Tag: Showers

What a Difference a Week Can Make

Brad Leave a comment

The difference between the weather experienced last week and that which is coming for early this week will be quite extraordinary. Temperatures on Monday look to be nearly 20 degrees cooler than values experienced last week.

850mb temperatures (about 5000ft above the ground) are forecast to sink to near or below zero degrees on Monday

850mb temperatures (about 5000ft above the ground) are forecast to sink to near or below zero degrees on Monday

High temperatures on Monday are not expected to stray far from the 10C mark in Southern Manitoba. Eastern most sections in the south may manage to hit the mid teens, but the rest of Southern Manitoba shouldn’t be much warmer than 10 degrees. This comes as quite a contrast to the 30 degree temperatures of last week. The above graphic shows the extent of the cold air, with freezing temperatures just 5000 or so feet above the ground. We will most likely see some shower activity develop across Southern Manitoba on Monday, but amounts should be relatively light in most areas. Thankfully Tuesday and Wednesday will be warmer, with highs moving sharply higher. Tuesday should be near or above twenty degrees (depending on which model you believe), while Wednesday is expected to be in the low to mid twenties. There may be some convective rain and/or thunderstorms on Wednesday as humidity levels increase ahead of an approaching low pressure system.

The Preliminary outlook for later this week is for more warm to hot weather. Highs back in the middle or upper twenties will be possible on Thursday and Friday according to the latest modelling. However, my confidence level in the late week forecast is lower than normal since there is some uncertainty as to how quickly a series of fronts will pass through the province late in the week. Given my lack of confidence in the Thursday-Friday forecast I won’t say much about the weekend. You can read more about longer range predictions in the next paragraph.

The long-range forecast calls for above-normal temperatures in Southern Manitoba for the second half of June

The long-range forecast calls for above-normal temperatures in Southern Manitoba for the second half of June

The NAEFS forecast seen above shows the long-range temperature forecast for the June 18-25 period. It appears that we will stick with above-normal weather for most of the second half of June. Also note that we are on the edge of the warmest air, meaning that approaching systems coming out of the colder air to our west (a trough) could potentially trigger strong thunderstorms as they interact with the warmer air to the east. This type of trough-meets-ridge pattern is to blame for the severe thunderstorms on Saturday night.

AWM Chases!

The A Weather Moment team took to the highways of Southern Manitoba on Saturday for our first chase of the year. Hot and humid surface weather combined with an approaching low pressure system and a strong jet stream aloft made conditions ripe for severe supercells thunderstorms which could potentially produce tornadoes.

A thunderstorm east of Altona on June 9, 2012

A thunderstorm east of Altona on June 9, 2012

The AWM team decided to drive toward Holland, MB to start the day. After arriving in Holland it was decided that Pilot Mound would be an appropriate new target given the new weather information available. Upon arriving in Pilot Mound and watching the latest weather conditions evolve we felt our location was ideal. At that point it was time to wait…and wait..and wait. After watching numerous towering cumulus clouds fail to breach the cap we decided to abandon Pilot Mound and follow some storms to our east which were approaching the Red River Valley. As we began to get a good visual of the storms around the Altona region it was clear that there was little chance of a tornado. Cloud bases were high and there were no significant lowerings to be found – the storms were elevated – not surface-based tornado producers. Nevertheless we stopped for awhile near Altona to take a closer look at the storms, a look which revealed nothing of significance. Having taken a few anvil and sunset photographs it was time to head back toward Winnipeg, just missing the infamous hailstorm (which put down tennis ball sized hail) that hit the city around sunset.

Overall it was a good chase. It was not a complete bust since there were storms, but it was definitely a bust in the fact that tornadoes were really nowhere to be found (I’ve kept the door open here for you to decide whether or not this is a tornado: http://tornadohunter.ca/tornado-hunter-blog/2012/6/10/the-longest-chase-day-ever-but-we-got-a-tornado.html). It is only early June and the severe weather season is just beginning, the next chase will be here before we know it.

The AWM team (Brad, Scott and Matt) would like to thank the 311 unique visitors who made 624 visits to this website yesterday, a new record number of visits for this website. Thank-you.

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.

The Big Warm-Up Begins; Moist, Gulf Air Mass Incoming

Brad Leave a comment

Today marks the beginning of skyrocketing temperatures over Southern Manitoba. Although daytime highs will be cooler again today, plenty of warming will be going on just off the surface, bringing us substantially warmer overnight lows and temperatures soaring into the upper twenties and low thirties by the end of the week.

Thursday Temperatures

Surface temperatures from the GEMREG model valid 00Z Friday (Early evening Thursday).

Winds will pick up out of the southeast today as we move onto the backside of the surface ridge that moved over our region behind the cold front that brought damaging winds to Southern Manitoba on Monday evening. This marks the beginning of a large-scale shift in the upper atmosphere that will rapidly push heat and moisture from the Gulf of Mexico northwards. Temperatures will only climb to around 20°C today, but our overnight low will show evidence of all the warm air moving in aloft by dropping down to only around 13°C, about 10°C warmer than our overnight low last night.

The heat and moisture will begin to build in on Thursday as the warm front lifts north of Winnipeg; our daytime high will push towards the upper twenties and settle around 28°C. This will feel quite different than our 29°C Monday afternoon because of one particular feature: moisture. While dewpoints will stay low today, they’ll begin to increase overnight and through the day on tomorrow, climbing into the low teens by Thursday evening. The heat and moisture will continue to build in for Friday, with daytime highs climbing to near 30°C with dewpoints climbing further into the mid-to-high teens. This will make things on Friday feel positively tropical, with Humidex values in the mid 30’s.

No precipitation is expected today or tomrrow, but as the heat and moisture build in, there’s certainly a chance of showers or thundershowers on Friday and Saturday. The chance for precipitation is elevated for Saturday as there will be additional lift and triggers present in the RRV as a low pressure system pushes through and drags a cold front across S. Manitoba. More on that later in the week.

Get out there and enjoy the summer-like weather! Friday and Saturday will see more cloud, but the higher dewpoints will help keep it feeling nice and warm out.

Summer Returns to Southern Manitoba…For a Short While

Brad Leave a comment

Beautiful weather is on tap for Southern Manitoba with plenty of sunshine the next couple days and positively summer-like temperatures. Things will return back to normal on Friday, after a cold front sweeps across the province on Thursday night.

500mb Winds/Height for Wednesday Evening

500mb Winds & Heights from the GEMGLB, valid for 00Z Thursday 10 May. The upper ridge has been highlighted over Manitoba.

A deep southerly flow has moved into Southern Manitoba underneath an upper ridge sliding east over the Prairies, pushing warmth from the Central Plains of the United States into our area. Temperatures will climb to around 20°C today with winds increasing to 20-30km/h out of the south by the afternoon. Temperatures will only drop to around 10-12°C tonight as the southerly winds keep our temperatures up in this warmer air mass.

Tomorrow the real heat moves in, and we’ll see temperatures soar in the Red River Valley, with daytime highs between 24 – 27°C. We’ll see a bit more cloud, though, and dewpoints in the low teens will make it feel closer to 30°C.

Day 2 Thunderstorm Outlook valid 21Z May 10 to 12Z May 11

Day 2 thunderstorm outlook, valid from 21Z May 10 (Thursday afternoon) to 12Z May 11 (Friday morning). No severe thunderstorms are expected.

By tomorrow evening, a cold front sweeping across the province will move into the Red River Valley. With the extra moisture in the air from the higher dewpoints, CAPE values will be enhanced slightly, and we’ll be looking at 500-750J/kg of CAPE as the front pushes into the RRV. A band of showers and thunderstorms will fire along the cold front on Thursday afternoon over SW Manitoba and continue eastwards through the evening, crossing the RRV through the evening and pushing through the Whiteshell overnight.

Seasonal conditions are expected to return for Friday into the weekend.