more than 10mm is still > 50%.  This solution will likely change, however I’m fairly confident in saying that people in the RRV can expect a gloomy, rainy Monday into Tuesday.

Things settle down for a couple days with highs near 20°C until the next system rolls through the Dakotas at the end of the week.

This system is currently forecast to be a bit further south, but the NAEFS still plasters the RRV with a 50-70% chance of > 5mm of precipitation from 00Z Sept 9 to 00Z Sept 11.

All in all, likely a rainy start to our week and rainy end to our week after a rainy middle of this week.  And to make things “worse,” there doesn’t look like there will be too much of a chance of thunder making an appearance, except for (most likely) the US side of the border with the first system.

I’ll go get my rubber boots and put them by the door.

Unsettled Weather in Store Next Week

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Having broken the 30° barrier another time in the 2010 summer, summertime sun will give way to more unsettled weather next week.

A weak cold front will pass across Southern Manitoba tonight, bringing with it a very slight chance of showers (most likely nothing) and moving us into a cooler airmass for tomorrow, which should be a mostly cloud day.

By Monday morning, a warm front (shown above in the 850mb temperatures) will be positioned SW-NE across Southern Manitoba, extending from a surface low positioned in central North Dakota.  For several days, as the low moves northeast along the baroclinic zone, scattered showers will ride along the warm front.  Each night, there exists a potential for non-severe nocturnal thunderstorms in the RRV and east near the intersection of the warm front and a weak 850mb jet extending up into Southern Manitoba.  Most of the energy associated with the 850mb jet will remain in the states, so I don’t think that any severe weather will be on tap.

Get out and enjoy tomorrow, Sunday through Wednesday will be cooler (think low 20’s for highs) and rather unsettled, with mainly cloudy skies with occasional sunny breaks and showers lurking around during the days, with areas of organized precipitation occurring overnight. on Sunday night and Monday night.

Hot Today, Gone Tomorrow

Brad Leave a comment

Temperatures in the low 30’s combined with dewpoints in the low 20’s will make it feel like 40 degrees today.

A slow-moving low pressure system associated with a sharp, digging upper trough over the west coast is bringing southerly winds to the RRV under strong southwesterlies aloft.

850mb temperatures are climbing into the mid-20’s ahead of these features, which when combined with a southerly 40G60 km/h wind and sunny skies, will result in the temperatures soaring into the low 30’s today across much of Southern Manitoba, with temperatures reaching to near 35°C just on our side of the international border.  The strong winds will also last into the evening, keeping the air well mixed, which means we can expect very warm temperatures (> 25°C) probably past midnight.

Tomorrow we will recover a few degrees from our overnight low and then cool in the afternoon with the passage of a cold front.  There is a chance of showers and thunderstorms tomorrow associated with the cold front, however timing of the passage will be critical in determining who will or won’t get any precipitation/storms.  Currently, models are suggesting that the cold front precipitation will fire up just east of Winnipeg, so areas like Dugald & Steinback would see afternoon showers.  The GEM has been under-doing the lift associated with this entire system, however, and positioning will be crucial, so it’s too early to say much, other than tomorrow will be cooler, cloudier, and a chance of showers and thunderstorms will hang around the RRV from late morning to the evening hours.