 |
500 mb pattern for mid week
Weather pattern over Prairies will
be dominated by strong NW
flow aloft between Arctic vortex
over Hudson Bay (cold) and
strong Pacific ridge (mild) |
The weather this week over southern Manitoba will be one of "modified" cold, as a cold Arctic vortex spins over Hudson Bay while a strong upper ridge becomes established over the West Coast. The result will be a strong northwest flow aloft over southern Manitoba that will bring alternating spells of cold air from the Arctic modified by incursions of milder Pacific air spilling in from the west. These modified spells will be brought in by occasional clipper systems rounding the top of the ridge and diving southeast across southern MB, bringing milder temperatures but periods of snow as well. The first clipper system is expected by Tuesday night with 2-5 cm possible over southern Manitoba, with another clipper by Thursday. Colder Arctic air will follow in the wake of these systems passing through.
59 comments:
Rob,
A little off-topic perhaps, but I wondered if dewpoint, wind and/or thunderstorm data was taken prior to 1953 (when hourly data begins on EC's historical data website) in Winnipeg? If yes, is it off-limits to the public; if not do you have a link?
Thank you
Anonymous, I think that wind and dewpoint data at YWG airport go back to the 1940s, but as far as I know, they're only available in hard copy format, and not digitally accessible at this time.
That kind of hard copy data would be kept at EC's climate archives in Downsview, Ontario.. but I don't know what kind of public access policies they have.
17.4C today in Vineland, Ontario (Niagara). Highest temperature this year in the country.
BTW, the all-time Canadian high in January is 22.2C in Niagara Falls (1950).
and just to the east of Niagara...
Rochester, New York recorded a high of 69F (20.6C) today...
Rob, I know this is out of your area of expertise but i've been hearing that February is also likely to be colder than normal as the strong -AO continues.
If you had to venture a guess would you support that idea of colder than normal temps for next month?
Just can't say at this point. If I had to guess, I would lean towards colder than normal with periodic warm ups... but I wouldn't bet on it. Getting the forecast right a week from now is challenging enough, never mind next month!
What is Winnipegs current average snow depth?
I see Morden recorded 156.0 mm of precip yesterday! On a Sunday, so likely wasn't the technicians dumping data...wonder what's going on?
Anonymous..
I'm currently reporting a snow depth of 30 cm at my site in Charleswood.. but after Friday's storm, snow depth is quite variable due to drifting.. anywhere between 20-40 cm.
The snowdepth sensor at YWG airport is recording 17 cm depth as of yesterday morning.
Thursday's forecast is all over the place! Ranging from -5 (EC) to -23 (CBC) with many others somewhere in-between. Don't remember ever seeing a difference of nearly 20C in a 4-day forecast before.
+5c in Whitehorse right now... Gives you an idea how far north that mild Pacific airmass is spreading.
Too bad that very mild pacific airmass won't make it's way to Southern Manitoba.
Temperatures dropping off quickly this evening outside the city, with -27C (Sanford) to -29C (Carman) already being reported outside the Perimeter. YWG airport is at a modest -23C due to a light southerly flow off the built up city that will keep temperatures up a bit at the airport site, but south Winnipeg and areas near and outside the Perimeter will be a bit colder, perhaps down close to the -30C mark before clouds and southerly winds increase overnight sending temperatures back up again.
For those that are interested, there have been numerous updates to the METAR viewer over on the A Weather Moment blog. I know a few people here use it. I'll have a full post on all the changes once I'm done updating the other tools as well.
Thanks Brad.. keep us posted.
BTW, no wind or windchill data being displayed for Winnipeg airport current conditions on Weatheroffice.
Wow.. +7C in Edmonton and +3C in Saskatoon. Winnipeg on the wrong side of the baroclinic zone!
Rob any idea on how long the radar will be down?
Daryl..
No, don't know about the radar status. Hopefully it'll be back up soon with the snow moving in.
Nice warmup over Alberta and southern Sask, with clipper tracking into western MB advecting mild Pacific airmass from the west. Clipper dives through southern MB this evening with warm air occluding out to our southwest, but even Winnipeg will see temperatures climb to -5C mark later this evening as our winds shift into the west, before we cool off again overnight. Look for a couple of cm of snow in advance of the brief warm up this evening.
That abnormal temperature trend is not evident with the forecast low of -19C, but trend shows up nicely on Spot Wx graphs available under the Winnipeg forecast icon on my main webpage.
Rob, do you why the wind and windchill data is not displayed for the YWG Airport's current conditions on EC's site and when it will be fixed?
No, I don't know what the issue is with the Winnipeg current conditions on Weatheroffice. It may have something to do with uploading the wind data from the NavCanada auto station at YWG to Weatheroffice, but I don't know for sure.
What's odd is that if you click on "More info" and "past 24 hours" for Winnipeg current conditions, you will get the wind and wind chill data for YWG, along with the correct current conditions. For example, the current conditions for Winnipeg on Weatheroffice says "Partly cloudy" even though it's overcast with drifting snow.
To me, it appears that there was a change to the data source for YWG weather (perhaps moving to the NavCanada station), but apparently data feeds to Weatheroffice weren't tested thoroughly. But I'm just speculating at this point.
At least radar's back..
Snow has started in Charleswood.
Looks like this system is moving pretty quick.
Yeah, back edge should be through Winnipeg between 8-9 pm. A quick couple cm possible by then.
Temperature has popped to +2C over Melita and far SW MB this hour as clipper brings in mild Pacific airmass from west. Too bad Winnipeg won't see it, although temps of -5C over western RRV should spread into Winnipeg by midnight.
Heavy snow changed to snow pellets not too long ago here in south end. This has significantly reduced the amount of blowing snow.
Here we go with that darn Freezing Drizzle again. Wow, temps keeps rising at YWG Airport....now -4.0C at 10 PM.
Just saw a flash outside my window which seemed to be across the sky at 10:04 p.m. It was out of the corner of my eye, so I very well could be mistaken, but I swear it looked like sheet lightning.
Actually I saw that also......very weird.
Glad someone else saw it. I'm located centrally several floors off the ground looking southeast out a large window, so it wasn't street traffic. Winds at the airport changed from SW to W from 2100 to 2200 and the temperature bumped up from -6 to -4. Radar showed the tail end of some very light precipitation moving through the city. I've heard of the odd flash of lightning in winter, albeit rarely. Any better informed comments as to whether a random flash would have been possible with this clipper? If so, would a single discharge definitely show up on lightning detection?
Another possibility for the flash since it was kinda raining might have been an electrical short flashing off the clouds. But there has been lighting in the winter.
Hard to say...Haven't heard any reports of power outages in the city at this point.
So an electrical shortage is i guess possible but it's usually associated with a power outage of some sort.
Uh oh, Rob. Now the confusion starts again with the data. When you go on the Winnipeg page on EC's site and go at the bottom where it says 'yesterday' it gives the temperatures and precipitation from the 'A CS' station. Is this A CS station the official station now?? The precip amounts and temps are not the same as the awos station which we've been considering as official for a while now.
Unfortunately, I don't think this A CS station has better precip amounts. An example is that this station only reported 0.4 mm of precip on March 2, 2012. But there was 10-12 cm of snowfall that day!!
I'll check into what's going on. I think you're right, there's been a switch with the station supplying our data feed, but whether its the CS station or NC , I don't know at this point.
Rob, can I ask you how many centimetres of snow fell last night?
Anonymous..
I picked up about 2.5 cm at my place last evening.
Rob
Further to the problems with Winnipeg current conditions on Weatheroffice..
Evidently, Weatheroffice is switching to a new data feed to update current weather conditions. There have been a few problems popping up, including with wind and windchill data from Winnipeg airport. They're using data from the Winnipeg CS autostation as a backup.
They're looking into the problem to see what's going on, but I don't know when it may be fixed. In the meantime, look at "provincial summary" or "past 24 hours" for latest Winnipeg wind and windchill values (which are significant today in the -30s)
Did anyonee see the lightning detection maps last night and did it show a strike?
Different people from CBC mentioned either a meteorite or lightning. I didn't see the lightning map last night; I was sleeping so if someone saw it would be good to know.
I was driving south on Osborne over the St. Vital bridge last night around 10:00 and saw a flash of light. It must have been lightning. It must have been sheet lighting as it just lite up the whole area around us.
I ran our lightning plot from last night, and didn't see any strikes anywhere in southern MB last evening. So I don't think it was lightning, unless it was an isolated one-off strike that the lightning detector missed.
Some have mentioned the possibility of a blown transformer due to some freezing drizzle around that time?
One more comment about the flash in the sky last night... I just caught the CBC article about it. They noted it was in central Winnipeg, and cited 3 possibilities: 1) meteorite; 2) lightning strike; 3) arcing at the Scotland Ave Manitoba hydro substation (near Stafford and Grant). They noted that MB Hydro said there was arcing at that station around that time. If that was the case, it must have been quite a flash, as I'm about 2.5km away from there and the sky was lit up, but I suppose it's possible.
(I too looked at the public 0400 UTC and then later the 0500 UTC lightning detection page and saw no strikes, which is why I was querying if they capture all discharges)
Its looking like early next week is going to be brutally cold. Lows approaching -35. Maybe some moderation by late next week.
I doubt it was lightning too.
With the 1100ft ceiling, a meteorite would have to be awfully low to be visible, and would likely be heard. However it's the perfect height to reflect the light from an arcing substation (which may arc during the freezing drizzle at the time, as Hydro said). That green color is also typical or arcing.
Not sure what the GEM was thinking with its low of -35°C this morning... Let's hope its forecast of -40°C on Tuesday is fake also.
That was the Global GEM with the extreme lows. The regional GEM was more realistic with a low of -24C this morning. I've noticed that the Global GEM has been giving unrealistically low surface temps with these cold outbreaks. I don't see -40C next Tuesday, but low -30s certainly possible.
Well, temps keep falling this morning....now -25.9C at YWG Airport as of 10 AM
Hmmm. I noticed that when you load up the the Winnipeg current conditions
on the weatheroffice website you see that at 11 AM the temp is -25C or -24.7C at YWG Airport but then you go the more info and past 24 Hours it shows the temp as -24C.....Very strange.
I think the temperature and wind/windchill data from "past 24 hours" is from XWG (Winnipeg CS autostation) Yesterday's climate stats also are coming from XWG.
Supposedly, Weatheroffice will be switching all YWG data over to the NavCanada autostation today, but I'm not sure that will solve all the data issues. Hopefully.
This also makes a mess of the climate data for YWG. Lots of data issues that will need to be ironed out.
Rob, I'm seeing a variety of forecast lows for Monday and Tuesday going from -31 C to - 37 C. In your opinion how cold is it likely going to be both Monday and Tuesday morning here in the city?
Its saying snow for tonight into tomorrow. How much can we expect?
>>Rob, I'm seeing a variety of forecast lows for Monday and Tuesday going from -31 C to - 37 C. In your opinion how cold is it likely going to be both Monday and Tuesday morning here in the city?
Looks like the coldest air of the season coming in over the weekend into early next week.. and our above -30C streak will likely end by Monday morning, maybe even Sunday morning if skies are clear.
I'm thinking that lows of -30 to -35C are possible for Winnipeg Monday and Tuesday mornings, coldest readings at the YWG airport site where a light northwest flow will allow for maximum cold air drainage.
Re: How much snow?
First wave of snow moves in overnight into Friday morning with a a cm or 2 for Winnipeg. We get a stronger clipper tracking through the Interlake Friday night into early Saturday with another 2 or 3 cm possible, a little more north.
Strong northerly winds and falling temperatures will make for a brutal day Saturday with wind chills well into the minus 30s, and locally poor vsbys in blowing snow through the RRV.
Looks like they've switched to the NavCanada feed for YWG data on Weatheroffice. Now getting wind and wind chill data again. Going to need it over the weekend into next week!
For what it's worth and for those thinking of Spring like myself, I've noticed that the long range ECMWF output model is showing warmer than average temperatures for the upcoming Spring and Summer. I certainly hope so, but we'll see.
So Rob, when it comes to precipitation amounts and temperatures, which station is the official station for Winnipeg now?
Officially, it's the NavCanada AWOS autostation at YWG airport. The observations are input by a FSS observer, who theoretically can correct any suspicious observations from the AWOS station.
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