Cool, Wet Weather For The Weekend

Brad Leave a comment

Winnipeggers: get ready for a shock. The next few days are going to be startling chilly with daytime highs over 10°C below normal and overnight lows over 5°C below normal. Another thing that will be noticably absent other than warmth? The sun will make only a few rare appearances over the next several days as another system pushes into Southern Manitoba, bringing another round of rain and thunderstorms to the Red River Valley.

850mb Temperatures valid 00Z Friday

850mb temperatures vaild at 00Z Sat. May 26 (Friday evening). An elongated cold trough is sweeping across Southern Manitoba, bringing 850mb temperatures in the -2 to -5°C range.

This cool weather has brought late-season (or is it early-season now?) snow to several communities over Western Manitoba including The Pas, Flin Flon and higher elevations over SW Manitoba (Duck Mountain & Riding Mountain areas). A few leftover flurries will scoot across the Interlake this morning and exit out of the province. The Red River Valley wil be spared, however we’ll be stuck under low clouds with a daytime high that struggles to make it to 10°C.

Tonight, a widespread frost potential exists over the most of Southern Manitoba. As a surface ridge moves into our area, winds will abate and we’ll see the cloud begin to break up a bit this evening. The greatest potential for frost looks to be over Southwestern Manitoba in the Virden, Melita, Pilot Mound & Brandon regions. Further east, here in the Red River Valley, some scattered clouds and a bit of moisture trapped in the valley should help temperatures stay above freezing, with overnight lows in the 2-3°C range. Areas outside the City of Winnipeg in the RRV certainly have a slight risk of a light frost. Winnipeg will likely be frost-free, with an off-chance of patchy frost in outlying areas near the Perimeter Highway.

Saturday will be our transition day with temperatures reaching 13-14°C and cloud streaming northwards from the Dakotas with the next incoming system. Rain will push up towards the International Border by morning, likely staying in the States but certainly poses the chance of a few showers along the border. The rain will stay near the border until Sunday, when the next big northward push arrives.

24. hour precipitation accumulation Saturday morning to Monday morning](https://img.skitch.com/20120525-mkq1sh9w3aa3twa7r6stuq9j2q.png)

Precipitation accumulation from the GEM-GLB model for Saturday morning to Monday morning. A broad swath of rain is forecast to fall from extreme SW Saskatchewan through Southern Manitoba.

And what a push it will be! Showers and thunderstorms will rapidly develop into an expansive area of rain on Saturday night, slowly pushing northwards across the Red River Valley. Most regions across Southern Manitoba should expect rain to start fairly early on Sunday and last through most of the day. Rain will likely taper off from west to east overnight, with only a few wrap-around showers moving across the RRV on Monday. It’s still early to give accurate estimates of rainfall totals for this next system, however in general, most regions across Southern Mantioba look to see at least 10-20mm of rainfall, with the potential for nearly 30mm in some areas of the RRV if some embedded convection can get going. Regions of Southwestern Manitoba that end up north/northwest of the main upper low track will see higher amounts as well, with 20-30mm of rain likely. This isn’t the best news for this year’s Teddy Bears Picnic, but hopefully shouldn’t dampen spirits too much at an event that has, historically, had to deal with some pretty awful weather. Wait, I’m getting deja vu…

Conditions look to improve through the middle of next week, with temperatures pushing back towards the 20°C mark and some sun finally making an appearance. That’s a ways to go, though, so grab your slippers and heat up some soup! We have some great stay-inside weather coming up. We’ll be sure to keep a close eye on this system and provide updates in the comments.

Some Simple, Seasonal Weather

Brad Leave a comment

After a hectic few days across Southern Manitoba, Winnipeg is in for a few relatively calm, seasonal days before the next system moves into the region this weekend.

We’ll see the clouds breaking up this morning with a temperature that makes it up to around 19°C by this afternoon. We’ll see a slight chance of showers this afternoon, however they shouldn’t amount to very much and will quickly move out this evening. Tonight’s low will be around 10°C here in Winnipeg. Thursday and Friday will bring us a mix of sun and clouds with chances of afternoon showers across most of the Red River Valley as the upper low from yesterday’s system slowly tracks out of the Province. The daytime highs over the next couple days should be near 19°C.

A more significant system is forecast to move into our region this weekend, bringing what currently looks like a pretty rainy day to this year’s Teddy Bears Picnic.

Stormy Weather To Return to Southern Manitoba

Brad Leave a comment

After a cool night, temperatures will rebound nicely today before more unsettled weather pushes into the province tonight and lingers through mid-week.

850mb temperatures valid Tuesday Evening

850*mb* temperatures valid 00Z Wed May 23 (Tuesday Evening). Warm and cold front are represented by red and blue lines, respectively. Orange arrows represent warm air lifting northwards over the warm front.

Temperatures today will work their way to 20°C today with increasing cloud. The first of several impulses forecast to track across Southern Manitoba will push a warm front across the Red River Valley late this afternoon, bringing with it a good chance of showers
through regions along the Trans-Canada highway and northwards into the Interlake. Regions in the southern half of the Red River Valley will see just a chance of showers through the afternoon and evening today.

Tomorrow, a low pressure system will push into North Dakota, strengthening a warm front draped across the region. Southern Manitoba will stay north of the warm front, keeping daytime highs in the 20-23°C range. Strong capping will restrict surface-based thunderstorms to Central/Southern North Dakota where a cold front advancing across the Plains will help trigger storms later in the day. For us, however, we’ll be in great placement for the development of nocturnal convection. A strong 30-40kt low-level jet overriding the warm front will pump fairly moist air northwards; dewpoints at 850mb over Southern Manitoba are expected to rise to the mid-teens. Combined with negative lifted indicies, CAPE values are expected to climb to nearly 1500J/kg.

This will likely result in the development of showers and thunderstorms on Tuesday evening, developing somewhere over Southern Manitoba and pushing northeastwards through the night. Nocturnal convection is always a very tricky thing to forecast, so we’ll definitely keep a close eye on things and provide updates in the comments as we get closer.

The upper low associated with this system will push across the Prairies through the week, bringing a mix of sun and clouds and some unsettled weather and more chances of showers.

Elsewhere in Weather News: May 19th, 2012

Matthieu Leave a comment

Strong Winds, Wildfires Rage On

South-eastern Manitoba has seen its fair share of fires burning this spring but it wasn’t comparable to the conditions experienced this past week in Arizona and Colorado where wildfires are burning out of control across the states. Fanned by very strong southwesterly winds associated with a ridge of high pressure that is strengthening over the west coast, the fires quickly grew out of control in Arizona. Wind gusts of 80km/h were recorded in the area which easily spread the flames and expanded the fire by blowing embers, making it nearly impossible for firefighters to contain the blazes. In addition to the strong winds, both states have been impacted by severe droughts this month; especially Arizona where soil moisture content is bone dry.

Fire map

Map showing in red where the largest fires are. (Map provided by Google Maps.)

As of Friday morning, one dangerous fire was burning in north-eastern Colorado; a couple in the Tonto National Forest just north-east of Phoenix, Arizona; and other smaller fires had flared up in New Mexico and Utah.

As for the Colorado fire, conditions will improve slightly as thundershowers are in the forecast and will bring rain however cloud-to-ground lightning from the storm could potentially spark more fires. The Colorado fire was 11% contained as of Friday afternoon; it consumed more than seven thousand acres and has forced a couple dozen people out of their homes.

Colorado wildfire

Image of the large Colorado fire burning just west of Fort Collins. (Source: Denver Post)

For the Arizona fire it’s a different story though – as a big ridge builds over the region, relative humidity will continue to drop dramatically, reaching values in the low teens to single digits. This, combined with extremely hot temperatures of around 40°C, will surely cause hardship and less than ideal conditions for firefighters as they work feverishly to battle the flames. The Arizona fire was 5% contained and 80 homeowners were on alert to get ready to leave on Friday afternoon. With the tinder-dry conditions persisting in the area for the next couple of days, residents must pay attention to every slight fire danger they may pose during everyday activities –whether it’s having a barbeque or using their ATV in the wilderness.

Arizona wildfire

Cloud of smoke coming from the couple wildfires in Arizona’s Tonto National Forest. (Source: MSNBC)