Monday, January 15, 2007

Warming up by Wednesday.. then colder again

It's another frigid morning over Southern MB with temperatures of minus 30 to minus 35 in Winnipeg this morning (-34 at my Charleswood station) Luckily winds are light today, so windchills are not a factor. Still, even walking at these temperatures will be enough to give exposed skin frostbite within a few minutes.. so bundle up!

Temperatures will start to moderate beginning tomorrow, with noticeably milder conditions on Wednesday with highs climbing back into the minus single digits by then (break out the sunscreen!) Before that however, we will have to deal with a blustery Tuesday as gusty south winds begin developing ahead of the milder airmass. So don't be fooled by Tuesday's forecast high of minus 10.. that's quite misleading as to what kind of day it will be. First of all, that high of -10 (if we even reach it) won't be reached until late in the day or evening. Temperatures will be in the minus 20s all morning and in the minus teens all afternoon. Second, those gusty southerly winds of 40 to 50 km/h with higher gusts will add a significant wind chill.. minus 35 to minus 40 in the morning moderating to minus 25 to minus 30 in the afternoon. In fact, Tuesday will feel just as cold as today even though actual temperatures are a good 10 degrees colder today (but winds are light.. it's all about the wind!)

Unfortunately, the milder temperatures on Wednesday will be short lived as colder air moves in again by the end of the week. Beyond that, temperatures are expected to remain generally below normal for the rest of January with occasional brief warm ups as a large scale upper ridge builds over the west coast, while an upper cold trough digs over Ontario and eastern Canada. This will give a northwest flow over the Prairies that will give Southern MB generally below normal temperatures for the next couple of weeks.

4 comments:

  1. With a very light southwest flow the airport stayed warmer than your site last nite. If the flow at the airport had been light northwest the temperature would have plunged. At Gimli, the overnight low was a difficult to believe -40 C !!

    The arctic air modified very little in reaching sourthern Manitoba .. while just south of us in North Dakota rapid modification occured. Less snow cover?

    Dan

    ReplyDelete
  2. Dan..

    Yep, I'm sure YWG would've been around -38c again last night with a light NW flow.

    I see that the high for Tuesday has been lowered from -10 to -14, and wind chills are increased.. which looks more reasonable given the setup. Kind of strange though that the wind forecast is lighter.. only 20 km/h from the previous 30. Normally Winnipeg sees stronger southerly winds in this type of set up.

    ReplyDelete
  3. You were right Rob... sustained winds of 45 kmh out of the south at Winnipeg airport ... brutal!

    Further west ... Portage, Dauphin and other sites at the base of the escarpment are warming nicely...between -5 and -10 C while McCreary just reported 0 C ... what a weird place southern Manitoba is.

    Hopefully temperatures will rise tonite in Winnipeg .. but if conditions become clear and calm as is forecast ... I guess temperatures will tank again even with warm air aloft :-(

    Dan

    ReplyDelete
  4. Those southerly winds were even strong enough to give some reduced visibilities in blowing snow over open areas this afternoon.

    Will be interesting to see if our temperatures drop much tonight.. like you say, if the winds become light, our temps will fall (-18 or so) with the clear skies. However, if we stay with a southerly breeze, we shouldn't drop much at all. Whatever the case, it'll sure be better than minus 35!

    I'm also thinking that Winnipeg will do better than the forecast high of -9 tomorrow. We lose the strong southerly wind on Wednesday, and we even get a bit of a southwesterly flow to tap some of that milder air over southern SK today. Maybe -5 for Winnipeg on Wednesday?

    ReplyDelete