Monday, May 19, 2008

Nice week ahead

After a light rainfall to end the holiday weekend, it looks like Winnipeg and southern MB will be enjoying a nice sunny mild week this week as an “omega block” weather pattern sets up over Central Canada. An omega block refers to a nearly stationary weather pattern characterized by a strong blocking ridge of high pressure in between stationary upper lows to the east and west. The weather pattern, similar in appearance to the Greek letter omega, results in a prolonged stretch of dry and warm weather under the ridge, while cool unsettled weather persists to the east and west. In this week’s case, southern MB will be under the upper ridge all week, while cool and unsettled weather prevails over the west coast all the way to California, as well as to the east over southern Ontario and Quebec. What this will mean for Winnipeg will be a week of sunny skies with progressively warmer temperatures each day this week. In fact, highs of 25 degrees or higher are likely by Thursday or Friday.

12 comments:

  1. It certainly does look like a good week! Next weekend also looks like we will have a good chance of seeing severe thunderstorms. Dewpoints could rise as high as 14 to 18 degrees in Southern Manitoba, which will create CAPE values of 1000 to 2000J/kg. Wind shear is looking favourable for tornadoes, but it is still too soon to say that. And as for Omega block...it looks like a spitting image of the omega symbol, just take a look at the 500mb winds for later in the week!

    Rob...Thanks for the good weather coverage as always! We sometimes don't realize how lucky we are to have the inside scoop from a meteorologist.

    ReplyDelete
  2. So the snow that was forecast for mid-week a few days ago is now VOID?

    Omega blocks are GOOD, except when they occur in mid-Winter and we are "trapped" in a frigid spell.

    ReplyDelete
  3. Actually, by reading this on Wikipedia about omega blocks I was probably wrong about the period when they occur -- Spring rather than mid-Winter.

    http://en.wikipedia.org/wiki/Omega_block

    Some of the La Nina Summers that we've had -- 1992, 1993, 2004, 2005 were when we had the inverted jetstream.

    ReplyDelete
  4. can any of you tell me why Shaw's WX info on Ch 48 is stuck? EC's problem or Shaw's

    ReplyDelete
  5. Well it looks like the problem is fixed now!!!!!

    ReplyDelete
  6. Frost warning posted for much of southern MB tonight including Winnipeg. Most places should see lows of zero to -3C by morning.. with -5C possible in usual cold spots like Wasagaming. Here in Winnipeg, we get a light northeast flow tonight which may protect areas from downtown through the southern suburbs from a hard freeze.

    ReplyDelete
  7. It's 12:24 AM and the temperature is dropping fast. The airport is down to 3 °C. I think this will be a cold one.

    ReplyDelete
  8. No frost here in Charleswood this morning.. looks like that light wind off the city spared most of us in the south end.

    ReplyDelete
  9. Rob...

    What is Environment Canada thinking about a severe thunderstorm threat this weekend. NWS Grand Forks is starting to sound fairly confident that their area will be under a significant threat of storms. We are close enough for their statements to get us excited, so what do you think. I am seeing Saturday night as the best chance of storms, when there will be the most moisture. EC is calling for 17 and showers, while the WRF says it should be in mid twenties and chance of storms...

    ...What do you and others think?

    ReplyDelete
  10. Ya I see there is a good chance of storms Saturday night!
    I mean if you look at the SPC outlook they have northern north dakota in a severe threat saturday evening!
    Things could move north of the border fairly easily.
    Even if they are not severe thunderstorms we could get a least a few rumbles of thunder!!

    ReplyDelete
  11. Looking at the latest guidance, I would agree that the best chance for any severe thunderstorms would be in North Dakota Saturday, moving into southern MB Saturday night. Squall line with strong winds would be the main threat for us, however large hail a possibility if we can get some higher dewpoints feeding into this system.

    ReplyDelete
  12. Extensive low level cloud deck over NW Ontario has pushed westward into eastern MB this morning robbing us of a nice sunny day. Hopefully with daytime heating, this cloud breaks up this afternoon. Goes to show you how even if you get the upper pattern right, the low levels can give you a different story!

    ReplyDelete