Warm Start to the Week

This week will start out on the warm side as a high pressure ridge edges into Manitoba. Temperatures on Monday and Tuesday are expected to reach or exceed 20C, which will mark the first occurrence of a 20 degree reading since April 6.

A large ridge centred over Western North America will bring warm weather to Southern Manitoba on Monday and Tuesday

A large ridge centred over Western North America will bring warm weather to Southern Manitoba on Monday and Tuesday

Highs on Monday should be around 20C in most of Southern Manitoba. Skies will range from mainly sunny to mainly cloudy, with Winnipeg and the Red River Valley tending to be on the cloudier side and Western Manitoba on the sunnier end. As such South-Western Manitoba will likely be a bit warmer than the rest of Southern Manitoba. Tuesday will feature much the same weather as Monday with temperatures once again climbing up to around the twenty degree mark over Southern Manitoba. Skies on Tuesday will mostly likely be a mixture of sun and cloud, preventing temperatures from climbing much above 20 degrees. Should Monday or Tuesday be sunnier than currently expected you can easily add a couple degrees onto the temperatures listed above.

20 degree temperatures are expected in Southern Manitoba on Monday and Tuesday

20 degree temperatures are expected in Southern Manitoba on Monday and Tuesday

A cold front will slice through Manitoba on Wednesday, dropping our temperatures back down to normal values. Highs on Wednesday are expected to hover in the low teens in Southern Manitoba, while on Thursday temperatures will remain stuck in the single digits. A recovery in temperatures in expected to begin on Friday and stretch into the weekend.

No significant precipitation is expected this week, although some weak shower activity might form as a low pressure system and associated cold front pass through on Tuesday night and Wednesday.

Elsewhere in Weather News

Australian Rains

As Australia’s summer transitions into fall, heavy rains have pummelled its capital, Sydney, and surrounding regions resulting in flash floods throughout the area.

Rainfall map from this past week in NSW, including Sydney’s approximate location. (Source: Bureau of Met.)

Rainfall map from this past week in NSW, including Sydney’s approximate location. (Source: Bureau of Met.)

Between Monday, April 16th and Wednesday, April 18th, the New South Whales (NSW) region was hit hardest from the flooding where some areas received between 150mm-200mm of rain. The flash floods were triggered by a number of towns receiving rainfall of 40mm/h over a couple hours, and the fact that the soil was saturated in those areas due to heavy rainfall that occurred over the past month.

Parking lot swamped by water. (Source: Seven Network)

Parking lot swamped by water. (Source: Seven Network)

Emergency crews were called to assist residents whose cars were overtaken by water and also to help those trapped in their homes as water levels rose in a matter of hours. Utility crews were also busy due to more than a thousand people losing power.

Video of car struggling to cross flooded roads. (Source: mascott1963)

Unfortunately, more rain was forecast to fall this weekend as another slow moving trough/cold front stretched across the whole region. No additional flash flooding was reported with this latest rainfall, however more rainy days are expected to hit the coast this coming week which increases the risk of further flooding in the region where another 15mm-25mm are expected through to Wednesday.

This event comes just two months after the region located north of NSW, Queensland, was hit hard by flooding (brought to you on February 27th post). Australia’s eastern coast has seen its fair share of dangerous flash flooding already this year.

Elsewhere in Weather News has been provided by Matt

Saturday Rain Followed By A Warm Up

After a pleasant Friday, Southern Manitoba will see a showery Saturday as one last system pushes through the province before a large-scale shift in the upper atmosphere brings above-normal weather back to our neck of the woods.

500mb Speed Map

500mb Wind Speed map from the NAM depicting the strong jet core associated with a low forecast to track across Southern Mantioba.

For today, the Winnipeg & the Red River Valley will see sunny skies with milder temperatures, courtesy of the cold trough that we’ve been under the influence of the past few days finally moving off towards the east. We should see a daytime high of about 12°C today, which is right around normal for this time of year.

Tonight, clouds will roll in ahead of a system that is sliding across the Prairies. Showers will push into Southwest Manitoba this evening along a NW-SE line aligned with the lift associated with a strong 90kt jet streak at 500mb. This line will push eastwards through the night and enter into the RRV by morning. The showers should weaken and spread out into a band of light rain by the time it reaches Winnipeg. Although the rain won’t be particularly heavy, the system looks to be relatively slow moving, and because of that it seems like most areas in Southern Manitoba will see between 2-5mm of rain. We’ll refine rainfall amounts in the comments a little closer to the event.

The rain clears out on Saturday evening and clouds will scatter overnight. Skies should completely clear by Sunday afternoon through the RRV leaving us with sunshine and a high near 15°C.

For next week, temperatures will remain in the low teens as an upper ridge begins to build into the Southern Prairies, however we’ll have to wait and see how much sun we’ll have. The potential for several powerful systems to track across the Prairies exists; we’ll be sure to keep an eye on whether or not these systems will impact Winnipeg and the Red River Valley!

Improving Weather

Southern Manitoba will see improving conditions today and round out the work week with nice conditions and near-normal temperatures.

Ridge Dominating Southern Manitoba

Model 3hr. QPF & MSLP w/Surface analysis valid 00Z Thursday April 19th

There will be a slight chance of some light snow this morning over the western half of the Red River Valley as a weak short wave slumps into North Dakota. As it exits the province, clouds will clear and we’ll be left with a sunny afternoon with a high near 8°C.

Clear skies will be the weather story for the rest of the week as a ridge of high pressure builds in from Northern Saskatchewan. We’ll have an overnight low near -6°C tonight and warm back up to a repeat of today on Thursday, with a high near 7°C. Rinse and repeat for Thursday night. As a system pushes into the NW United States, slightly warmer air pushes into Southern Manitoba and we’ll likely see our daytime high bumped up a few degrees to around 10°C.

Saturday brings with it a chance of rain as an upper trough swings across the Prairies. We’ll keep an eye on that as the week progresses!

In short, it’ll be a sunny, albeit a little cool, rest of the week!

Cool Week Ahead; Tornado Alley Hit by Major Outbreak

Cooler weather has settled over Southern Manitoba and while it won’t stay below normal for long, we won’t really be hitting above normal temperatures any time soon, either. The week ahead looks like a middle-of-the-road week with some sun, some cloud, an a chance for some showers.

Tuesday Evening Model Analysis @ 850mb

850mb Analysis of the θe field from the NAM, valid at 00Z Tuesday Evening

Today will bring clear skies to Winnipeg with diminishing winds. Our expected daytime high of 2°C will be a whopping 9°C below our normal daytime high of 11°C for this time of year. Tonight we’ll drop down to a chilly -7°C under clear skies.

Tomorrow will start off sunny and then cloud over in the afternoon as a low pressure system moves across Southern Manitoba. The main shortwave will track through the interlake, bringing in slightly warmer temperatures aloft across Southern Manitoba. The main surface low, however, will track just south of our border, keeping the warmer near-normal, temperatures to our south. Given that Southern Manitoba will have the southern low skirting just south of the International Border and be under the influence of large-scale ascent associated with the shortwave tracking further north, it looks quite likely that an area of showers will blossom as the system moves into Manitoba, and that regions along or just north of the Trans-Canada highway southwards to the U.S. Border will see showers on tomorrow afternoon. As ususal, the exact track will be key, however it’s fairly likely that most communities in the Red River Valley will see some showers tomorrow.

Shortwave vs. Surface Low? A shortwave is the term applied to a troughing disturbance in the upper atmosphere that travels along with the main flow aloft. A surface low is a low pressure system present in the lowest levels of the atmosphere. Each shortwave will often have a surface low pressure system associated with it and the two work in tandem to link the upper and lower atmospheres together. They are not co-located, however, and when compared on a map, can be hundreds of kilometers away from each other.

Things will clear out quickly tomorrow evening and then the rest of the week looks fairly benign, with daytime highs around 7°C and overnight lows around -5°C. Temperatures may jump back to normal on Friday with the approach a more significant low pressure system, but models disagree on it’s exact placement and some keep us on the cooler side of thigns; we’ll have more on that later in the week.

8-14 Day Temperature Anomoly Outlook

8-14 Day Temperature Anomoly Outlook from the NAEFS model from 12Z April 15, 2012.

Temperatures across the Eastern Prairies have been slightly below normal lately due to a persistant upper low anchored near Southampton Island in Hudson Bay. This low has maintained a trough and NW flow aloft over the Eastern Prairies and has been responsible for helping shunt systems further south and keeping us cooler. This large-scale pattern is expected to hold for the next 6-9 days, however signs are pointing to a breakdown of the low and a significant upper ridge to build across the Prairies in the Day 9-12 range. Ensemble models seem to agree with this idea, and as shown above, the NAEFS currently has fairly high confidence for a return to above-normal temperatures next week.

Elsewhere In Weather News

Tornado Alley Hit by Major Outbreak

The major tornado outbreak that occurred in the US Plains on Saturday, April 14th 2012 will be remembered for many years to come. Every single ingredient for long-tracked, damaging tornadoes was present. The storms developed due to a low pressure system centered over the Nebraska/Kansas border which drew in moist air from the gulf and into the Plains –- this spawned extremely strong supercells along its dryline as it slowly moved eastwards.

In anticipating major storms, the SPC had given plenty of warning to the affected areas, issuing a high risk in the 2-day outlook which is a very rare occurrence that has only happened once before. The high risk for tornadoes meant that within a 40km radius there was a 45% chance of an EF-2 to EF-5 tornado in parts of Nebraska and Kansas.

Probabalistic Tornado Graphic issued by the Storm Prediction Center on Saturday, April 14th

Probabalistic Tornado Graphic issued by the Storm Prediction Center on Saturday, April 14th.

Supercells had already exploded in the morning in the state of Kansas but did not produce any tornadoes until about 11:30am when a tornado had been spotted just north-east of North Platte, KS. From then on, tornado sightings were reported every 15 minutes until nightfall as just about every supercell from Nebraska to Oklahoma had a good chance of producing a tornado. Also to be kept in mind is that these supercells produce huge hail, reaching softball size (11.4cm in diameter), and cause significant damage to just about everything as they fall.

Violent tornado near Cherokee, OK

In all, around 100 tornadoes were sighted and luckily, many of them kept populated areas out of harm’s way as they missed villages and major cities. Unfortunately, there was one major city that had not been spared. The city of Woodward, OK (town of 12,000) was directly hit by a tornado, with a preliminary rating of EF-3. Five deaths and 29 injuries occurred in this city as the sirens did not go off, due to the tornado having cut their power. What aided the probability of injury and loss of life was also that the tornado had hit just after midnight, when most residents were asleep and it is extremely difficult to spot a tornado.

Some of the strongest tornadoes produced on Saturday – preliminary ratings:

  • EF-4 that just missed Salina, KS.
  • EF-3 that struck south-east Wichita, KS.
  • EF-3 that killed 5 in Woodward, OK.
  • EF-2 that damaged more than 75% of Creston, IA (town of 250).

Here are a couple of the many breath-taking photos/videos captured yesterday by storm chasers and those affected:

EF-4 tornado that just missed Salina, KS.

A large tree limb punched through the car's side, product of the Wichita tornado. (Source: Cory Mottice)

A large tree limb punched through the car’s side, product of the Wichita tornado. (Source: Cory Mottice)

Home moved off its foundation and destroyed in Wichita, KS. (Source: AP)

Home moved off its foundation and destroyed in Wichita, KS.

Very powerful tornado north of Soloman, KS. (Source: AP)

Very powerful tornado north of Soloman, KS. (Source: AP)

Unfortunately the severe weather threat didn’t end there. More tornadoes were reported in the Upper Mississippi Valley on Sunday associated with the same system. As the system will race east on Monday, tornado probabilities are greatly reduced across the eastern half of the country however, severe thunderstorms are certainly not out of the question as cold air clashes with the warm air situated ahead of the system.

Elsewhere in Weather News is written by Matt