Saturday, 24 March 2012

Record Breaking Warmth Ends

      The warm weather is now over. Temperatures will return to more seasonal values for a couple days before warming back up next week. The cold front responsible for the cool down came through southern Manitoba early Saturday, producing some freezing rain, thunderstorms and heavy rain. 3 to 9 mm of rain fell over Winnipeg this morning with a band of heavy rain. Areas around Brandon had 'freezing thunderstorms' overnight (t-storm with freezing rain), a rare occurance in our area.
      At leat 25 records were broken in Winnipeg this month, truely exceptional and unprecedented. This is certainly the most intense warmth we have ever experienced in March, and the same is true for much of the eastern half of North America.
     Here is the entire list of records broken:

10 Records for daily highs

Date... REC HIGH (old record year)
Sun 11 ..... 12.8C (old 12.5C 1981)
Mon 12 ..... 9.7C (old 7.2C 1922)
Thu 15 ..... 14.4C (old 11.1C 1927)
Fri 16 ...... 19.9C (old 12.4C 1981)
Sat 17 ...... 19.2C (old 12.8C 1938)
Sun 18 ..... 20.9C (old 14.4C 1910) *also earliest 20C reading on record*
Mon 19 .... 23.7C (old 18.9C 1938) *also new all time March maximum*
Thu 22 ..... 21.7C (old 18.3C 1878)
9 Records for daily high minimums + 2 ties

Date... REC HIGH (old record year)
Mon 12 ..... 2.5C (old )
Wed 14 ..... 1.2C (tied with 1977)
Fri 16 ...... 2.8C (old )
Sat 17 ...... 3.2C (old )
Sun 18 ..... 4.4C (old )

Mon 19 .... 13.3C (old ) *also new all time March high minimum* *also earliest 10C+ daily minimum*
Tue 20 ..... 2.8C (tied with 1946)
Thu 22 .... 3.7C (old 1.7C 1945)
Fri 23 ..... 8.7C (old 6.7C in 1910) *also second warmest March daily minimum on record*

6 Other records
Earliest strong thunderstorm (March 19)
March 19 high daily rainfall (12.5 mm) (old 4.6 mm in 1931)
All-time March high humidex (humidex of 28.0, on March 19) (old 18.8 on March 30, 1967)
All-time March high dewpoint (? no data available)
Most significant departure from normal temperature for any day of the year (+23.4 above normal on March 19)
Most 20C+ days in March (3 days)

     This March will likely end up being the warmest March on record, unless if we get a dramatic cool down next week, which does not look likely.
     Stay tuned over the next few days as I track an upcoming major storm system for Monday and Tuesday. This one could be a doozy in southern Manitoba. Thunderstorms will be possible again, as well as drenching rains and very strong winds over 50 km/h possible. Some models are showing over 40 mm of rain, so it will certainly be the main story of next week.


  1. Lingering cloud cover may linger a little longer than expected for tonight. If that is true, we likely wont plummet to -9 or -10, like the forecasts are saying. At this point, a low of -4 to -6 seems more likely.

  2. Low overnight was about -5°C thanks to the lingering low cloud I mentioned last night.

    Now Monday night through Wednesday looks interesting. Models currently showing a Montana Low rapidly intensifying as it moves eastwards.

    Rain and thunderstorms look likely tomorrow night, with hail, intense lightning and significant rainfall possible. Appears we may see a break in the precip. Tuesday morning in the dry sector, but periods of rain looks to move back in by Tuesday afternoon. A bit of snow is possible Tuesday night and Wednesday morning, though we shouldn't get any significant accumulations as temperatures remain too warm.

    In total, it looks likely most of southern Manitoba will receive at least 10 mm of rain, and some areas could locally see up to 25 mm with thunderstorms.

    Winds will be the other issue, especially tomorrow. Winds will be very strong from the southeast at 50 km/h, and gusts up to 70 km/h possible. Hang on to your hats!

  3. My forecast for Monday night and Tuesday has not changed much from this morning. The biggest change would be that it does not appear we will see much wrap-around precip. from this system here in southeastern Manitoba Tuesday afternoon and Tuesday night. Most of our precip. looks to fall Monday night and Tuesday morning with widespread rain with embedded thunderstorms possible.
    Speaking of thunderstorms, I do not expect to see severe storms here in Manitoba, though severes are possible south of the border in the Dakotas if you just happen to be travelling there. That would be for tomorrow and tomorrow night.

    I'll give another update in the morning, and possible later this evening if I notice something different.

    1. Forgot to mention heaviest rainfall amounts look to be in southwestern Manitoba, in the Interlake and along the Ontario Border. Up to 30 mm or more will be possible in those areas, while here in the RRV we should see closer to 10 to 20 mm.

      All these amounts will vary though depending on who gets thunderstorms. Higher amounts are possible anywhere that thunderstorms hit.

      Snow will also be possible in western Manitoba, though I'll give more info in the morning on that potential. Most of southern Manitoba could see at least some flurries at minimal, and that would be Tuesday night and Wednesday morning.

  4. I'm still not changing much in my forecast just yet, but I'll have my more thorough forecast this afternoon.