Elsewhere in Weather News: February 23rd, 2013

Major Snowstorm Hits US Plains

Another trough digging through the southern half of the US this past week, caused trouble for travellers and residents of the Great Plains. Moist air from the Gulf of Mexico made its way north into Kansas which fell as freezing rain and snow ahead of the warm front. In the warm sector a line of thunderstorms, some severe, formed along the trough line that plowed through part of Texas and Louisiana.

850mb analysis

850mb analysis of early Wednesday morning. Heavy snow was already falling at this time. Highest accumulations circled in pink. (Source: Twisterdata)

Highway conditions quickly deteriorated after snow started falling and 150km of I-70 had to be shut down in Kansas due to many vehicle accidents. This system also prompted the closure of schools, delayed flights at airports or even closed airports such as the Kansas City airport. This same trough is to be blamed for suspending play at the PGA in Marana, Arizona where an uncommon sight could be seen; snow – about 4cm of it, covered luscious greens with cacti nearby in the background.

Snow affecting PGA

PGA golfers leaving the course while it’s snowing. (Source: AP)

Snowfall rates of 3-5cm/h were not uncommon for several hours in Kansas and Nebraska and contributed to significant snow accumulations. Highest accumulations were just below the two foot mark (60cm) in south-central Kansas with a good part of Kansas receiving over 20cm of snowfall. Most of the Southern Plains residents welcome any type of precipitation at this time however due to a severe/extreme drought is currently in place through much of the Plains (as talked about in last week’s EIWN). Last Thursday’s storm should at least make for slight improvements in the short term drought index but for longer range improvements the Plains need to get out of a persisting dry pattern.

Recent model runs show another major snowstorm, with as much as another foot of snow, Sunday night into Monday for the US Plains.

Elsewhere in Weather News: January 20th, 2013

Intense Heat Wave Continues in Australia

A significant heat wave has remained in place for most of Australia’s southern half, this past week. The large ridge of high pressure has kept about 70-80% of Australia under extreme high temperatures (over 40°C) and in turn has created dangerous conditions in which bushfires can occur. Total burn bans were in place for a few communities in the southern half of Australia and firefighters are on high alert. As of Friday there were 142 bushfires burning in New South Wales alone and 29 of them were 0% contained.

Temperature map

Map of Australia’s extreme temperatures on January 12th, 2013. (Source: Australia’s BOM)

Residents of Tasmania have been experiencing similar weather conditions this New Year, contributing to a massive brushfire that had been raging through a large area of its south-eastern peninsula two weeks ago. Here, 1,000 people had to be rescued by boat from their homes. The damage in that area has not yet been tallied, but at least 20 houses, including a school, has burned down to the ground and at least one person is confirmed dead.

On Friday, January 4th, the village of Wudinna, located on Australia’s southern coast, reached extreme temperatures of 48.2°C, and various other cities broke their daily temperature records as well. Adelaide recorded all-time January high temperatures on the same day as the mercury rose to 44.1°C. Even more impressively, on January 12th Moomba (South Australia) managed to reach a temperature of 49.6°C – Australia’s hottest temperature in 15 years. The average temperature for Southern Australia ranges between 25°C and 35°C in January, and a little cooler for areas along the coast. This past week, Australia’s Bureau of Meteorology even had to go to the extreme by changing the temperature scale on their maps because temperatures constantly exceeded the scale during this intense heat wave.

Trough

Potential through coming through which would help cool down the temperatures late next week. Also to note a possible tropical disturbance on Australia’s north side. (Source: Australia’s BOM)

Although it is not uncommon to see heat waves affecting specific areas of Australia, to see between 70 and 80% of Australia experiencing a significant heat wave such as this one, is not a common sight. Significant heat will persist into next week before a large trough moves into the region and brings an end to the sweltering heat by next Friday. Interestingly enough, models are also showing a tropical cyclone forming off the Australia’s North Coast around the same time that the heat is predicted to come to an end.

September Marks a Return to Seasonal Weather

September closed out with a few beautiful days, bringing a month that had a bit of a cool start back to seasonal conditions. As for whether Winnipeg continued it’s 14-month above normal streak, that depends on which average you use. If you’re partial to the 1971-2000 means, then yes, we’ve extended the streak to 15 months. If you use the 1981-2010 means (which are the ones we use here at AWM), then unfortunately, our streak has come to an end.

September 2012 Summary

2012 Departure from Normal Temperature, with Year-to-Date mean

2012 departure from normal (or monthly anomaly of) temperature. The year-to-date mean is also plotted.

September 2012 closed out with an average temperature of 12.6°C, 0.28°C below the the 1981-2010 normal of 12.9°C. At -0.28°C below normal, the month of September ended Winnipeg’s above-normal streak at 14 consecutive months1. The warmest day in September 2012 came near the end of the month on the 29th when the mercury climbed to 29.6°C, a mere 0.4°C off the record for that day of 30°C set in 1905. No new daily high record temperatures were set this September. The coldest night was the night of September 22/23 when the mercury dropped to -7.1°C. This broke the previous record low for that night of -6.1°C set in 1879 and was 1.2°C off the record coldest night in September of -8.3°C, set on September 29, 1899. In total, just the one record low temperature was set this September.

2012 Departure from Normal Precipitation, with Year-to-Date total

2012 departure from normal (or monthly anomaly of) precipitation. The year-to-date total is also plotted.

September continued the significant precipitation deficit when compared to the normal. Usually we see about 48mm2 in September, but this year we saw a mere 4mm of precipitation. Receiving less than 10% of our normal rainfall for the month continues the precipitation deficit to 4 consecutive months in Winnipeg.

In other miscellaneous September statistics:

  • We finished the month with 0 days above 30°C, but 7 days at or above 25°C.
  • September 2012 did not break the top 50 warmest Septembers on record.
  • Despite our practically non-existent precipitation for the month, we still nearly quadrupled the record driest September of 1948, where only 1.3mm fell.
  • Our 4mm precipitation total for the month was only 2.5% of the precipitation that fell in the record wettest September of 1872, when 156.2mm fell.

2012 So Far

Year-to-Date Temperature Anomalies for Winnipeg, MB

Year-to-date temperature anomaly, by month, for 2012 (red) compared to the other 139 years on record for Winnipeg, MB, with the five warmest years (orange) and five coldest years (blue) noted.

As mentioned before, September’s deviation of -0.28°C from normal has brought an end to the above-normal conditions of 2012. Until September, every single month this year had been above-normal. Looking again at our Winnipeg temperature anomaly climatology, we can see that despite our slightly below-normal September average, we’ve managed to still remain the most above normal (by a hair) that we’ve ever been. Things still look to be on track for us to end up in the top 5 warmest years ever and we’ll keep updating each month to see where we end up.

Rest of 2012

As mentioned last month, sea ice in the Arctic is at a record low, which while it hasn’t prevented us from getting the odd cold outbreak, still looks to have the potential to reduce the strength/onset of the Hudson Bay arctic vortex that sets up and maintains a cool, northwest flow over the Eastern Prairies. While a month ago it also looked like El Niño was going to help us possibly see a warmer-than normal winter, over the past couple weeks the El Niño signal in the Eastern Pacific has significantly weakened. This means that any large-scale hints towards what sort of winter we’ll see are becoming rather muddled and no strong signal currently exists.


  1. Based on 1981-2010 normals. Winnipeg sits at 15 months above normal if using the 1971-2000 normals. 
  2. The normal precipitation for September is 47.6mm

Warmer Weather Set to Return to The Red River Valley

After a prolonged and sudden stretch of normal to below-normal temperatures, warmer weather is on it’s way for Winnipeg.

500mb Winds valid Wednesday Evening

500mb wind speeds valid for this evening. Of note is the advancing upper ridge (denoted by the blue squiggle) over British Columbia.

The long-wave trough that has remained solidly parked over the Eastern Prairies over the past week is finally pushing off to the east, allowing a building upper ridge over British Columbia to spread eastwards into the Prairies and bring with it some milder Pacific air. With an incoming upper ridge, our chance for precipitation over the next few days is pretty much nil. We’ll see temperatures climb to about 17°C today, which will be a couple of degrees above our normal daytime high of 15°C for this time of year. Things warm up on Thursday as a warm front pushes through and we climb to a high of 23°C. Temperatures will remain in the low 20’s right through the weekend under sunny skies.

A Dry End to September

Rob put up a great summary on the precipitation situation for Southern Manitoba this month.

As of [September 24, 2012], only 4 mm of rain has fallen at Winnipeg airport this month, with no precipitation forecast all this week through the end of the month. If so, September will end up as the 2nd driest September on record in Winnipeg since records began 140 years ago in 1872.

I highly recommend you head over and read the brief summary Rob put up. It continues to look like we’ll be dry through the end of the month, so there’s a very good chance that Winnipeg may see it’s second driest September on record. We’ll have a complete summary for the month of September on Monday, October 1st in addition to our regular post.