Yes, fall's come early this year.. but it could be worse. On this date in 1903, an early season snowstorm left 10 to 30 cm of wet snow across western Manitoba. The image on the left shows a shot of Birtle MB near the SK border on Sept 13 1903 (image from Brock Holowachuk's book "Impact - A History of Disasters in Manitoba")Elevation usually plays a major role in early season snowstorms and this one was no exception. Precipitation from this system fell mainly as rain in the Red River valley with 39 mm of rain recorded in Winnipeg and a high of only +9C. Further west however, rain changed to snow over higher elevations west of the Pembina escarpment with the highest amounts over southwestern MB. Snowfall amounts over western MB included..
Hillview .............. 30 cm (between Brandon and Virden)
Rapid City........... 25 cm
Deloraine............. 23 cm
Turtle Mtn ......... 20 cm
Minnedosa ......... 15 cm
Elkhorn ............... 15 cm
Dauphin .............. 15 cm
Brandon .............. 10 cm
Eastern Saskatchewan reports:
Moosomin........... 38 cm
Manor ............... 23 cm (near Carlyle)
Alameda ............. 15 cm (near Oxbow)
Crescent Lake ..... 15 cm (near Yorkton)
The heavy snow and high winds wreaked havoc on crops and infrastructure with heavy losses reported in the wheat crop and numerous telegraph poles downed. So as cool and wet as it's been this September, it has been worse!
Speaking of cold weather, it will be a tricky frost forecast tonight in southern Manitoba. 850mb temps of 0 to 2C are expected, along with decreasing cloud cover and increasing pressure ahead of a surface ridge sliding in from the NW. My suspicion is that W MB will experience the most widespread frost (noted obviously by EC warnings). Harder call is in areas near the trans-canada, which are in the second most likely position for frost. The determining factors will likely be:
ReplyDeletea) How quickly will the clouds thin out?
b) Is there still enough low-level moisture from recent rain to keep dewpoints elevated throughout the night?
GEM Model hints at the Portage-Winnipeg corridor getting down to near 0C tonight...will be interesting to see what happens.
Scott.. I think the threat of frost is pretty low tonight for areas along and south of the TransCanada.. including Winnipeg. Cloud cover upstream is fairly extensive and will limit our temperature from falling too quickly tonight.. plus our dewpoints this evening are still in the +5 to +7C range.. way too high for a widespread frost event. Even if we clear out overnight and get to +1 or +2c by morning, I think we'll end up with more of a heavy dew than frost.
ReplyDeleteMay be harder to dodge the frost this weekend if that long range outlook is correct! (although I remain somewhat encouraged by the latest runs keeping the coldest core to our north)
I definately agree that a widespread frost in areas around the Trans-Canada is unlikely, as you point out. However, I do think that there may be localized rural patches (Marchand comes to mind - already down to 6C as of 10pm) that see temperatures sneak down to 0. The RRV is likely too moist for frost, which I agree with, but the sandier soils of the more forested regions in the SE often react similar to Wasagaming on nights like these.
ReplyDeletePerhaps I was a bit unclear with my previous latter point...the GEM is showing temperatures near 0C, something I don't necessarily endorse.
By the way, interesting post on the 1903 snow storm. I'm looking forward to some good storms this winter, but September is a bit too early...
Yeah, the SE corner still seeing some clear skies this evening so they have the best chance of radiating towards zero as you mentioned.. but increasing cloud cover upstream may save them from frost.
ReplyDeleteAs for that 1903 storm, I was intrigued by that Birtle photo in Brock's book.. so I did a little more investigating and found out it was a significant early season storm out that way. Other early snowfalls include 10-25 cm over Riding Mtn Park on September 4 1965, and 5-15 cm of snow over the Turtle Mtn area Sept 10-11, 1989. Amazing what a few hundred feet of elevation can mean this time of year. Winnipeg's earliest significant snowfall was on September 25th 1872 when 18.3 cm was recorded. More recently, the airport reported 6 cm of snow on Sept 24th 1984..
Sheesh, last September I was talking about heat records.. this year I'm talking about snow!
The rain that is heading into Southern Manitoba is a bit of a surprise!
ReplyDeleteEven a small amount of rain is the last thing we need!
Thursday night's cold front is still looking mighty impressive but
some models indicate lots of rain with the front while others show a passing shower!
What is your thoughts on the front Rob??
Ensembles are showing an average of about 5-10 mm for Winnipeg Thursday night.. which seems reasonable. Looks like there will be some embedded convection that may give some locally higher amounts, but area of precipitation should be moving through fairly quickly which should keep overall amounts down.
ReplyDeleteNasty looking cold front though Thursday night.. with accumulating snow possible over northern MB Friday night into Saturday!
I love the wet snow events. Last year we were traveling to Saskatoon in the middle of May for a conference event and when we stopped overnight in Yorkton we had a 30 cm dump of very wet snow. The world was transformed into a white wonderland. I could have stayed all day, but we had to push on. By the time we were half way to Saskatoon there was no snow at all.
ReplyDelete