EC has issued its first winter storm watch of the season for the Red River valley, Interlake and SW MB areas. A storm system intensifying over the Dakotas Thursday will spread an area of rain over southern MB through the day Thursday that will change to snow over higher elevations west of the Red River valley. Rain will change through a period of ice pellets and possible freezing rain along the Red River valley Thursday evening before changing to all snow Thursday night. The transition to snow will be slowest southeast of Winnipeg which will keep snow amounts down in those areas. Snowfall totals with this system will be tough to forecast given the uncertainty in timing and location of the rain/IP/snow line, terrain effects, pcpn rate intensity (which can affect rain/snow transition), as well as melting effects of the still warm ground. At this point, preliminary snowfall accumulations by Friday could range from trace-2 cm over SE MB, 5 cm over Red River valley including Winnipeg (perhaps 10 cm north and west of the city into the southern Interlake), and 10-15 cm along the western red River valley/SW MB areas with the highest amounts over higher elevations. Stay tuned for further updates on this developing situation..
Note also that the province of Manitoba has issued a high water advisory for the west shore of Lake Winnipeg, due to the combination of high water levels and strong northeast winds Thursday due to this storm system. Winter storm warnings and blizzard warnings in effect for central and western ND, with flood watch for eastern ND including the Red River valley due to potential flooding with heavy rainfall on saturated ground.ReplyDelete
I have installed a rain gauge heater on my station, so you can check my accumulations online.
Good stuff Scott.. You'll really notice how variable the 10:1 rule is with snow amounts vs melted pcpn in our climate.ReplyDelete
By the way, upper air soundings indicating Thursday's rain may be mixed with ice pellets (sleet) over Winnipeg/RRV before changing over to snow Thursday night. Soundings showing a layer of below freezing air between 1 and 5 thsd feet that would freeze the rain into ice pellets before reaching the ground.
It's gonna a miserable day tomorrow no matter if it rain or a wet snow~ReplyDelete
A 70 km/h wind with a cold soaking rain or a heavy wet snow is not pleasant!
It seem the National Weather service has different standards for a "Blizzard Warning" than Environment Canada does.
Clearly the same conditions that are going to happen in North Dakota would not give a blizzard warning here in Southern Manitoba.
The temperature would not be cold enough!
EC blizzard criteria is extensive low visibility (below 1 km), winds of 40 km/h or more, temperature below 0C, and conditions occurring for 4 hours or more. NWS criteria is even shorter (3 hrs), but wind speeds are higher (35 mph - 50 km/h) Note that snow amounts, or even falling snow, is not a criteria. You just need enough blowing snow causing poor visibility for several hours. So overall, criteria is fairly similar on both sides of the border.ReplyDelete
Personally, I think some of these criteria are too soft.. and should be modified to reserve blizzard warnings for the more severe, longer-lasting storms. (who remembers a 3 hour blizzard?)
By the way, surface reports will be critical Thursday to determine where that rain/snow line is setting up, and if any ice pellets or freezing rain is occurring. Feel free to post weather updates on this blog Thursday to keep us advised on what's happening out there (especially west of Winnipeg!)ReplyDelete
Impressive thunderstorms developing over eastern North Dakota! Lots of lightning with a warning on a cell near Jamestown for hail.ReplyDelete
Rob, question about precipitation data.ReplyDelete
If a map or chart says that at 06Z, for example, there will be 5mm of precipitation, does that mean 5mm of rain will fall before or after 06Z. Assuming the example uses 6 hour intervals, would this mean 5mm would fall between 06Z and 12Z or 00Z and 06Z?
The precip value refers to the accumulated amount up to that hour. So in your example, the 5 mm would be the amount that falls between 00Z-06Z.
Somewhat concerning are the very low surface dewpoints... right now dipping below zero. Much higher dewpoints in SE N Dakota with low to mid teens (!!) As the band of precip finally moves up into the Winnipeg area we may wet bulb out to near freezing. Unless we get some warm air advection ahead of the upper low.. doesn't look good for us in Winnipeg. Too early for winter, please go away.. let us tap into that warm juicy air just once more lol.ReplyDelete
Looks like a Winnipeg is starting to get some ice pellets already this morning with temperatures struggling to get above the 0 C mark.ReplyDelete
Freezing rain warning for Portage La Prairie area!
Maybe Winnipeg will change over to snow earlier that thought with temperature actually falling this morning!
Winter storm Warning for the city of Winnipeg now.ReplyDelete
Looks like the rain will change over to snow a little earlier that anticipated ~
Bring on the SNOW~
I agree Daniel, I could use some exciting weather. I don't even know if my regions was under a winter storm warning anytime last winter, so this is a welcomed start to winter.ReplyDelete
EC is predicting 15 to 20cm for Steinbach, according to their latest forecast...10cm tonight, and 5 to 10cm tomorrow.
Precip shield having a really tough time making it to Winnipeg. While Grand Forks picked up 30 mm of rain last nite, so far we have a whopping 3 mm. RADAR returns looked ragged and sparse on the NW fringe of the system.ReplyDelete
Models completely over did precip for RRV... and with the GFS at least, lightening up precip after 00z Friday its gonna be tough to get much precip. EC right now calling for 15-20 cm for Winnipeg in total.. might be tough with just light precip on the back side of the system.
I was wondering about that as well as I watched the Radar it seems to disperse as it moves up. Looks like maybe in a couple of hours it might intensify a bit unless it disperses as well.
There was about 10-20 mm of rain across far southern MB near the US border overnight, but meager amounts elsewhere. Radar is starting to fill in nicely now, so we should see an increasing trend in pcpn this afternoon into tonight.ReplyDelete
Pcpn type remains a tricky forecast today, with rain and ice pellets right now in Winnipeg/RRV, changing to freezing rain just west of us through Portage and Morden, then snow west of there. Current temperature in Winnipeg is just above zero (+0.3C) so we're in danger of freezing rain this afternoon if the temperature dips below zero. 0C line at the surface currently running from Gimli to Carman to US border.. with rain/snow line between Brandon and Portage south to Manitou area.
Suspect there won't be much change in these pcpn-type zones over the next few hours, but then a gradual change to snow from west to east late this afternoon into tonight as colder air aloft moves in. I agree that 15-20 cm seems a bit overdone for areas over the RRV and SE MB.. but 5-10 cm is certainly possible if the pcpn changes to snow this evening.
Wind driven ice pellets in Winnipeg.. starting to give light accumulations on grassy areas/sidewalks. Not a pleasant walk in that howling north wind!ReplyDelete
Upper air sounding for Winnipeg shows classic ice pellet profile with warm nose of +6.5C air between 850-700 mb, above a deep below freezing layer between 1-4 thsd feet.
Rob is this storm developing as the forecasters predicted?ReplyDelete
The temperature has not moved from 0.2 C for the last 3 hours.ReplyDelete
If we could just drop a degree then all this wind driven rain and ice would turn into a heavy wet snow~!!!!
Overall, things are progressing pretty much as expected. Models did a very good job at predicting the location and progression of the various pcpn-type zones. Precipitation amounts however appeared to be overdone. I still think however we'll see 5-10 cm of snow tonight into Friday in Winnipeg/RRV before it's all said and done. I expect precipitation should change to snow early this evening in Winnipeg as we lose the warm air aloft.ReplyDelete
The GEM indicated that surface temperatures should be at 0 by 21Z everywhere North and West of Steinbach, which is now.ReplyDelete
As for snowfall amounts...I think it will all depend on how much precipitation wraps around after the rain changes to snow. I still think 10 to 20cm is possible, but probably not as widespread as EC thinks. It will probably be hard to tell, but the RADAR should help to show which areas will be getting heavier precipitation this evening and overnight.
Highways are getting extremely slippery with reports of 25 cars in the ditch between Winnipeg and ElieReplyDelete
Horrible conditions out there this evening.. heavy ice pellets continue in Winnipeg with strong winds, temperatures around freezing, slushy slippery roads. Pcpn still hasn't changed over to snow here so final snow amounts in Winnipeg will likely be less than expected. Still an awful evening to be out there..ReplyDelete
Classic bright band (melting snow) showing up on RADAR backing into the Winnipeg area. Precip has changed to snow as suggested by this RADAR feature.ReplyDelete
Looks like a winter wonderland out there!ReplyDelete
by the sounds of it about 5 cm of snow fell last night!
With some more snow today!!
I measured about 7-8 cm here in Charleswood as of 7 am this morning.. very heavy wet stuff with tons of moisture in it from yesterday's ice pellets. According to the airport obs, we changed over from ice pellets to snow around 2 am. Melted precipitation over the last 24 hours in Winnipeg was 25-35 mm. Had that been all snow, we could have had 30 cm of snow!ReplyDelete