Tuesday, March 19, 2013

A nice break from the snow this week.. warming trend expected over weekend

Visible satellite image of eastern Prairies Mar 19 2013
showing extensive snowpack over MB, SK and ND.
Snowdepths are generally 50-75 cm across much
of the Assiniboine and Red River basins
After digging out from another 15 cm of snow to start the week, southern Manitobans will get a nice break from any more shovelling this week as high pressure dominates the weather pattern for the next few days with generally sunny skies but cold temperatures.  That will be welcome news as snow depths continue to increase across southern Manitoba including the Red River valley. As of this morning, snow depths across the region were generally in the 50-75 cm range, one of the deepest snowpacks in the valley since the spring of 1997.  Fortunately, no sudden thaw is forecast in the near future, with well below normal temperatures this week. A moderating trend is expected over the weekend into next week with temperatures climbing towards the freezing mark, but at this point, no major shift to an abnormally mild weather pattern is expected over the next couple of weeks. A sudden thaw of such a deep snowpack would increase the risk of significant spring flooding, particularly if accompanied by heavy rainfall.

Select snowdepths as of this morning (March 19) across southern MB and vicinity..

Winnipeg airport .................. 45 cm  (AWOS)
Winnipeg Charleswood ........ 58 cm  (COOLTAP)
Carman ................................ 69 cm  (COOLTAP)
Miami ................................... 57 cm  (COOLTAP)
Portage La Prairie ................. 71 cm  (COOLTAP)
Brandon A ............................ 77 cm (EC)
Pilot Mound .......................... 82 cm (AWOS)
Winkler ................................ 63 cm  (COOLTAP)
Morris ................................. 68 cm (COCORAHS)
Emerson ............................... 60 cm (COCORAHS)
Steinbach .............................. 57 cm  (COCORAHS)
Pinawa .................................. 55 cm  (COCORAHS)
Estevan SK ............................. 38 cm (EC)
Grand Forks .......................... 35 cm (NWS)
Fargo .................................... 50 cm (NWS) 
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12 comments:

  1. Andrew3:51 PM, March 19, 2013

    Is there an analogy with the spring of 1956? If EC's records are correct, remnants of the snowpack persisted until May 2 that year at Winnipeg Airport!

    ReplyDelete
  2. Andrew4:00 PM, March 19, 2013

    Check out the springs of 1996 and 1997 as well. Interestingly, there was about one month of below-normal temperatures after the snowpack disappeared in these three years, followed by normal or above-normal summers.

    ReplyDelete
  3. Dan - NWS GF4:34 PM, March 19, 2013

    Keep in mind that 35cm snow depth in Grand Forks as our office measures it in an open field to the east of the office that is subject to major blowing. In town much closer to 50-55cm

    ReplyDelete
  4. snowpack stats8:13 PM, March 19, 2013

    Andrew..

    Every year is different, but generally if the airport had at least a 25 cm snowdepth at the end of March, it took at least until the second or third week of April for the snowcover to disappear. (using airport snowdepth stats from 1955-2003) 1955 was an exception, when a 35 cm snowpack on March 31st disappeared by April 5th. 1964 and 1965 saw deep March end snowpacks disappear by April 10th or so. As you point out, the years of 1956, 1996, and 1997 had the latest snowpack melts.

    Click on "snowpack stats" for a table of when snowpack disappeared in Winnipeg based on airport snowdepth stats 1955-2003

    When will snowpack dissapear this year? No idea, but let's hope we're not matching 1956 or 1997 dates! Cast your vote on latest Robs Obs poll.

    Rob

    ReplyDelete
  5. rob9:30 AM, March 20, 2013

    Well, good news as far as flooding fears go, in the short term anyways. Long range guidance is indicating no major storm systems affecting southern MB through the next week to 10 days, with a slow moderating trend in temperatures. That is exactly what is needed to start eroding this snowpack slowly and gradually. However, it's still early and we'll have to see what happens in April.. but generally speaking, looks like ideal weather for the next 7 to 10 days anyways.

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  6. Anonymous10:26 AM, March 20, 2013

    Don't worry about flooding. Officials said they already took that early March storm into account in their previous forecast, plus accounted for an "unfavourable" scenario which still didn't result in major flooding.

    Trust the experts (he wrote with a snarky grin on his face).

    ReplyDelete
  7. Anonymous5:57 PM, March 20, 2013

    A flood update was issued 2 days ago.

    http://news.gov.mb.ca/news/index.html?archive=&item=17037

    They say it's unlikely that we'll have prolonged river flooding and high lake levels.

    ReplyDelete
  8. Anonymous7:44 AM, March 21, 2013

    7am temps:
    YWG: -24.1C
    XWG: -24.0C
    XWN (The Forks): -18.3C

    ReplyDelete
  9. rob9:46 AM, March 21, 2013

    Beautiful day on tap with strong March sun and light winds making it feel warmer than -9C this afternoon. Temperature readings will likely be some 5C warmer in the city due to urban heat island effect which is quite pronounced this time of year when snow is still on the ground.

    ReplyDelete
  10. Anonymous1:08 PM, March 21, 2013

    Fargo expecting major flooding. Also Pembina.

    http://www.cbc.ca/news/canada/manitoba/story/2013/03/21/mb-fargo-top-five-floods-in-history.html

    ReplyDelete
  11. Box13412:46 PM, March 22, 2013

    I'd like to see spring as much as the next guy, but these bright snow days are fantastic.

    ReplyDelete
  12. rob8:51 AM, March 23, 2013

    Yeah, that strong March sun certainly helps make the below normal temperatures more tolerable, especially with light winds. At least we're doing better than other parts of Canada including Saskatchewan, and even the Maritimes.

    By the way, for those keeping track.. Winnipeg's average March temperature so far this month is running around -12C, which surprisingly isn't even in the top 20 coldest Marches in Winnipeg! (since 1872) So even with the below normal temps this last week, we likely won't set any records for cold weather this March (hard to believe after being so spoiled last year) Coldest March on record in Winnipeg was back in 1899 at a January like -16.1C, the only March on record where we stayed below freezing all month. We have yet to climb above freezing this month as well, although long range guidance is indicating we may sneak above 0C by the 30th or 31st.

    Regardless, this March will likely be the coldest since at least 2002 (-11.7C) and possibly 1996 (-13.0C)

    ReplyDelete

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